<![CDATA[NBC Connecticut - Connecticut Weather News and Coverage - On Ryan's Radar]]>Copyright 2017http://www.nbcconnecticut.com/weather/storiesen-usThu, 23 Nov 2017 02:44:45 -0500Thu, 23 Nov 2017 02:44:45 -0500NBC Local Integrated Media<![CDATA[Nice Looking Thanksgiving Week]]>Mon, 20 Nov 2017 21:59:17 -0500https://media.nbcconnecticut.com/images/311*120/euro112017.PNG

I love snow but not this week! Too many errands, too many travel plans, too much going on, and too much pressure for your friendly neighborhood weatherman! 

A few showers on Wednesday followed by cooler than average temperatures on Thanksgiving is about all we have of note this week. We'll take that. You can see some colder air diving south into southern New England on Thursday thanks to a dip in the jet stream.

The one thing I am watching closely is Sunday and Monday (11/26-27). A bigger dip in the jet stream coupled with a big ridge of high pressure over Greenland known as a -NAO is an intriguing setup. At this point not much is modeled but it's not a bad idea to keep an eye on this window.

We have colder temperatures and flurries currently in the forecast. Hopefully we won't have to change it!


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<![CDATA[Afternoon Hail ]]>Thu, 16 Nov 2017 21:51:53 -0500https://media.nbcconnecticut.com/images/213*120/DOx_PuoXUAE2NzO.jpg

Beautiful clouds, hailstones, rainbows, and downpours. It was a fun afternoon for a weather geek! 

Cold air aloft produced a pocket of instability over Connecticut which lead to the stormy weather. About 10,000 feet up the temperature was close to -12C while the temperature near the ground was in the low to mid 50s. This was a classic setup for low topped thunderstorms with a fair amount of moisture above our heads.

The fact the storms were fairly isolated, shallow, and occured near sunset produced such vibrant colors and rainbows across the state. Check out this photo gallery for some of your amazing shots. This afternoon's weather was pretty sweet :) 

Looking forward our next storm approaches this weekend and with it comes some gusty wind and another round of rain. At this point it looks like most of the rain will be Saturday evening through early Sunday morning. A well timed rain event! There is the potential for strong wind Sunday on the backside of the low and a low risk for tree and power line issues.


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<![CDATA[A Look Ahead to Thanksgiving Week]]>Tue, 14 Nov 2017 21:33:48 -0500https://media.nbcconnecticut.com/images/160*120/eps_t850_anom_noram_216.png

At first glance the weather pattern for Thanksgiving week is a concerning one. A colder than normal pattern thanks in part to an infamous "NAO block". Many of our big snowstorms are associated with a negative North Atlantic Oscillation of -NAO and we have that next week!

Before we get too far ahead of ourselves there's a big reason why we shouldn't be too worried. While a sprawling ridge of high pressure blocks up the jet stream over Greenland and Baffin Bay (the -NAO) the jet stream configuration over Canada and the United States isn't too ideal for snow here. The biggest reason why is that the ridge of high pressure that stretches from the Four Corners through North Dakota is a bit too far east and it's too positively tilted (i.e. tilting eastward as you head poleward).

Given this look it's not a surprise that there's not much in the way of snow or coastal storminess modeled. While a -NAO can be a huge help for getting a big snowstorm in New England it doesn't always mean we'll get snow. In this case other factors upstream in the jet stream will preclude this -NAO as currently modeled from producing. In fact, in the 6-10 day period not one out of 51 European ensemble members have significant snow in Connecticut! 

Can things change? Of course. A slightly different orientation of that ridge axist o the west or even a change in location could allow things to get more interesting. More spacing between the ridge axis and the -NAO block would give disturbances more opportunity to amplify and smack us. Things are just spaced too close togther right now.

For now, I'm cautiously optimistic the Wednesday-Friday period around Thanksgiving will be chilly but not too stormy. Stay tuned!


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<![CDATA[Overnight Black Ice?]]>Mon, 13 Nov 2017 21:01:05 -0500https://media.nbcconnecticut.com/images/160*120/hrrr_ref_neng_10_01.png

Dropping temperatures and a bit of low level moisture means a few towns could see a bit of black ice developing later tonight. While it certainly doesn't look like a big deal some towns could get a big slick.

This sounding from the NAM shows a pocket of low level moisture with near 100% relative humidity. While it is below freezing the coldest the clouds get is only about -2 or -3C which means they'll be ice free. This can result in pockets of freezing drizzle. 

Beyond Tuesday the weather pattern remains active but not too active. A bit of rain on Thuesday and more rain on Saturday. There is a chance for something wintry around Thanksgiving with a brief -NAO (North Atlantic Osciallation). Not much else to say about it now other than that we're watching it! 


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<![CDATA[NBC Connecticut Names Ryan Hanrahan Chief Meteorologist]]>Mon, 13 Nov 2017 16:51:50 -0500https://media.nbcconnecticut.com/images/213*120/Ryan+Hanrahan+Nov+2017.jpg

NBC CONNECTICUT NAMES RYAN HANRAHAN CHIEF METEOROLOGIST

HARTFORD, CT – NBC Connecticut / WVIT today announced Ryan Hanrahan as the First Alert Weather team’s new Chief Meteorologist, effective immediately. He will deliver real-time weather forecasts for the station’s weekday evening newscasts from 4 p.m. to 6:30 p.m. and at 11 p.m.

“Ryan delivers accurate, no-nonsense forecasts. I am confident he will thrive in this new role,” said Susan Tully, President and General Manager of NBC Connecticut. “His expertise and Connecticut roots blend to provide an unmatched knowledge that our viewers can trust.”

“Becoming a Chief Meteorologist in Connecticut has been a dream of mine since I was a kid growing up on the shoreline,” added Hanrahan. “I’m thrilled for this opportunity and excited to continue to share my love of weather and science with our viewers and in my home state.”

A native of Guilford, Connecticut, Hanrahan’s interest in weather was sparked by the 1989 tornado in Hamden, as well as hurricanes Gloria and Bob. After graduating with a bachelor's degree in Meteorology from Pennsylvania State University, he worked at WNYT, the NBC affiliate in Albany, New York. Hanrahan joined NBC Connecticut in 2005, after studying atmospheric science in graduate school at SUNY Albany. During his tenure at NBC Connecticut, Hanrahan has forecasted many of the state’s biggest storms including hurricanes Irene and Sandy, the October snowstorm of 2011, the blizzard of 2013 and the 2011 tornado in nearby Springfield, Massachusetts. In 2016, he was awarded a New England Regional Emmy in the “Weather Anchor” category in recognition of his weather forecasts and coverage.


About NBC Connecticut

Owned by NBCUniversal, NBC Connecticut / WVIT serves its audience with local news and weather information across multiple platforms, including more than 40 hours of newscasts each week on WVIT, news segments on CT COZI TV and online at NBCConnecticut.com. The station is Connecticut’s leader with Facebook and Instagram followers and provides mobile users on-the-go breaking news updates and weather information through a customized application. NBC Connecticut’s commitment to excellence in journalism has been recognized with numerous Emmy Awards, and the prestigious Peabody Award and Alfred I. duPont-Columbia University Award.

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<![CDATA[Winter Cold]]>Fri, 10 Nov 2017 21:31:16 -0500https://media.nbcconnecticut.com/images/213*120/DOUSiFHWkAEH1yQ.jpg

It's a cold night across the state with temperatures dropping through the 20s. We're going to be close to record lows by morning but may fall just short.

The cold shot peaks by morning and temperatures will moderate over the coming days.

Most of the next week looks pretty quiet. I don't see a whole lot to get excited about through next weekend. What we call a "zonal flow" will exist across the most of the Lower 48 through next week which will keep temperatures fairly close to normal and preclude any big storms from forming nearby.

By next weekend, however, our zonal flow becomes much more amplified. A large blocking ridge over Greenland which flips the North Atlantic Oscillation to negative. This will increase our chances for stormy weather and possibly even some snow before Thanksgiving. 


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<![CDATA[Timing out the Tumbling Temperatures]]>Fri, 10 Nov 2017 12:44:26 -0500https://media.nbcconnecticut.com/images/213*120/cms989.jpg]]><![CDATA[First Flakes of the Season]]>Tue, 07 Nov 2017 21:12:47 -0500https://media.nbcconnecticut.com/images/213*120/DOEr8ETXkAAa7H4.jpg

As expected rain has transitioned to a mix of rain and snow in the hills and some towns have even flipped to all snow. A combination of dry low level air resulting in evaporational cooling and a slow drain of colder air from the north. 

No accumulation is expected (on the roads at least) though I can't rule out a slushy coating in some of the high hill towns such as Norfolk, Colebrook, and Hartland. Even Wolcott at about 1,000 feet could see a slushy coating. As always, dual polarization radar was an incredible tool in tracking the the height of the above freezing level in the clouds. Radar allows us to pick up where melting snowflakes are occuring. 

Beyond tonight the big story is going to be a blast of Arctic cold moving in on Friday. A brief but impressive surge of cold air will send wind chills into the single digits and teens by afternoon. A big change from our record warm October! 


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<![CDATA[Some Arctic Chill]]>Mon, 06 Nov 2017 21:00:31 -0500https://media.nbcconnecticut.com/images/160*120/gefs_t850a_conus_17.png

A blast of Arctic cold on Friday looks very impressive. Temperatures in the 30s and gusty winds will result in wind chills in the teens. Ouch. Before we get there we've got a minor issue on Tuesday. 

A weak wave of low pressure will move south of southern New England Tuesday evening. There's some question exactly how much moisture will move in AND how dry it will be near the ground.

The dry air near the ground is key to the forecast. We know the clouds above us will be producing snow - the question is whether that snow will make it to the ground. If the air is too dry (as the sounding above off the GFS shows) the snow will sublimate or dry up before reaching the ground.

If the dry air near the ground isn't too dry and better moisture and lift moves in aloft the dry air will allow the atmosphere to cool through evaporative cooling and will likely be cold enough for a bit of snow - or at least some rain mixed with snow. The NAM sounding above in Hartford shows that potential with the dry layer being wiped out. While quite unlikely we can't rule out a slushy coating in the hills but this is not currently in the forecast.

Beyond Tuesay evening's minor excitement the big story will be the big cold moving in on Friday. At this point the GFS MOS is printing out a remarkable 14F low on Saturday morning with temperatures in the 30s on Friday. 

While we're currently forecasting 22F this kind of cold is unusual for early November. The temperature has only reached 20F of lower 19 times since 1905 in the Hartford area prior to November 11th. In fact if the 14F for Hartford verified it would be the second coldest temperature on record for so early in the year. Only November 11, 1956 would be colder at 12F.  The last time temperatures reached the teens this early in the fall was November 10, 2004. Stay tuned - and stay warm! 


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<![CDATA[A Cold Shot!]]>Fri, 03 Nov 2017 19:37:53 -0500https://media.nbcconnecticut.com/images/160*120/gefs_t850a_noram_29.png

After the warmest October on record it looks like we may see a legitimate shot of cold air - though it may only last for a day or two. Most of our computer models are picking up a brief Arctic shot next Friday and Saturday with cold air pouring down from southeastern Canada. 

This isn't a big surprise. For a while our long range models have shown a return to more "normal" weather this month with periodic shots of cooler and warmer weather. Cold isn't all that exciting - let's be honest. The bigger question for me is whether we can squeeze out any snowflakes with this pattern. At this point it isn't looking good. 

As the cold comes down there's an offshore low will likely wind up and track near New England. It seems likely that it will impact us with any snow though it's not out of the realm of possibility. There's also a chance cold air overhead could lead to some scattered rain or snow showers has the disturbance moves overhead. 

Check out the European Ensembles for the next 15 days. The Euro has 12 of 51 members showing measurable snow with only 2 of 51 showing more than 2" of accumulation. So yeah there's a chance but don't wax your skis yet.


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<![CDATA[After a Record Warm October - How's November Look?]]>Thu, 02 Nov 2017 19:00:42 -0500https://media.nbcconnecticut.com/images/160*123/record1.PNG

Across Connecticut this past month was the warmest October on record. In the Hartford area the average October temperature was 59.9F which beats the old record of 59.7F set back in 2007. In Bridgeport the old record of 61.4 degrees best beat by nearly a full degree with 62.3 degrees!

October was also an awfully wet month. Finally! After drought conditions started to creep back from a dry end of summer and beginning of fall we made up for that in a big way. Volunteer CoCoRaHS observers recorded more than 10" of rain in three towns - Prospect, Monroe, and North Granby. In my backyard in West Hartford we received 9.31" of rain this month!

Looking forward, we finally do see some cooler weather ahead. While the Climate Prediction Center outlook for the month shows above average temperatures being the most probable scenario it's not a particularly strong signal. In fact, we can't totally rule out a bit of minor mixed wintry precipitation next week as colder air scoots down from the north and moisture lurks nearby.

Getting anything to accumulate seems exceptionally unlikely but it is a sign of the season for sure.


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<![CDATA[Powerful Sunday Storm]]>Mon, 30 Oct 2017 19:44:33 -0500https://media.nbcconnecticut.com/images/160*120/IMG_0024rh.JPG

What is it with these powerful storms during the last weekend of October? The October snowstorm of 2011, Hurricane Sandy in 2012, and now a powerful "southeaster" that knocked out power to 180,000 utility customers in Connecticut.

The storm set an October record for lowest pressure in many stations in New York State which is a testament to its strength.  Damage was widespread with uprooted trees and snapped power lines throughout New England. 

Across Connecticut the strongest winds occured in southeastern Connecticut. The WeatherFlow station on the Outer Breakwater in Stonington Harbor gusted to 73 mph. The Groton-New London Airport gusted to 67 mph and there were widespread 50-60 mph gusts across the state. 

The storm was quite remarkable on radar with a southerly low level jet of near 100 knots (115 mph) showing up over Long Island and moving north into Connecticut.

Thankfully, only a fraction of these powerful winds mixed down to the ground. Farther north, Mount Mansfield in Vermont gusted to 115 mph as the core of the low level jet crossed the mountain's more than 4,000 foot summit. Mount Washington in New Hampshire gusted to 131 mph! Out on the Cape a gust to 96 mph occurred in Mashpee and Conimicut Light in Warwick, RI gusted to 81 mph. 

Thankfully the storm's peak arrived at low tide. Believe it or not most of the coastal flooding (and it was minor) occured in the morning as residual water levels in Long Island Sound were shoved toward the coast around daybreak near high tide as the wind shifted to southwesterly. A wind gust of 40 knots in Groton corresponded with this peak in tide levels. Minor issues and flooding were reported from Old Lyme through Stonington. 

The forecast worked out quite well. We were forecasting 60-70 mph winds along the shoreline and 45-60 mph inland and most areas fell in that range. The peak of the wind occurred almost exactly when we expected between 10 p.m. to 2 a.m. as the core of the low level jet moved overhead. The question always is how much of the wind a couple thousand feet above our head will mix do the surface. Gravity waves and thunderstorms can do it and result in a particularly nasty bout of winds and another way to do it is to decrease the low level stability. We did that through most of Connecticut by increasing the temperature near the ground which promoted a bit of mixing. Here's a look at Hartford which managed to gust to 44 mph as the temperature spiked to 70F after being in the mid 60s a few hours prior.

One of the reasons the damage was widespread was the incredible amount of rain we've seen over the last 7 days. Bristol has picked up over 10" of rain with my backyard in West Hartford receiving just shy of 10"! Heavy rain and saturated soil managed to uproot a number of trees.

The good news is our drought is gone and so are any rainfall deficits we've been dealing with this year. The weather looks quiet for the next few days which is great - the weather team could use a break :)


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<![CDATA[Destructive Winds Possible Tonight]]>Sun, 29 Oct 2017 19:45:24 -0500https://media.nbcconnecticut.com/images/213*120/Wind+Gusts+Sunday+Night.png

8:30 p.m. Update: The storm is behaving as expected so far. Winds are now gusting to 37 mph in Groton and we have a handful of power outages across the state.

The key is still how much wind will be able to mix down to the surface from aloft. We have a rapidly deepening low off the coast of Delaware lifting north. You can see 3 hour pressure falls in excess fo 9mb/3hr moving north!

Aloft, our models still show an exceptionally powerful low level jet overhead around midnight. The winds about 5,000 feet above our heads will be in excess of 100 mph. While most of this will not reach the surface some of it may.

The HRRR model insists a period of destructive winds even inland. That remains a possibility though most of our models keep a narrow stable layer near the surface which will effectively prevent the strongest winds from mixing down. With the potential for convection, gravity waves, and an impinging dry slot I am concerned for gusts in excess of 60 mph statewide. Right now our forecast is for 60-70 mph gusts at the coast and 45-60 mph inland but there is a low risk for the entire state going above 60 mph. With tremendously saturated soil after recent rain a large number of uprooted trees is possible.

Earlier update: A powerful storm which may set records for sea level pressure in October across New York State is likely to produce a brief period of strong damaging wind tonight across the state. The most likely location for damaging winds is along the shoreline where it's not out of the question that winds could gust to hurricane force!!

The storm that develops will be quite intense. Most of our computer models show a storm with a pressure below 980 mb cutting to our west. This will put us on the windy side of the storm. Most of our computer models show a low level jet somewhere between 60 knots and 100 knots overhead between 10 p.m. and 2 a.m. While winds about 5,000 feet above our heads will be that of a category 2 or 3 hurricane the question is how much of that will mix down to the ground.

Generally, you need an unstable layer near the ground to mix the stronger momentum down. This sounding from the High Resolution Rapid Refresh for tonight in Groton shows the potential for 76 knots of wind (85 mph or so) to mix from that low level jet to the ground due to a shallow unstable layer near the surface (temperatures drop rapidly with height). Other models do not show this feature and keep much more of the wind bottled up above our head. Other things, however, can mix damaging winds to the surface including convection (thunderstorms) that induce vertical circulations and gravity waves which can do the same. We're forecasting wind gusts over 60 mph at the coast and at this time there is a possibility for hurricane force wind gusts around 75 mph! 

This is a classic setup for damaging wind. Something called a tropopause fold will develop right overhead. This is something we see only in the most intense storms. Effectively, the stratosphere (the layer right above the troposphere) will lower to about 8,000 feet above our heads. A dramatic increase in Ozone will occur at this height. Also, we can see a distinct warm core to this low which tends to happen only in some of the most intense Atlantic cyclones. In fact, 850mb temperatures exceed 20C off the Jersey shore!

It's really no surprise the atmospheric pressure will plummet. Here's a look at the European Ensemble forecast for this storm - notice a number of lows with pressures below 970mb! If you compare this to record low October pressures this one is outside of climatology for a good chunk of the northeastern U.S. if you exclude Sandy.

In terms of rainfall 1"-3" of rain is likely across Connecticut with some potential for heavier totals out in western Connecticut. After totals near 5" in some towns last week there may be more uprooted trees than usual given the saturated soil and weakened roots. Flooding is not expected to be a major concern. 

Be prepared to lose power and we may have issues Monday morning with downed trees and lines. Be careful driving late tonight during the brief, but wild, peak of the storm. 


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<![CDATA[Lingering Questions About Sunday's Storm]]>Fri, 27 Oct 2017 07:04:19 -0500https://media.nbcconnecticut.com/images/160*120/p120i.gif

It's going to be a big storm - there's no doubt about that. The question is how bad will it be here in Connecticut as it moves north. That's an open question.

Above is the National Weather Service rainfall forecast showing a widespread 3"-4" of rain across the region. But that's by no means a sure bet. Take a look at the European Ensemble probabilities for over 2 inches of rain. With the exception of the Litchfield Hills the odds are less than 50/50. 

The amount of rain is highly dependent on the storm's track as it comes north. How far east or how far west. We just don't know yet but there is the potential for high end totals given the amount of tropical moisture involved AND the amount of lift in the atmosphere.

The second question left is the potential for strong damaging winds. We have an old fashioned Euro vs GFS battle going on here. The American model develops the storm a bit later than it's European counterpart. It's weaker and farther east. This would shift the damaging wind threat well north and east of Connecticut. The European model has the storm nearing peak intensity just west of us which would introduce the potential for 60 mph wind gusts.

In the end it's hard to know which model will be right. Both seem like reasonable solutions and both are supported to varying extents by their ensemble members. Keep in mind that this storm is the result of a complex interaction of tropical moisuture from the Caribbean and a bit jet stream distrbance diving south from Canada. There's a lot that can go wrong.

A way to visualize the possible scenarios is to look at the Euro Ensemble surface low positions late Sunday night. Each "L" represents one of 51 European model solutions with each number indicating the strength. There are some super deep and powerful storms and some that aren't all that impressive. Some storms are as far west as Pennsylvania and some storms are off the Cape! We need the model spread to shrink in order to get more specific. 

For now be prepared for damaging winds and the potential for flooding on Sunday. While both are possible they are by no means guaranteed. We've erased our yearly rainfall deficits after this week's rain so I'm OK with a more tame Sunday storm!


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<![CDATA[Growing Signals for a Powerful Weekend Storm]]>Wed, 25 Oct 2017 20:58:13 -0500https://media.nbcconnecticut.com/images/160*120/GFSMA_prec_prec_102.png

All of our reliable computer model guidance shows a powerful east coast storm heading toward New England on Sunday. The devil, as always, is in the details with the exact impacts far from certain here in Connecticut.

Starting with the big picture there's a cluster of showers and thunderstorms in the western Caribbean Sea that shows some small signs of development into a tropical system. A large blob of moisture between Cuba and Mexico is going to stream north over the weekend as a powerful storm forms. Part of the uncertainty with the forecast is whether or not a tropical storm forms in the Caribbean or if it is just moisture advecting north. Regardless, a strong storm will still impact the northeastern U.S.

As the moisture lifts north there will also be a powerful coupled jet streak signature. One jet streak over Quebec and a second off the Carolinas will provide an environment that will favor strong rising motion and a strengthening storm. In essence, the right entrance region of the Canadian jet streak and the left exit region of the Mid Atlantic jet streak will line up right over southern New England. This is a strong signal for a big storm.

Not surprisingly, all of our models show a strong signal for both heavy rain and powerful winds. The GFS ensemble M-Climate rainfall forecasts (comparing this computer model to previous runs of the model) are maxed out at this lead time. That is a strong signal for flooding rain which isn't a surprise given the upper level setup and the amount of moisture coming north.

With a strong storm nearby there will be the risk for strong, damaging winds as well. Already low level wind anomalies approaching 3 standard deviations are showing up on our models.

How much wind and how much rain we get will be determined based on where the storm tracks. A rough way of looking at this is that the heaviest precipitation will likely reside west of the storm's track and the strongest winds will be east of the storm's track. A storm track over Cape Cod vs a storm track over New Jersey would make a huge difference in actual outcomes.

At this point be prepared for another round of flooding and tree damage and power outages. How bad either will be is to be determined but this one certainly bears watching.


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<![CDATA[Drought Busting Rain for Parts of the State]]>Wed, 25 Oct 2017 16:41:59 -0500https://media.nbcconnecticut.com/images/213*120/COVER+PHOTO3.png

Rainfall from Tuesday night and Wednesday morning was enough to put a serious dent in the year to date deficit throughout the state.

Windsor Locks picked up 4.63" which was the biggest rainfall since Irene in 2011. The rainfall total replaced a 3.2" deficit with at 1.43" surplus from year to date. 

Bridgeport was in a 4.2" deficit however with the two day rainfall totaling 3.88" it brought that deficit to only 0.32".


The deficits will be replaced by a surplus statewide with another round of heavy rain forecasted this weekend.

For more on the weekend wind and rain threat click here.


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<![CDATA[More Rain Coming After a Month-Worth of Rain in 2 Days]]>Wed, 25 Oct 2017 09:20:50 -0500https://media.nbcconnecticut.com/images/213*120/Barnum+Avenue+Between+Kent+and+Sage1.jpg

Parts of Connecticut received a months worth of rain over two days and more periods of rain are likely today, with scattered showers tonight and a chance for more showers tomorrow. 

On Sunday, showers and thunderstorms are in the forecast with heavy rain Sunday and Sunday night before diminishing on Monday.

The highest rainfall totals from the storm from Tuesday night into Wednesday morning were in eastern Fairfield and western New Haven counties. 

The highest rainfall total recorded was in Ansonia with just under 5 inches of rain. 

Seymour is dealing with leaves down and minor flooding Wednesday morning and police are asking people who live and work in town to be cautious during the morning commute.

The high rainfall totals led to flash flooding throughout the state. Take a look at the situation late Tuesday night on the Bridgeport/Stratford line. 


In addition to the heavy rain the other significant factor with the storm system was damaging winds.

Winds gusted over 40 miles per hour in parts of the state, which led to thousands of power outages on Tuesday. 

A tree came down onto power lines on Mattabassett Street in Bristol just before 4 a.m. Wednesday. In Willington, a tree came down on Cowles Road. 

Country Club Road and Miner Street in Middletown are closed after trees came down on wires.

In Madison, a tree came down on wires over railroad tracks near Scotland Road, suspending Amtrak service.

In Newington, wires came down o Maple Hill Avenue, closing the road.

Eversource reported 4,300 outages throughout the state as of midnight, with the highest outages in eastern Connecticut, including the towns of Plainfield and Preston. Power has since been restored for thousands.

Check out interactive radar which shows scattered showers continuing throughout the state.



Photo Credit: NBC Connecticut
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<![CDATA[Big Autumn Storm Moves In]]>Mon, 23 Oct 2017 20:39:01 -0500https://media.nbcconnecticut.com/images/213*120/DM1PwrqX0AA_8-w.jpg

Powerful winds, flash flooding and even severe thunderstorms. There's a lot to talk about with the Tuesday storm. Let's start with the rain.

Flash flooding is a possibility in some areas with locally heavy rain totals expected. On average 1.5"-3.0" of rain is forecast but I would not be surprised to see a localized pocket of as much as 5" of rain! The most likely location for this is in western Connecticut in a handful of towns. Our high resolution models show the potential for some big totals including the RPM (pictured below) which prints out nearly 6" of rain parts of the Litchfield Hills.

The good news is our recent stretch of dry weather will mitigate the river flood threat. Smaller rivers and streams may see flooding but the bigger rivers such as the Farmington, Housatonic and Connecticut will stay in their banks.

While scattered showers and thunderstorms are possible through the day on Tuesday the heaviest rain will be centered on Tuesday evening and overnight.

The other issue tomorrow will be strong and damaging winds. Something called a low level jet will develop across Connecticut during the day tomorrow. This occurs often. The question is how much of the strong winds in the low level jet will mix down to the ground. Hurricane force winds 3,000 feet above our heads can exist with barely a puff of wind at the ground! In this case there seems to be a bit more mixing than we typically see in these events which should promote strong and gusty winds across the state. Our forecast is for 45 to 60 mph wind gusts peaking Tuesday evening and night.

The other thing we'll have to watch tomorrow is the possibility for severe thunderstorms. This is a setup known as a low CAPE/high shear setup. While these don't always produce with such strong low level shear any thunderstorm that does develop need to be watched closely. Damaging winds and an isolated tornado are possible. 


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<![CDATA[Heavy Rain & Damaging Wind Possible]]>Mon, 23 Oct 2017 10:23:48 -0500https://media.nbcconnecticut.com/images/160*120/NAMMA_925_spd_060.png

Quite an autumn storm is moving toward Connecticut and we're becoming more confident in a period of strong, damaging winds along with heavy rain. The worst of the storm will be Tuesday evening through Wednesday morning. Possible impacts from the storm include:

  • Strong, damaging winds of 50-60 mph in some towns.
  • Scattered power outages and downed trees.
  • Heavy rain and localized urban flooding.

The wind will begin to pick up Tuesday morning across Connecticut with a stead increase through the day and into the evening. The reason for the wind will be a strong pressure gradient between an area of high pressure over the Atlantic Ocean and an area of low pressure over the Great Lakes. 

With that pressure difference the winds will really roar above our heads Tuesday evening and Tuesday night. Winds will reach well over 60 mph about 2,000 feet above the ground out of the south. 

The question is how much of that wind will mix down to the ground and how much will remain bottled up just above our heads. It all comes down to how stable (or unstable) the atmosphere is. Typically, a shallow layer of stable air near the ground protects us from the powerful winds above our heads. Another factor can be whether or not thunderstorms can create vertical circulations (updrafts & downdrafts) that are able to transport stronger winds from aloft to the ground. What is somewhat unique Tuesday PM/Wednesday AM is that there is not much stability near the ground AND there's a bit of instability aloft which may promote thunderstorm development. Both of those factors make us concerned about damaging winds.

Besides strong gusty winds from Tuesday evening through Wednesday morning there may be enough instability to trigger a severe thunderstorm or two. We will have to watch the radar very closely. While not likely there will be sufficient wind shear for tornadoes to develop. With most trees still covered in leaves the threat for tree damage is a bit higher than it would typically be this time of year.

The other issue with this storm will be heavy rain. Plenty of moisture and a slow moving cold front will result in several periods of torrential downpours. Flood issues should remain relatively minor given our recent spell of dry weather, however a few pockets of urban street flooding are certainly possible.

We'll keep you posted on the storm as it draws closer!



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<![CDATA[Warm Weekend and an Unsettled Week Ahead]]>Fri, 20 Oct 2017 20:35:23 -0500https://media.nbcconnecticut.com/images/213*120/Evening_forecast_on_October20th2017_1200x675_1078177859921.jpg

Another incredibly warm weekend is ahead of us with temperatures making a run at 80 degrees Saturday. The record for the day is 82F set back in 1920. Already this fall has been the warmest on record (9/1-10/20) and we'll tack on a bit more to those big anomalies by Sunday. 

Beyond the weekend's warmth my attention is shifting to a storm moving in on Tuesday. A deep trough of low pressure and a connection of tropical moisture will allow a strong storm to develop. With a strong area of high pressure to our east and the low to the west the wind will roar later Tuesday. This sounding from the GFS computer model shows winds of hurricane force only 2,000 feet above the ground! While not all of this will reach the ground strong wind gusts are certainly a possibility.


Additionally, unusually warm water temperatures will help keep the atmosphere a bit more mixed than we typically see in these southerly flow setups. A lot of times in fall and winter cold water temperatures lead to a shallow layer of stability that prevents stronger wind from mixing down to the ground.

The extent of the damaging wind threat is still unclear. How strong the storm is, and where it tracks, will determine how strong the winds will get. The other wild card is whether enough instability develops for thunderstorms to form. We'll be watching this closely!


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<![CDATA[Record Warm Fall]]>Wed, 18 Oct 2017 20:46:39 -0500https://media.nbcconnecticut.com/images/213*120/Evening_Forecast_for_October_18_1200x675_1076255811713.jpg

Meteorological fall is defined as September, October, and November and this is the warmest start to fall we've seen on record. More than 47 days in we're absolutely roasting. 

Of the last 113 starts to fall this fall has been the warmest. The mean temperature in the Hartford area season-to-date is 65.4 degrees. According to the Southeast Regional Climate Center a temperature like this in fall is more typical of Roanoke, VA than Hartford, CT. 

In New Haven the average temperature this season is 66.4 degrees of 4.3 degrees above normal. This would equate to what a fall is typically like in Philadelphia, PA.

It's no surprise with temperatures this warm our fall foliage is behind schedule. Leaves change color as chlorophyll breaks downs allowing a leaf's yellow and orange pigment to become dominant.  Typically, the fall colors occur around the same time every year as the biggest factor in chlorophyll breakdown is the shortening days and longer nights. 

This year, however, it's been so warm the chlorophyll is breaking down slower than usual in most trees according to UConn Extension Forester Thomas Worthley. He also points out foliar fungi on sugar maples following a wet summer have sent those trees into early dormancy. 

Even across Vermont, New Hampshire and Maine fall colors are way behind schedule. This satellite image from GOES-16 shows hues of orange and red in the mountains of northern New England. Here in southern New England (outside of the Berkshires) things remain quite green. That said, we're expecting vibrant colors to pop in about a week which is a remarkable two weeks behind schedule in the Northwest Hills. Peak color in the Hartford area likely won't be until just before Halloween. 


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<![CDATA[First Frosts are Getting Later and Later]]>Tue, 17 Oct 2017 19:06:14 -0500https://media.nbcconnecticut.com/images/160*120/DMVmrzgVQAEgfZr.jpg

The growing season is getting longer and longer and our first freeze is occuring later and later in fall. While this may be good news for your backyard garden it's yet another local symptom of climate change. 

The numbers are quite striking. Since 1970 Climate Central found that the average first freeze (32 degrees) in Hartford is occuring nearly 12 days later now than it did 47 years ago. The meticulously maintained weather records in Norfolk at the Great Mountain Forest show a similarly disturbing trend. 

Since records began in 1943 the average first freeze has moved from September 26 to October 15! That is 19 days based on a linear regression analysis. The average last freeze in spring has also gotten earlier and earlier as the earth has warmed.

The Environmental Protection Agency found that the growing season across the contiguous 48 states as increased by 2 weeks on average. There are both good and bad things that can come from a longer growing season according to the EPA.

Changes in the length of the growing season can have both positive and negative effects on the yield and prices of particular crops. Overall, warming is expected to have negative effects on yields of major crops, but crops in some individual locations may benefit.1 A longer growing season could allow farmers to diversify crops or have multiple harvests from the same plot. However, it could also limit the types of crops grown, encourage invasive species or weed growth, or increase demand for irrigation. A longer growing season could also disrupt the function and structure of a region’s ecosystems and could, for example, alter the range and types of animal species in the area.

So when is the average first freeze of the year? Based on the 1981-2010 normals the average first freeze at Hartford Bradley International Airport is on October 13 and at Bridgeport Sikorsky Airport November 3. 


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<![CDATA[Ophelia Strikes Ireland]]>Mon, 16 Oct 2017 20:51:45 -0500https://media.nbcconnecticut.com/images/218*120/DMRBfcMXcAMubgX.jpg

After a wind gust to 118 mph in County Cork parts of the Irish countryside are littered with debris following Storm Ophelia. The storm was a remarkable one.

Hurricane Ophelia strengthened to a category 3 hurricane near the Azores and was a hurricane as late as 11 p.m. Sunday night just hours before striking Ireland. With the exception of Hurricane Debbie (1961) this is the farthest northeast a hurricane has been observed in the Atlantic Ocean.

The cold water around Ireland is not hospitable to hurricanes, however. Ophelia lost its tropical characteristics as expected before making landfall on the Dingle Peninsula early Monday. While the storm was no longer a hurricane - much like Sandy - it didn't weaken. In fact, Ophelia strengthened as it continued to get its energy from the a powerful jet stream over the North Atlantic. 

Ireland is no stranger to powerful Autumn and winter storms though Ophelia was one of the stronger ones in recent years. 400,000 utility customers lost power from the storm and there was quite a bit of structural damage in Counties Cork and Kerry. Storm surge flooding was quite widespread in some areas on the southern and western coasts of of Ireland - including Galway.

One incredible side effect of Ophelia was the storm's wind managed to fan wildfires in Portugal and the storm's circulation sucked the smoke north into the United Kingdom. In London, the afternoon sky turned a creepy orange/red thanks to Ophelia and the horrific wildfires Ophelia helped fan on the Iberian Peninsula. 

A remarkable storm during a remarkable hurricane season. 


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<![CDATA[Weekend Outlook]]>Thu, 12 Oct 2017 20:17:24 -0500https://media.nbcconnecticut.com/images/213*120/Nightly_Weather_Forecast_for_October_12_1200x675_1072229443764.jpg

It's a tough forecast for the weekend with a few chances for showers both Saturday and Sunday. What is clear is that warmer air will move in - in fact temperatures on Sunday may come close to 80F in a few towns. 

Typically, as warm air moves in air is forced to rise. This results in clouds and sometimes precipitation. What we're trying to figure out now is whether or not we'll see any rainfall this weekend as warmer air (and moisture) streams in from the Mid Atlantic. 

Right now it appears that a sprinkle or two is possible Saturday and a few showers are possible Sunday morning. A cold front sweeps in Sunday night and a period of lovely October-like weather moves in for early next week. 

By the end of the 10 day forecast there is a signal for warmer air buidling back in with a large ridge of high pressure. Record warmth is possible in parts of New England, the Great Lakes, and southeastern Canadaby the weekend of October 21-22. 


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<![CDATA[Incredibly Beautiful Clouds]]>Fri, 29 Sep 2017 10:22:51 -0500https://media.nbcconnecticut.com/images/246*120/22135701_10159362460305162_1588521342200052701_o1.jpg

If you didn't look up this afternoon or this evening you missed out on an atmospheric treat. A gorgeous batch of cirrocumulus clouds spread across the sky resulting in an epic sunset across the state. But that wasn't all!


Cirrocumulus clouds are made up of both ice crystals and supercooled water droplets. These clouds were likely more than 25,000 feet above our heads! In this case a "hole punch" or "fallstreak hole" developed over some towns this afternoon. Nora Dudchik took this incredible picture at the parking lot of Hilltop Barbeque in Moodus. 


A fallstreak hole forms as ice crystals begin to grow rapidly through deposition (see the streaks) and the supercooled water surrounding the ice crystals begins to evaporate. Essentially, the ice crystal grows at the expense of liquid water. This change in phase exists because the atmosphere is subsaturated with respect to liquid but supersaturated with respect to ice. A hole in the cirrocumulus cloud with streaks of ice crystals (snow) falling out of it is the result. A fallstreak or hole punch cloud!

The cool clouds had a neat look from above on our new GOES-16 satellite but an even neater look from below.

If the cirrocumulus wasn't beautiful enough we also had some irridescence that occured as sunlight passed tiny ice crystals or water droplets in the clouds. The ice crystals or droplets diffract the sunlight resulting in what appears to be a rainbow in the cloud. Cool stuff, right? 

Even when the weather is a bit boring (for us meteorologists!) there is almost always something to marvel at :) 



Photo Credit: Keith Urbowicz / Old Lyme
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<![CDATA[Cooler Temperatures (For Now)]]>Tue, 26 Sep 2017 20:39:36 -0500https://media.nbcconnecticut.com/images/213*120/DKsYATpX0AYo2cK.jpg

For a few days we've been looking ahead to a temperature drop this weekend. On Saturday we're forecasting a high of 64 degrees which isn't exactly unusual for the time of year but will come as a bit of a shock after the last month. There are signs, however, that our cool down will be somewhat short lived.

In about a week another surge of warmth will overspread a good chunk of the eastern U.S. and Canada. Above you can see the day 6-day 11 temperature anomalies across North America. A deep trough of low pressure over the Pacific Northwest will force the jet stream north into Canada flooding us with more warmth. Another period of record warmth is possible for Columbus Day weekend.

Otherwise the weather pattern looks awfully quiet. A few showers are possible pre-dawn Thursday with some moisture streaming north (indirectly from Maria) and another period of showers on Saturday. Don't get too excited - most towns will struggle to see more than a tenth of an inch.


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<![CDATA[Another Scorcher but Where's the Rain?]]>Mon, 25 Sep 2017 20:02:30 -0500https://media.nbcconnecticut.com/images/213*120/DKnBVyTXUAEiVk4.jpg

92 degrees on Sunday and 91 degrees on Monday. This is hot stuff. Getting above 90 degrees this time of year is a challenge given the low sun angle and shorter days but we managed to do it 2 days in a row. The only other time that has happened was exactly a decade ago - September 25th and 26th, 2007. 

After this stretch of record warmth we will see a gradual temperature drop. By the weekend high temperatures will struggle out of the 60s with a chance for some rain - especially Saturday morning. 

The weather pattern looks pretty quiet going forward but we do need some rain. Here in West Hartford we've only picked up 1.61" of rain for the month of September. In Windsor Locks 2.19" has been recorded. The 6-10 day forecast has a high probability of below normal precipitation. 



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<![CDATA[Watching Maria]]>Fri, 22 Sep 2017 20:56:28 -0500https://media.nbcconnecticut.com/images/160*120/gefs_AL15_2017092218.png

Finally, Jose is drifting away and falling apart in the Atlantic Ocean. Good riddance. Our attention now is on Hurricane Maria which is north of the Turks and Caicos and heading north. 

There is some risk to North Carolina from Maria. Another blocking ridge of high pressure in the Atlantic will, at least initially, prevent the hurricane from rocketing into the North Atlantic. The Euro and GFS ensembles show some risk for the Mid Atlantic and especially the Outer Banks as Maria interacts with an upper level low over the southeastern U.S. which essentially tugs it west a bit.

Locally, we have two possible impacts from Maria we'll be watching. One, is that the storm could meander near the Outer Banks before racing out to sea and some moisture gets transported north resulting in a period of rain Wednesday and Thursday. That's a distinct possibility and currently reflected in our forecast. 

A second, and much less likely scenario, is that Maria moves much farther west over North Carolina than currently suggested and the storm races northeast and impacts us with some wind and rain (as a much weakened storm). 

There is virtually no chance of a direct or serious tropical storm impact here for a couple reasons. One, is a weakness in the blocking ridge east of us due to Jose and the second is a digging trough coming in from the west that will kick Maria out to sea.


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<![CDATA[Remembering the Hurricane of 1938]]>Wed, 20 Sep 2017 22:08:26 -0500https://media.nbcconnecticut.com/images/213*120/hurricane+of+1938.jpg

NOTE: This article was first published in 2013

On September 21, 1938 one of the most violent storms to impact New England since colonial times raced ashore near New Haven and spread a deadly combination of wind, rain and storm surge from Long Island to Quebec.

This was the only category 3 hurricane to strike Connecticut in recorded history. Sustained wind speeds reached 115 mph in parts of New London County, and wind gusts over 100 mph were common across the rest of the state. Five-to-ten inches of rain sent rivers flooding over their banks and weakened the roots of trees that were uprooted by the millions across New England.

Wilbur Beckwith was in 4th grade in Niantic when the infamous hurricane of '38 struck without warning. The wind was blowing open the windows in his classroom and his teacher ordered the students to try to keep the windows closed to prevent the wind from coming in. Around 3 p.m. Beckwith walked across the street to his home just moments before the worst of the hurricane moved in.

"My sister and I were scared to death," Beckwith recalled. "One of our windows blew out and my father grabbed a hammer and nails and a card table and hammered the card table against the window."

Beckwith and his classmate Norman Peck watched out their bedroom windows to the east when parts of New London burned to the ground. The flames set the night sky aglow for miles across the Connecticut shoreline.

In Guilford Edith Nettleton was working in the library that day. She only had one customer on September 21st, 1938. Virtually no one knew a storm was coming including Nettleton who came to work that morning like she did every weekday on the Guilford Green.

"It was just a normal, rainy, wind blowing day," Nettleton recalled. "The trees were beginning to go down around the green and you could see them going and it was not a pretty sight"

Nettleton, who is now 105 years old, remembers that day well. "When they eye went through some of the trees that were toppled over were blown upright and toppled the other way."

Others in Guilford remember the eye of the storm and some were caught off guard when the back side of the storm roared through.

"I well remember the lull," Martha Rebuzzini who was 13 years old at the time said, "it became quite lovely and then it started to blow again and it's true some of the trees that went one way came back another."

Rebuzzini's family hosted stranded travelers at their home since the Post Road was blocked by the East River and trees that were down seemingly everywhere.

In more rural areas it took weeks to return to normal. In North Guilford, Ruth Nettleton said her family was stranded for 2 weeks because of the trees that had to be removed from roads by axe and handsaw.

"I can just remember the trees going across the road," Nettleton said.

Many of the people who remember the '38 storm today were only kids when it struck. 8 year old Gordy Whitman was on his brother's magazine route when the storm started raging. After the hurricane neighborhood kids started playing on the jungle of downed trees across the Guilford Green.

"We looked at all the trees on the green and one of us said to the other I bet we can go from Broad Street to Boston and back again on all the trees that have blown down without touching the ground," Whitman said. "So that was the game to see who could do it."

In Niantic Norman Peck remembers being put to work after the storm, "even though I was young I was helping drag brush on Pennsylvania Avenue."

But it was the beach communities on Long Island Sound that bore the brunt of the hurricane's fury. Many beach homes were swept into the ocean and some entire neighborhoods were demolished by the storm. Nearly 100 people died in the state many of whom drowned by a fast moving record storm surge.



Photo Credit: Liz Kuchta]]>
<![CDATA[Watching Jose and Maria]]>Tue, 19 Sep 2017 20:00:37 -0500https://media.nbcconnecticut.com/images/213*120/DKIKN4FXcAE6wH7.jpg

Hurricane Jose strengthened a bit today as it passes over the Gulf Stream. The storm, tracking about 75 miles east of where we thought it may this weekend, will result in only very limited impacts here in Connecticut. A bit of wind and rain will be about the extent of the impacts here. 

The showers should diminish later tonight and I'm expecting a mainly dry day tomorrow as the outer bands of Jose fizzle. The inner core of Jose should remain quite in fact as it wobbles southeast of Nantucket. Wind gusts of over 60 mph are still possible there. We've very lucky Jose jogged east some as the Cape and Islands would have had a really nasty storm.

While the rain ends for tomorrow the wind will actually pick up some with 30-40 mph gusts possible in some towns. Nothing too bad. 

Beyond Jose we've got a few items of note in the extended forecast. The first will be a giant ridge of high pressure that will build in from the west and allow unusually warm temperatures to develop. In the map below you can see very large temperature anomalies (>10C) as the jet stream retreats north. It's not out of the question that temperatures could approach the 90 degree mark Sunday or Monday with how warm this air mass will be. 

If we were to get to 90 it would only happen with Jose remaining far enough offshore to keep clouds away and if the wind direction cooperated (westerly winds a must). 

One wild card for next week is what will happen with Jose off of Nantucket and how Jose will interact with Hurricane Maria. For one, the giant ridge of high pressure that builds in and warms us up, will effectively block Jose from harding east into the North Atlantic. Until we figure out what Jose will do as it meanders off New England it's hard to know where Maria will track. This spaghetti plot from the European model is a pretty accurate depiction of possibilities - ranging from an east coast US threat to safely out to sea.

Maria will have to be watched and after what it's about to do to St. Croix and Puerto Rico they will certainly need a lot of our help. 


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<![CDATA[Gusty Winds, Rain in Connecticut as Jose Approaches]]>Tue, 19 Sep 2017 18:13:30 -0500https://media.nbcconnecticut.com/images/214*120/NHC-NOAA.jpg

Hurricane Jose is roughly 280 miles to the south of Southern New England. Winds are currently sustained at 75 mph. 

Jose is still expected to track approximately 125 miles to the southeast of Nantucket. 

Connecticut will only experience some fringe effects, especially for the southeast corner. A tropical storm watch was issued over the weekend for southern Connecticut, but it was canceled at 11 a.m. on Tuesday. 

Winds are currently gusting over 30 mph in southern New London County. Wind gusts will gradually pick up throughout the night with gusts up to 45 mph along the southeastern Connecticut shoreline. 

Waves are becoming quite large just over the Connecticut border in Rhode Island. Waves are currently 6 to 8 feet, waves heights will increase by tomorrow morning with waves of 10 to 14 feet expected. 



Photo Credit: NHC NOAA]]>
<![CDATA[Tropical Storm Watch Canceled; Minor Impacts Still Expected]]>Tue, 19 Sep 2017 15:18:23 -0500https://media.nbcconnecticut.com/images/180*120/jose091817.gif

4PM Update: Hurricane Jose is roughly 280 miles to the south of Southern New England. Winds are currently sustained at 75 mph. 

Jose is still expected to track approximately 125 miles to the southeast of Nantucket. 

Connecticut will only experience some fringe effects especially for the southeast corner. 

Winds are currently gusting over 30 mph in southern New London county. Wind gusts will gradually pick up throughout the night with gusts up to 45 mph along the southeastern Connecticut shoreline. 

Waves are becoming quite large just over the Connecticut border in Rhode Island. Waves are currently 6 to 8 feet, waves heights will increase by tomorrow morning with waves of 10 to 14 feet expected. 

____________________________________________________________

Hurricane Jose is limping north, battling dry air and strong wind shear.

The National Hurricane Center dropped all Tropical Storm Watches as of 11 a.m. on Tuesday.

Hurricane Hunters flying through the storm haven't even been able to find hurricane force winds in the system. As the storm moves north, we will see some impact here locally but I'm not expecting much.

The storm will pass a bit east of where I expected it would on Sunday night. That will result in less wind and less rain than previously expected. We anticipated a minor to moderate impact locally and now we are confident in just a "minor" impact. This is why we show the "cone of uncertainty" as Jose will track on the east side of last night's cone, which was always a distinct possibility.

Rain will fall off and on Tuesday as the outer bands of Jose rotate in. Occasional squalls of wind and rain will be common throughout the day and evening. Up to 1 inch of rain is possible in most towns with a bit more in southeastern Connecticut. Winds may gust as high as 30 or 35 mph Tuesday afternoon and night. 

As the storm pulls away Wednesday rainfall will diminish but the winds will pick up. I expect the strongest winds will occur on Wednesday morning and midday as the storm pushes east. Gusts as high as 45 mph are possible in southeastern Connecticut with scattered tree and power line issues possible.

Another piece of good news is that the coastal flood threat remains quite low as winds will be mainly offshore.

While winds remain gusty on Wednesday afternoon, clouds will gradually break and much better weather will move in for the end of the week.


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<![CDATA[Tropical Storm Watches Posted Ahead of Jose]]>Sun, 17 Sep 2017 19:44:44 -0500https://media.nbcconnecticut.com/images/213*120/rh091717_1200x675_1048599619905.jpg

Our computer models have wobbled west and wobbled east over the last couple days. This is to be expected. What's remained relatively consistent is our forecast of a "glancing blow" from Jose with a minor to moderate local impact. The National Hurricane Center forecast looks good to me with the storm passing about 100 miles south of Nantucket on Wednesday. 


We're right on the western fringe of this one and only a small deviation in track will make a big difference in impact. Here's what I'm thinking right now:

  • Rain begins Tuesday morning with occasional squalls Tuesday, Tuesday night and Wednesday morning.
  • Winds will increase Tuesday and peak Tuesday evening through Wednesday morning. Peak gusts in excess of 40 mph are possible from New Haven on east along the shoreline. Gusts should remain below 40 mph inland.
  • Rainfall totals of over 1 inch are possible in southeastern Connecticut. Rainfall amounts will diminish the farther north and west one goes.
  • Storm surge flooding does not look to be a big deal. A northerly wind is mainly offshore on the Connecticut coast. Minor issues at worst.
  • Isolated or sporadic tree and power issues are possible in some towns - particularly along the shoreline. 
There is still time for things to change. A track on the western side of the NHC cone would result in more significant impacts - more wind and more rain. A track on the eastern side of the NHC cone would result in less impact - with less wind and less rain. If there was a side I am currently favoring it would be the eastern or less impact side. We'll have to watch trends over the next 24 hours.

The European model (pictured above) is on the left side of the NHC forecast while the GFS is on the right side. Again, the extent of impacts is still not quite clear though at least some minor to moderate wind and rain event seems like a good bet. 


Believe it or not it's possible Jose may do a loop-de-loop southeast of New England over the next 7 days. While this is unusual it's not unprecedented. In fact, the weather pattern right now is very similar to 1961 when hurricane Esther did a loop off the Cape. Unlike Esther, Jose is a much weaker storm and impacts will be much more limited.


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<![CDATA[Hurricane Jose Path Jogs Further East]]>Sat, 16 Sep 2017 16:03:44 -0500https://media.nbcconnecticut.com/images/214*120/Saturday+5+pm+national+hurricane+center+saturday.JPG

5 p.m. Saturday update: A new advisory from the National Hurricane Center moves Hurricane Jose a little further away from Connecticut.

11 a.m. Saturday Update: A new advisory from the National Hurricane Center is similar to the one at 5 a.m.

5 AM Saturday Update: A new advisory from the National Hurricane Center this morning shows little change from last night. The track of Jose keeps Connecticut in the "cone of uncertainty." The odds of Connecticut experiencing tropical storm force winds (winds sustained over 39 mph) have increased throughout the state. 

The greatest chance for tropical storm conditions is in southeastern Connecticut especially right along the shoreline from Groton to Stonington. We're continuing to look over new data and will have several updates throughout the day.

________________________________________________

It appears we have a good 'ol fashioned American vs European model fight brewing with Hurricane Jose. The two spaghetti plots of the GFS and European ensembles are very different - the former being closer to the coast and the latter being further out to sea.

The differences in track make a huge difference in terms of what kind of impact Jose would have here in Connecticut. More often than not a blend of the two disparate model camps yields the best forecast - though it's important to not the Euro is typically the better model. With that in mind here is what I'm thinking in terms of local impact probability for Tuesday and Wednesday when Jose makes its closest pass.

A scenario painted by the GFS ensembles is possible and it would be a significant wind, rain, and coastal flooding storm. At least for now this seems like the least likely scenario. One thing that makes me think it's unlikely is the fact the jet stream pattern is generally not the pattern that fits most New England tropical storm and hurricane strikes. Generally, you want a deep trough of low pressure to capture the hurricane and slingshot it north.

A more likely scenario is more of a glancing blow with some rain and some wind but nothing that would result in more than a handful of power outages.

Still, it's important to watch the path of this storm. Sometimes the least likely scenario is the one that verifies and that scenario is still in the cone of uncertainty. What I am confident in is that even with a "direct hit" the storm will not be of hurricane strength. Cold water temperatures and slow forward motion of the storm should manage to weaken Jose relatively quickly. 



Photo Credit: NBCConnecticut.com
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<![CDATA[Jose Now a Hurricane; Connecticut Remains in Possible Path]]>Fri, 15 Sep 2017 15:53:22 -0500https://media.nbcconnecticut.com/images/213*120/josefriday5p.jpg

UPDATE: Jose strengthened into a Category 1 hurricane on Friday afternoon, according to the National Hurricane Center.

Connecticut in the possible path of Hurricane Jose. The NBC Connecticut meteorologists have issued a First Alert for Tuesday and Wednesday of next week. 

Jose became a whole lot more interesting Thursday as our suite of computer models brought the storm much closer to Connecticut by Tuesday of next week.

The storm is moving west and by the weekend will begin a turn north along the east coast of the United States. What's unclear is how far west Jose will get and how strong Jose will be. The current forecast from the National Hurricane Center has Jose in a somewhat precarious position east of Norfolk, Virginia by 5 p.m. Tuesday.

Jose is essentially blocked from curving out into the Atlantic Ocean by a strong ridge of high pressure that stretches from Bermuda through the Canadian Maritimes. A blocking high to the east of New England is the single most important piece of the puzzle historically for landfalling northeast hurricanes.

The second piece of the puzzle is a trough of low pressure over the Great Lakes and Ohio River River Valley to "capture" the hurricane and pull it west while accelerating the storm north. We are missing this ingredient.

Only having one of the two ingredients likely rules out a landfalling hurricane in New England. The odds of this happening are extremely low. However, with the blocking ridge to the east Jose may be able to meander off the coast of the Mid Atlantic and bring us a period of wind and rain. 

How close to Connecticut depends on how strong the west Atlantic ridge is (stronger would push Jose farther west) and how sharp the Great Lakes ridge is (oriented southwest to northeast would prevent Jose from getting too far north). With ridges all around Jose will be trapped for a period of time with nowhere to go and may slow to a crawl. 

Where this crawl happens is uncertain. The GFS and Euro ensembles show significant spread but show about 25 percent of solutions close enough to southern New England for concern. 

This setup reminds me a bit of Hurricane Edouard in 1996 that menaced New England Labor Day weekend. The storm slowly drifted north (blocked by a strong downstream ridge) and then scooted east at the last minute.

Without the capture and acceleration north (ingredient number 2 mentioned above) - Jose is likely to weaken gradually. A direct hurricane hit remains extremely unlikely and a moderate or strong tropical storm is a reasonable worst case scenario. Some wind and some rain.

How significant the storm is locally remains quite unclear but it's certainly worth watching. 



Photo Credit: National Hurricane Center
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<![CDATA[No Way Jose]]>Wed, 13 Sep 2017 20:21:39 -0500https://media.nbcconnecticut.com/images/180*120/jose0914.gif

Right off the bat I should say that the odds of Hurricane Jose impacting New England (besides big waves) are quite low. That said, our computer models today started to show a slightly more interesting evolution of the storm which will need to be watched.

The reason we're interested in Jose is what's happening across the North Atlantic. A huge, blocking ridge of high pressure will situate itself from Hudson Bay through the Davis Strait. This may be enough to prevent Jose from curving out to sea.

In fact, today's European Ensemble forecast shows 20% of modeled scenarios hooking Jose back toward the close with a slow stall or wobble off the Mid Atlantic. Note that this also means 80% still go out to sea. The GFS ensembles have 4 of 21 doing something interesting with a path into the Mid Atlantic. Again, about 20 percent.

While this is interesting that's about all we can say now. This type of path is very unusual. A few storms have stalled or drifted near the coast between North Carolina and Cape Cod - Felix in 1995 and Esther in 1961 come to mind along with, to a less extent, Edouard in 1996. Additionally, even if this were to happen the storm likely wouldn't be particularly strong and would likely be no worse than a strong fall nor'easter. 

Anytime something's lurking off North Carolina we'll have to watch it. The window for a possible impact appears to be Tuesday-Thursday of next week. 


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<![CDATA[Keeping a Close Eye on Hurricane Jose]]>Mon, 11 Sep 2017 16:38:37 -0500https://media.nbcconnecticut.com/images/213*120/Cover+Photo+Jose.png

We're paying close attention to Hurricane Jose which is currently to the northeast of the Turks and Caicos Islands. 

Jose is currently a Category 2 Hurricane with sustained winds of 100 mph. 

The latest track from the National Hurricane Center has Jose circling in a complete 360 and eventually tracking toward the Bahamas and East Coast.


Meteorologist Ryan Hanrahan says anytime you have a hurricane tracking to the northeast of the Bahamas it's important to keep an eye on.

With that being said there is still a lot of spread between our computer models on where Jose will be located by the end of this coming weekend.

A few of our computer models have it making landfall in New Jersey, others have it scraping the New England coast, and many models take the storm completely out to sea.


It's something we're going to pay extra attention to throughout the week. Make sure to check back for updates on Hurricane Jose throughout the week.


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<![CDATA[Irma Jogs West]]>Fri, 08 Sep 2017 22:43:59 -0500https://media.nbcconnecticut.com/images/180*120/rb_lalo-animated090817.gif

Hurricane Irma's forecast track is shifting west. This has significant consequences for both the east and west coasts of Florida. 

As of Friday evening the National Hurricane Center says Miami only has a 38% chance of seeing hurricane force winds. This means there's less than a 50/50 chance that Miami gets hurricane force winds. This is a drop from earlier. What is now better news for Miami is worse news for the Florida Keys and Southwest Florida. 

For the last 36 hours - with few exceptions - our computer models are turning Irma to the north later and later. This results in a direct impact west of Miami-Dade County close to Naples and Fort Myers, FL. 

While the wind and storm surge will be ferocious around Miami the impact appears much less than what we were thinking 24 hours ago. The impact in western Florida, however, looks much more significant. A catastrophic surge and wind event is possible near the point of landfall in southwestern Florida and on the Florida Keys. 

There are still some questions. One is how much Irma's interaction with Cuba will weaken the storm. Also what's unclear is what happens to Irma's intensity post-Cuba. Exceptionally warm water in the Florida Straits is fuel for a hurricane and there is room for additional intensification. The last question is just how far west Irma gets. It's making landfall at a somewhat oblique angle so a jog another 20 miles west will bring landfall much farther up the coast potentially putting Tampa at greater risk.

Stay safe Florida! 


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<![CDATA[Irma Looks Really Bad]]>Thu, 07 Sep 2017 20:10:09 -0500https://media.nbcconnecticut.com/images/180*120/rb_lalo-animated_090717.gif

Last year I grimaced every time I heard someone talk about how devastating Hurricane Matthew would be for Florida. It didn't look great but it wasn't anywhere near a worst case scenario. Hurricane Irma, however, truly scares me. 

Irma's track is becoming a bit more clear. The storm will take a hard right turn into Florida. Yesterday there was a cluster of computer models that brought Irma east of Florida - which would have greatly reduced the impact in Miami. That eastern cluster is now gone. You can see on the European and GFS ensembles below which both agree on tracks very close to - or over - the Florida peninsula. Each line indicates a different model and the colors represent how clustered the models are (the brighter the colors the more models bring Irma over that location).

This represents a pretty close to worst case scenario for South Florida. A powerful category 4 hurricane emerging from the Florida Straits and putting Miami-Dade and Broward Counties on the most dangerous right hand side of the storm is currently forecast. The left side, not quite as strong, would still produce widespread and serious coastal flooding on the Gulf Coast. 

What Could Change?

While it looks like Irma will be devastating there are things that could make it better. A track east or west of Florida could spare the state a direct landfall. While this seems unlikely the "cone of uncertainty" still remains very large at this juncture.

The storm's intensity is also a bit uncertain. While the most likely scenario (as currently forecast) is a category 4 hurricane there is certainly an opportunity for the storm to weaken a bit more OR strengthen more than forecast. Hurricane intensity is notoriously challenging to forecast. 

It's not a certainty this will be catastrophic but it sure doesn't look good now. 

Will it Be Worse Than Andrew?

Maybe. Maybe Not. Until we know exactly the path and intensity of Irma it's too early to draw comparisons. One thing that is clear is that Irma will be much larger in size than compact Andrew was. This could make storm surge worse and spread damaging winds across a larger area. 

Should I Be Worried About Friends and Family?

If they live in a mandatory evacuation zone they need to leave. Storm surge and flooding is what kills people during a hurricane. Outside of storm surge zones hurricanes are quite survivable - event category 5 storms.

That said, anyone in South Florida should prepare for days and days without power and be able to shelter in place for an extended period of time veen if not in an evacuation zone.


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<![CDATA[Destructive Morning Storms]]>Wed, 06 Sep 2017 19:07:34 -0500https://media.nbcconnecticut.com/images/213*120/090617storm+%281%29.gif

Getting morning severe thunderstorms in southeastern Connecticut is not terribly unusual. There have been other example of storms racing north from Long Island and causing mischief in New London County and South County, Rhode Island. Today's storms were no exception. 

The storm was not preceded by an official warning for some reason but we knew these storms looked like trouble. Prior to the storm's arrival we began streaming coverage and sending out social media messages for people to watch out.

What was so concerning to us was the extreme velocities being picked up by doppler radar. A "bowing segment" was accompanied by winds over 80 mph at the bow's apex several thousand feet above the ground. In essence, the strong winds in the storm were forcing the storm to bow out or race forward.

In fact, as this storm moved over Groton it produced a 95 mph wind gust on the north crane at Electric Boat. Just nearby, you can see the incredible display on a street corner as the winds picked up, transformers blew, and trees snapped below.

The storm was a classic morning severe weather event along the shoreline. Very moist and humid air with a somewhat unstable atmosphere (CAPE values of about 1,000 j/kg indicate some instability). Above the ground very strong winds produced strong shear values which allowed storms to organize and mix some of this high momentum air to the ground. This was maximized near the bow segment's apex which tracked from Waterford into New London, Groton, and Ledyard. 

The weather balloon launch (pictured above) from Long Island shows the instability and strong winds throughout the atmosphere. The lack of a stable layer (inversion) at the surface allowed winds to mix readily to the surface.

Sadly, 1 man was killed when a tree fell on his car. This narrow band of destructive winds moved through a populated part of the state knocking down trees and wires in too many neighborhoods to count. 


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<![CDATA[Hurricane Irma - 9/1 Update]]>Fri, 01 Sep 2017 20:42:46 -0500https://media.nbcconnecticut.com/images/213*120/Tropical+Track+2090117.png

Irma remains a powerful hurricane in the Atlantic Ocean this evening and there is no real change to the forecast thinking tonight.

As I talked about last night hurricanes located where Irma is now frequently curve out to sea harmlessly. About 90 percent of them do. It does look like Irma will be different. The only thing we can say right now is that Irma has an unusually high risk of impacting the United States compared to typical storms in the same spot.

The reason is a big, sprawling blocking high to the north of Irma from Bermuda stretching all the way east toward Europe. This high will effectively prevent Irma from turning north. Both the GFS and European computer models have this feature and agree a curve out to sea is unlikely in the next week.

Beyond that the forecast is very uncertain as any hurricane forecast is in the 7-10 day range. In fact a typhoon off the coast of Japan is one of the key ingredients in figuring out where the heck Irma is going.

Typhoon Sanvu is racing northeast in the open Pacific Ocean and like so many recurving typhoons it will have big impact on the downstream weather pattern. Sanvu will dramatically alter the jet stream flow over the North Pacific in the next 5 days and this will force the jet stream to buckle over North America. Everything is connected! 

Where, when, and how Typhoon Sanvu shakes up the jet stream pattern will dictate how close Irma gets to the United States and which parts of the east coast are most at risk.

The evolution of the jet stream pattern is key to figuring out whether Irma is able to scoot out to sea or if Irma is able to continue her course toward the United States. The GFS Ensembles are in remarkably good agreement for 8 or 9 days out with an east coast threat which makes sense given the setup. The European ensembles (not pictured) are more dispersed and do show a cluster of solutions that are harmlessly out to sea - let's hope this cluster is the one to verify!

Enjoy your Labor Day weekend. By Monday we'll know if this is something we should worry about or not.


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<![CDATA[Hurricane Irma]]>Thu, 31 Aug 2017 20:50:09 -0500https://media.nbcconnecticut.com/images/180*120/avn_lalo-animated083117.gif

Hurricane Irma is something you're going to hear about a lot over the coming days. The category 3 hurricane near the Cabo Verde Islands is forecast to strengthen over the next 5 days. The question is where does it go after that?

This visualization from Ryan Maue shows the possible tracks of Irma quite well. One thing you'll note is that very few of the European model members take Irma out to sea. The range of possibilities stretches from Cuba all the way north to the Canadian Maritimes. Given it's current location in the Atlantic it's unusual to see a storm that's not trying to find any possible way to escape into the open ocean well east of us. 

More than 90% of hurricanes near where Irma is now do not make landfall in the United States. Generally, they have to be farther south and west. This graphic from Connecticut native, and hurricane expert, Bob Hart shows the probability of a tropical cyclone passing over the United States based on their location. This doesn't include the current weather pattern or steering currents and is only based on climatology or past storms. Irma's location is not one that's particularly favorable for a United States landfall based on past storms so why the heck are we talking about it? 

Check the forecast from the National Hurricane Center. Notice over the Labor Day weekend Irma takes an unusual path - bending to the south as it approaches the Lesser Antilles. Some storms do this but most don't. The farther south Irma gets it winds up in a more favorable position for a United States Impact. 

An additional note is how strong the hurricane is forecast to get. Right now the National Hurricane Center is forecasting a category 4 hurricane near the Lesser Antilles. This isn't a weak tropical storm we're talking about here!

Essentially a large ridge of high pressure (see the orange colors over the North Atlantic) will close the escape hatch and prevent this hurricane from doing what 9 out of 10 do - scoot harmlessly out to sea (though sometimes Bermuda gets unlucky with those "out to sea" storms). 

At least right now the weather pattern is a bit ominous for the East Coast of the United States and potentially the Gulf of Mexico as well. Nothing we can do now other than watch it. In a few days we'll know if this is something that's worth getting worried over - but for now keep calm and carry on. 


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<![CDATA[Hurricane Carol ]]>Thu, 31 Aug 2017 13:14:13 -0500https://media.nbcconnecticut.com/images/200*120/DIkBBHUXcAALLNZ.jpg

Hurricane Carol was one heck of a storm. The category 3 hurricane made landfall near Groton and brought devastating flooding and wind damage to parts of southeastern Connecticut and Rhode Island (from South County to Providence). Carol is a bit forgotten – the impact was less than 1938 and it was overshadowed in the state by the remnants of Connie and Diane in 1955 that paralyzed the state with a biblical flood.

The reanalysis by Chris Landsea and the work by Jarvinen shows a landfall of Carol near Groton. This is about 20 miles east of the “Best Track” landfall location in Old Saybrook. The reanalyzed landfall location makes sense given the damage documented in Connecticut.

Carol made landfall on the morning of August 31, 1954. The storm brought category 2 force winds (sustained near/over 100 mph) in Groton and Stonington and a vicious storm surge. In New London the storm tide reached 9.6 ft MLLW, only exceeded by the 1938 storm which was 10.6 ft MLLW. The surge in New London at the tide gauge was 6.5 feet though a study by the Army Corps of high water marks after Carol revealed surges of 8-10 feet were common throughout southeastern Connecticut. In Stamford – many miles from the landfall location – the storm tide reached 10.3 ft NGVD which was only exceeded by Sandy and the 1938 hurricane.

Hurricane Carol is widely viewed to be the “most tropical” of hurricanes to hit Connecticut. What’s meant by that is that while the storm was likely going extratropical transition – Carol was the most purely tropical of the storms to strike Connecticut. Here’s one example of that – take a look at this picture taken from the old Griswold Hotel in Groton near the mouth of the Thames River.

The storm had a classic “eye” and the precipitation distribution from the storm – both east and west of the storm track – was relatively symmetrical. That’s very unusual for a landfalling New England hurricane!

In Bridgeport the monthly climate report indicates 1.62″ of rain fell on the day with a peak sustained wind out of the NNE at 40 mph with a gust to 60 mph. The report read as follows “Hurricane Carol did extensive damage to the shorelines of Connecticut. Storm center passed 50 miles east of station. Lowest pressure noted at 0920 EST, with NNE winds of 40 MPH and gusts to 60 MPH noted at 0928 EST. Airport was inundated with a maximum of 2 feet of water.” The lowest pressure reading in Bridgeport was 28.87″.

In Hartford at Brainard 2.36″ of rain fell. No wind data was recorded. In New Haven at Tweed 2.63″ of rain fell with a sustained wind of 38 mph out of the northeast. The report read “Heavy storm on the 31st. Gusts to 65 MPH 9-10 A.M. Caused heavy water manage along shore. Lowest pressure 28.77″ 9:10 A.M.”

At Windsor Locks 1.95″ of rain fell with a suatained wind of 56 mph out of the northwest! A 64 mph wind gust was recorded in the monthly report.

Cooperative observer reports for August 1954 include some interesting highlights.

  • Baltic, CT recorded 4.10″ of rain “HURRICANE” was listed in the important wx conditions space.
  • Brooklyn, CT recorded 4.00″ of rain
  • The observer in Colchester wrote a great blurb about Carol – though I can only decipher about half of it! 
  • The Danbury coop observer reported wind gusts near 60 mph
  • In Derby the coop observer reported the following “High winds on Aug. 31. Hurricane “Carol” considerable damage to trees. An additional amount of rain – 1.05″ fell from 8:30 a.m. to 12:30 p.m. on Aug 31″ That 1.05″ is in addition to the 1.56″ reported at 8:30 a.m. in Derby.
  • Even in Falls Village the observer mentioned the wind on the 31st “wind on the 31st caused considerable damage to untilities.”
  • In Groton the observer wrote “Aug 31. Winds of hurricane force from 9:00 A.M. to 11:30 A.M. did much damage to buildings, trees, and boats in this area. Power and telephone lines severely damaged causing loss of service for several hours.”
  • In Mansfield at the dam the coop observer from the Army Corps mentioned on the 31st “Note: temperature readings may be inaccurate because the box blew over during height of storm”
  • Here’s what the Middletown observer wrote:
  • Here’s the observer’s remarks in New London at Fort Trumbull.
  • In Norfolk, observer Norman Smith summarized Carol this way, “The feature of the month that was most notable was the passage on the 31st of an Atlantic hurricane. The storm here brought 2.59″ of beneficial rain with shifting gale winds from the E NE and NW. There was some damage to power and telephone lines and roads were blocked by uprooted trees and branches.”
  • In Putnam 4.25″ of rain fell and the observer noted the hurricane passed east of Putnam with considerable damage to crops and trees with some property damage.
  • In Storrs 3.35″ of rain fell. The observer wrote, “On the 31st of August Hurricane “Carol” hit eastern Connecticut hard with 60 mile wind – higher gusts – and nearly 2″ of rain between 8 and 11 a.m.
  • 4.36″ of rain fell in Westbrook – here’s the observation remarks.

The observations show a core of very heavy rain – 4″-6″ of rain near the center of the storm with less rain on the western periphery. Again this symmetry is unusual and shows that the eyewall was likely quite in tact and the storm was still quite “tropical” at the time of landfall.

Carol produced $50,000,000 in damage in 1954 dollars in Connecticut and killed 65 across New England. The storm is the only category 2 to strike Connecticut in modern times (1938 was a category 3 in Connecticut) and remains the strongest storm to strike the state in the last 59 years.



Photo Credit: Charles Orloff
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<![CDATA[Tropical Trouble]]>Wed, 30 Aug 2017 20:40:20 -0500https://media.nbcconnecticut.com/images/180*120/irm0830.gif

The remnants of Harvey and newly formed Tropical Storm Irma have our attention. The peak of hurricane season is in a little less than two weeks and not surprisingly the tropics remains quite active. 

Remnants of Harvey

Harvey will likely go down as our nation's costliest natural disaster. Thankfully the rain is coming to an end in Texas and the remnants of the storm are lifting north. That will impact our holiday weekend in some way. 

A plume of tropical moisture will approach from the south and give us a rising chance for showers. Right now it appears Saturday evening, Saturday night, and Sunday will be unsettled. At this point I have scattered showers in the forecast for that window. I expect better weather to move in for Labor Day.

As Harvey's remnants move through no severe weather or flooding rain is expected.

Tropical Storm Irma

A new tropical storm in the Atlantic Ocean is on a somewhat concerning path west. Most storms at this longitude manage to find a weakness and curve out to sea but Irma may have other ideas.

Check out this "spaghetti plot" of the European computer model showing possible paths for Irma. A few things to note is that one, Irma is expected to become quite intense. And two, a number of European ensemble members bring Irma near the United States. 

Any impact is more than a week away so there's nothing to worry about now. That said, we're going to be watching it closely for you every step of the way.


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<![CDATA[A Closer Look at Hurricane Harvey]]>Mon, 28 Aug 2017 19:51:19 -0500https://media.nbcconnecticut.com/images/213*120/Harvey_Death_Toll_Rises_as_Shelters_Fill_Up_in_Houston.jpg

Hurricane Harvey will go down as one of the costliest natural disasters in United States history. With destructive winds and a destructive floods this hurricane has been horrific.

How Rare is Harvey?

A category 4 hurricane landfall in the United States is unusual but certainly not unprecedented. The last was Charley in 2004. What makes Harvey so unique is the exceptional fresh water flooding in the Houston area. It appears that a large chunk of metropolitan Houston is dealing with a 1-in-1000 year flood - in other words a flood that has a 0.1% chance of occuring in any given year. 


Harvey will come close to breaking the tropical cyclone rain record for Texas of 48" set back in Amelia in 1978. What makes this so much worse is the fact this extreme rainfall is falling in one of the most densely populated areas of the country. 

How Was The Forecast?

The rainfall forecast for Harvey was phenomenal. For days prior to the flood in Houston forecasters were talking about record breaking rainfall. For several days our computer models all agreed on a huge flood threat and it most certainly verified.

The intensity forecast for wind was more problematic. The National Hurricane Center's forecast 48 hours prior to landfall was for a strong tropical storm or minimal hurricane. The storm's actual intensity at landfall was a category 4 hurricane. If the hurricane made landfall in Houston, New Orleans, Tampa, Miami, or any other large city the initial busted intensity forecast could have been disastrous. A late and panicked evacuation likely would have been deadly.

Harvey shows us how far along computer modeling and forecasting has come - with a nearly perfect rain and flood forecast several days out. Harvey also reminds us of the shortcomings in hurricane forecasting. Periods of "rapid intensification" are notoriously challenging to predict. We have much work to do!

Did Climate Change Make Harvey Worse?

Maybe. Earlier today I posted something on Facebook and Twitter about how we really don't know right now how big (or little) of an impact climate change had on Harvey. The post managed to annoy liberals and conservatives on Twitter almost immediately.

The relationship between tropical cyclones and climate change is complex and poorly understood. For one, a warmer atmosphere is able to effectively "hold" more water vapor and therefore one could argue hurricanes would be able to produce increased precipitation rates as they make landfall. Increased rainfall from tropical cyclones in a warmer world is something many climate scientists agree on. 

Professor Kerry Emanuel, a climate scientist at MIT, wrote about Harvey's exceptional rainfall today. He notes the frequently of tropical cyclone landfalls in southeast Texas, "shows no discernible trend in either the historical data or in the downscaled event. So the higher rainfall cannot be attributed to more frequent tropical cyclones."

While the frequency of tropical storms hasn't changed - temperature and steering currents have changed. Emanuel said the change in temperature (and therefore water vapor) isn't enough to explain the amount of rainfall.

As for the slow motion of the hurricane Emanuel did note a drop in the speed of modeled hurricanes over the last 7 years. Harvey's exceptionally slow movement is responsible for its extreme rainfall but Emanuel notes there is no long term signal for a drop in translational speed outside of the last few years which would indicate that climate change due to humans is not responsible.

Over the coming months and years research will be done as to what about Harvey can and can't be attributed to climate change. We know a lot about climate change but how a warming world will impact tropical cyclones in specific areas is much more uncertain.

What We Know Made Harvey Worse

Houston is the 4th largest city in the United States and has been growing at an incredible pace. The city has an elaborate system of bayous and reservoirs and it struggles to drain during most rain storms. This great piece by The Texas Tribune and ProPublica goes through some of the problems in Houston related to land use, urban srpawl, and poor urban planning. 

Could Houston Have Been Evacuated?

Probably not. And certainly not safely. The vast majority of flood deaths occur in automobiles. The last time a large scale evacuation in Houston was ordered was ahead of Hurricane Rita in 2005 and it resulted in days of gridlock. Unfortunately, the sheer number of people and the sheer size of this flood event made it impossible to mass evacuate the city. 

How To Help

NBC Connecticut is partnering with the Hartford Yard Goats to hold a Hurricane Harvey Relief Drive. Click here to learn more. 


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<![CDATA[Harvey Making Landfall]]>Fri, 25 Aug 2017 19:24:01 -0500https://media.nbcconnecticut.com/images/213*120/DIHGwZEWsAA3GGh.jpg

Harvey has been a humbling storm for tropical forecasters. Just 48 hours ago the forecast from the National Hurricane Center was for a strong tropical storm or minimal hurricane to make landfall just east of Corpus Christi. Tonight it appears clear Harvey will make landfall as a category 4 hurricane. We're not that good forecasting rapid intensification of hurricanes and Harvey is another example of that.

The story tonight will be the wind and the storm surge. A deadly combination. This hurricane will likely be the first category 4 hurricane to make landfall in the United States since Hurricane Charley in 2004 and in Texas since Hurricane Carla in 1961.

If there's any positive news on a day where Harvey strengthened quickly it's that the worst of the storm will be in a fairly rural area. Not Houston, not Galveston, and not Corpus Christi. Matagorda Bay (no stranger to hurricanes - do a Google search on Indianola, Texas) will bear the brunt of the storm initally. 

Beyond tonight the story with Harvey will likely be the rain. In fact it's possible the inland rain and flooding may be more destructive and costly than the initial wind and storm surge. While the storm's intensity was not well forecast what hasn't changed over the past few days is the forecast for exceptional rainfall in Texas. Harvey is already slowing down and expected to stall near the coast. Days of rain will inundate Texas as the storm crawls along the coast.

So what are the state and national tropical cyclone rain records? 48.00" in Texas from Amelia in 1978. In Connecticut the record is 16.86" from Tropical Storm Diane (which cause the historic 1955 flood). 


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<![CDATA[Tuesday's Storms - A Close Call]]>Thu, 24 Aug 2017 19:09:28 -0500https://media.nbcconnecticut.com/images/180*120/68fd8b6052e9492e91bddeaf210f21fc.jpg

We got lucky late Tuesday night. Kaitlyn and Josh were holding down the fort in the weather office until well after midnight with a very concerning weather setup. A bit of instability and a whole lot of wind shear left the atmosphere primed for an isolated tornado.

Looking back at the radar data it appears we really had some luck on our side. The setup was fairly common. A cold front sweeping in from the west, a surge of extremely humid/moist air coming in off the warm ocean waters, and a bit of instability during the overnight. What was a bit unusual was the amount of low level wind shear that was present. 

This environment reminded me a bit of the August 22 overnight tornado in Concord, MA that was exceptionally well warned by Hayden Frank at the National Weather Service in Taunton, MA. 

This sounding off the RAP models shows very modest instability but very powerful winds just off the surface. It wouldn't have taken much for some 60 mph winds to reach the surface. 

There were two radar signatures that were quite concerning. Given the low CAPE/high shear environment I wasn't surprised to see two rotating storms develop. One was in Goshen/Torrington shortly after 11 p.m. and another in Wolcott after midnight. Thankfully, no tornado touched down.

Both the Torrington and Wolcott storms had just shy of 50 knots of what we call delta-V. Basically the strongest outbound and strongest inbound velocity are added together to characterize the strength of a storm's rotation. The median value for northeastern U.S. tornadoes in a delta-V of 60 knots - with a delta-V of 50 knots immediately prior to touchdown. 

In an environment like we had Tuesday night we got lucky. One or both of those storms were candidates for brief and weak overnight tornadoes. A small increase in strength in either storm likely would have been enough to drop a tornado. 



Photo Credit: Kally Johnson
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<![CDATA[Solar Eclipse 2017 - What an Incredible Experience!]]>Wed, 23 Aug 2017 21:23:29 -0500https://media.nbcconnecticut.com/images/160*120/IMG_1053.gif

At 2:46 p.m. on Monday, August 21 I saw the most incredible thing I've ever seen in my life. 

I woke up Monday morning in Mount Pleasant, SC to a thunderstorm and overcast skies. Not a great sign. All morning I obsessively checked radar, satellite, and computer model data looking for any sliver of hope that clouds would clear for the eclipse. There wasn't much to be found. 

Shortly before noon we made it to the beach in Sullivans Island, SC and skies were still overcast though beginning to brighten a bit. If we had any hope it would be right on the beach as the sea breeze moved inland and pushed showers and storms away from the coast.

By 1:30 p.m., as the eclipse began, the clouds continued to break and finally I saw some signs of improvement on the satellite loop as clouds began to break just offshore. Could we get lucky?

It's wasn't until around 2:15 p.m. the clouds thinned enough that the ongoing eclipse was even visible with our eclipse glasses. By the time of totality the clouds were so thin we got the full show. 

It's really hard to explain how incredible the experience of totality is.  In the few minutes before totality the temperature dropped rapidly. You could feel a chill with the wind accelerating down the beach. Even the darkness is odd. The light was unusually flat and on the horizon you could see brightness south, east, and north. It felt like a sunset in every direction. It is bizarre.

Pelicans and other shore birds weren't enjoying the strange midday darkness. You could hear them moving around and flying up and down the beach as totality set in. The sounds, the feeling, and the sight was an absolute shock to the senses.

After the last sliver of the sun disappeared the eclipse glasses came off and everyone stared upward. For a second I thought, "that's it?" and then it happened. A brilliant bright ring appeared surrounded by incredible darkness. The sun's corona danced and shimmered in the most breathtaking spectacle I've ever seen. It literally took my breath away. I wasn't the only person in my group on the beach to get choked up at the immense beauty and sensory overload. 

As totality ended the "diamond ring" effect caused a brilliant flash of light as the moon moved past the sun. It was beyond exhilirating. 

As a weather geek it actually could not have been any better. Throw out all the astronomical stuff for just a second! While totality occured the western horizon was covered up by a thunderstorm with a number of gorgeous cloud-to-ground flashes and rumbles of thunder. How many people have been able to see totality while a thunderstorm roared a few miles away? Not many. It was freaking awesome.

To be honest, leading up to the eclipse I thought some of the ways people describe totality were a bit over the top. Life changing? Spiritual? Emotional? After 2 1/2 minutes of totality I can say that those vivid descriptions aren't off the mark. It was one of the most magical things I've ever seen. It exceeded every expectation I had.

I'm already counting down the days to 2024.


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<![CDATA[The Great Flood of 1955]]>Fri, 18 Aug 2017 20:15:34 -0500https://media.nbcconnecticut.com/images/160*131/55flood17.gif

Besides the 1938 hurricane, the 1955 flood was arguably the greatest natural disaster in Connecticut since colonial times.

The amount of rain that fell in August 1955 is so off the charts no event has come anywhere close to it in the last 100 years. That year's monthly record of 21.87″ at Bradley Airport stands alone as the wettest month on record – the second highest 16.32″ from October 2005 lags far behind.

Hurricane Connie made landfall over the Outer Banks as a minimal hurricane on August 12, 1955. The storm moved slowly up the Chesapeake Bay and dumped 5″-10″ of rain in portions of northwest Connecticut. Connie barely produced any wind in Connecticut as she passed to the west but dropped enough rain to saturate the soil and raise river levels above flood stage.

Five days after Connie, Hurricane Diane made landfall in North Carolina very close to where Connie struck. The storm moved inland and then was picked up by a strong trough diving into Michigan's Great Lakes. An exceptional band of rain setup over northwest Connecticut and western Massachusetts as the storm passed over Long Island. Having 10″-20″ of rain was common in many areas. When preceded by Connie’s 5″-10″ of rain Diane’s record 24-hour rainfall was enough to push rivers to levels that hadn’t been seen in hundreds of years.

The all-time 24-hour rain record in Connecticut occurred on August 19 in Burlington with 12.77″ falling. In Westfield, Massachusetts, an incredible 1-day total of 19.75″ fell. A close look at the 8-day rain totals from August 12, 1955 to August 20, 1955 reveal just how exceptional this flood event was.

A streamline analysis of Hurricane Diane in the August 1955 Monthly Weather Review shows a stalled out front across Connecticut between 0730 EST August 18, 1955 and 0730 EST August 19, 1955, out ahead of Diane’s circulation. For nearly 24 hours, strong convergence setup across Connecticut with deep tropical moisture advecting northward from Diane.

A preliminary report by the U.S. Weather Bureau from August 25, 1955 includes hourly rainfall totals for Bradley Field which are incredible. Here’s an excerpt from that report:

The rains in southern New England were prolonged as the storm center which was moving eastward directly along the 40º parallel for about 12 hours from 5 p.m. of the 18th to about 5 a.m. of the 19th, recurved to an east-northeast direction paralleling the southern New England coast. The hourly precipitation rates recorded at the Weather Bureay office at Bradley Field, Windsor Locks, Conn., are shown on the map. Until about 9 p.m. on the 18th, the intensities fluctuated considerably, but from then to 10 a.m. on the 19th the rate was quite constant, averaging nearly .6 inch per hour for 15 hours. The greatest amount from this record in a 24-hour period, 12.05 inches, is from 10 a.m. August 18 to 9 a.m. August 19. This compared with the previous maximum 24-hour rainfall of record at Hartford, Conn., of 6.82 inches occurring on July 13, 1897.

The 1955 floods destroyed entire neighborhoods, entire downtowns, and entire families. Waterbury, Winsted, Naugatuck, Derby, Ansonia, Farmington, New Hartford and Putnam are just some of the towns and cities that were changed forever.

With the amount of rain that fell it’s not surprising the 1955 floods set records on the Quinebaug, Farmington and Naugatuck Rivers. The Army Corps of Engineers built a monstrous system of levees and dams on those rivers to prevent a flood like the ’55 one from happening again. Barring an unforeseen catastrophic failure of the dam and levee system a flood to the level of 1955 will never happen again on those rivers.

1955 Rain Totals (From Coop Stations)

Barkhamsted – 25.06″

  • Connie – 9.11″
  • Diane – 15.95″

Burlington – 24.65″

  • Connie – 8.73″
  • Diane – 15.92″

Norfolk – 21.81″

  • Connie – 8.93″
  • Diane – 12.88″

Warren – 18.60″

  • Connie – 7.74″
  • Diane – 10.86″

Windsor Locks – 18.42″

  • Connie – 4.02″
  • Diane – 14.40″

Falls Village – 16.83″

  • Connie – 6.75″
  • Diane – 10.08″

Danbury – 14.83″

  • Connie – 8.74″
  • Diane – 6.09″

Hartford – 11.75″

  • Connie – 3.90″
  • Diane – 7.85″

Prospect – 10.96″

  • Connie – 3.41″
  • Diane – 7.55″

Middletown – 10.90″

  • Connie – 4.53″
  • Diane – 6.37″

Bridgeport – 8.34″

  • Connie – 5.32″
  • Diane – 3.02″


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<![CDATA[Friday Storms]]>Thu, 17 Aug 2017 20:57:02 -0500https://media.nbcconnecticut.com/images/213*120/Model+RPM4+Precip+Cloud+CT+no+banner.png

A complex storm will approach Connecticut Friday and there is a low risk for a severe thunderstorm tomorrow. A warm front will slowly ooze across Connecticut during the day with a risk for occasional showers and thunderstorms.

  • Any thunderstorms will be isolated - not every town gets one!
  • Several rounds of showers and storms are possible during the morning, midday, and afternoon. 
  • The atmosphere will feature low instability and high wind shear. There is a conditional threat for a rotating storm that could produce a tornado or damaging winds. 

We call these setups low CAPE/high shear. Basically there isn't a whole lot of energy for storms to form but any storms that do will have enough wind shear to work with that they can rotate. Not all rotating storms produce tornadoes - far from it in fact. But as a storm begins to rotate the odds of it producing severe weather increase.

At this point we're giving this a general "low" impact for storms as anything we get would be isolated. We'll be watching it all day for you! 


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<![CDATA[Solar Eclipse Forecast]]>Wed, 16 Aug 2017 22:26:06 -0500https://media.nbcconnecticut.com/images/213*120/170816_CTSolarEclipse_1200x675_1026149443805.jpg

We know at 2:45 p.m. on Monday, August 21 about 2/3 of the sun will be obscured by the moon. That's a forecast we can be 100% confident in! The question is, however, will we be able to see the eclipse? Will skies be clear or cloudy?

Here in Connecticut it looks like we're in good shape. The afternoon GFS computer model shows clear skies overhead on Monday afternoon. With high pressure overhead this seems like a reasonable solution. The European Ensemble (the European model run 50 different times with small tweaks and perturbations) shows extremely low chances for overcast skies in Connecticut.

Farther south in the path of totality the forecast is even more important. I'll be in Charleston, SC for the total eclipse and cloudy skies would really be a bummer. The current GFS forecast is just about perfect for South Carolina in August.

While this is probably too optimistic solar eclipses can help change the weather. As the amount of sunlight decreases the temperature starts to drop. As temperatures drop daytime cumulus clouds and showers that form in the heating of the day begin to dissipate. I'm crossing my fingers we wind up with a sunny afternoon but we'll see!


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<![CDATA[Hurricane Gert Will Lead to Dangerous Rip Currents at RI Beaches]]>Wed, 16 Aug 2017 09:42:05 -0500https://media.nbcconnecticut.com/images/213*120/LMX___R_VO_BIG_WAVES_KNSD_130606_16F76071_1200x675_991621187914.jpg

Hurricane Gert is leading to high surf advisories and strong rip currents for coastal areas of Rhode Island, Long Island, and Cape Cod. 

Buoys off the coast of Block Island measured powerful swells of 8.5 feet this morning. 

<blockquote class="twitter-tweet" data-partner="tweetdeck"><p lang="en" dir="ltr">7 foot swells with a 12 second period at the Block Island buoy now. Those are very powerful waves thanks to Gert. <a href="https://twitter.com/hashtag/nbcct?src=hash">#nbcct</a> <a href="https://t.co/xZrCeW68KQ">pic.twitter.com/xZrCeW68KQ</a></p>&mdash; Ryan Hanrahan (@ryanhanrahan) <a href="https://twitter.com/ryanhanrahan/status/897783817951432704">August 16, 2017</a></blockquotethis morning - and still rising. These large waves and strong rip currents can be seen as close by as Misquamicut State Beach in Westerly, Rhode Island.

At Blue Shutters Beach in Charlestown, Rhode Island lifeguards closed the beach to swimming around 10 a.m. as swells began to build. 

Rip currents are currents of water that flow from the beach to the surf zone and can rapidly pull a swimmer out to sea. 

If you are ever stuck in a rip current make sure to swim parrellel to the beach until you're eventually out of the current. 

A High Surf Advisory is in effect for parts of Rhode Island and Massachusetts until 8 p.m. Wednesday. 



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<![CDATA[Hurricane Gert - Where's it Going?]]>Mon, 14 Aug 2017 21:42:24 -0500https://media.nbcconnecticut.com/images/180*120/avn_lalo-animated081417.gif

Gert became the second hurricane of the 2017 Atlantic tropical season shortly before 11 p.m. on Monday. It is expected to pass well south and east of New England later this week.

While there won't be any direct impact from Gert there is the potential for powerful swells and rip currents at the ocean beaches as close as Watch Hill. 

The long period swells from Gert will move north from the storm and impact Rhode Island beaches as early as Tuesday night. Peak swell of nearly 6 feet will arrive on Wednesday. While waves of this height aren't unusual when a hurricane passes offshore Wednesday is likely to be a very busy beach day and dangerous rip currents will be widespread. This is great news for surfers but swimmers will have to be very careful on Wednesday.

Beyond Gert the tropics look like they will remain very active. A combination of factors will favor development of tropical storms and hurricanes in the Atlantic Ocean through the next 10 days. This plot from Mike Ventrice of The Weather Company shows the likely track of the next disturbance churning off the coast of Africa. This storm would have the potential to impact the Caribbean and maybe eventually the United States. It's name will likely be Henry. 


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<![CDATA[Solar Eclipse 2017 and What to Expect in Connecticut]]>Mon, 21 Aug 2017 14:27:47 -0500https://media.nbcconnecticut.com/images/213*120/eclipse+lunar.jpg

On Monday, August 21 a rare total solar eclipse will be visible from coast to coast in the United States for the first time in 99 years. In fact, the total solar eclipse will be the first in the continental United States since 1979!

Here in Connecticut we will not be in the path of totality (you'll have to wait until 2079 for that) but there is still plenty to see!

What to Expect

The solar eclipse in Connecticut will start around 1:25 p.m. when a small sliver of the sun will be masked by the moon. By 2:45 p.m. about 2/3 of the sun will be obscured by the moon making which is the most we'll see. By 4:00 p.m. the solar eclipse will end. This is known as a partial solar eclipse and has occured in Connecticut most recently on December 25, 2000 and May 10, 1994.

The total solar eclipse will occur only in a narrow path from Oregon to South Carolina including Charleston, SC where I'll be for the event!

How to View

The only way to safely view a solar eclipse is through special glasses that block damaging radiation from your eyes. You can purchase these glasses at many stores including CVS, Best Buy, and Lowes. Be sure to only purchase glasses with an ISO label ensuring they're safe for using.

A pinhole or projection method can be used and is a nice idea for a project to do with kids. I remember making one of these in school to observe the 1994 eclipse in Guilford. 

Another option is shade 14 welding glasses - though these are likely to be sold out at many hardware stores.

Looking at the solar eclipse with sunglasses or the naked eye can lead to permanent eye damage or even blindness. While it is safe to take your glasses off during totality Connecticut is outside the path of totality.

What is an Eclipse Anyway?

Solar eclipses occur during a new moon when the moon's shadow is cast on earth. During a new moon the sun, moon, and earth are in line with each other. The reason there isn't a solar eclipse every new moon is because the moon's orbit around earth and the earth's orbit around the sun are not in the same plane. Only once in a while do these planes intersect and a solar eclipse occurs.

The moon's shadow is made up of a penumbra and a umbra. Only under the umbra is the moon's shadow complete resulting in a total eclipse (occasionally even with the umbra the moon is too far from earth resulting in an annular solar eclipse where a ring of the sun is still visible around the moon). In totality, a dramatic temperature drop (as much as 10 degrees) will accompany full darkness. From daylight to midnight in moments - a truly remarkable sight. Legendary WRC-TV meteorologist Bob Ryan described his first (Nantucket in 1970), and subsequent, solar eclipses in this wonderful Washington Post piece.

In the penumbra (where we'll be) part of the sun will be obscured by the moon and less solar radiation will make it to us than we typically see in the afternoon. A temperature drop (likely several degrees) will accompany this as we enter in a portion of the moon's shadow. 

How Common Are They?

Partial solar eclipses happen with a fair amount of regularity (2000 and 1994 being our most recent) while total solar eclipses are rare. The last total solar eclipse in Connecticut was in 1925 and the next isn't until 2079! 

If you're thinking there's no way you won't be around for the next total solar eclipse in Connecticut (check this calculator to see how old you'll be!) a total eclipse on April 8, 2024 will just miss us and plunge portions of Vermont and upstate New York into total darkness. We'll only be a tank of gas away from totality!




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<![CDATA[Another Round of Showers]]>Fri, 11 Aug 2017 06:47:36 -0500https://media.nbcconnecticut.com/images/160*120/NAMNE_prec_prec_045.png

The forecast challenge today is once again about weekend rain. At this point it appears the best chance for rain is Saturday morning - and there are some indications a period of locally heavy rain is possible. 

How much rain is a big question. Take the Short Range Ensemble Forecast model, or SREF, for instance. It shows a range from nearly 0" of rain to 3" of rain on Saturday - the bulk of which falls in the morning. The biggest clustering of ensemble members is <0.5" of rain - so it's fair to say that while heavy rain is possible it's not the most likely outcome. A lighter rain event remains the most plausible scenario.

By Saturday midday and afternoon even though the clouds stick around we should get a period of drier weather. A renewed chance for showers develops by Saturday evening as a trough of low pressure advances in from the west.

Beyond Saturday much nicer weather moves in for Sunday and Monday. There is a low risk for showers on Tuesday with a weak wave of low pressure to our south but at this point things are looking pretty good for next week. 


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<![CDATA[Weekend Storms Bring Cooler Weather]]>Thu, 03 Aug 2017 15:43:10 -0500https://media.nbcconnecticut.com/images/160*120/ECMWF_6hr1.png

Meteorologist Josh Cingranelli here guest writing for Ryan Hanrahan while he's enjoying his vacation in Italy. 

The warm air and high humidity will come to an end this weekend as a strong cold front moves through the region.

The European forecast model has the front moving through the state around 18 UTC which is equivalent to 2 p.m. 

The front will bring in showers and thunderstorms Saturday afternoon. I've been monitoring the severe weather potential over the past couple of days.

Take a look at the forecasted weather sounding for 12 UTC on Saturday for the Hartford area. 

A couple things we look at for severe weather is, CAPE (convective available potential energy) and shear. Shear is how much the wind speed and direction changes as the height from the ground into the atmosphere increases.

This sounding is displaying decent shear values but lacks CAPE. While we're still forecasting thunderstorms we don't anticipate a widespread severe weather outbreak. 

The front will bring in much drier air which will rapidly decrease humidity values. Check out the dew point values prior to the front moving in and the dew point values after the front passes. 

DEW POINT VALUES BEFORE THE FRONT:

DEW POINT VALUES AFTER THE FRONT PASSES:

In addition to the drier air, an anomalous shot of cooler air will settle in for early next week. High temperatures are forecasted to be 10 to as much as 20 degrees below normal through the middle of the week.

We expect temperatures will climb back into the low 80s by the end of next week. 


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<![CDATA[Weekend Nor'Easter - Where's it Going?]]>Thu, 27 Jul 2017 20:16:45 -0500https://media.nbcconnecticut.com/images/160*120/gfs_tprecip_ma_10.png

An unusual July nor'easter off the coast of the Mid Atlantic has all the makings of a gigantic weekend weather problem. The good news is - for now - the worst of this system is likely to miss Connecticut. 

The storm is very anomalous for the time of year. While nor'easters aren't unheard of in July and August it's tough to get a strong low to develop off the coast that isn't tropical in nature. What makes these storms dangerous is that with so much moisture in the atmosphere a tremendous amount of rain can fall in a short period of time.

The jet stream is going to take a big dip to the south of New England Saturday as a strong disturbance digs south. This unusual disturbance, coupled with warm ocean water, instability in the atmosphere, and oodles of moisture means a powerful storm for July will develop.

What has been so incredible about this storm is the amouint of rainfall modeled just to our south and the extreme gradient between a lot of rain and very little rain. The midday NAM solution shows approximately 8.4" of rain at John F. Kennedy Airport in Queens and 0.3" of rain in Hartford (most of which was forecast to fall tonight). 

All along we've been thinking that this storm is unlikely to come fully north into New England. One of the reasons why is that the amount of moisture and instability south of New England tends to tug these areas of low pressure south a bit. Large clusters of intense thunderstorms east of the DelMarVa penninsula can prevent moisture from streaming north into Connecticut and occasionally can be strong enough to force an area of low pressure to develop a bit farther than it ordinarily would. Especially this time of year that can be a big factor and why we haven't bitten on the really wet solutions in Connecticut.

That said, you always need to watch these things and unexpected changes can occur. Even with a storm that results in little rain in Connecticut clouds and strong gusty winds are a possibility. In fact, a Gale Watch has been issued for Long Island Sound with the potential for strong winds and rough seas.

The most likely scenario is a period of clouds, strong winds, and maybe a few showers over the shoreline. A jog to the north would mean stronger winds and heavier rain and a jog south would mean fewer clouds, less wind, and little or no in the way of showers.

We'll keep you posted!


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<![CDATA[Saturday Questions]]>Tue, 25 Jul 2017 19:29:14 -0500https://media.nbcconnecticut.com/images/160*120/gfs_pr6_slp_t850_nyc_16.png

To say the Thursday night through Saturday forecast is uncertain is a bit of an understatement. The forecast from yesterday is quite a bit different today. Even with that change, the spread among our different computer models remains quite large!

One way to view the uncertainty in the forecast is to use ensembles. Basically one computer model is run 20 different times with slightly different tweaks to represent a range in plausible scenarios. When all 20 show the same thing you can assume the forecast is high confidence and when all 20 are all over the place you can assume forecast confidence is low.

So what will happen? Right now we've put a chance for showers in the forecast Thursday afternoon through Friday morning with one system moving in and then a second round of showers Saturday night. If we can time everything out we'll salvage a mainly dry Friday (day) and Saturday (day). 


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<![CDATA[Solar Eclipse: What to Expect]]>Fri, 21 Jul 2017 20:34:17 -0500https://media.nbcconnecticut.com/images/240*120/usa_eclipse_map_print.jpg

One month from today the moon will pass in front of the sun resulting in an incredible display across the United States. The total solar eclipse on August 21st will be the first coast-to-coast total eclipse since 1918. 

To truly get the full experience you'll have to travel. While the sun will be approximately 70% obscured here in Connecticut totality will occur in only a narrow zone from Oregon to South Carolina. I'll be in Charleston, SC for the eclipse to experience totality and I cannot wait! If it's cloudy or rainy or otherwise overcast I will be very sad :(

The last time Connecticut experienced a total solar eclipse was January 24, 1925. The next time Connecticut will experience a total solar eclipse is May 1, 2079. They're pretty rare! The 1925 solar eclipse was viewed in totality here in Connecticut. In New York City the New York Times reported the eclipse was total above 96th street as the City was on the southern extent of the total eclipse path.

In totality the moon will complete cover the disk of the sun creating a spectacle most humans have never seen with their own eyes. The sun's atmosphere, the corona, will flash and shimmer as your surroundings plunge into darkness. The temperature drops rapidly and animals are rightfully freaked out. 

Here in Connecticut the partial eclipse will be cool to look at - but you can only do so using eye protection or some type of contraption. Read more here from NASA. I remember the May 10, 1994 partial eclipse here in Connecticut and going outside at school to watch the spectacle. 

If you can't travel to experience this total eclipse you can wait a few years and head up north. Burlington, Vermont and parts of Quebec and upstate New York will experience a total eclipse on April 8, 2024. 

Only one month to go!!


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<![CDATA[Three Tornadoes in Western New York]]>Fri, 21 Jul 2017 15:40:03 -0500https://media.nbcconnecticut.com/images/160*120/tornado+1.jpg

Three tornadoes touched down in western New York this afternoon associated with a beast of a supercell that moved onshore from Lake Erie. The storm produced an EF-2 tornado that was on the ground for 5 miles in the town of Hamburg and a second EF-1 tornado on the ground for 2.5 miles in the town of Holland.

Today, the National Weather Service confirmed a third EF-1 tornado in Allegany County that was on the ground for an additional 4.2 miles.

For most of the storm's life radar detected a large amount of lofted debris as the tornado sucked all sorts of debris up in to the clouds.

This Tornado Debris Signature (TDS) was apparent for about 25 minutes as the storm traversed Erie County, NY. Unfortunately, the radar confirmation of the tornado was not relayed by the National Weather Service in warnings, statements or even in the NWS Chatroom available to the media and emergency managers.

The complex of thunderstorms responsible of the tornado and a smattering of other damage reports in New York and Pennsylvania moved south of Connecticut tonight. Behind it, quieter weather is moving in with plenty of sunshine and warm weather for Friday. High temperatures between 90 and 94 degrees will be common across the state. 


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<![CDATA[Warming Water ]]>Wed, 19 Jul 2017 20:22:10 -0500https://media.nbcconnecticut.com/images/160*120/image107192017.JPG

A few hot days and the water in Long Island Sound has warmed quickly. The 3-day average water surface temperature from the Ocean Remote Sensing Group and Johns Hopkins Applied Physics Laboratory shows a pool of very warm water in the western 2/3 of the Sound.

25C water temperatures are common from Madison to Greenwich but, as usual, a pocket of much colder water (near 20C) exists around The Race and Fishers Island Sound. 

Here are two water temperature traces from New Haven Habor and New London Harbor showing the big disparity from the central Sound and the eastern Sound. You can see a definite diurnal trend in the water temperature in New Haven (warmest water during the evening and coolest around mid morning) while the New London water temperature shows no such trend. 

If you're wondering average water temperature peaks in New Haven during August while New London maxes out during the last 15 days of July and first 15 days of August at 75F and 72F, respectively.

The coldest water in summer on the east coast is in Eastport, Maine that peaks at a bone crushing maximum temperature of 51F.  


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<![CDATA[Another Heat Wave]]>Tue, 18 Jul 2017 19:33:28 -0500https://media.nbcconnecticut.com/images/160*120/gfs_t2maf_slp_east2_9.png

Tuesday likely marked the first day of 2017's third heat wave. The mercury reached 90F at Bradley Airport and we're expecting several additional days at or above 90. Today also was our ninth 90 degree day of 2017. 

It's a pretty classic setup with a Bermuda High allowing warmth to move in from the west as the jet stream retreats into Canada.

It doesn't look like the warmth will stick around for too much longer as another dip in the jet stream and cooler weather moved back for the weekend. At this point a round of showers and thunderstorms appears likely for a portion of the weekend ahead of our next jet stream disturbance. Stay tuned for more specifics. 


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<![CDATA[28 Years Ago - The 1989 Tornado Outbreak]]>Mon, 10 Jul 2017 12:48:40 -0500https://media.nbcconnecticut.com/images/174*120/Schohariecountyemergencymanagement1.jpg

There are only a few “classic” northeastern U.S. tornado outbreaks that jump out in your mind. The 1985 Pennsylvania outbreak is one, the 1998 Pennsylvania/New York outbreak is another, and so is the 1989 northeast outbreak. The epicenter of that outbreak was right here in Connecticut with an F4 tornado touchdown in Hamden and New Haven.

The atmosphere couldn’t have been more primed for a big tornado event. Here’s the morning weather balloon launch and sounding from Albany.

A classic elevated mixed layer with a dry adiabatic layer from 625mb through 750mb is present. What is most striking, however, is the exceptional wind shear in the atmosphere. Winds at 500mb are out of the northwest at 80 knots while in the boundary layer winds are out of the south-southeast at 10 knots! That’s about as strong as it gets.

The presence of the “EML” allowed for significant instability to develop during the heating of the day. Prior to the tornado in Connecticut temperatures reached the low and middle 80s with dew points in excess of 70F. A quick and dirty modification of that sounding for 30/22 shows just how explosively unstable the atmosphere was.

The first tornado touched down in upstate New York west of Albany and was on the ground for an incredible 42 miles. That same supercell went on to produce a series of tornadoes in Connecticut. The first tornado touched down near Route 4 in Cornwall and continued south into Bantam. The second tornado touched down in Watertown and Waterbury. The most violent of the tornadoes touched down in Hamden and continued south into New Haven.

The weather charts during the event were just incredible for a northeastern U.S. tornado outbreak with a strong disturbance moving out of southern Quebec into northern New England.

Through the day 500mb heights actually rise over southern New England with the best QG forcing displaced far to the north. Still, after the initial convective initiation in the morning those storms were able to propagate southeast into our area. The elevated mixed layer not only allowed strong instability to develop – it likely also helped keep convection relatively discrete. The atmosphere in many locations was “capped” – just enough CIN to prevent widespread convective initiation – but not capped enough to prevent all convection. The best QG forcing to the north also helped convection remain relatively scattered.

The damage in Connecticut was substantial with hundreds and hundreds of homes and businesses destroyed. Many people in the New Haven suburbs – including North Haven and North Branford were caught in the hail core of the storm with golf ball size hail or larger. Southeast of where the tornado lifted in Newhallville substantial wind damage occurred with many of the pine trees near Lake Saltonstall on the Branford/East Haven line snapped in half.

Here is some of our coverage from the 6 p.m. news on July 11, 1989.

There were other tornadoes that day – some in northern Massachusetts, others just west of Danbury in Putnam County, and another swarm in northern New Jersey. If we were able to look at radar data (which sadly, we cannot) we’d probably see a line of supercells across the region.

On a personal note, the 1989 tornado event is my first weather memory as a kid. At the time I was living in Branford but on vacation with my family on Cape Cod. When I heard about the tornado back home I was devastated! I couldn’t believe that I missed “the big one” back home. I guess I’ve been a weather weenie for 25 full years now!



Photo Credit: Schoharie County Emergency Management
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<![CDATA[Friday Soaker?]]>Wed, 05 Jul 2017 18:42:07 -0500https://media.nbcconnecticut.com/images/160*120/hires_ref_nyc_43.png

Some of the pieces are coming together for a Friday morning soaker though it is by no means a certainty. A small area of low pressure called a mesolow is going to scoot toward Connecticut but it's track is still not clear. Virtually all of our computer models show this feature to various degrees around daybreak but a few miles will make a big difference between a soaker and a few showers. 

These things are fickle. Unlike a large winter nor'easter these lows are very small, can be difficult to predict, and can form with little advance notice as they're primarily driven by complex interactions with thunderstorms. For example, the mesolow could easily form 200 miles farther south in an area of deeper convection over the Gulf Stream delivering us virtually no adverse weather.

The track of the low is critical. In a very narrow area just north of the low a substantial amount of rain is possible. Along a warm front moist air from the ocean will be forced to rise rapidly resulting in heavy precipitation (very deep warm cloud depths also increase the risk for very heavy rain). This band will likely be relatively stationary and it's the kind of setup than can produce 2"-4" of rain in a short period of time. Is it over central New Jersey or is it over New Haven? I don't know. 

In addition to heavy rain there is the potential for severe weather along and just south of the warm front. Very strong shear and modest instability in the warm sector could promote severe storms. At this point that will most likely be over the Atlantic Ocean but it's awfully close to tickling the south coast and Long Island. We like to call this a "Sunrise Surprise" with these warm fronts draped along the coast. 

Stay tuned for more on this one!


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<![CDATA[Maine's Tornado Outbreak]]>Tue, 04 Jul 2017 19:51:13 -0500https://media.nbcconnecticut.com/images/160*120/DDq9N0UXYAEgfPZ.jpg

It didn't feature a significant tornado but Saturday's tornado outbreak in Maine was exceptionally impressive with four separate touchdowns in a small area in the southwestern part of the state. While the "outbreak" wasn't particularly well forecast the National Weather Service in Gray, ME did an outstanding job issuing tornado warnings Saturday afternoon. 

The weather setup that developed Saturday afternoon was a classic one for tornadoes. A sufficient amount of low level moisture, locally strong wind shear in the lowest few thousand feet of the atmosphere, and adequate instability to allow storms to form all came together in a small area of northern New England. A warm front draped across central New Hampshire and southwestern Maine was sufficient to maintain supercells that occasionally produced tornadoes. 

This sounding off the HRRR shows an even more impressive environment than the SPC mesoanalysis pictured above indicates. High levels of instability and even higher values of low level shear may be more indicative of the actual environment here. 

The storms on radar were exceptionally impressive for Maine and New Hampshire. 7 tornado warnings were issued on July 1st which was the most the Gray, ME office has issued in an entire year!

The Maine tornadoes are a good reminder that ingredients for severe weather - including tornadoes - can quickly come together even when it seems unlikely 6 or 12 hours earlier. This event is a really good reminder of the importance of being aware of fast changing weather conditions. The folks at the NWS Gray office did a tremendous job maintaining situational awareness and getting the word out quickly. 



Photo Credit: Courtesy: Jackson Witherill
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<![CDATA[Remembering the 1995 Hail Storm]]>Tue, 20 Jun 2017 20:38:49 -0500https://media.nbcconnecticut.com/images/165*120/1995hail31.jpg

June 20, 1995 was a sultry and oppressive day. Temperatures in the 90s down to the water with dew points in the mid 70s drove heat index values above 100º. At the same time an elevated mixed layer (EML) moved overhead creating an exceptionally unstable and volatile air mass.

This weather balloon sounding from Albany shows the EML with very steep lapse rates between 650mb and 500mb. This means that the temperature above 10,000 feet was decreasing very rapidly with height (nearly 10ºC/km). With an oppressively hot and humid airmass in place the atmosphere was primed for a big explosion.

That explosion came north of the Massachusetts border when a supercell developed and began moving south.

What was remarkable about this storm was the amount of large hail it dropped during its trek through Connecticut. Baseball-sized hail was reported in 3 towns – Vernon, Manchester, and Deep River.

The relatively isolated storm (typical of EML days) continued to move due south and produced a gorgeous looking radar image. The outflow boundary of rain cooled air surged west across Hartford and Waterbury while a backdoor cold front that started near Boston around 10 a.m. finally caught up with the storm at the mouth of the Connecticut River.

The storm was the most intense over Deep River and Lyme, possibly due to the interaction with the backdoor cold front moving from east to west. Here’s an excerpt from the National Weather Service Storm Data publication.

A cold front moving across the area generated severe thunderstorms which produced large hail and gusty winds. Baseball-size hail lasted for up to 20 minutes in Deep River causing hundreds of thousands of dollars in damage. The hailstones broke hundreds of windows in buildings and automobiles, tore holes in roofs, dented siding and automobiles, and ruined gardens. Some automobiles were totaled. In one historic building, the hail broke 25 windows, including a 100-year curved window. Thirty-two windows were smashed in an elementary school and its roof was damaged. Most of the damage was covered by insurance.

Here’s a 3-D cross section of the Deep River supercell as it crossed the Connecticut River. What is remarkable is how high the hail core of this storm was.

In fact this storm had 70 dbz radar echoes up to 30,000 feet with 60dbz up to 45,000 feet! That’s just wild. Here are some memories from people on my Facebook page.


People in Deep River still remember the hail storm vividly. Arlene Macmillan sent me these pictures of the hail (and hail damage) at her house from the 1995 storm. You can see ripped off leaves, broken shutters and windows, along the piles of hail stones. Arlene recalls the largest of the stones being billiard ball size (which is 2.25″ in diameter).

I asked Arlene a few questions about what she remembered from that day: The biggest stones were the size of billiard balls.

I got my car into the garage before the hail started. My husband was around Middletown, driving home, when he saw a black cloud over Deep River. He arrived at home less than 5 minutes after hail stopped, and saw a foot high pile of leaves covering the ground. Nothing happened to his car, not even rain. We rented out another house behind ours. $3,000 in glass damage alone at both. Sorry I don’t have a picture of our house. It was sided with weathered cedar shakes and looked as though the house had been machine gunned.

While the storm had a broad mesocyclone and was rotating during its lifetime it never produced a tornado. The rotation remained broad and aloft and never came to the surface. The closest the storm came to becoming tornadic was south of Deep River in Essex and Old Saybrook when the rotation began to lower following the interaction with the backdoor cold front.

The overall setup was not conducive to tornadoes but certainly was conducive to mega-hail, particularly where the complex interaction between the supercell and a backdoor cold front was taking place over Lyme and Deep River.



Photo Credit: Arlene Macmillan / Deep River
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<![CDATA[Severe Weather Possible Monday]]>Sun, 18 Jun 2017 11:31:20 -0500https://media.nbcconnecticut.com/images/160*120/hires_ref_nyc_36.png

A round of strong thunderstorms on Monday may bring strong winds, flash flooding and even the threat of a tornado to parts of southern New England. The highest severe weather threat appears to be in western Connecticut. 

Loads of moisture coupled with the development of powerful winds (over 60 mph) several thousand feet above our heads has us concerned about the severe weather threat on Monday. This is a model sounding from the NAM model showing the potential for rotating thunderstorms given the strength of low level wind shear. The rapid increase and turning of wind with height is known as wind shear and this is a critical ingredient for tornado development. 

While only a low risk - tornadoes are possible in this kind of environment. Whether or not they form is a question and the highest threat appears as if it will set up just west of Connecticut. Any storm that starts rotating also has the potential to produce damaging straight line winds. 

The timing of storms remains a bit uncertain. The highest threat will be late afternoon and early evening as a line of thunderstorms approaches but we cannot rule out storms developing ahead of the line as early as 1 or 2 p.m. We call these discrete storms. Additionally, as the mid level winds will be out of the southwest and parallel to the front, there is the potential for very heavy rain. A flash flood threat exists in western Connecticut. 

Stay weather aware Monday! 


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<![CDATA[Rising Chance for Rain]]>Thu, 15 Jun 2017 13:05:23 -0500https://media.nbcconnecticut.com/images/160*120/hires_ref_boston_29.png

Tomorrow is looking a bit damp after an awesome 2 days of weather. The timing - and amount of rain - is quite difficult to pin down. 

Warm air will stream in tomorrow above our heads and that will force air to rise resulting in clouds and even a bit of rain. You can see this by looking at the atmosphere about 5,000 feet above our heads. A southerly wind will transport warm and moist air from the ocean northward into Connecticut resulting in clouds and a rising chance for rain.

Our models are struggling with the timing of the strongest lift. Does it come in during the morning or hold off until afternoon? It's still a bit unclear. At the very least prepare for some rain tomorrow and even a few downpours. With an onshore wind temperatures will be stuck in the 60s for most of the day.

Beyond tomorrow the news is better for the weekend. As a warm front passes Connecticut we will gradually clear things out with warmer weather and even some sunshine by Father's Day. The next round of rain with a few pockets of heavy rain and storms will approach later Monday and Monday night. 


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<![CDATA[Powerful Thunderstorms Possible Tuesday]]>Mon, 12 Jun 2017 13:26:01 -0500https://media.nbcconnecticut.com/images/160*120/mgWeb_WRF_20170612-150000_ANE_ECONUS_F00283000_PwinterThickness_R4km.png

The ingredients are in place for powerful thunderstorms in some towns tomorrow afternoon. An abundance of instability will fuel storms after 1 p.m. and the potential is there for severe thunderstorms as well.

One of the questions we have is how widespread will the storms be. The "forcing" in the atmosphere isn't overly strong and so it's unclear how many storms will be able to tap in to all the instability out there. With CAPE values exceeding 2,000 j/kg due in part to steep mid level lapse rates (rapid temperature drop with height 10-20,000 feet above our head) some storms may really take off.

Instability is just one piece of the puzzle. What will prevent this from becoming a more significant severe weather event is the lack of wind shear. Wind shear, or winds changing speed and direction with height, is critical for storms to organize. While supercells or powerful well-organized storm clusters are unlikely I expect we'll see a number of strong "pulse" storms that strengthen and weaken quickly. Localized downbursts and hail is possible along with an unusually large amount of lightning and very heavy rain. 

One thing to note is that with the unusually steep lapse rates and a northwest flow (offshore wind) the storms will be able to make it all the way to the beaches. This is one of those rare setups that favors Stonington Borough just as much as a town in Litchfield County. 

Be prepared for some nasty storms tomorrow. We'll have you covered all day on-air and online! 



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<![CDATA[From March-Like to August-Like]]>Tue, 06 Jun 2017 21:03:00 -0500https://media.nbcconnecticut.com/images/160*120/gfs_z500a_conus_1.png

A huge pattern change is coming in the next few days and we will see about as impressive of a weather 180 as you'll ever get in New England. Today's high in Hartford was a miserable 53 degrees - making today's high the 4th coldest on record for June. 

The hideous weather pattern that we've been locked into as been due to an anomalously deep trough and upper level low that has parked itself over the northeastern United States. Unusually cold temperatures in the airmass coupled with an onshore flow off the ocean spelled disaster.

Alas, the pattern is changing in a big way. We have the potential for a 4-day heat wave beginning Sunday as an unusually warm airmass rushes in. We go from a giant trough over the northeast to a giant ridge. At least right now the wind direction appears favorable for big warmth with a general west or northwest flow over New England.

At this point we're forecasting two days in the 90s bookended by 85-90 degree heat but don't be surprised to see all these numbers go up. For the time being, even with exceptional levels of instability being modeled for Monday and Tuesday, the strong ridge of high pressure should keep us capped and hold thunderstorms at bay.


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<![CDATA[More on Wednesday's Tornado]]>Fri, 02 Jun 2017 20:54:47 -0500https://media.nbcconnecticut.com/images/160*130/Webp.net-gifmaker+%281%29.gif

Wednesday's tornado warning was the first here in Connecticut in quite some time. The storm didn't produce a tornado here but did just west of here in Dutchess County, New York. Yesterday I answered a bunch of questions on the severe event but today I wanted to take a closer look at how the tornado itself formed. 

The storm produced golf ball size hail and an EF-1 tornado near Poughkeepsie. While the environment seemed fairly hostile to tornado development one managed to form anyway and radar reveals a few possible reasons why. One possible explanation is that the tornado touched down as the a line of thunderstorms moving in from the Catskills was merging with a storm out ahead of it.

Cell mergers are funny things. Sometimes as two storms interact they both manage to weaken. Other times the merger is constructive and the storm manages to increase in intensity. The Dutchess County storm was the latter. There is a marked increase in the intensity of the storm as the merger is underway. Just speculation here but the cell merger may have been able to trigger a tornado and here are possible reasons why.

  • There wasn't much low level wind shear out ahead of the line. There was deep layer shear (meaning the storms that were 40,000 feet tall were able to spin) but for tornadoes you really want strong wind shear in the lowest 10,000 feet of the atmosphere. Not all spin is created equal! As the storm interacted with the line merging from the northwest the low level wind shear may have been locally enhanced allowing a tornado to develop in an otherwise hostile environment.
  • The storm motion for a period of time was quite deviant to the right as the merger was underway and immediately after. This can also serve to increase storm relative helicity (storm relative wind shear).
  • The increase in low level shear happened in tandem with a sizable jump in the storm's updraft.

Let's dive into the radar data. The animation at the top of this post shows the storm merger occurring. Below is the radar from Long Island valid at 6:54 p.m. where you can see a sizable velocity couplet. We have a gate-to-gate shear (or delta V) of 61 knots which is higher than most tornadoes in the northeast (the median value is 45 knots). Additionally, you can see a high spectrum width (SW) overhead which indicates turbulent and chaotic flow. SW spiked at the time of the velocity couplet passing over the tornado touchdown location and immediately diminished after the tornado lifted.

The second radar grab is also around the time of tornado and it shows a spike in differential reflectivity (or ZDR) at 12,200 feet above the ground. This indicates that big liquid water drops were being lofted above the freezing level - and this occurs for only 1 scan - right during tornadogenesis. This ZDR column is a good proxy for the storm's strength and shows a notable brief jump in updraft strength.

It stands to reason that the cell merger increased low level shear AND the increase in the updraft strength that occured simultaneious was enough to result in tornadogenesis - with more efficient vortex stretching and tilting.

Even environments that wouldn't normally support a tornado can when there are complex storm interactions going on. Radar data, in retrospect, gave us a few clues as to what was going on with the storm. 



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<![CDATA[Vicious Storms: Some Answers to Your Questions]]>Thu, 01 Jun 2017 10:09:03 -0500https://media.nbcconnecticut.com/images/160*120/060117tordutchess.jpeg

Wednesday evening's storms were powerful and created some incredible displays of clouds, lightning, and hail. Over the course of the evening we had tons of questions about the storms that were moving through so I wanted to take some time to answer some of them here. 

Why was there a tornado warning issued? Did a tornado touch down?

The tornado warning issued for Fairfield and Litchfield Counties last night because of strong rotation indicated on radar. The picture above shows a powerful rotating wall cloud near Poughkeepsie as the storm moved through. 

While there was strong rotation with the storm visible from the ground and on radar at least as of now there are no reports of a tornado touchdown. While there was very strong wind shear in the atmosphere - there wasn't a whole lot in the lowest 5 to 10,000 feet which is critical for tornado development. The National Weather Service in Albany is surveying damage in Wappinger's Falls, NY to see if a tornado did indeed touch down.


By the time the storm got into Connecticut the storm began to weaken substantially and as I said on air last night the tornado threat was diminishing over Sherman and New Milford.

Why was there so much hail? 

Last night's storms were prolific hail producers in some spots. Quarter size hail (or even a bit larger) in New Milford with many pea to dime size hail reports elsewhere. 

All thunderstorms contain a fair amount of ice in their clouds way above our heads. The more powerful the storm the larger this ice grows as the storm's updraft is able to keep these ice particles - also known as hail stones - suspended. As a piece of hail in the clouds (where it's below freezing) comes in contact with super cooled water it keeps growing and growing until gravity ultimately wins. These ice chunks then accelerate from the cloud down to the ground. 


Frequently, this hail melts on the way to the ground in Connecticut. Hot summer days can produce a 15,000 foot thick layer of warmth that's just too much for the hail to survive. What initially could have been a golf ball size chunk of hail in a cloud will be reduced to a mere pea size stone as it melts rapidly while falling through warmer and warmer air. Last night was a little different. 

The 32 degree wet bulb temperature was only about 8,500 feet above our heads. This means the hail only had a relatively short distance to fall to survive melting. The unusually cold environment allowed hail produced in the storm to make it to the ground more readily. 

Normally when we get thunderstorms it's warm and humid - but yesterday was sort of cool. What's the deal?

Thunderstorms thrive off instability. You want a really warm and humid air mass near the ground (think 95 degrees and sweltering humidity) and unusually cold air aloft. 

Obviously yesterday wasn't 95 and humid! What we did have yesterday was a really cold pocket of air about 18,000 feet up - which is our favorite place in the atmosphere to look. The temperature at this level approached -19C which is unusually cold. So cold in fact we didn't need big heat and humidity in  order to produce instability. It's a balance between the low level warm and upper level chill - as you want the biggest difference between the two. 

Those clouds were nuts! What were they?

The clouds we saw in many towns last night right around and just after sunset are known as shelf clouds. You get shelf clouds as cool thunderstorm outflow rushes away from a storm and forces air up on the leading edge of a storm. These shelf clouds can be beautiful - but can also be a signature that's associated with damaging winds. Thankfully, the winds in Connecticut remained below severe limits and we didn't receive any reports of wind damage.

Thank you!

On another note - a big thank you to our viewers for sending in pictures and reports all night. We really appreciate the help in these storms. You can view some of those pictures here.



Photo Credit: Emergency Response Volunteer Ryan Michaels, Dutchess County
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<![CDATA[Strong Storms Move Through Connecticut]]>Thu, 01 Jun 2017 07:53:18 -0500https://media.nbcconnecticut.com/images/213*120/massive+bristol+storm+cloud.jpg

11:45 PM UPDATE

Thunderstorms are weakening across the state and though thunder, lightning, and downpours will continue until 1:30 a.m. in some areas the threat for damaging thunderstorms has passed.

The National Weather Service reports significant damage about 15 miles west of Connecticut in the town of Wappingers Falls, New York from the storm that prompted the tornado warning. An emergency manager reports a house partially collapsed and a number of trees were snapped in town. 

9:07 PM UPDATE

The thunderstorms have weakened drastically since the last update. Scattered thunderstorms and heavy rain showers continue to move east. Here's the latest timing of the showers and storms. They're moving into Windham and New London counties.


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8:29 PM UPDATE

We're continuing to track a line of strong to severe thunderstorms move east across Connecticut. We have had reports of quarter sized hail in New Milford. These storms have a history of heavy rain, strong winds, and small hail.

Here's a look at the latest track:


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7:56 PM UPDATE

Severe Thunderstorm Warnings continue for parts of Connecticut. Here's the latest track. These storms have a history of damaging winds, hail, heavy rain, and frequent lightning. 


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7:45 PM UPDATE

The tornado warning for northern Fairfield and southern Litchfield county has expired. Severe Thunderstorm Warnings Continue for Northern Tolland, Hartford, Litchfield, and Fairfield counties. 

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7:41 PM UPDATE

Tornado Warnings and Severe Thunderstorm Warnings are still in effect. 


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7:36 PM UPDATE

A Tornado Warning has been issued for Litchfield and Fairfield counties.

Severe Thunderstorm Warnings have been issued for Tolland, Hartford and Litchfield counties.

The National Weather Service in Albany has issued a Tornado Warning for Southwestern Litchfield County in northern Connecticut and Southeastern Dutchess County in east central New York.

At 7:14 PM, a severe thunderstorm capable of producing a tornado was located near Hopewell Junction, or 7 miles northwest of Pawling, moving southeast at 25 mph.

HAZARD: Tornado and half dollar size hail.

SOURCE: Radar indicated rotation.

IMPACT: Flying debris will be dangerous to those caught without shelter. Mobile homes will be damaged or destroyed. Damage to roofs, windows, and vehicles will occur. Tree damage is likely.

This dangerous storm will be near Wingdale around 7:30 PM, Pawling around 7:35 PM and Gaylordsville around 7:40 PM EDT.

Other locations impacted by this tornadic thunderstorm include Stormville, Baker Corner, Beekman, South Dover, Hoxie Corner, Candlewood Trails, Clove Valley, Lower Merryall, Poughquag and Billings.

PRECAUTIONARY/PREPAREDNESS ACTIONS:

Move to a basement or an interior room on the lowest

floor of a sturdy building. Avoid windows. If you are outdoors, in a

mobile home, or in a vehicle, move to the closest substantial shelter

and protect yourself from flying debris.

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7:17 PM UPDATE

A Tornado Warning has been issued for Litchfield and Fairfield counties.

Severe Thunderstorm Warnings have been issued for Tolland, Hartford and Litchfield counties. 

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6:13 PM UPDATE

Storms are beginning to intensify just to our west through the Hudson River Valley. A Severe Thunderstorm Warning has been issued for Columbia, Dutchess, and Ulster county in New York. 

These storms are tracking east and we're expecting them to arrive on the CT/NY border around 6:50 p.m. 


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5:10 PM UPDATE

The strongest storms continue to track to the north and west of Connecticut. We're still expecting storms to arrive in western Connecticut around 6 or 7 this evening. 

The sun is shining over a good portion of Connecticut. This is allowing for the atmosphere to become even more unstable over the state.


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4:42 PM UPDATE

Storms are still on track to move into Connecticut at or after 6 p.m. A storm currently moving through the Capital region of New York is a great indication of how strong the storms can become and how unstable the atmosphere is. 

This storm moving across I-87 and through Albany is producing 60 mph wind gusts and golf ball sized hail. 


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3:14 PM UPDATE

We're monitoring a cluster of storms moving towards Interstate 81 in eastern Pennsylvania. These storms will likely intensify over the next few hours prior to arriving in Connecticut.

We're still looking at thunderstorms to arrive in western Connecticut around 6 p.m.


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2:16 PM UPDATE

We're continuing to monitor the severe thunderstorm threat. Storms are beginning to develop across portions of Central Pennsylvania and Upstate New York. We're forecasting the storms to move into Connecticut between 5 and 6 p.m. 

A Severe Thunderstorm Watch has been issued for Litchfield and Hartford counties. This is where the severe weather threat is the highest. This doesn't mean that other parts of Connecticut can't or won't experience severe weather it just means the threat isn't as high.


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A severe thunderstorm watch has been issued until 9 p.m. for Hartford and Litchfield counties and NBC Connecticut meteorologists have issued a First Alert for potentially strong to severe thunderstorms Wednesday evening.


Storms will begin to move into western Connecticut around 6 p.m.

Some of the storm have the potential to become strong to even severe. Strong and severe storms have the capability of producing damaging winds and hail. The storms will also produce a fair amount of lightning.


Make sure to stay with the NBC Connecticut First Alert Weather Team for continuing updates on this thunderstorm threat.



Photo Credit: Gale Waldron Caruso
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<![CDATA[Wednesday Severe Weather Threat]]>Tue, 30 May 2017 19:48:10 -0500https://media.nbcconnecticut.com/images/213*120/DBHWeynU0AEdoxp.jpg

Severe thunderstorms remain possible Wednesday evening across parts of Connecticut. Of course, as is almost always the case with severe thunderstorms, there are some questions that remain.

My biggest question is how much sunshine we'll see tomorrow afternoon across the state. The more sunshine the warmer temperatures will get and the more instability that will develop. As I mentioned yesterday temperatures about 20,000 feet above our heads get quite cold tomorrow evening - the question that remains is how warm and moist it will be near the surface. The warmer and moister near the ground - and the colder aloft - the stronger the instability. Instability is essential to thunderstorms.

One way to visualize the amount of instability in the atmosphere is looking at something called CAPE or Convective Available Potential Energy. Basically, the more CAPE the faster parcels of air can accelerate up. The faster that acceleration the more powerful a storm. Above is a plume diagram showing 21 different projections of CAPE from our Short Range Ensemble Forecast. If the higher CAPE values verify (which would happen with more sunshine and warmer temperatures) the bigger the storm threat we would see.

Instability is just one ingredient for a storm. Wind shear, or how winds change speed and direction with height, is another ingredient that's critical for storms. There's a boatload of wind shear around tomorrow which would allow storms to organize rapidly with a wind and hail threat as long as there's adequate instability

There is a greater than normal risk for large hail in Connecticut tomorrow given the relatively low freezing levels which will prevent hail stones from melting too much on their way down to the ground. 

A few scattered storms are possible as early as 4 p.m. in the hill towns tomorrow but more widespread activity should hold off under around and after 7 p.m. Even though the best chance of storms is across the interior - strong storms are possible across the shoreline as well.


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<![CDATA[Strong Thunderstorm Threat Wednesday]]>Tue, 30 May 2017 06:36:49 -0500https://media.nbcconnecticut.com/images/213*120/Model-RPM4-Precip-Cloud-CT3.jpg

In order to get severe thunderstorms you generally need two things - instability in the atmosphere and strong wind shear. Where the two are juxtaposed there's the potential for severe thunderstorms as long as there's a mechanism for the storms to form in the first place.

Wednesday appears to be one of those times where the ingredients may overlap for a period of time. The winds near the ground will be light out of the south while the winds a couple miles above our heads will be out of the west at more than 60 mph. When winds change speed and direction with height you have wind shear. In this case we have 40 to 50 knots of wind shear between 0 and 6km up which is a sizable amount.

We also have a triggering mechanism moving into southern New England to fire storms in the first place. A cold front and upper level disturbance will swing in from the Great Lakes on Wednesday which should be enough to get showers and thunderstorms going by early afternoon to our northwest.

The question that remains, however, is how much instability will be in place. It's important to figure out how buoyant - or unstable - the atmosphere is. Generally when the air is unusually cold overhead and unusually warm and moist below you have a unstable airmass. The stronger the instability the faster air can accelerate upward resulting in strong updrafts and thunderstorms. 

We have a cold pool of air that will be moving in aloft but it's unclear how warm and moist the low levels of the atmosphere will be. This graph from the Short Range Ensemble or SREF (see below) shows a large spread in possible instability values. CAPE (Convective Available Potential Energy) ranges from several hundred j/kg to nearly 1500 j/kg. If the higher amounts of CAPE verify we could very well see some big storms Wednesday evening. If it's on the lower side of things the storms will likely struggle to maintain themselves.

Given the unusually cold mid level temperatures and strong wind shear - if the instability cooperates damaging winds and large hail would be a threat. It's still early but this is something I'm watching closely. At this point we have a threat for strong/severe thunderstorms in the forecast after 4 p.m. on Wednesday. How widepread or significant the threat is remains to be seen. 


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<![CDATA[The King Tide is Back]]>Thu, 25 May 2017 12:22:33 -0500https://media.nbcconnecticut.com/images/213*120/18671655_1573861059314185_5674995177705546099_o.jpg

You may not know this but today's high tide on Long Island Sound is the highest high tide of the entire year! The moon is new (sun-earth-moon all in line) and the moon's orbit is at perigee (closest pass of the moon to earth) which makes the gravitational pull of the sun and moon on earth the strongest. The stronger that pull the higher the tides.

When the moon is at first quarter or third quarter the sun and moon are at 90 degrees. This results in lower high tides and higher low tides as the gravitational pull of the sun and earth are not working in tandem -  we call this a neap tide.

This is a graph of the high tides in New Haven from January 1 to December 31, 2017. You can see a few of them spike up - corresponding to new and full moons every month. The biggest spike is tonight at 11:45 p.m. when the astronomical tide will be 7.97 feet MLLW. Most tides are closer to 6.5 feet MLLW. 

These tide predictions are assuming there's no contribution from anything meteorological. No heavy rain flowing into rivers and streams and emptying into the Sound and no strong wind piling water into Long Island Sound. Of course there's always some impact on tides from the weather. During Hurricane Sandy Long Island Sound was nearly 10 feet above astronomical tide level due to the wind. We call that storm surge.

Thankfully the storm we're dealing with today isn't much of a storm. Winds will diminish by high tide tonight and water levels will only flood the the typically vulnerable low-lying spots right along the Sound.


Flooding from King Tides is becoming more and more common these days thanks the sea level rise. What is known as "sunny day" flooding has increased substantially over the last 10 years as ocean levels climb due to melting ice and warmer oceans. The latest research indicates more than 50% of nuisance flood days can be attributed to human caused sea level rise in New London. When these king tides occur during a storm serious coastal flooding can be the result - and with rising ocean levels more serious coastal flooding is something we will have to learn to live with.


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<![CDATA[An Unsettled Week]]>Tue, 23 May 2017 12:28:43 -0500https://media.nbcconnecticut.com/images/160*120/gfs_z500_norm_conus_7.png

The weather pattern isn't great and it's a bear to forecast. The biggest item of interest on the weather map is an exceptionally deep and strong upper level low hanging out over the Deep South. This low is going to strengthen even more over the next 24 hours and will directly influence our weather.

For starters, let's talk about how unusually strong this low is for the time of year. The midday GFS computer model (above) shows 500mb heights of -5.7 standard deviations from normal over Mississippi tomorrow afternoon. Think of about as far to the left on the bell curve as you can get. You can think of how high a certain pressure level is above our heads as a proxy for how strong the low is.

Today's high clouds are a sign something is up in the atmosphere. Moisture is streaming in way above our heads associated with the big low to our south. Lots of cirrus clouds all around!


With this low to our southwest we are watching a little wave of energy that will eject northeast toward New England later tonight and tomorrow morning. Yesterday, virtually all of our computer models (with the exception of the RPM) didn't do much with this wave. Today, all of our models are trending much more impressive with the wave producing a period of clouds and rain late tonight and tomorrow morning. Figuring out the strength, timing, and track of these ejecting waves is never easy. The SREF precipitation forecast shows virtually all of the ensemble members (21 out of 21) producing rain Wednesday morning prior to noon. The midday GFS model has also jumped above the rain train and this morning we updated our forecast to include more widespread morning rain. Given ample moisture and a stronger piece of energy moving in tomorrow morning rain is a prudent forecast.

Beyond tomorrow's wet morning we'll have more rain to contend with Thursday and Friday as the entire low wobbles northeast. Rain and thunder appears likely for the end of the workweek. Hey, at least the drought is over. 


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<![CDATA[Record Warmth and Some Storms]]>Fri, 19 May 2017 13:13:24 -0500https://media.nbcconnecticut.com/images/160*120/18556894_1985536368399353_2752888253459198901_o.jpg

It's not the earliest heat wave on record but it was pretty darn impressive. 94, 96, and 91 (at least) over the last 3 days makes this the first heat wave of 2017. The earliest heat wave on record occured back in 2002 when the mercury exceeded 90F for three consecutive days April 16-18.

With record warmth we managed a few loud storms last night. While the storms remained sub-severe with limited, if any, damage reports in the state they did wake many people up!

Many storms around here tend to weaken after the sun goes down. As the sun sets the atmosphere cools and instability wanes. Thunderstorms need an unstable atmosphere to form! Last night was different in that several clusters of storms actually strengthened around midnight. We actually expected this to happen as there were a few ingredients in place that were a bit unusual. The biggest was the unususally steep mid level lapse rates.

Lapse rates are easy to understand. It's simply the temperature difference between two levels of the atmosphere. We express lapse rates in degrees per kilometer - so the larger the value (or steeper the lapse rate) - the faster temperature decreases with height. This helps promote instability in the atmosphere. Last night the lapse rates were steep (in excess of 7C/km) and there was a surge in moisture a few thousand feet up after dark. The combination of increasing moisture underneath the steep mid level lapse rates helped fueld storms that lasted well into the night. 


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<![CDATA[Weekend Nor'Easter Update]]>Thu, 11 May 2017 08:25:14 -0500https://media.nbcconnecticut.com/images/160*120/gfs_pr6_slp_t850_ma_13.png

The Mother's Day nor'easter is on track and we're getting more confident in some of the specifics. Yesterday on this blog I posed a couple of questions of things we still didn't know the answers to and now we can start answering them with some confidence. 

The first issue was how early will the rain begin on Saturday? We're thinking 10 a.m. to 2 p.m. for a start time across the state - and many areas on the I-91 corridor and points east will be dry until at least noon or 1 p.m. If you have stuff you need to do outside there should be a window Saturday morning where things are dry. If we're lucky we may be able to push the start off by a couple hours still! 

As for rainfall totals our 1"-2" forecast still looks good - but I do think some areas could pick up 3"+ of rain. Localized bands of heavier precipitation are a good bet. One thing that jumps out at me is the "M-Climate" or "model climate" off the GFS being maxed out. Basically, the GFS model is re-run for the last 30 years and compared to the current forecast to computer M-Climate. The amount of rain being produced in a 12-hour period Saturday night on the most recent GFS run is greater than any of those 30-years of reforecasts for this time of year! That's a good signal for locally heavy rain and possibly flooding.

As for Sunday - the forecast is still a tough one. The heavy rain will end around daybreak and we should see some light rain lingering during the morning. I do think there will be a bit of a break late morning/midday - the sun may even come out! That said, showers will likely redevelop during the afternoon as a powerful upper level disturbance swings through southern New England. 


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<![CDATA[Weekend Soaker]]>Wed, 10 May 2017 20:42:33 -0500https://media.nbcconnecticut.com/images/160*120/gfs_tprecip_neng_18.png

There's a few questions we're still trying to answer regarding this weekend's nor'easter. We're quite confident in 1"-2" of rain across the state with the heaviest falling Saturday evening and night. There are a few other details we need to work on. 

1) Will we wind up seeing more than 2" of rain? Some of our computer models (namely the GFS) have been showing extremely heavy rainfall totals - some runs have had in excess of 4"! The GFS ensemble mean is between 1.5" and 2.0" and the Euro Ensemble mean is between 1.0" and 1.5" across the state. With very strong convergence, a powerful upper level jet streak and closing off low, along with an anomalous surge of moisture the ingredients are there for localized totals over 2". 

2) When does the rain begin on Saturday? Will the storm slow down just a bit on Saturday and give us a dry morning and midday? That's a possibility and could salvage people's early Saturday plans. 

3) After the rain winds down Sunday morning (it may end as early as 8 or 9 a.m.) will we see a second round of rain in the afternoon? The GFS keeps us dry while the Euro brings in a second and powerful upper level disturbance in the afternoon. If the latter solution verified a period of heavy rain and even some thunder could redevelop Sunday afternoon. I really don't have a good sense of what is going to happen here later Sunday so stay tuned for more on that. 


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<![CDATA[May Snow]]>Mon, 08 May 2017 20:56:59 -0500https://media.nbcconnecticut.com/images/213*120/18359039_1556683611031930_52906596634272983_o.jpg

People in Litchfield County woke up to a bit of a surprise this morning - snow was falling at a steady clip! The official observer in Norfolk, Russell Russ, told me the snow was mixed with rain this morning from 8:00-9:00 and then at 9 a good burst of heavy snow occured. No accumulation occurred. 

This snow was nothing like what occured 40 years ago in Connecticut. The infamous May 1977 snowstorm dropped an incredible 20" of snow in Norfolk and 1.3" at Bradley International Airport. Still, in Norfolk a trace of snow has been recorded 85 times since 1943 and there have been 16 instances of measureable snow. 

The storm was a ferocious nor'easter that was almost as unsual as the October 3, 1987 storm or October 30, 2011 storm with widespread tree and power line damage due to the large number of leaves on the trees. 


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<![CDATA[Unusual Wind Storm Clobbers Vermont, New York]]>Sat, 06 May 2017 07:45:03 -0500https://media.nbcconnecticut.com/images/160*120/18199542_1667501939934485_8450409264263574595_n.jpg

An unusual "gravity wave" induced wind storm produced wind gusts of hurricane force in parts of western Vermont and eastern New York Friday afternoon. The unusual wind storm occurred suddenly in the late afternoon and appears to be driven by what is known as a gravity wave.

A gravity wave is a wave (think just like the ocean) that occurs in a stable atmosphere. This vertical wave pushes the air up and down just like a ripple in a pond after you toss a rock into it. We can see this perturbation in the atmosphere by looking at the surface pressure on a barometer. These two pressure traces from Williamstown, MA and Stockbridge, MA in the Berkshires show a sharp drop and rise in the atmospheric pressure just after 4:00 p.m. This happened as the gravity wave moved over Massachusetts - the ripple overhead in the atmosphere produced a quick drop and rise in the pressure. 

North of the Berkshires - on the west side of the Green Mountains - the gravity wave was more than just a curiosity. A ferocious period of winds developed as the gravity wave moved overhead with gusts up to 74 mph in the town of Wells, VT and substantial tree damage in the cities of Rutland and Bennington, VT. 

East of Albany in the town of Brunswick, NY you can see a big pressure drop (~7mb in an hour) along with a sudden surge of winds up to 65 mph. 

The gravity wave appears to have been of a substantial enough amplitude to bring down very strong winds from aloft. The winds from 5,000 feet in the atmosphere were about 75 mph and appear to have mixed right down to the ground as this vertical wave resulted in one hell of an atmospheric ripple. The terrain absolutely played a part in this - as all of the powerful winds occurred just west of the Green Mountains (Killington, near Rutland, is ~4200 feet) and another band of strong winds occured just west of the Taconic Mountains in eastern New York. 

What triggered the gravity wave isn't clear either. Gravity waves are not uncommon - we see small ones all the time during storms but hravity waves that produce a 9mb pressure drop in an hour are very unusual and can produce really nasty winds. 


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<![CDATA[Friday Soaker]]>Wed, 03 May 2017 19:26:08 -0500https://media.nbcconnecticut.com/images/160*120/gfs_pwat_conus2_9.png

A surge of tropical moisture and a deep low pressure to our west is going to bring a soaking rain into Connecticut on Friday. While the rain is expected to be heavy for a period of time we may be looking at a smidge less than we were thinking a day or two ago. 

Most of our computer models show a general 1"-2" rainfall across the state - including our high resolution models like the NAM. 

One strong signal for heavy rain is mean values of ~2" in southern Connecticut showing up on the Euro Ensembles. More than 50% of Euro Ensemble members drop over 2" of rain in the New Haven area - that's a big signal! 

At this point it appears there's a minor threat for flooding Friday afternoon. Strong lift, a good moisture plume, and even a bit of elevated instability should be enough for embedded thunderstorms and locally heavy rain. The storm is moving fast enough - and our models have cut back on precipitation totals over the last 24 hours - that we're not expecting widespread or significant flooding.

This is just another storm putting a dent in the multi-year drought we've been dealing with. It appears our fortunes have turned and we're seeing big improvement in virtually every drought indicator. 


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<![CDATA[Cut-Off Low Woes]]>Mon, 01 May 2017 19:25:26 -0500https://media.nbcconnecticut.com/images/160*120/eps_z500a_noram_29.png

A dreaded cut-off low is going to pay Connecticut a visit this weekend and early next week. The result will be days and days of gloom. Cut-off lows get their name because they effectively become "cut-off" from the jet stream and they can stall out and linger for days on end. 

The pattern is a classic one for something like this to form. A dramatic block over Greenland will help force a large dip in the jet stream over New England. What doe it mean for us? An extended period of clouds, chilly temperatures, rain, and possibly even thundersytorms and small hail. 

It's tough to time out which days will be coldest or wettest or stomiest but things are not looking great for those who want sunshine. In June or July these cut-off lows are notorious for producing localized areas of excessive rainfall and even severe weather but in early May the impacts should be a bit more muted - though some heavy rain and strong thunderstorms are certainly a possibility.

Unfortunately, even after the cut-off low weakens its grip on us the day 11-day 15 period isn't looking so hot (literally) either with a cooler than normal regime over the northeastern U.S. 



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<![CDATA[Morning Thunderstorm Threat]]>Fri, 28 Apr 2017 14:58:30 -0500https://media.nbcconnecticut.com/images/213*120/Model+RPM4+Precip+Cloud+Temp+CT_042817.png

With warmer air making it feel a bit like summer - we may have to deal with a few thunderstorms Saturday morning across the state. A nose of unstable air will push north in southern New England around daybreak and this may be enough to fire a cluster of strong thunderstorms in the morning.


Many of our high resolution models show a round of thunderstorms tomorrow morning and that's not surprising given the brief instability spike. The NCAR ensemble has strong odds of CAPE exceeding 1000 j/kg across Connecticut tomorrow morning which should be enough for storms.


One thing to watch is there is a fair amount of effective shear for these elevated storms tomorrow morning. While strong winds are quite likely (a shallow layer of cooler and stable air near the ground should preclude damaging wind) the combination of CAPE and shear may allow some vigorous updrafts to develop resulting in heavy rain, lightning, and even small hail.These daybreak storms aren't uncommon in these setups. Once in a while they can produce severe weather but this doesn't seem like one of those times.


As the storms move east a westerly wind develops which should allow very warm temperatures even to the beaches. Enjoy it! 


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<![CDATA[Weekend Forecast Becomes More Clear]]>Wed, 26 Apr 2017 12:05:54 -0500https://media.nbcconnecticut.com/images/160*120/gfs_t2maf_slp_ma_13.png

Warmer temperatures and some sunshine by Friday and Saturday - I can't wait! The forecast is becoming more clear as we get a nice consensus on our computer models.

There is one interesting piece of the forecast Saturday afternoon and evening showing up on some of our computer models. Both the GFS and NAM show a surge in instability late in the day Saturday which would introduce a risk for thunderstorms - and maybe even a severe thunderstorm. One thing we look at is mid level lapse rates - basically how quickly temperatures decrease with height about 15,000 feet up. The faster temperatures drop the more unstable the atmosphere is. These steep lapse rates are a hallmark of many of our high end severe weather events.

That said, there are lots of questions here including how much moisture we'll have in the low levels of the atmosphere and whether we'll have enough forcing to generate storms in the first place. These are open questions but given the instability surge modeled on some of our models this is worth watching.

As for temperatures - upper 70s and low 80s seem to be a good bet Friday and Saturday. The Short Range Ensemble Forecast (SREF) above shows good agreement for both days with a gradual warming trend. There still some uncertainty, however, as to what will happen on Sunday. Winds will become onshore which should result in a drop in temperatures. How cool and how much cloud cover we see is still a bit up in the air - stay tuned.


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<![CDATA[Rain Continues This Evening]]>Tue, 25 Apr 2017 19:24:41 -0500https://media.nbcconnecticut.com/images/160*120/CODNEXLAB-2km-VA_WV-ir-ani24-201704252307-100-100-raw.gif

A sprawling cut-off low off the Carolinas is drifting north and will produce locally heavy rain in Connecticut later tonight. These cut-off lows can produce all sorts of problems (like the flash flooding in North and South Carolina over the past few days) but this one is weakening rapidly. 

If nothing else tonight's rain will be a welcome drought-denter. We're not talking about enough rain to cause flooding (a big puddle under a railroad bridge doesn't count) but we are talking about enough to fill up streams, rivers, and even reservoirs some. Another drop in a bucket that needed a whole lot of filling after 2 years of below normal rain. 

So far rainfall amounts have been below 1/2 inch but there are some signals that things will pick up. For one, colder cloud tops (indicative of higher clouds and even some thunderstorms) are developing off the coast of Delaware and streaming north. 

Our computer models show a surge in instability (CAPE) tonight which is a good sign for heavy rain. Convective Available Potential Energy is an acronym you'll hear a lot in the warm season and it tells us how unstable the atmosphere is. Our models show modest instability developing across southern New England after 10 p.m. this evening which should favor some more vigorous updrats leading to some thunderstorms and downpours. 

Where thunderstorms develop (especially if they linger over the same towns) we have the potential to see 1"-2" of rain in a relatively short period of time tonight. Right around midnight some towns will see one heck of a downpour. I don't think an additional 1.5" or 2.0" will be widespread but some areas will get a very good drink of water tonight. The NAM model shows localized pockets of 2" of rain which is reasonable tonight in a few towns given the large amount of moisture and the instability that develops. 

Beyond tonight things gradually improve over the next 36 hours. By Friday temperatures near 80 degrees will be common inland!


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<![CDATA[From Rain to Warmth]]>Mon, 24 Apr 2017 12:11:55 -0500https://media.nbcconnecticut.com/images/160*120/gfs_tprecip_ma_11.png

Another drought-denting rain is on the way Tuesday and Wednesday. Another inch of rain will put another small dent in the drought that was about 2 years in the making. 

Rain will begin Tuesday morning and continue off and on through Wednesday. The setup is fairly common this kind of year with a big cut-off low off the southeastern U.S. drifting up the coast. This is the kind of setup that can deliver flooding rains to Connecticut in April BUT this system is weakening dramatically. Still, a period of locally heavy rain is a possibility in some towns later Tuesday and Tuesday night.

Even though the low weakens as it moves up the coast there's quite a bit of moisture that will move in. The graphic above is what's called "precipitable water" (PWAT) and it's a good way of looking at how much moisture exists throughout the atmosphere. What we've done here is compare the PWAT values for Tuesday night to what's typical for late April - values are ~200% of normal so that indicates there's a lot more moisture in the air than there typically is this time of year. This shouldn't come as much surprise, though, when you see where the air is coming from. A long fetch of southerly winds is transporting moisture from the Caribbean and southern Atlantic Ocean right into New England. 

It appears as though the peak of the rain will be Tuesday night. The low level jet stream (about 5,000 feet above our heads) will peak Tuesday evening and night and that is when there's a maximum in low level convergence and moisture transport. That's when we'll get the wettest.

How much rain are we looking at? Most of our computer models have between 0.5" and 1.5" across that state and that looks reasonable. This will not be enough for flooding. With a low that's weakening (and, as a result, modest amounts of lift in the atmophere) it will be tough to see truly excessive precipitation even with an unusually high amount of moisture. I should note, however, that some of our short range ensemble members (see graph above) do show over 2" of rain. While unlikely, this would be a possibility especially if thunderstorms develop.

We're still on track for an extended period of warm weather later this week through early next week. At least one or two days near 80F seems likely. 


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<![CDATA[A Warm Start to Summer?]]>Thu, 20 Apr 2017 11:42:07 -0500https://media.nbcconnecticut.com/images/215*120/off01_temp042017.gif

Today the National Weather Service released their 3-month forecast for May, June, and July. It's a scorcher for the east coast. The June-July-August forecast is just as warm for New England.

The NWS is predicting a better than 50% chance of warmer than normal conditions for all of New England south through Florida. Most of the United States with the exception of the northern Rockies and northern Plains is also expected to experience a hot summer. 

Here in Connecticut a greater than 50% chance of a hot summer means there's less than a 50% chance of either "normal" or "below normal temperatures this summer. "Warmer than normal" is defined as the 10 warmest in the last 30 years while "colder than normal" would be 10 coldest in the last 30 years, etc.  

This forecast isn't a huge surprise given how warm our recent summers have been and continued warming due to climate change. 

Of course things can change. While these kinds of outlooks show skill (compared to say rolling a die or shaking a magic 8 ball) they're not always correct. Even saying there's <50% chance of a normal or below normal summer doesn't preclude that from happening. We shall see! 

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<![CDATA[Subtropical Depression 1]]>Wed, 19 Apr 2017 18:43:47 -0500https://media.nbcconnecticut.com/images/180*120/avn_lalo-animated041917.gif

Unless you're a weather geek you probably haven't heard about the subtropical depression that formed in the Atlantic Ocean today. It didn't make it in any of my weather segments today as it sure didn't pass the, "who the heck cares" test. 

A subtropical depression is like a hybrid tropical-non tropical storm. Our nor'easters in the winter are non-tropical low pressures. Hurricanes like Gloria, Carol, 1938, and Bob are tropical lows. But like so much in meteorology it's really not cut and dry and there's a continuum or spectrum of lows - fully tropical, fully non-tropical, and somewhere inbetween. This is a somewhere inbetween storm. The biggest difference between tropical and non-tropical storms is where they derive their energy with the former gaining energy from warm ocean waters and the latter from processes including fronts, jet stream disturbances, and other such things.

Here's an official definitition of a subtropical system from the National Hurricane Center:

Subtropical Cyclone:

A non-frontal low-pressure system that has characteristics of both tropical and extratropical cyclones. Like tropical cyclones, they are non-frontal, synoptic-scale cyclones that originate over tropical or subtropical waters, and have a closed surface wind circulation about a well-defined center. In addition, they have organized moderate to deep convection, but lack a central dense overcast. Unlike tropical cyclones, subtropical cyclones derive a significant proportion of their energy from baroclinic sources, and are generally cold-core in the upper troposphere, often being associated with an upper-level low or trough. In comparison to tropical cyclones, these systems generally have a radius of maximum winds occurring relatively far from the center (usually greater than 60 n mi), and generally have a less symmetric wind field and distribution of convection.

If Subtropical Depression #1 manages to strengthen a bit more it will even get a name - Arlene! It's a nice looking swirl 830 miles west of the Azores that's no threat to land and expected to dissipate shortly. Besides the fish this thing is impacting no one. 

As usual, there was a bit of complaining this morning on weather twitter about whether this system should have been declared, whether it would have been declared one in the past, and whether this whole thing is a waste of time. I fall on the side of sure - let's call it what it is a "subtropical depression" and even name it if it strengthens. But that doesn't mean it's worth spending time talking about - it's nothing more than a swirl of clouds in the middle of nowhere that manages to get a fancy web page and graphics built for it because the National Hurricane Center called it something. 

So now you know what a subtropical depression is whether you've been curious or not. 


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<![CDATA[Turning Cooler]]>Tue, 18 Apr 2017 12:01:48 -0500https://media.nbcconnecticut.com/images/160*120/ireland12456.jpg

After an amazing week vacationing in Ireland where it was between 50 and 60 dregees I sort of chuckled when the pilot informed the cabin it was 81F at JFK on Sunday. Bradley Airport managed a wild 88 degree temperature on Easter Sunday! But for those who like the warmth we've got a change on the way for the next week or so.

The weather pattern has changed. A big ridge of high pressure that pumped warmth up from the south and kept a westerly wind in New England is being replaced by a somewhat persistent  trough and periods of onshore wind. This time of year wind direction is critical for our temperatures with exceptionally cold water in the Atlantic Ocean. 

There are signs, however, that by the end of April a return to unseasonable warmth may occur. For example, both the Euro and GFS models rebuild a southeast ridge of high pressure and move a milder airmass in here in the Day 11-Day 15 time frame. 

While we'll have to deal with a few cloudy, showery, and cool periods over the next week or so if you like warmth there are some positive signs ahead.


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<![CDATA[A High Risk for Forest Fires]]>Tue, 11 Apr 2017 16:45:35 -0500https://media.nbcconnecticut.com/images/213*120/Fire+Danger3.png

Meteorologist Josh Cingranelli here. I'm guest writing 'On Ryan's Radar' while he's taking some much deserved R&R in Ireland. 

Abnormally high temperatures coupled with gusty winds are leading to an increased risk of brush and forest fires.

Conditions are dry with relative humidity values between 20 to 30 percent. 

One of the reasons conditions become so dry this time of year is because of the lack of leaves on the trees. 

The leaves help to provide moisture into the atmosphere in a process called transpiration. 

The dry conditions have caused a high fire danger level.

When the fire danger is high, very high, or extreme open burn permits become invalid. Click here to check out the latest fire danger level.

The dry conditions will continue through the end of the week. Relative humidity values will range from 20 to 30 percent with breezy conditions. 

Fire officials across the state urge everyone to be vigilant when discarding any ashes. 


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<![CDATA[Heavy Rain, Flooding, and Storms]]>Thu, 06 Apr 2017 19:59:34 -0500https://media.nbcconnecticut.com/images/213*120/CODNEXLAB-GOES16-Infrared-14-42Z-20170406_871-877-10-10011.gif

9:00 P.M. Update: As we expected strong thunderstorms rolled through between 4 p.m. and 7 p.m. While there was a report of nickel size hail in Higganum the storms mainly behaved otherwise with occasional pea size hail, lightning and heavy rain.

There were several reports of wind damage in Smithtown, Long Island and also a 58 mph wind gust at Mount Sinai Harbor to our south. Minor flooding is still expected on some rivers in the state as today's rain runs off. 

Rainfall totals in many areas did underperform as the storms were exceptionally fast moving (90 mph!) and there was a fairly large dry slot over Connecticut during the afternoon.

11:00 A.M. Update:  Rain has tapered off for the time being but heavier rain will move back in this afternoon through early evening. Thunderstorms across the Mid Atlantic - from Washington, D.C. to North Carolina will approach later today.

9:00 A.M. Update: The rain has arrived and there is the potential for some flooding this afternoon and early evening. There are a few things to note about today's flooding potential:

  • Flooding should be isolated and relatively minor. Rainfall amounts will likely fall short of what's needed for more widespread or significant issues.
  • Rainfall amounts of 1"-2" likely across the state - most areas will be closer to the 1" amounts, however.
  • Small rivers and streams may approach bankful and some urban areas may see poor drainage flooding.
  • Larger rivers (Farmington, Yantic, Quinnipiac, etc) should remain in their banks - flooding is not expected on these rivers.
  • The Connecticut and Housatonic Rivers should experience minor (typical in spring) flooding Friday and Saturday as swollen tributaries feed the two biggest rivers in the state.

One thing we will be monitoring closely this afternoon is the potential for strong thunderstorms between 4 p.m. and 7 p.m. While severe weather is not likely - I can't rule out a stronger storm. We have a very stable layer of air near the surface but there will be a significantly unstable layer just off the ground - we call this elevated instability. 

With this in mind I expect we'll see some elevated thunderstorms that could result in small hail, very heavy rain, and lightning. While unlikely, occasionally these thunderstorm can produce strong winds at the surface. Winds only 2,000 feet above the ground are near hurricane force so if those storms can punch through the stable layer near the ground we could see strong winds. Again this is unlikely but something we'll be watching closely. 


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<![CDATA[Thursday Soaker]]>Wed, 05 Apr 2017 21:30:37 -0500https://media.nbcconnecticut.com/images/213*120/Model+NAM+Accum+Precip+CT2+%281%29.png

Another round of rain on top of saturated ground could result in minor flooding in parts of Connecticut Thursday. Our computer models show somewhere between 1.00" and 2.00" of rain across the state with the potential for locally higher amounts in a few towns. 

Even with this additional heavy rain most of the rivers in Connecticut can handle it. The Farmington River (hydrograph pictured below) is expected to remain below flood stage as is the Yantic River and Quinnipiac River. Smaller rivers and streams, however, may see quick rises tomorrow afternoon as the rain runs off quickly. Urban areas with poor drainage may also be succeptible to flooding. Don't be the person we get video of with a stalled out car under a Metro North underpass! 

One other item of interest tomorrow afternoon is the potential for a strong thunderstorm in southeastern Connecticut. Some of our computer models develop quite a bit of elevated instability (nearly 1,000 j/kg of CAPE) just above the ground. Additionally, very strong wind fields will be present with winds near hurricane force about 2,000 feet above our heads. While there is a very strong stable layer forecast to be present near the ground thunderstorms can do funny things and occasionally mix down stronger winds from aloft even in the presence of steep inversions/stable layers. At the very least, lightning, thunder, downpours and small hail are possible.

Most of the rain will taper off after 6 or 7 p.m. as dry air moves in from the south. 


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<![CDATA[Big Warmth Expected Next Week]]>Tue, 04 Apr 2017 10:21:40 -0500https://media.nbcconnecticut.com/images/160*120/gfs_t2max_boston_32.png

Signals are growing for an impressive surge of warmth next week. It won't be record breaking but it certainly will be a welcome change after an unusually cold March across Connecticut.

The key this time of year is the wind direction. A wind out of the south, east, north - or any combination of the 3 isn't going to get warmth into southern New England. Water temperatures in the 40s off of Cape Cod and Long Island make it almost impossible to warm when the air is blowing off the Atlantic. The key is to get a westerly wind off the land and that is what we're expecting early next week.

Right now, we have 70F forecast for Tuesday but that number may need to be increased. In fact some of the raw model numbers we're looking at have temperatures approaching 80 degrees by Tuesday! 

Looking back a bit, this morning's rain was pretty impressive as we expected. Most areas picked up about an inch of rain in a short period of time while some spots in southwestern Connecticut managed over 2" of rain resulting in some minor flooding. 


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<![CDATA[A Wet Week of Weather]]>Mon, 03 Apr 2017 21:29:46 -0500https://media.nbcconnecticut.com/images/213*120/C8h4mmQW0AA5ICY.jpg

Two storms each dropping 1"-2" of rain - finally! Combined with snow melt to our north this rain may even be enough to result in minor flooding on some of the larger rivers in the state. 

The heaviest rain tomorrow will fall during the morning commute with occasional rain during the midday and afternoon hours. A few thunderstorms are possible tomorrow along with any heavier downpours that develop.

One of the things we'll have to watch tomorrow is a localized are of heavy rain in southern Connecticut with strong onshore flow. Some of the NCAR ensemble members show a localized band of 3" of rain near the Merritt Parkway. This is a phenomenon that has been documented before (Colle and Yuter, 2007) as southerly flow over the ocean is slowed by friction over Long Island and Connecticut resulting in convergence - in addition to increase lift forced as air is forced up and over the small hills on Long Island and Connecticut. A local minima in precipitation is observed over Long Island Sound.

Another storm approaches on Thursday and that may result in even more rain. The GFS model shows very good odds of over 2" of rain in Hartford by the time the Thursday storm is over (each line represents a different computer model precipitation forecast) and other models have even more rain.

If the rain gets you down - don't worry. There is a strong signal for above normal temperatures next week as a southwesterly wind flow develops and warm air moves toward New England. 

Right now we're forecasting 70F on Tuesday. Who's excited?


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<![CDATA[What Drought?]]>Sun, 02 Apr 2017 20:02:05 -0500https://media.nbcconnecticut.com/images/160*120/gfs_tprecip_neng_29.png

About 50 percent of the state is still under a "severe drought" but it sure seems like our fortunes are changing. Windsor Locks managed an "above normal" March with 3.93" of precipitation while I managed 4.95" in West Hartford! This week, like the last several, also looks awfully stormy.

The European model shows good odds (>50 percent) of more than 2" of rain for southern and western Connecticut over the next 7 days. With snow melt up north along with locally heavy rain we may see a period of minor flooding on the Connecticut River. You can see impressive rises possible based on rainfall and snow melt from the GFS ensembles.

While it will take time to completely eliminate the drought we're moving in the right direction. If we can string together 2 more months of above normal precipitation we may finally be able to put this drought in the rear view mirror. 


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<![CDATA[Icy and Rainy Night]]>Fri, 31 Mar 2017 17:53:47 -0500https://media.nbcconnecticut.com/images/160*120/NAMNE_850_temp_018.png

Today's storm is beginning to pick up in intensity as colder air filters in from the north this evening. Already freezing rain has developed in many locations in Litchfield County and also the northeast hills as rain falls into subfreezing temperatures near the ground. The biggest concern for tonight is the potential for tree damage and power outages as freezing rain glazes up power lines and trees across the hill towns.

The NCAR ensemble from this morning is extremely bullish on the freezing rain potential with up to 1" of icing tonight! While the NCAR ensemble frequently overdoes freezing rain we need to monitor this closely.

You can see the issue on this sounding off the NAM which shows a warm layer that's sufficient to melt snowflakes. How warm that warm layer is will determine how much precipitation falls as freezing rain and how much as sleet. 

This is the area we're highlighting for freezing rain issues this evening - particularly above 600 or 700 feet. 

By morning there is the possibility of a flip back to snow or sleet along the I-84 corridor and possible as far south as Norwich and Middletown. Cold air will sink south as a band of heavy precipitation develops across Connecticut, Rhode Island, and Massachusetts. This is a tough, tough forecast. Don't be surprised to see a burst of mix developing around daybreak in many areas that just get rain tonight. 


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<![CDATA[Ice and Rain to End March]]>Thu, 30 Mar 2017 14:20:11 -0500https://media.nbcconnecticut.com/images/213*120/Model+RPM4+Precip+Cloud+CT+Web.png

This is probably a fitting way to end March 2017. The month has been nearly 5 degrees below average compared to January 2017 which was 6.6 degrees above average! As I wrote about yesterday late March/early April is full of weird storms (2016 April freezing rain and 2014 morning commute surprise snow) that have given forecasters fits and ticked off the vast majority of Connecticut residents ready for spring. 

A storm is going to dive south of southern New England and produce a period of rain, sleet, freezing rain, and even a bit of snow. If you're excited for a big snowstorm - temper your enthusiasm immediately! This storm is looking more and more like a slushy/icy mix for areas north of I-84 and a mainly rain event south of there. Even in the Hartford area a lot of what will fall will likely be in the form of rain.

The "snow/sleet" forecast is actually fairly straightforward. Plenty of mid level warmth will limit the amount of snow we can get. In fact most areas see very little. The bigger question is what form the ice takes Friday evening and Friday night. Is it ice pellets or freezing rain. Ice pellets (or sleet) is the bouncy stuff that is a nightmare to shovel and not great to drive on but it sure beats freezing rain which clings to powerlines and trees and can result in all sorts of problems.

The key to figuring our what we'll see is how thick and how warm the warm layer is aloft AND how cold temperatures are right at ground level. First we'll start at the ground. This product from the NCAR ensemble shows the probability of temperatures below 32F at the surface at 8 p.m. Friday. There are good odds for <32F temperatures for the hilltowns later Friday. 

Upstairs the forecast is a bit more convoluted. I can look at the 850mb pressure level (about 5,000 feet up) and see what the temperatures are doing there and you can see a significant spread between the NAM and the GFS. The NAM is warmer with a low farther north and the GFS is colder thanks to a low farther south.

So which one's right? The truth likely lies in the middle and that's where the European model has been. The Euro shows a warm layer Friday night and Saturday morning which is enough to preclude snow and likely deliver a period of sleet and freezing rain in the hills north of I-84 and rain farther south.

Here's the bottom line on the Friday/Saturday storm...

  • Mainly light mix of snow, sleet, and rain on Friday with little if any road issues given strong March sun angle, temperatures generally above 32F, and light rates of precipitation. There is still a small chance for a bit of snow accumulation around daybreak if we get an unexpected heavier birst around the morning commute.
  • Heavier rain, sleet, freezing rain mixture Friday evening and Friday night.
  • 1"-2" of liquid precipitation expected with a few slushy inches of accumulation possible in the hills.
  • A prolonged period of icing (freezing rain) remains possible in the hills though I think prolonged sleet is more likely. If we get a lot of freezing rain it could lead to tree and power line issues. This would also result in minimal accumulation (i.e. the 2"-4" won't happen). In this event the valley locations around Hartford will just see rain as surface temperatures will be above freezing.
  • An icy mix lingers into Saturday morning and tapers off by mid morning. A flip back to snow from the wintry mix is possible even in the valley/Hartford area - this is one thing we'll watch closely.


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<![CDATA[Friday Mix]]>Wed, 29 Mar 2017 19:58:51 -0500https://media.nbcconnecticut.com/images/213*120/C8HIHzCXUAAGfPw.jpg

Over the last couple years we've had a few unusual late season snow and ice events. Last April we managed an extremely rare springtime freezing rain event that produced 0.20" of ice accretion in New Haven during the day on the second coldest April day on record! 3 years ago I had a spectacular forecast bust with a burst of heavy snow that suddenly occured during the morning commute dropping 5" of snow in only about 2 hours on parts of the I-91 corridor on March 31, 2014.

With those two storms in mind - what kind of surprise does Friday's storm have in store for us? We know we're going to see a good burst of precipitation - particularly Friday evening and Friday night - with over 1" of liquid falling. Good for the drought! The temperature profile is what makes this storm so tricky. As I wrote about yesterday there's not a good cold high pressure anchored to the north so getting excessive snowfall is going to be tough. Take a look at this time-height cross section of temperature for Bradley Airport off the European model. You can see a pocket of warmer air a few thousand feet above the ground with colder air below it. This would favor sleet and freezing rain. 

The GFS model is colder than the Euro and a blend of the two would yield a period of snow, sleet, and even some freezing rain across areas north of I-84. We will have to monitor this closely as a degree in either direction would mean a drastic change in the forecast. Here's what I'm thinking right now:

  • Light mixture of snow, sleet, and rain during the day Friday. While a few slick spots are possible Friday morning if snow develops around daybreak most of the day should be problem-free on the roads. Light snow and sleet rates and the strong sun angle should do the job to keep roads wet.
  • Heavier precipitation will develop Friday evening and Friday night. 
  • Mainly rain is expected along the shoreline Friday evening/night with occasional sleet pellets.
  • Inland areas will see a mixture of sleet and rain along I-84 in the higher elevations and in the hills sleet and freezing rain may be the dominant precipitation type. Some snow is possible as well near the Massachusetts border with several inches of accumulation possible.
  • The storm will peak during the overnight hours with everyhing winding down shortly after daybreak Saturday.
  • While there is likely to be an icy mix and slushy accumulation north and west of I-84 (especially in the hills) there are two less likely things we'll have to watch foe. One is the potential for a colder solution which would mean more snow - including in the valley north of Hartford. The second thing to watch for is the potential for an extended period of freezing rain in the hill towns which would weigh on trees and powerlines.
Let's hope April winds up better than March. I'm ready for spring!


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<![CDATA[Wintry Mix for the End of March]]>Tue, 28 Mar 2017 19:42:35 -0500https://media.nbcconnecticut.com/images/187*120/ne_f90.png

March is supposed to go out like a lamb - not like this! On the 20th anniversary of the epic April Fools storm of 1997 it appears that parts of southern New England may see another winter storm. 

Here in Connecticut the storm is going to be much too warm for all snow but a messy mix of snow, sleet, freezing rain and rain appears likely. The storm will be of a somewhat long duration with a period of some snow/mix as early as Friday morning with some mix continuing off and on through Friday night. 

At this point, I'm not expecting a major event here in Connecticut. This time of year getting a major winter storm is tough to do - and with no cold high pressure anchored to the north this becomes all the more challenging to accomplish. A cold and raw mixture of rain, sleet, and snow seems more likely than a more significant wintry event.

That said, both our GFS and European models show the potential for some mixed precipitation and problems. The GFS model sounding valid prior to daybreak Friday shows a column cold enough for snow even in the valley around Hartford. If this were to verify we'd have to worry about the potential for a bit of slick travel in the morning prior to a change to rain. 

Another way of showing the temperature profile for this storm is to look at this time-height cross section from the European model at Bradley Airport which shows a classic signature for ice or sleet with warm air located above colder air near the surface. You can see this on the right side of the image below where temperatures 6,000 feet up reach 2C or 3C while temperatures near the ground are just below freezing. 

At this point, I wouldn't expect a major winter event but some nuisance kinds of accumulation are possible - even in valley locations. Of course, it's possible this turns a bit colder and more wintry - especially in the hilltowns. One concern would be a stronger low pressure south of Connecticut Friday night with a period of heavier lift in the atmosphere in precipitation. This could promote a flip to heavy wet snow. Another possibility worth watching is an extended period of icing in the hills but given the time of year and lack of a good and cold high pressure to the north this seems unlikely to me right now. 

We'll be watching this closely over the coming days. 


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<![CDATA[Winter Strikes Back]]>Tue, 21 Mar 2017 19:54:16 -0500https://media.nbcconnecticut.com/images/160*120/gefs_t850a_conus_5.png

After a gorgeous 2 days of weather we're going to see a dramatic change by tomorrow, Thursday and the weekend. The first item of interest in unseasonably cold weather for the next 48 hours. 

Temperatures will be nearly 20 degrees colder than average with a dramatic shot of Arctic air. 850mb temperatures (about 5,000 feet above our heads) will be between 15c and 20c colder than average! That's a big negative anomaly. While there is a surge of more typical March air on the way for Friday and Saturday the weekend forecast remains intriguing.

A storm to our west will send moisture streaming into New England Sunday and Monday. This is a classic "overrunning" setup with warm air advecting north into New England BUT near the ground it's a much different story. The big key to the forecast is a large high pressure over northern Quebec that will nose south into New England. This will lead to a wedge of low level cold air with warmer air aloft and as a result the possibility for ice.

Let's take a look at the ECMWF (euro) and GFS temperature forecast. The Euro forecast shows a layer of mild air about 7 or 8,000 feet above us with colder air below it. This is an inversion. Snow will melt into rain drops in the warm layer and then either refreeze into an ice pellet or reach the ground as freezing rain. The GFS temperature forecast (shown here as a SKEW-T) shows a similar setup for later Sunday with an area of above freezing air above a shallow but notable subfreezing layer of air close to the ground.

At this point it's unlikely we'll get a major winter storm (i.e. excessive amounts of ice) but this is looking like it could be a nasty and unpleasant mix with some icy travel and chilly temperatures - especially for the time of year. Obviously lots can change over the next few days but this is something we're going to be watching closely. 


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<![CDATA[Blizzard Delivers for Some and Falls Short for Others]]>Wed, 15 Mar 2017 10:34:23 -0500https://media.nbcconnecticut.com/images/160*120/C65cHUVWsAA-v4v.jpg

Snowfall totals ranged from 1" to 24" across the state from yesterday's blizzard that peaked during a remarkably impressive 2-3 hour snow blitz around midday. I've heard a number of complaints and compliments from our viewers on the forecast. Along the shoreline there's no question the storm was a bust - across the interior there's not question the storm lived up to expectations.

The biggest reason the forecast missed along the shoreline was the fact the storm passed approximately 75 miles west of where I thought it would. This analysis from the Storm Prediction Center shows the low tracking inside or west of Block Island. This is a low pressure track that is sure to bring warm air into a large chunk of the state. 

In West Hartford I measured 12.9" of snow (it likely would have been a bit higher had a been able to measure more frequently and earlier) and it melted to 2.02" of liquid! That is an extremely dense snowfall with a snow:liquid ratio of 6.4:1 which is well short of a typical 10:1 ratio.

The snow flakes grew at temperatures that were between -5C and -10C while the favored region for snow flakes (-12c to -18c) was dealing with a dry slot. Basically, only small snow flakes were able to develop during the day. As warmer air moved in we saw sleet and in southern Connecticut some rain.

An old rule of thumb for figuring out who will get the heaviest snow is to look at the mid level low pressure (around 10,000 feet). Lows are tilted back to the west with height and this low is typically well west of the surface low. In yesterday's storm was over Philadelphia. We saw a band of intense lift out ahead of the low (see that purple over Connecticut) associated with something we call frontogenesis (basically forces a vertical circulation to form resulting in areas of rising and sinking air). But - the areas that really cashed in were located along and west of that low track. In fact some areas in the Catskills saw almost 40" of snow!

Some of our computer models had that low much farther west (over Connecticut or even just east of us) up to 24 hours prior to the storm. Had that tracked a bit farther east we would have seen huge totals - even down to the coast.  

So what did we learn? Our computer models struggled with the western trend right up until Tuesday morning. Credit where credit is due to the NAM and RGEM models for keying in on a warmer and western solution. This was on the far western solution of the European Ensembles (80 or 90% of them were east of where the storm tracked). Additionally, always respect the mid level dry punch. The drier air that moved in effectively shut off good snow growth and resulted in substantially lower snowfall rates than one would typically expect. That said, our forecast for almost the entire I-84 corridor worked out great with a record March snowstorm at Bradley Airport - 15.8".


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<![CDATA[On Ryan's Radar: March Blizzard Moves Closer]]>Mon, 13 Mar 2017 11:07:05 -0500https://media.nbcconnecticut.com/images/160*120/nam_total_precip_neng_16.png

There has been a jump to the west with the forecast track of tomorrow's blizzard. This introduces a few issues including a mix with rain and sleet south and east of Hartford and may push the heaviest snow band a bit farther to the north and west. 

This morning I updated the snow forecast to illustrate where we expect the heaviest snow bands to set up. I wouldn't be surprised if these bands moved 20 to 30 miles either west or east by tonight. 

The numbers that our models are showing are eyepopping. A band of tremendous lift will move through tomorrow morning and midday with a ferocious period of snow. I expect the heaviest snow to fall between 10 a.m. and 5 p.m.

At the peak of the storm a surge of warmer air will move in to the shoreline east of New Haven and a period of rain and sleet now appears likely. 8"-12" of snow is expect in parts of southeastern Connecticut with heavier totals farther north and west where it stays all snow.

There are a few things to keep in mind. This map of the European model shows possible location of low pressure tomorrow afternoon. If one of the western-most solutions verifies (over Rhode Island) we will deal with mixing all the way back to I-91 and a dry slot that would shut the snow and mix off early. If it's a bit farther east (say east of Nantucket) the heaviest snow band of 18"+ has the potential to wind up over Hartford and New Haven.

Still, the most likely scenario is a foot of snow for Hartford and New Haven and over 18" of snow in the Litchfield Hills. This is also the area that's being highlighted by the European model with the highest probability of over 18" of snow.

Additionally, at the peak of the storm we are expecting winds to gust between 40 and 60 mph. Sporadic tree and powerline issues may develop especially where the snow is of a wetter consistency. 


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<![CDATA[On Ryan's Radar: March Blizzard On The Way]]>Sun, 12 Mar 2017 16:30:53 -0500https://media.nbcconnecticut.com/images/213*120/C6vP2tbWoAAvDTc.jpg

This has all the makings of a classic. A powerful nor'easter will move up the coast producing a heavy burst of snow throughout southern New England. Of course - there are still some questions that I'll dive into in just a bit. First, what we know.

  • Over 6" of snow is extremely likely with over 12" of snow now a good bet.
  • Current forecast is 12"-18" of snow statewide with locally higher amounts to 24" - especially in the hills. 
  • Snow begins around daybreak with the heaviest snow between 10 a.m. and 8 p.m. This time table may change a couple hours in either direction.
  • Wind gusts over 40 mph at the shoreline may result in blizzard conditions. 
Now, what we don't know.
  • Where exactly does the storm track - too far east and it's more of a glancing blow (still 6-12" of snow) or too far west and we introduce some mixing issues at the coast and dry slot issues everywhere (still 6-12" of snow). Something in between (which is what we're expecting) and we get more than a foot. 
  • If the storm takes the "perfect track" and winds up near Cape Cod we will get crushed. Where the heaviest snow band sets up (we're talking 18"-24" totals here) is unknown... is it eastern Connecticut or the Northwest Hills. We won't even begin to have an idea until tomorrow morning.
  • How strong will the winds be on the coast - this will be determined based on the strength and exact track of the storm. 50 or 60 mph winds are possible with a stronger storm tracking near the Cape.

We pretty much have two camps of models - some east (GFS) and some west (Euro, NAM, UKMet, etc). The model differences are due to how the computer models interact two pieces of energy in the jet stream. There's one disturbance over the Great Lakes that is effectively capture a juicy, moisture-laden disturbance swinging northeast from the Gulf of Mexico. 

The GFS suite (including the ensembles) take the system a bit more seaward - with a late capture. Basically the system isn't absorbed quickly and we wind up with a slightly weaker and a slightly farther east solution. Incidentally, the GFS ensemble members that are stronger are much farther west. Still, even with the eastward jog there's a sizable signal for excessive snow. 0.7" to 1.0" of liquid on average would be a 6"-12" snowstorm across the state. Big but not epic.

A track farther west like most of our models have would mean a beast of a storm. The question will then become how far west and whether or not any dry slot issues develop. Generally you want to be undernearth or just northwest of the mid level low pressure about 10,000 feet up - where this tracks is critical to figuring out where the heaviest snow band will be. For example the NAM, pictured above, keeps the 700mb low to our west and then sort of develops it overhead Tuesday afternoon. This would favor heaviest snow totals in the Northwest Hills and Berkshires, effectively shut off the heavy snow quickly after 3 p.m. as dry air races in aloft, and introduce mixing/precipitation type issues in southeastern Connecticut. 

The midday European model, however, has a classic mid level low track which would ensure epic snow totals over 20" in many areas. Additionally, powerful winds would develop Tuesday afternoon as the low strengthens extremely rapidly just southeast of us. At this point, based on the pattern and a lot of the guidance, we're leaning toward the Euro with some consideration for the lesser models. 

I'm very confident we're going to have a big storm - the question right now is how big. Are 10"-14" common or are we closer to the upper bounds? This has the potential to be extremely impressive so stay tuned!


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<![CDATA[Major Winter Storm Likely Tuesday]]>Sat, 11 Mar 2017 11:03:20 -0500https://media.nbcconnecticut.com/images/160*120/gfs_pr6_slp_t850_neng_15.png

It's about as strong of a signal I've seen for a major winter storm 4 days ahead of time. A powerful nor'easter will develop after emerging from the Gulf of Mexico on Monday. At this point it's fair to say a significant storm is likely and I would be surprised if at least a portion of Connecticut didn't get a foot of snow.

The storm has all the makings of a blockbuster.

  • A deep and cold antecedent airmass with a sprawling large high pressure to the north. 
  • A bit of downstream blocking of the jet stream near Greenland.
  • A potent and moisture laden disturbance exiting the Gulf of Mexico with a second disturbance diving south from the Great Lakes. How these interact will be the key to where the storm tracks.

Let's look at our overnight computer guidance for example. The European Ensembles (the European model run 51 different times at slightly lower resolution with a few tweaks) shows a 50-70 percet probability of more than a foot of snow across Connecticut. The odds of 18" of snow are between 5% and 20%. For a 96 hour forecast these are huge probabilities!

Of course things can change a bit. The key is going to be the storm's strength at our latitude and how close to the coast does it track. Is the storm near Block Island or near Nantucket? If the storm tracks too far west we would introduce sleet and rain issues - if it's too far east the heaviest snow would miss us to the east (i.e. Boston and Cape Cod get clobbered while we get a lesser storm). This map shows all the different locations of the low from those 51 different European Ensemble members.

Here's what we can say right now:

  • A major coastal storm/nor'easter is likely on Tuesday and Tuesday night
  • The most likely start time is Tuesday morning with the peak of the storm Tuesday afternoon and evening. Let's say 3 p.m.-midnight as a first approximation.
  • 1 to 2 feet of snow is a good possibility just northwest of where this storm tracks. Whether that is in eastern New York, eastern Massachusetts, or Connecticut it's too soon to say. 
  • A jog to the west of the storm that introduces precipitation type issues (sleet and rain) is still a possibility.
  • Blizzard conditions and strong or even damaging winds are possible with this storm.
  • By later tonight and tomorrow we can start throwing out some preliminary numbers. I have a feeling they'll be big. 


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<![CDATA[Friday Snow and a Bigger Tuesday Threat]]>Wed, 15 Nov 2017 10:45:27 -0500https://media.nbcconnecticut.com/images/213*120/C6gjAEVWYAA_mXE.jpg

Editor's Note: This story is from March 2017.

Snow will be flying across most of Connecticut Friday morning. The morning commute looks sloppy. We're not talking about a major storm but I am expecting some issues.

The biggest question I have is how much dry air hanging out over western Massachusetts will sink south into far northern Connecticut? Will dry air eat up the snow in the lowest levels of the atmosphere in the Connecticut River Valley north of Hartford? This is definitely a possibility.

At this point a model blend/consensus indicates 2"-4" is a likely outcome in most locations with a bit more possible in a few spots near the shoreline and a bit less possible along the Massachusetts border. A few of our high resolution models have little, if any, accumulation near Windsor Locks and Enfield - this is a possibility if the dry air comes in a bit more impressive than currently modeled. 

What is looking more interesting is the potential for a major nor'easter on Tuesday. Many of our computer models now show a substantial snowstorm - capable of double digit snowfall totals. In fact, the European Ensemble has more than 60% probabilities of over 6" of snow on Tuesday across Connecticut - that's a really, really big probability for a storm 5 days out! This storm could be a big deal so stay tuned!


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<![CDATA[Winter's Back With 2 Snow Threats]]>Thu, 09 Mar 2017 17:50:46 -0500https://media.nbcconnecticut.com/images/213*120/Launch+Custom+Map+4.png

A blast of Arctic cold bookended by two storm chances - winter is definitely back! The first threat for snow is Friday and at this point I'm becoming more bullish about the snow potential and I think my accumulation forecast from this evening needs to be increased.

This storm will feature a narrow band of heavy snow around daybreak Friday and the issue is going to be where exactly that narrow band sets up. There's a growing model consensus that a 20-30 mile wide band of up to 5" or 6" of snow is possible - but whether that's over Hartford or over New Jersey it is hard to say. The 18z GFS model has trended in a bullish direction with more than 0.5" of liquid (~5" of snow especially away from the coast where it is all snow) in the southern half of the state. 

While this GFS model is one possible - and snowy - solution other models such as the 18z NAM are much less impressive with less than 2" of snow across the state. So where do we go from here? The probabilities on our European Ensembles of more than 1" and 3" of snow seem reasonable - and they show the best probabilities (a 30% chance) of over 3" of snow right over the southern half of Connecticut. 

Putting this all together I think a solid argument can be made for statewide 2"-4" of snow with locally higher amounts. We'll wait for one more round of computer guidance before changing the numbers "officially". 

Snow may begin as a bit of right at the onset along the shoreline Thursday night and Friday morning before flipping over to snow. The snow should accumulate readily through daybreak and then gradually taper off. After mid-morning, even with flakes in the air, accumulation should be tough to accomplish on paved surfaces with warming temperatures and time to treat the roads. I do think that whoever gets under that heavy band could see an impressive 1-3 hour snowfall. This sounding off the NAM in Hartford reveals a classic signature for efficient snowflake growth with lift maximized at a temperature of -15C. Big, fluffy snowflakes. 

After temperatures in the 20s Saturday and Sunday - extremely cold for the time of year- storm 2 approaches on Tuesday. The pattern appears favorable for a nor'easter and the midday European ensembles show a 40% of >3" of snow on Tuesday which is a very high probability at 6 days out! 

A busy stretch of weather after a few weeks of early spring!


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<![CDATA[Cold Arrives But What About Snow?]]>Tue, 07 Mar 2017 18:59:13 -0500https://media.nbcconnecticut.com/images/160*120/gfs_t850a_conus_17.png

An exceptionally impressive blast of cold air will settle over southern New England for a second weekend in a row. Temperatures at 850mb (about 5,000 feet above the ground) are expected to drop below -20C which is near record levels for March. The record based on weather balloon launches at Chatham, MA dating back to 1948 is -23C!

So yeah, it's going to be cold! The question is what about our snow threats. At this point it appears there are two distinct chances for snow - one on Friday and another on Tuesday. The earlier threat on Sunday appears to have disappeared with the storm track being shunted well south by this big blast of cold air. 

It's worthless to try and pin down details or go through every individual model run because as one would expect there's a lot of spread and uncertainty in the suite of models at this time range. The best way to assess the likeliehood of snow is not by freaking out over each model run 4 times a day but rather use "ensemble forecasting" which ideally represents a spread of likely solutions for any given storm.

Take the European ensembles for example. The Euro Ensembles are basically the European computer model run at a somewhat degraded resolution with 51 small tweaks 51 different times. For the Friday storm about 4 out of 10 European ensemble members have over 1" of snow here in Connecticut. 

This has been a relatively consisent signature over the last couple days. While a shift to the south could occur at this point I think at least some accumulation is a reasonable bet in a portion of the state. 

The more impressive storm potential is Tuesday of next week. At this point nearly 1 in 4 European ensemble members show more than a half foot of snow. This is a really strong signal for 7 days out and an indication that we'll need to watch this closely. 

Where we go beyond Tuesday is anyone's guess. Will the cold pattern relax and our early spring resume? We'll see. At this point we're forecasting a return to near normal temperatures by St. Patrick's Day. 


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<![CDATA[Weather Pattern Turns Stormy]]>Mon, 06 Mar 2017 16:54:53 -0500https://media.nbcconnecticut.com/images/160*120/gefs_t850a_conus_21.png

It seemed too good to be true for winter haters. Our remarkable stretch of 60s and 70s in the end of February has come to an end and now we may see on heck of a flip not just to a colder pattern but also to a snowier pattern.

One thing that has been missing all winter has been the infamous "Greenland block" or a "-NAO". The negative North Atlantic Oscillation features anomalous warmth and high pressure over Greenland and forces a storm track south of New England and frequently is a precursor to east coast snowstorms. All of our computer models show this feature developing by the weekend and early next week.

The first system we're watching is a weak clipper system on Friday which is by no means a certain snow-maker. The 51-member European Ensemble suite of computer models has a 30 to 40 percent chance of seeing more than an inch of snow Friday. One note of caution is that light snow in the afternoon during March can prevent snow from readily sticking to the pavement - that wouldn't be reflected in the 30 to 40 percent probability.

What appears to be a more significant storm approaches on Sunday. There's a large amount of model spread right now that includes a Connecticut snowstorm on some of the enesemble members to a glancing blow on the GFS computer model to a complete whiff on the Euro. At this point all three are possible. What's not likely is a storm that cuts to the west and brings warm air in as the -NAO block should do its job and keep the storm south of us with the cold locked in as well.

 

Whether or not any of these snow threats (including a third threat around Tuesday of next week) comes to fruition what does seem likely is another shot of very cold air over the weekend. Right now we're forecasting highs in the 20s for both Saturday and Sunday at Bradley Airport.


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<![CDATA[Weekend Cold]]>Wed, 01 Mar 2017 19:25:13 -0500https://media.nbcconnecticut.com/images/160*120/gefs_t850a_5d_conus_231.png

The last couple weeks of spring couldn't last forever. An impressive blast of cold will move in for the weekend with temperatures struggling out of the 20s in most towns on Saturday. With some wind and after our recent stretch of warmth it's going to be a rude awakening!

A big dip in the jet stream will allow the cold to sink south. You can see a sharp and somewhat impressive trough of low pressure over the northeastern U.S. 

The real chill moves in Friday night as temperatures drop into the teens with strong winds. 

While this surge of chill will seem impressive it's not going to last too long. A surge of milder than normal air lurks to the southwest of southern New England for Tuesday and Wednesday. 


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<![CDATA[Convoluted Severe Weather Threat Wednesday]]>Tue, 28 Feb 2017 21:06:46 -0500https://media.nbcconnecticut.com/images/160*120/mgWeb_WRF_20170228-210000_ANE_ECONUS_F00243000_PwinterThickness_R4km.png

Right off the bat it seems important to say that the fact we're even discussing severe weather on February 28th is pretty wild. The setup is very very complex and very convoluted - this is a tough forecast!

There's no question that there is an elevated severe weather threat tomorrow. We have a very unusual (for the time of year) combination of shear and instability. These are the two pieces that are necessary for severe thunderstorms to develop. These graphs off the short range ensembles (SREF) show very impressive shear and enough instability for some really intriguing storms - including supercells!

But there are some big cavaets here. For one, it's unclear how the severe storms over the midwest and Great Lakes will evolve tonight. Secondly, there's not much of a trigger tomorrow afternoon and evening during the maximum shear/instability combo. What do I mean by that? The best forcing (i.e. cold front) is displaced well to the west. Just becayse we have a combination of shear and instability large enough for severe storms it doesn't necessarily mean storms will form but rather indicates that if storms form they have the potential to become severe.

Our in-house WRF model - the RPM - has been all over the place with where and when thunderstorms will develop. Other high resolution models (including the 3, 4, and 12km NAM) have been equally jumpy with location and timing of storm development. This adds to the uncertainty. 

The bottom line is that there is most certainly a severe weather threat tomorrow - including damaging winds and tornadoes. That threat, however, is conditional on thunderstorms developing in the first place during the late afternoon and early evening. For now we'll leave the severe weather impact at low/medium. If it becomes clear storms will develop and be coincident with maximum instability and shear in the early evening then the numbers will need to be boosted. 


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<![CDATA[Winter Severe Thunderstorms]]>Thu, 02 Nov 2017 21:37:41 -0500https://media.nbcconnecticut.com/images/160*123/COVER+PHOTO.jpg

Severe thunderstorms in the winter are rare in southern New England. Saturday night's EF-1 tornado in Goshen and Conway, MA ranks up there as one of the most unusual.  

The radar signature for the Goshen/Conway tornado was one of the more impressive signatures you'll see around here. The amount of rotation was well in excess of the typical thresholds we have for tornadic storms. Not surprisingly, the tornado was on the ground for 5 miles and peaked in strength in the town of Conway (one town north of where my mom grew up, incidentally) with winds of 110 mph. To see something like this in June would be impressive - to do it in February is unheard of. Or is it?

Looking back through the weather archives there are several storms that have produced exceptionally unusual weather in the cold season. The first one I stumbled across I thought was a mistake - an F2 tornado on Martha's Vineyard on December 18, 1951. I was sure it was an error in the database but it wasn't. The description in a 1951 climate report sure makes it sound like a tornado. 

On December 18, 1951 snow fell from Washington, D.C. north to New England. A warm front appeared to be draped along the coast and south of the warm front temperatures made it into the 50s (I see a high temperature of 52F at the Edgartown, MA coop station). Apparently this warm sector was unstable enough to produce a significant tornado. 

While the 1951 December tornado on the Vineyard may have been the oddest winter severe weather event there have been others in the cold season of note. The March 29, 1984 nor'easter produced heavy snow, violent winds, and coastal flooding. In Southborough, MA a strange "downburst", as it was described flattened several acres of trees.

While this may have been more related to a gravity wave allowing powerful wind just off the surface to mix down to the ground (Blue Hill Observatory had a 108 mph wind gust about 600 feet above sea level) there may have been some convective element to this as well. Bizarre.

The Thanksgiving 2005 tornadoes in Maine on the warm side of a warm front occurred while areas just inland were getting snow (including Portland). Several homes were swept off their foundations.

Of course there was also last February's widespread damaging wind event from powerful thunderstorms during the overnight hours. That produced winds in excess of 60 mph and knocked out power to tens of thousands across the state.

While severe weather in the winter is unusual it's not completely unprecedented. As our climate continues to warm, and more atypical weather patterns develop over the northeast, it wouldn't surprise me if our "severe weather" season becomes more year-round but history shows us even over the past several decades there are cases of severe storms in the cold months over New England. 


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<![CDATA[Rare Winter Tornado Rips Through Western Massachusetts]]>Sun, 26 Feb 2017 18:32:36 -0500https://media.nbcconnecticut.com/images/160*160/annefarrell.PNG

A violent thunderstorm tore through western Massachusetts around 7 p.m. last night spawning a tornado in the towns or Conway and Goshen just to the west of Northampton and Deerfield.

The tornado has been given a rating of EF1 with winds up to 110 mph according to the National Weather Service.

The radar imagery was extremely impressive when the storm was over the Berkshire foothills. This radar grab from 7:10 p.m. shows very strong rotation about 4,500 feet above the ground - about 100 knots of gate-to-gate shear. This is well beyond typical thresholds for tornadoes in southern New England (the median value for New England tornadoes is closer to 50 knots). 

The environment in Massachusetts did not appear particularly favorable for severe weather. While there was very strong low level shear there was limited instability. In fact, nearby soundings off our high resolution computer models showed <100 j/kg of CAPE which is very meager. That said, it is possible the actual environment was more favorable than our computer models indicated. 

Farther west, in Pennsylvania where severe weather yesterday was more widespread, values of CAPE were between 500 j/kg and 1,000 j/kg. In fact, a tornado was confirmed in Luzerne County, Pennsylvania near Wilkes-Barre along with golf ball size hail. 

This is the first tornado ever recorded in February in Massachusetts. What is so bizarre is that this severe weather event occured exactly one year after the epic overnight severe weather event in February that was so incredibly unusual. Look out on February 25, 2018 - we have quite the unlucky streak going here.


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<![CDATA[Don't Get Used to the Record Warmth]]>Fri, 24 Feb 2017 15:40:19 -0500https://media.nbcconnecticut.com/images/213*120/Custom+List+6+%282%291.png

Today was the second warmest February day on record for inland Connecticut. Absolutely remarkable warmth today! The question so many are asking is whether or not we're done with winter. 

 

Today's warmth is being driven by an unusually powerful "Bermuda High" type pattern - pumping unseasonable warmth to the north. Full sunshine managed allowed temperatures to soar across the state - and even the shoreline managed to see temperatures around or just over 60F. With an onshore wind and water temperatures in the 30s this is a real testament to how anomalous the airmass was.

 

But - don't be fooled. The calendar is still in February and the long range computer model projections do not look particularly warm beyond day 7. Is it possible we won't get another inch of snow? Sure, but I wouldn't count on it.

 

Both the GFS and European computer models show a virtual flip to the jet stream pattern over North America. The persistent trough over the western U.S. responsible for the record snow and rain in California will be replaced by a ridge of high pressure. That teleconnects to a trough over the eastern half of the U.S. which will allow some Canadian cold to move south into New England. While the pattern doesn't look particularly cold - even a seasonable pattern is cold enough to produce snow in early March. 

 

With cold air nearby and a relatively active storm track some of our computer models are starting to show a few snow threats starting Friday of next week and lasting through March 10 or so. While we can't lock any of these in just yet I wouldn't put the shovels away for good.


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<![CDATA[Warm for Some, Cool and Dreary for Others]]>Thu, 23 Feb 2017 15:22:02 -0500https://media.nbcconnecticut.com/images/160*120/CODNEXLAB-1km-LongIsland-vis-ani24-201702231845-100-100-raw.gif

If you love warm weather, living along the shoreline can be frustrating in the end of winter and beginning of spring. The reason? Long Island Sound's cold water. 

Today the mercury climbed to 65F at Bradley Airport - just shy of the daily record of 68F set back in 1990. Along the shoreline temperatures were stuck in the 40s for the better part of the day with a southerly wind blowing right in off the Sound.

Cooler temperatures are fine when the sun is out but today was grey and foggy at the beaches. Warmer air blowing over the cold Long Island Sound and Atlantic Ocean resulted in a persistent but shallow layer of stratus clouds that got about as far north as Wallingford and Middletown.

This is known as "advection fog" and it isn't terribly unusual for coastal Connecticut. Several warm and sunny spring days are ruined every year around New Haven as this fog rolls in. Another way to look at this is through the atmospheric temperature profile. 

This sounding from New Haven at 8 a.m. this morning shows how temperatures change with height. About 1,500 feet above the ground temperatures were in the mid-50s while temperatures near the surface were in the mid-40s. This temperature inversion allows low clouds and moisture to be trapped and can result in clouds and thick fog like we had today. Across inland Connecticut the inversion was mixed out resulting in almost complete sunshine and warm temperatures.

Today's cooler temperature and fog along the Sound was actually well forecast. Our computer models have improved immensely over the years and generally do a good job sniffing out foggy days like this. If you're in New Haven or Branford or Old Saybrook and want some sunshine - drive north for about 15 miles and you'll have plenty of it.


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<![CDATA[Weather's Impact on Connecticut's Worst Air Disaster ]]>Wed, 22 Feb 2017 15:53:07 -0500https://media.nbcconnecticut.com/images/190*120/hvn.jpg

Just short of runway two at Tweed-New Haven Airport, Connecticut's worst aviation disaster occurred on June 7, 1971. Allegheny Airlines Flight 485 crashed into a row of East Haven beach cottages on final approach to Tweed, killing 28 people in a horrifying fireball.

Wednesday morning's plane crash was only a few hundred feet north of where Allegheny Airlines Flight 485 crashed. However, this most recent crash was likely not related to weather.

Visibility at 10 a.m. today was more than 10 miles, wind was light out of the southwest and the ceiling, or cloud base, was 7,500 feet above the ground.

The Allegheny disaster in East Haven more than 40 years ago was blamed on pilot error but weather played a large role in the accident. Fog and very low cloud ceilings obstructed visibility across the Connecticut shoreline on the morning of June 7, 1971, according to the National Transportation Safety Board report.

 

The conversation recorded by a cockpit voice recorder between Captain David Eastridge and First Officer James Walker indicated the extremely limited visibility on final approach for the flight that had left Trumbull Airport in Groton on its way to Tweed-New Haven Airport, just before impact. 

 

Three people survived the crash, but 28 passengers and crew members died.

According to the NTSB report, the deaths were due to asphyixiation or burns after the initial impact. The report concluded the probable cause of the accident was, "the captain's intentional descent below the prescribed minimum descent under adverse weather conditions, without adequate forward visibility or the crew's sighting of the runway environment."



Photo Credit: New Haven Register
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<![CDATA[From Unusually Warm to Unusually Mild ]]>Tue, 21 Feb 2017 19:16:39 -0500https://media.nbcconnecticut.com/images/160*120/gefs_t850a_5d_noram_611.png

If you love winter weather the next 10 days look pretty brutal. A very impressive surge of warmth over the next few days will result in temperatures in excess of the 60 degree mark across areas away from the water.

Going into next week we're going to see some changes but the end result isn't going to be particularly cold but the 60s will be gone. A large dip in the jet stream will result in a surge of cold weather across a good chunk of Canada and the central and western part of the U.S. 

What is important to note is that the primary storm track that sets up will be primarily to our west. While this doesn't preclude the threat of wintry weather (i.e. a well timed high pressure to the north could result in snow or ice with a secondary redevelopment south of us) it does introduce a rain/mild risk as we head into March. I don't think our snow chances are over yet but nothing is poiting toward a cold and snowy pattern. Mild with some chances for snow is a better way of putting it. 

Snow lovers - don't despair. The fat lady is warming but she's not singing just yet. 


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<![CDATA[Springfield 'Tornado Scar' 6 Years Later]]>Mon, 20 Feb 2017 13:53:21 -0500https://media.nbcconnecticut.com/images/196*120/TornadoScar.PNG

6 years after the 2011 Springfield tornado tore through western Massachusetts dramatic new satellite imagery captures the damage path covered in fresh snow.

The deadly tornado occurred touched down on June 1, 2011 at 4:30 p.m. in Westfield, MA. The tornado was on the ground for 39 miles and lasted over an hour before finally lifting in Southbridge, MA.

This satellite image was taken on Thursday, February 17th following the two snow storms that moved through the region. The satellite is called MODIS (Moderate Resolution Imaging Spectroradiometer). It's a high resolution weather satellite that takes snapshots of earth every 1 to 2 days. 

The satellite has a resolution of 250 meters - which is small enough to capture something as small as a tornado track.  The satellite is the size of a small school bus and it orbits the earth 438 miles above our heads.

The weather satellite clearly depicts the scar that the tornado left just north of the Connecticut border. The 1/2 mile wide tornado tore apart forests and neighborhoods and today the damage to the trees throughout Hampden County is still visible even more than 400 miles above the earth's surface.

The destruction was widespread, hundred of homes and businesses were destroyed and three people were killed. 

These photos show what a home in Brimfield, MA looked like prior to the tornado and afterwards.

Before:

Aftermath: 



Photo Credit: NASA
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<![CDATA[Evening Snow and a Thaw]]>Wed, 15 Feb 2017 20:49:09 -0500https://media.nbcconnecticut.com/images/160*213/image1aa57akena.JPG

A burst of snow and even some thunder and lightning put down two pockets of accumulation this evening. One, as expected, occured in the Litchfield Hills where a persistent snow squall dropped nearly an inch of snow in some towns (0.8" of snow reported in Warren).

A second squall produced an area of accumulating snow from Haddam south to Killingworth and Clinton - temperatures dropped enough to flip the rain to snow. Very impressive for the shoreline given how mild it was when the squall started!

As temperatures drop this evening watch out for some pockets of black ice.

Going forward, people who love winter are going to get a bit sad. No real change to the thinking from yesterday with a prolonged period of above normal temperatures moving in. The 6-10 day temperature anomaly about 5,000 feet above our heads again today shows huge positive temperature anomalies across the eastern half of North America.

I don't think winter is done. While it is looking warm over the next 10 days we've been able to sneak a number of snow events into a generally warm weather pattern so far this winter. We'll see how this unfolds going forward.



Photo Credit: Jonathan Ventres
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<![CDATA[From a Blizzard to a Thaw]]>Tue, 14 Feb 2017 13:35:33 -0500https://media.nbcconnecticut.com/images/160*120/C4oB5_sXAAAOCJS.jpg

The jet stream pattern across North America is going to experience a fairly dramatic shift over the coming days and the impact will be a surge of milder than normal air across a large chunk of the country - including Connecticut. While the core of the warmth will be west of us I think we're looking at a prolonged stretch of at or above normal temperatures. 

 

This is really being driven by a number of factors. The tropospheric "polar vortex" is strong and showing no sign of slowing down. A strong polar vortex - over the North Pole - is effectively keeping cold air bottled up over the Arctic. We call this a +AO (positive Arctic Oscillation).  Additionally, a persistent trough over the western US is going to bring another round of storms to rain drenched California. This teleconnects to a strong ridge over the central and eastern half of the country - this is a -PNA (negative Pacific-North America oscillation). 

With this in mind we expect a growing trend of warmer than normal temperatures. While it's always possible to sneak in a winter storm - or even a day or two of below normal temperatures - this is a pretty powerful signature for warmth over a good chunk of the country. The warmth begins in earnest by Sunday with the European Ensembles showing a better than 50/50 shot of high temperatures over 50 degrees.

Skiers shouldn't despair, however. Conditions have been incredible of late and a few days of warmer than normal weather won't do anything other than soften up the snow. What can be disasterous for ski areas is a warm rain storm with temperatures in the 50s but we're not expecting anything close to that. A few days with highs in the 40s or even near 50 with sunshine and cool overnights will just give us a taste of beautiful spring conditions a month early. 

Here's a look at the current conditions at our mountains here in Connecticut. 


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<![CDATA[A Busy Weekend]]>Fri, 10 Feb 2017 21:39:17 -0500https://media.nbcconnecticut.com/images/213*120/C4QQtCsWIAM-h9j.jpg

Two storms this weekend on the way- it was another busy day at work! Tonight's snow isn't really that big of a deal but we're going to see a bit of accumulation. 1"-3" of snow should do it across the state with a bit of moisture and plenty of cold air around. 

One thing that's notable about the snow this evening is that it should be quite fluffy. This sounding shows a really, really deep layer of temperatures around -15C which should assure big and fluffy snowflakes. These flakes tend to pile up readily. 

Any snow tonight will wind down pretty quickly around daybreak tomorrow morning. Most of Saturday looks great! Sunday's storm looks a whole lot more impressive but man it's a tough one to figure out. An area of low pressure to our west is going to redevelop just south of us and turn into a pretty powerful storm east of Cape Cod.

The question is how warm will temperatures get before that storm redevelopment occurs. Can we lock in some cold? We're right on the line between heavy snow and heavy rain (with a bit of sleet mixed in too). The GFS shows this well with the 0 degree isotherm at 850mb (around 5,000 feet up) bisects the state. 

A subtle shift in storm track and/or subtle shift in temperature will make a huge difference here. Our forecast is basically a blend of the GFS and Euro right now (the latter being the snowiest and the former being the warmest/rainiest) but there's plenty of bust potential on either side here. I don't feel particularly confident in this one. Let's see what our overnight computer models show and we'll talk again about it in the morning :)


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<![CDATA[Major Snowstorm Begins]]>Thu, 09 Feb 2017 12:50:11 -0500https://media.nbcconnecticut.com/images/213*120/C4ONaPyXUAAg9x-.jpg

Midday Update: The heaviest snow is beginning to taper off from west to east across the state. Already 12"-16" have been reported in some areas and along the I-91 corridor we will see accumulating snow (though not as heavy) through 4 p.m. or so. Drier air will filter in from the northwest later today and get rid of the snow once and for all.

One thing that's worth mentioning again is just how exceptional the thunder and lightning has been with this storm. This has been one of the most prolific lightning producers I've ever seen. Remarkable.

Previous discussion below: 

Nothing has really changed since my post last night. A super impressive quick hitting storm is going to result in exceptionally heavy snowfall rates over the next few hours. Lots of lightning and thunder will occur to - this storm is going to be exceptional.  I'm using a lot of adjectives and superlatives for this storm because it deserves them. 

Most of our computer models have at least 1.0" of liquid across the state and I do think there will be a narrow band of incredible snowfall rates later this morning. Here's the reason why.

An area of low pressure is going to close off at about 10,000 feet above our heads and that is a hallmark of all of our big snowstorms in New England. Being under or just to the northwest of this feature is critical in getting into the best banding. 

One feature that's also been consistent in our computer modeling is the fact we're looking at violent upward motion where the temperature is close to -15C. This is the temperature at which snowflakes form most efficiently AND the favored type of snow crystal is a dendrite. Dendrites tend to pile up and accumulate quickly as the branches of the snowflakes get intertwined with one another. You can pull off crazy snow:liquid ratios when this signature develops - sometimes on the order of 20:1. 

Here's the bottom line...

  • 10"-18" statewide - if the banding really goes to town and becomes persistent we could see even higher totals in a localized area.
  • Extremely heavy snowfall rates 7 a.m. to 2 p.m. shutting off from west to east.
  • Snow winds down between 2 p.m. and 6 p.m.
  • Snow will be of a  heavy consistency first and then become a bit fluffier as the storm goes on.
  • Wind gusts up to 40 mph are possible on the coast especially


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<![CDATA[Snowstorm Turning Into a Beast]]>Thu, 09 Feb 2017 10:34:14 -0500https://media.nbcconnecticut.com/images/160*120/hiresp_tprecip_neng_32.png

I've got to say - I'm really, really, really impressed with how this storm is shaping up. It's looking more and more likely that we're going to see a band of epic snow rates for a period tomorrow morning and midday. I eschew weather hyperbole but this one looks like the real deal.

This storm will be a bit different than many of our "big ones" due to its speed. We're only looking at a 4-6 hour window of really heavy snow. If this storm was moving anyslower we'd be talking about over 2 feet of snow - but it's trucking pretty fast to the east. With that in mind there will be some limit as to just how much snow we can get. The storms speed - and intensity - introduces another problem into the equation and that's the fact we're going to see exceptional snowfall rates at the storm's peak - possibly up to 4" per hour. That is enough to basically immobilize the state for a period of time. This storm will be very bad at its peak.

The biggest reason we're expecting these heavy snowfall rates is a band of very strong convergence will set up about 10,000 feet up. This a classic signature for heavy snow with powerful winds slowing to a crawl overhead - essentially forcing air parcels to pile up and rise. The acceleration of air in an upward direction is how we get clouds and precipitation - and in this case snow. 

As I mentioned yesterday one of the things we're watching closely is the fact this strong "lift" or vertical motion is occuring where the temperature is around -15C up way above our heads in the clouds. That is the temperature at which snow flake growth is the most efficient AND the favored crystal type is a dendrite which allows snow to become fluffy and pile up quickly. A 15:1 ratio of snow to liquid is possible where this lift is maximized near -15C in the atmosphere.

I'm pretty confident there's going to be an area that gets more than 14" - maybe as much as 18". Again, the upward bound here is somewhat limited in that we're only going to have a short window of exceptionally heavy snow - it's a quick mover! Could there be more? Sure but let's not get too carried away just yet and also remember this heavy band will be very narrow geographically.

Where this heavy band sets us things are going to rip but it's important to note when these bands develop there tends to be bands of downward/sinking motion on either side of them. While some people get crushed other areas can miss out a bit. The haves and the have nots in a snowstorm (if my neighborhood is in a "have not" band I'll be livid and a supremely unpleasant person to be around tomorrow afternoon). Still, I think even with these "sucker holes" 8 inches of snow is a reasonable lower bound for most locations.

Here's the bottom line:

 

  • Snow develops across the state 5 a.m. to 8 a.m.
  • Heaviest snow between 8 a.m. and 2 p.m.
  • Snow gradually winds down 2 p.m. to 6 p.m.
  • 8"-14" will cover it in most areas - but a narrow band of higher snowfall totals is very possible. It's also conceivable that this heavy band sets up right along the I-84 corridor. 
  • Snowfall rates of 1"-4" per hour in some spots will make driving exceptionally difficult. This will be an extremely high impact storm given how quickly the snow will fall. 
  • Thundersnow is likely at the storm's peak.
  • Winds could gust to 40 m.p.h. in southeastern Connecticut but we are not expecting widespread wind issues or any coastal flooding.
What could go wrong:
  • The truly heavy snow with winds up setting up in one corner of Connecticut (say northwest or southeast) leaving the large population centers in one of those subsidence zones. A possibility - but not likely.
  • Storm trends weaker and the forcing doesn't verify as currently modeled. We'd still get the low end of amounts but the really exceptional snow rates never materialize and some of my adjectives wind up overdone.
  • Best lift winds up above or below the -15C level and snow ratios are much closer to 10:1 than 12:1 or 15:1 as we're currently thinking.
Hopefully you can stay home from work tomorrow and enjoy the storm. We'll have you covered all day on NBC Connecticut. 


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<![CDATA[Thursday Snowstorm]]>Tue, 07 Feb 2017 20:46:01 -0500https://media.nbcconnecticut.com/images/160*120/gfs_6hr_precip_boston_9.png

It's been an unusually warm winter but most people don't realize we've had almost average snowfall across the state. Not surprisingly the next 48 hours will follow that trend with near record warmth Wednesday and a snowstorm on Thursday. 

Our current thinking is that we'll have a sizable snowstorm Thursday across all of southern New England. The worst of the weather will be between 7 a.m. and 2 p.m. Thursday with a pretty impressive blitz of snow - possibly on the order of 1"-2" per hour.

Right now we've kept the range fairly large as we'd like a few more computer model runs to get a handle on a more stable solution. Also, it's not clear which part of Connecticut is most likely to see banding of heavy snow develop - is it along the shoreline or farther north? Right now we don't know. What we do know is that the odds of a significant snowstorm have increased quite a bit today. The 21 member GFS ensemble shows all members producing over 3" of snow with most over 6" in Hartford. These are also calculated using a 10:1 snow:liquid ratio which is likely to be a bit on the low side with 12:1 or 14:1 more common.

One thing we're looking at is a band of very heavy snow Thursday morning. This is a time-height cross section of the NAM model which shows an area of very strong lift at temperature of -15C way above our heads in the clouds. This is critical as this is the temperature at which snowflakes grow the most efficiently AND the favored type of crystal is a dendrite which tends to pile up rapidly. This can increase the snow:liquid ratio. Where this overlap between lift and the -15C temperature level occurs very heavy snow is likely.

While we can't rule out more than a foot of snow in some spots I think our upper bound of 12" works for now (I know other outlets are talking about 18" of snow). Here's why...

 

  • Storm is a quick mover - heavy snow will only last 4-6 hours across most of the state.
  • The storm's track is still awfully far south of New England - most of our computer models have it passing underneath the 40N/70W "benchmark".
  • A subtle shift to the south could reduce totals overall - this is a possibility.
  • There's no closed 700mb or mid level low which tends to be a feature in almost all classic New England snowstorm - this storm has a broad area of strong convergence and frontogensis at 700mb but no rapidly closing or closed low. 
  • The 51 member European Ensemble has 0 members that produce over a foot of snow in Connecticut.
The bottom line is that this storm continues to look significant. There is still a chance a small shift in the storm south could result in less snow but at this point we feel pretty confident in the 6"-12" forecast. All of this winds down by Thursday afternoon. Happy shoveling!


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<![CDATA[Ice, Warmth, and Snow]]>Mon, 06 Feb 2017 15:11:26 -0500https://media.nbcconnecticut.com/images/213*120/Model+RPM4+Precip+Cloud+Temp+CT+%282%29.png

There's going to be a lot going on over the next 3 days. Tomorrow's weather concern is ice, Wednesday's excitement is warmth, and Thursday's trouble is snow. Let's take it one day at a time.

The storm that is moving in tomorrow is only a shell of its former self. Sort of. Last week our computer models showed a powerful storm tracking near Toronto with all sorts of heavy precipitation moving into New England. That's no longer going to happen. Lighter amounts of rain will move in Tuesday morning but the problem remains that temperatures will be near 32 degrees as the rain begins. 

Temperatures above our heads will be well above freezing tomorrow - but at the ground a stale layer of cold air will be tenacious. There's a lot of inertia when it comes to dislodging cold and tomorrow won't be any different. As rain falls temperatures near the ground will be at or just below 32 degrees. For many areas just away from the Sound this could be an issue around daybreak with a few light showers. All it takes is a tiny bit of precipitation to ice up untreated surfaces!

While temperatures in the valley locations will warm above 32 degrees by midday the temperatures in the hills will not. In fact, it looks like a prolonged period of icing will occur in the Northwest and Northeast Hills where 0.1 to 0.25" of ice accretion is possible. Even by 7 p.m. tomorrow the NCAR ensemble model shows a >50% chance of temperatures below freezing for many places over 500 feet of elevation.

This is not enough ice to cause power outages but is enough to make any untreated walkway or driveway really slick. 

  • Brief period of icing possible in many areas around the morning commute. Treated roads will generally be OK but any untreated areas will be slippery.
  • By mid-late morning most valley and shoreline locations will be above freezing.
  • Prolonged freezing rain is expected in the hills tomorrow - and temperatures in some areas may never climb above 32 degrees. Thankfully ice accretion amounts should not be enough to cause tree or power line issues.

As for Wednesday - the cold at the surface will mix out allowing temperatures to spike. 60 degrees is not out of the question in some areas but right now we're predicting highs in the 50s.

I mentioned above that Tuesday's storm has become much less impressive over the last several days. One consequence of that is that a second piece of energy is able to swing far enough north to clip us with snow. Had the Tuesday storm been stronger the storm track would have been hundreds of miles farther south. 

Unfortunately, there's not much we can say about the Thursday storm other than accumulating snow is a possibility AND the storm as a reasonable shot of being decent (i.e. more than 4"). This storm is producing an unusually large spread of possible outcomes on our computer models. Take for instance the GFS ensembles (the GFS model run with slight tweaks 20 different times to show a range of possible solutions) which show a HUGE spread. Anywhere from 0" to 10" of snow for Hartford. 

That's about as detailed as we can get about this one - there's the potential for snow but I have no idea if it will be a big storm or we get brushed by with a few flurries or period of light snow. Small tweaks and changes in the jet stream pattern will mean a lot here. I get that a forecast of "we don't know yet" is annoying but as a scientist there's really not much more I can do at this point. This storm is showing a really unusual amount of spread in possible solutions.

As we like to say in TV... stay tuned!


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<![CDATA[Tuesday/Wednesday Storm Trends Warmer]]>Sat, 04 Feb 2017 11:25:09 -0500https://media.nbcconnecticut.com/images/160*120/gfs_t2m_b_neng_19.png

Whether it's just noise at this early juncture or the beginning of a more substantial trend it's hard to say. There's been a notable jump to a warmer solution for the Tuesday and Wednesday storm which would mitigate the ice threat on the front end and allow temperatures to soar into the 50s on Wednesday.

At the onset, it still looks cold enough for some ice on Tuesday. You can see the light to moderate precipitation moving into southern New England with temperatures pretty close to freezing. This would ice some things up for the morning commute.

The biggest reason for the change is a change in the strength and location of a cold high pressure to the north of us. This high appears weaker over Quebec and is also getting dislodged and shunted east quickly. Without a strong high to our north feeding cold and dry air into New England we're not going to avoid a surge of very warm air coming in. 

At this point I'd still be on the lookout for wintry weather on Tuesday as this could easily change back to something a bit colder and more interesting. We'll see if the trend continues.


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<![CDATA[Quiet Weekend Followed by a Large Storm]]>Thu, 02 Feb 2017 15:22:38 -0500https://media.nbcconnecticut.com/images/160*120/gfs_pr6_slp_t850_neng_25.png

For a couple days we've been watching a chance for a minor snow event on Sunday. This is becoming less and less impressive. A weak upper level disturbance will swing through and may be able to trigger a period of light snow on Sunday. At this point any accumulation is quite unlikely and I only have a 10% chance of measurable precipitation (0.01" of liquid or more) in the forecast.

The storm on Tuesday and Wednesday continues to look very impressive. Take today's European model valid Wednesday afternoon. It has a 971mb low (check out how far to the left that is on your home barometer) over southeast Canada. If this were to verify temperatures could approach the 60 degree mark along with periods of heavy rain and damaging winds. It would be quite a storm.

Even if the wet, windy, and stormy Wednesday happens exactly as the European model is depicting - the front end of the storm still looks snowy and icy. As the leading edge of the storm's moisture moves in a well positioned high pressure to the north will feed down a supply of cold and dry air. This argues for a period of snow followed by icing as warm and moist air rides up and over the cold air near the ground. 

All of our models show this potential on Tuesday - the Euro, the GFS, and many of their associated ensembles. Obviously at day 5 and day 6 the details will have to be worked out. Here are some of the questions we need to figure out the answers to.

 

  • How impressive does that high to the north get? Will it remain locked in and provide a more extensive period of ice and snow?
  • How quickly does the moisture move in - does this start Tuesday morning before dawn or hold off until later in the day?
  • How quickly does warm air flood in aloft... how much snow before the change to ice. 
  • How strong does the low to the west of us on Wednesday get? A strong low over Toronto like the Euro shows would assure a change to rain and strong winds here while a weaker and more strung out low would mitigate the wind threat and potentially lead to more prolonged icing.
Right now we can tell you that the most likely solution is a wintry mix on Tuesday and rain/wind/mild temperatures by Wednesday. When we get a bit closer we'll be able to get a bit more specific! 


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<![CDATA[Stormy Week Ahead]]>Wed, 01 Feb 2017 14:57:18 -0500https://media.nbcconnecticut.com/images/160*123/ecmwf_apcp_f174_ne.png

The weather pattern over the next 7 days is anything but boring. A large storm to our west is going to bring in all sorts of issues Tuesday and Wednesday as it ejects out of the Rockies and heads toward the east coast.

In the winter we frequently look for a negative North Atlantic Oscillation / -NAO to force storms offshore and prevent them from cutting far to our west. In general, this kind of storm track can keep cold air locked in and prevent warmth from flooding north. Next week's storm won't have a -NAO to work with. Generally below normal heights over the North Atlantic and Greenland will help favor a track to our west - a warmer storm.

That said, there are still some interesting things to watch here. Both the GFS and Euro models bring a piece of this storm in on Tuesday. Enough lingering cold and a fairly well placed high pressure to the north of Quebec should provide enough cold air for a period of snow or mix. 

The main storm is still likely to cut to our west bringing in warmth on Wednesday with a period of rain. Temperatures in the 50s would be possible - especially away from the CT River Valley north of Hartford that tends to see cold air get trapped between the hills west and east.

If we're lucky we'll get a lot of rain out of this storm - we could use it. We'll have to watching the leading edge of whatever we get, however, as we could be dealing with a period of snow or ice. 


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<![CDATA[Snow Continues Through This Evening]]>Tue, 31 Jan 2017 14:14:13 -0500https://media.nbcconnecticut.com/images/176*120/16473288_1440394399327519_2085433135843357189_n.jpg

Today's snow is behaving pretty much as expected. I did think the heavier snow this afternoon would be a bit more widespread but it has been relatively patchy. There have been occasionaly reports of heavy snow but the snow by and large has been of the light to moderate variety.

Not surprisingly, roads have been a mess with accidents all over the place. Cold pavement temperatures allow almost every flake to stick.

I do think the snow will have some staying power this evening. As the main batch of it moves through by 5 p.m. we will see an area of lift developing in the low levels of the atmosphere through Massachusetts and northern Connecticut. This should allow snow to continue at a light clip through later this evening and tonight. Some additional accumulation will be possible. By the time the storm winds down 1"-3" of snow should be the final range across the state. 


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<![CDATA[On Ryan's Radar: Burst of Snow Tuesday Afternoon]]>Mon, 30 Jan 2017 19:57:15 -0500https://media.nbcconnecticut.com/images/213*120/C3babc0XUAIxk4D.jpg

It's not a lot of snow but the timing is unfortunate. A burst of snow is going to cause some issues for the evening commute Tuesday. It's a classic Alberta Clipper system diving out of Canada and heading toward New England. Anytime an upper level system dives underneath us this time of year it's worth watching.

One thing that I'm watching closely is a strong zone of lift in the lower parts of the atmosphere. A strong low level jet will lend itself to strong low level convergence and lift over Connecticut. It appears we're in the area where this low level forcing is maximized. This argues for a period of moderate to heavy snow across Connecticut right during the evening commute.

Right now I'm thinking 1"-3" of snow is likely across Connecticut. There is an opportunity for a bit more than 3" of snow - in the hills especially - if the snow is able to be "fluffy" in nature. At this point I don't see a huge signal for very light and fluffy snow (i.e. 15:1 or 20:1 snow to liquid ratios) but this will have to be watched. I do expect light snow to continue through most of the overnight across northern Connecticut and possibly through right around daybreak Wednesday.

Beyond tomorrow the weather pattern is looking active and more wintry. I expect several chances for snow or wintry mix through day 10. Stay tuned!


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<![CDATA[Too Much Sleet!]]>Tue, 24 Jan 2017 20:18:14 -0500https://media.nbcconnecticut.com/images/160*120/16174778_1431893626844263_2233783930146303729_n.jpg

This morning I measured 2.0" of sleet here in West Hartford. With a bit of rain added in the sleeted melted down to 1.05" of liquid - weight-wise it was about the equivalent of 10 or 11" of snow!

For days we have been talking about the sleet and along the I-84 corridor the sleet managed to pile up more than the 1" we expected as the change to rain took forever to arrive here in West Hartford. So what cause all this sleet? 

We get sleet as snowflakes fall from the clouds and melt due to a layer of air that's over 32 degrees aloft. As the melted snowflake falls lower to the ground it encounters air that is below 32 degrees below the warm layer causing it to refreeze. The layer of cold air has to be cold enough and thick enough to get the liquid drop to refreeze. 

This is harder to forecast than it sounds! For example, the warm layer really shouldn't be too warm. If it's over 3C the snowflakes completely melt which makes it harder for the drop to refreeze. Also, the cold layer needs to be deep enough and cold enough to get a refreeze to happen (a thousand feet of 31F isn't going to cut it). Oh yeah and on top of that it can't be too warm near the ground so the sleet pellets start melting again. 

Our models were pretty different with how the atmosphere's thermal profile would look - particularly around Hartford. This sounding valid at 10 p.m. is a 3 hour forecast off the High Resolution Rapid Refresh Model.

The warm layer is around +3.5C which would signal a change to rain as the drops would be ice free and have a hard time refreezing. As it turned out the actual warm layer around that time was closer to +2C. These are really tiny differences in the temperature structure of the atmosphere that have a huge difference in the final outcome. All of our high resolution models played catch up all day and all evening limiting the warmth in that warm layer. 

In the end I'm pretty pleased with the forecast - though it wasn't perfect. We were more bullish with the sleet and wintry weather potential than anyone else in the market and even the typically bullish National Weather Service leading up to the event. The storm produced more sleet than I expected around Hartford given the very delayed transition to rain. Out east and along the coast, things worked out quite well with warmer temperatures in that warm layer and warmer near ground temperatures resulting in mainly rain as far north as Killingly. The possible change to snow in Litchfield County we thought was a possibility did not occur so they wound up on the low end of our very large 2"-6" range that allowed for that possibility. 

Onto the next one!


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<![CDATA[Ugly Evening of Weather]]>Mon, 23 Jan 2017 19:22:55 -0500https://media.nbcconnecticut.com/images/160*120/hrrr_ref_neng_7.png

A wind-driven sleet across the state this evening. Hideous. Temperatures are generally above freezing so we're expecting roads will be a bit slushy inland but with the exception of the hills they should not freeze up. Along the shoreline we'll see mainly rain besides a few sleet pellets. 

The reason for sleet is that we have warm air in the clouds causing snow flakes to at least partially melt with a cold pocket of air around 3,000 feet above our heads. That causes the partially melted snow flake to refreeze into an ice pellet! This sounding off one of our computer models for this evening in Windsor Locks shows a classic sleet setup. A warm layer of about +2C about 7,000 feet above our heads with a deeper subfreezing layer about 2,500 feet above our heads near -4C. 

The accumulation forecast is a real pain. 1" of liquid rain generally produces about 10" of snow - but only about 3" of sleet! With that in mind getting excessive sleet accumulation is really tough to do. I do expect we'll see accumulation of around an inch on the I-84 corridor with 1"-2" in the higher elevations just northwest of there and even in parts of the Farmington Valley and Northeast Hills.

In the Litchfield Hills, there is likely to be a bit of snow that mixes in as well. We've put out an unusually large range of 2"-6" forecast for the Litchfield Hills northwest of Torrington/Winsted to account for this possible change to snow which would allow for accumulation to add up more quickly. 

Strong winds will continue across the state with gusts up to about 50 mph along the shoreline. This should fall short of what I expected yesterday which is good. Also, tides are quite low today so even with 3 feet of storm surge coastal flooding will be minor. 


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<![CDATA[Big Nor'Easter Moves In]]>Sun, 22 Jan 2017 16:57:11 -0500https://media.nbcconnecticut.com/images/160*120/hires_tprecip_boston_52.png

Things are going to turn pretty ugly by tomorrow evening. A big nor'easter is going to cause all sorts of issues in Connecticut including damaging winds, heavy sleet, and coastal flooding. 

The one change to the forecast is to delay the storm's arrival by several hours - it looks like substantial precipitation will hold off until the afternoon at the earliest. Winds should crank prior to the precipitation's arrival, however.

The storm is a big one and we're talking about some really impressive anomalies here. The U-wind anomalies are approaching -6 standard deviations which shows that this storm is quite powerful. Strong wind gusts are expected in areas where the atmosphere can remain mixed - that is most likely to happen in the hills and along the shoreline. This sounding off the NAM model shows the potential for 60 mph wind gusts in New Haven as early as mid afternoon Monday. Scattered power outages are expected in some areas.

The second issue is going to be sleet - potentially a lot of sleet! There is going to be a warm pocket of air about 6,000 feet above our heads which should preclude snow in most locations. But as those snowflakes melt they'll run int a much colder pocket of air about 3,000 feet above our heads which should turn the melted snowflake over to an ice pellet. We are now expecting a relatively significant amount of sleet - 1" to 2" north and west of I-84 with up to an inch elsewhere (except the shore). Temperatures will remain at or above 32F in the valley and along the shoreline which should mitigate accumulation of sleet some. 

In the Litchfield Hills temperatures will be even colder through the atmosphere and some mix with snow is expected as well. In these areas 2"-6" of mainly sleet and some snow is expected. This is going to be tough to shovel and an all around pain in the butt. The range is pretty large for now because I expect there will be large differences in snow and sleet accumulation over a short distance. The valley locations get the low amounts (i.e. downtown Torrington) while the hill tops get the higher amounts (i.e. Norfolk and Hartland). 

Keep in mind that sleet accumulates at a much slower rate than snow. 1" of liquid precipitation yields about 10" of snow but only about 3" of sleet.

With this powerful storm we're also going to have to deal with excessive precipitation. Besides a wind-driven sleet we'll also see the precipitation mix with and change to rain in many locations. Some areas could see up the 3" of liquid precipitation by the time all is said and done with most areas around 1"-2". 

As for coastal flooding - we're in luck! Low astronomical tides plus the peak surge occuring at low tide should spare us from major issues. That said, with an easterly wind and big waves we should see at least some issues from splashover especially west of New Haven. 

Here's the bottom line:

 

  • Light precpitation Monday morning is not expected to cause any issues (temperatures will be above freezing so icing is not expected).
  • Winds will pick up Monday afternoon with gusts to 50 mph possible around Hartford (there's a bit of uncertainty as to how high the winds will get in the valley as there could be a shallow stable layer that prevents the strong winds from mixing down) and wind gusts as high as 65 mph in southeastern Connecticut. 
  • Scattered power outages are likely Monday afternoon and Monday night.
  • Heavier sleet (rain coast) moves in during the evening commute and could mix with or occasionally change to snow in the highest hill towns. 
  • A brutal evening of weather is expected with strong winds - especially at the coast - with a heavy, wind-driven sleet across the interior mixing with and changing to rain from time to time.
  • 1"-2" of sleet is expected along and north of I-84 with 2"-6" of sleet and a bit of snow in the hilltowns of northwest Connecticut. Up to an inch of sleet is possible elsewhere in the state away from the immediate shore.
  • The Tuesday morning commute will be OK in most locations with temperatures above freezing. Some lingering slushy patches from the sleet is possible in the hill towns. 


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<![CDATA[Monday's Nor'Easter]]>Fri, 20 Jan 2017 17:20:23 -0500https://media.nbcconnecticut.com/images/160*120/gfs_6hr_precip_neng_16.png

Monday's nor'easter isn't going to be the strongest we've ever seen but it is going to produce a few issues across Connecticut including a bit of snow and sleet followed by heavy rain and strong winds.

There's no question Monday's storm has trended a bit milder. Strong onshore easterly flow should result in a mostly rain even but it should be cold enough for some mixed precipitation at the onset. Here's a time-height cross section of the ECMWF model which shows a pocket of subfreezing air just 2-3,000 feet above our heads between 7 a.m. and 1 p.m. on Monday. This quickly warms by Monday afternoon. 

In the Northwest Hills there is still the potential for some minor snow and sleet accumulation but this is becoming a bit less likely. Odds of >3" of snow for places like Norfolk on our European ensemble is only about 1 in 4 - down substantially from yesterday's runs. A warmer trend.

A strong pressure gradient - the difference between the high to the north and coastal low to the south - is going to produce a period of powerful winds at the Connecticut shoreline. The NAM shows winds in excess of 70 knots over Long Island Sound by Monday evening just about 2,000 feet up. Thankfully, most of this will stay above our heads some of it will be able to mix down to the surface - particularly near the Sound. Wind gusts to 60 mph are a possibility.

Here's my latest thinking:

  • Snow/sleet develops Monday morning with rain at the shoreline.
  • Snow/sleet quickly changes to rain in most places with only some minor accumulation expected in the hills.
  • Winds become gusty during the afternoon and evening with gusts to 45 mph inland and up to 60 mph at the shoreline. Power outages are possible.
  • Minor to locally moderate coastal flooding (low astronomical tides). I don't forsee this being a major issues.
  • 1"-2" of rain in many areas with localized pockets of heavier rain - particularly in the Litchfield Hills. 


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<![CDATA[Monday Nor'Easter Trends Colder]]>Thu, 19 Jan 2017 20:56:08 -0500https://media.nbcconnecticut.com/images/160*123/gfs_op_apcp_f108_ne.png

Signals remain strong for an impressive coastal storm Monday and Tuesday off the coast of New England. A decent high pressure to the north and a strong low pressure to the south will create a substantial pressure gradient across the region.

It's no surprise that with a pressure gradient like this the low level zonal wind anomalies are quite substantial - exceeding -4 standard deviations! With such large anomalies there are all sorts of hazards that we'll have to watch for including excessive precipitation and damaging wind.

The questions I posed yesterday about this storm still remain. The most intriguing possibility is a trend to a slightly colder storm. Even with a very mild antecedent air mass this storm may just be able to threat the needle and produce some snow in parts of southern New England - especially in the elevated interior. Sleet remains quite likely for a period of time as well across the state. 

The European Ensembles show decent odds (>50%) of more than 3" of snow in Litchfield County later Monday and Tuesday. While heavy snow is very unlikely in the valley and shoreline I can't rule out heavy snow in the interior hills. 

With such a strong low level jet (winds near hurricane force a couple thousand feet above our heads) we'll also have to be concerned about damaging winds along the shoreline. This won't be a major issue (i.e. it happens a couple times per winter) but I could forsee scattered power outages and wind gusts up to 60 mph. 

This should be an interesting storm!


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<![CDATA[Big Storm Likely Early Next Week]]>Wed, 18 Jan 2017 20:00:03 -0500https://media.nbcconnecticut.com/images/160*123/ecmwf_apcp_f120_us.png

It's about time! Finally, a slow-moving storm has the potential to drop heavy rain across southern New England. The storm is still about 5 days out so there could be any number of changes between now and Monday. That said, some of the signals are impressive.

One signal I'm looking at is the GFS Ensemble M-Climate which is maxed out over eastern Connecticut for 24-hour precipitation totals. M-Climate looks at how this forecast compares to previous forecasts from 1985-2012. Basically every time period has been reforecast using the GFS ensembles and the current mean precipitation off the model is compared to those old forecasts. The "max" indicates that the current GFS ensemble forecast for rainfall is higher than any of those previous forecasts for a 3-month wind centered on January 24th. Impressive!

This plume diagram of the GFS ensemble for Providence, RI shows the huge values of precipitation being forecast for the time of year - nearly 2.5" of liquid. That is a big signal for a mean of 21 different ensemble members 5 days out. 

There are a few things to watch here:

1) Will this trend any colder? There's an awfully cold high pressure to the north of us over Quebec. While right now this is insufficient to produce snow in Connecticut it's getting awfully close just north of us in the elevated terrain. We will see a prolonged onshore flow so it will be tough with this kind of setup to get much snow of consequence in the valley or on the shoreline but it may be worth watching for the hills - particularly just north of us. If you're a snow lover in Hartford or New Haven I wouldn't give this storm much of a second thought.

2) How heavy will the rain be? Why the signal is there for excessive rainfall the really heavy stuff is always going to be dictated by small scale processes that are difficult to pin down 24 hours out - nevermind 5 days out! That said, the GFS ensembles and the Euro ensembles have impressive probabilities for heavy rainfall - the Euro has odds of >1" of rain between 50% and 80% across Connecticut. Additionally, the models are keying in on a few possible areas of heaviest rain - the east slopes of the Litchfield Hills (makes sense with upslope flow off an easterly wind) and eastern Connecticut through Rhode Island and Southeast Massachusetts which also makes sense given the setup.

3) Damaging wind threat. With a high to the north and an unusually strong and slow moving low to the south we could see some gusty winds for a period of time. This is very uncertain but is worth watching particularly along the shoreline. 


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<![CDATA[Ice Continues in the Hills]]>Tue, 17 Jan 2017 20:22:13 -0500https://media.nbcconnecticut.com/images/160*120/hrrr_ref_boston_2.png

As expected a nasty evening of weather has developed in the hilltowns of northwest and northeast of Hartford. Temperatures have dropped below 32F in many elevated spots thanks to a steady supply of colder and dry air beings drawn south by a developing low just south of Connecticut.

This northerly drain of cold will continue through the evening and the freezing rain will continue. Thankfully, ice accretion should be less than 1/4 inch which is generally the threshold at which trees and power lines can begin to see damage. 

For areas with temperatures above freezing it's a cold rain with occasional sleet pellets. I do think there will be some slick spots lingering in the hills tomorrow morning - don't be surprised if we see some school delays. 

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<![CDATA[Icy Tuesday Evening in the Hills]]>Mon, 16 Jan 2017 14:48:35 -0500https://media.nbcconnecticut.com/images/160*128/hires_t2m_boston_40.png

A prolonged period of icing across parts of interior Connecticut is becoming more likely on Tuesday evening and Tuesday night. This has been in our forecast for a few days now and it appears as if parts of Litchfield County could see 1/4" of ice accretion.

The setup is not a classic ice storm look - with a relatively weak high pressure over Quebec retreating east into the Maritimes. But, it is a setup where stale cold air becomes easily trapped up against the east slopes of the Litchfield Hills. This happens quite often every winter. The reason why temperatures will stay cold enough for ice in the hills is that a weak area of low pressure will form south of us keeping winds light and out of the north. If that low to the south didn't form the wind would be out of the south resulting in a large jump in temperatures as milder air would flow north with no obstruction.

The reason we're expecting freezing rain is that temperatures in the clouds about 5,000 feet above our heads will be well above freezing - near 40 degrees! This will melt all the snowflakes falling toward the ground. However, a shallow layer of cold air near the surface will keep surface temperatures below 32 degrees resulting in the rain freezing on contact. This sounding from Norfolk, CT off the NAM shows the sub-freezing layer in the lowest levels of the atmosphere quite well.

While there may be some brief icing in the valley locations around Hartford requiring at least some treatment it appears areas above 400 feet are most at risk for a solid glaze of ice. Up to 1/4 inch of glaze appears likely with great agreement on all of our computer models. Generally this much ice is not enough to cause more than an isolated power outage but will make any untreated surface very slippery. It looks like the freezing rain and icing will begin in western Connectciut after 4 p.m. - with most areas not seeing it until after 6 p.m. 


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<![CDATA[Prolonged January Thaw]]>Wed, 11 Jan 2017 11:29:37 -0500https://media.nbcconnecticut.com/images/160*120/gefs_t850a_5d_noram_53.png

If you love winter weather - draw the shades and go into a 10+ day hibernation. The pattern looks pretty hideous for people who like cold and snow for the 10-14 days.

This morning temperatures have climbed into the 50s in many areas with our few inches of snow vaporized overnight. A combination of high dew points and gusty winds resulted in a dramatic loss in snowpack across the region. Here's my sad dead Christmas tree on a dirty snow pile in my front yard. 

Looking forward besides a dip in temperatures over the weekend the weather pattern is going to turn quite warm. In fact, if you were to look at the forecast weather maps for next week without a date and timestamp you'd think it was a map for early spring!

So what's the cause? A large dip in the jet stream over Alaska and northern Pacific Ocean will allow warm pacific air across the northern hemisphere. The jet stream retreats far to the north resulting in very large positive temperature anomalies across central and eastern Canada and the U.S. Locally, you can see that with this GFS ensemble temperature trend over the next 16 days with virtually all the ensemble members above climatology. 

In the winter you can never rule out a wintry storm to sneak up on southern New England even in an otherwise warm pattern but it's not looking good - especially outside of the hills or inland areas with no source of cold air to the north. 


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<![CDATA[Very Light Icing Possible Tonight]]>Tue, 10 Jan 2017 09:11:38 -0500https://media.nbcconnecticut.com/images/160*120/hrrr_ref_neng_13.png

A surge of warmer air is going to drive a warm front through New England aloft this evening - but temperatures near the ground will still be close to 32F. As the warm air surges in we'll see a period of very light precipitation develop around sunset which could lead to some icing on any untreated surfaces. In the hills it should be cold enoughf or a period of very light snow. 

After a cold snap, especially with snow on the ground, temperatures on paved surfaces can remain subfreezing even as air temperatures warm. Any surface that's salted will be fine but anything that is not could become slick. We're looking at the 4 p.m. to 8 p.m. window this evening. This sounding from Hartford off the NAM model shows low level temperatures near 32F with some moisture moving in. 

All in all this doesn't look like a major issue but anything that appears wet around nightfall could be slippery. Temperatures will warm well above freezing after midnight with a period of heavier rain moving in. 


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<![CDATA[Snowstorm Totals]]>Mon, 09 Jan 2017 10:08:02 -0500https://media.nbcconnecticut.com/images/160*120/15871928_1414514568582169_7707860335976884737_n.jpg

The forecast for yesterday worked out pretty well! There was a sharp gradient in the state with relatively little snow falling in northwestern Connecticut and nearly a foot in some towns in the Quiet Corner. Here's a look at some snow totals across the state. 

  • Brooklyn - 11.3”
  • Moosup - 10.8"
  • Norwich - 9.5”
  • Dayville - 9.1”
  • Uncasville - 9.0”
  • Stonington - 8.7”
  • Stonington - 8.1”
  • Madison - 7.2”
  • Waterford - 7.2”
  • Griswold - 7.0”
  • Norwich (official) - 7.0”
  • Waterford - 6.7”
  • New London - 6.5”
  • Staffordville - 6.0”
  • Newtown - 6.0”
  • Westbrook - 6.0”
  • Glastonbury - 6.0”
  • Storrs -5.8”
  • Bridgeport (official) - 5.7”
  • Prospect - 5.6”
  • Prospect - 5.5”
  • Mystic - 5.5”
  • Hebron - 5.5”
  • North Grosvenordale - 5.5”
  • South Windham - 5.5”
  • New Canaan - 5.4”
  • Somers - 5.1”
  • Monroe - 5.0”
  • Shelton - 5.0”
  • Darien - 5.0”
  • Portland - 5.0”
  • Bethel - 4.9”
  • Milford - 4.8”
  • Bethel - 4.5”
  • West Hartford (NBC Connecticut) - 4.5”
  • East Hartford - 4.5”
  • Farmington - 4.5”
  • Norwalk - 4.3”
  • Stamford - 4.3”
  • Glastonbury Center - 3.7”
  • Bristol - 3.5”
  • New Hartford - 3.3”
  • Norfolk - 3.3”
  • Windsor Locks (official) - 3.3”
  • Collinsville - 3.2”
  • North Granby - 3.2”
  • Enfield - 3.1”
  • North Canton - 3.0”
  • Colebrook - 2.9”
  • Newtown - 2.7”
  • Watertown - 2.0”
Snow totals are from NBC Connecticut weather watchers, National Weather Service official cooperative observers, and CoCoRaHS observers. Joining CoCoRaHS is a great way to provide valuable rain and snow observations to meteorologists across the country! 
Note: Some towns may have more than one total if multiple measurements were taken at different locations within town.


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<![CDATA[Snowstorm on Track Today]]>Sat, 07 Jan 2017 20:48:08 -0500https://media.nbcconnecticut.com/images/213*120/C1lTsz0XcAAAwAd.jpg

Evening Update: Everything worked out pretty well! I'm a little disappointed with my 4.5" of snow in West Hartford but the forecast worked out well. Heavy snow southeast of here did pile up with a band in excess of 10" - in areas from East Haddam to Moosup. This was a band I was highlighting since about noon on the air so that worked out well. As expected, areas in far northwest Connecticut did poorly with only about 1.5" in Falls Village.

This storm is a good reminder of the difficulty the Connecticut River Valley north of Middletown has on the fringes of storms with a dry northerly wind. That northerly drain is a killer to snow as snow rates diminish as drier air moves in. 

Midday Update: Based on radar trends, short term modeling (like the HRRR), and continued signs of really great snow growth (high snow:liquid ratios) I've upped the snow accumulation forecast for many areas. I have Hartford and New Haven in the 5"-10" category now - with the best chance of 10" east of those cities. 

Morning Update: A subtle tick offshore/east on our overnight computer model runs means our going forecast is good to go. No need to make any changes here. Yesterday evening I thought I may need to bump totals up some - or at least move the bands to the west - but I no longer think that's necessary. 

The big reason we're forecasting decent snow is because the snow will be very light and fluffy. Just like yesterday morning's snow we're talking about snow:liquid ratios on the order of 15:1 or 20:1 which is 150% or 200% of normal. The reason why is that we will see most of our snow flakes form around -15C which is the favored temperature for dendrites - the beautifully ornate branched snowflakes. This sounding off the GFS shows a deep layer (over 10,000 feet) with temperatures between -12C and -18C that's also saturated - a good sign for fluff!

As I discussed yesterday the extra boost this storm is going to have is a nice area of low level convergence over Connecticut that will add to the "lift" and create a band of extra vertical motion over our state. Air will be forced to pile up as it exits a jet streak about 5,000 feet above our heads. This feature is still visible on all our morning model runs.

We'll keep you posted all day! 


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<![CDATA[Saturday Snowstorm on the Way]]>Fri, 06 Jan 2017 19:43:53 -0500https://media.nbcconnecticut.com/images/213*120/C1g18zFW8AAuawP.jpg

Evening Update: Tomorrow's storm is looking more and more impressive. For the last 2 days almost every computer model run has brought this storm closer to Connecticut. There is no question our forecast has changed since yesterday but that's what happens in the weather business! I think this storm is going to produce even more snow than the computer models currently show based on several factors. 

The first thing we can look at is how much liquid precipitation our models are dropping over New England. The GFS, the most paltry, has about 0.3" of liquid in Hartford/New Haven and close to 0.5" in New London. Other models are a smidge higher than this - including the Euro, Canadian, and NAM.

I expect the models to continue to trend higher with more liquid precipitation for several reasons. One of the reasons is that we have a pretty sizable amount of lift - centered in the mid levels of the atmosphere about 20,000 feet above our heads during the afternoon. Strong differential cyclonic vorticity advection (DCVA) over New England will promote rising motion and that leads to clouds and snow.

If that was the only feature we'd be talking about a couple inches and we'd move on. But what is quite intriguing is a burst of low level convergence that is consistently showing up on our models. Let's look at winds about 5,000 feet up. Winds will be quite strong out of the east out toward Providence and southeastern Massachusetts for a period of time. Here in Connecticut the winds will be much lighter. This produces convergence as air is effectively forced to pile up and the only place it has to go is up.

That signal should lead to additional snow and maybe even a heavy burst of snow farther west than we'd typically see it for an offshore storm. This signal is strongest right along the I-91 corridor. The fact this mini low level jet is so far removed from the low center, and shows up on all our computer models, means that this storm will behave differently than most storms that track well southeast of Nantucket. 

The other positive for heavy snow is the fact that all of this lift (both the mid level and low level stuff) will occur with cloud temperatures between -12c and -18c. For a snow geek these temperatures are pretty exciting :) At those temperatures ornate snow crystals known as dendrites will be the favored crystal type. These crystals grow the most efficiently and when they land on the ground they can accumulate very quickly! This will lead to snow:liquid ratios greater than the typical 10:1 around here. For the duration of the storm we will likely be closer to 15:1 or even 20:1. Almost 14,000 feet of the atmosphere will be between -12c and -18c and that is a VERY large dendritic growth zone and can promote a lot of efficiently growing, big, fat and fluffy flakes. Fluff factor!

I took pictures of dendrites this morning in West Hartford on the roof of my car that managed to accumulate at a 20:1 ratio. This morning's snow was also super fluffy.

Putting it all together I feel confident that this storm is going to perform better than most raw model guidance shows. I'm predicting 4"-8" of snow for Hartford and New Haven but I could easily see those numbers going up where some bands of heavier snow form. That will most likely be in eastern Connecticut but I can't rule out a jackpot farther west - including the Hartford/New Haven corridor. While the Route 8 corridor (Waterbury/Bridgeport/Torrington) is currently in the 2"-4" zone if the evening computer models show the current trends continuing these numbers will have to be increased. For what it's worth, I think the National Weather Service forecast is too conservative which is odd because frequently they are the most bullish and out there with snowfall predictions. 

Afternoon Update: Quick update to the forecast. I've really bumped up our accumulation forecast as far west as I-91. We're expecting fluffy snow to accumulate readily tomorrow - just like it did this morning. That, coupled with a western shift in the storm track, leads to even more snow. I can't rule out an isolated 10" amount near the Rhode Island border if the western jog continues. More to come shortly...

Morning Update: A morning fluff bomb managed to drop up to 3 inches of snow in southeastern Connecticut thanks to unusually high snow:liquid ratios. For example, Stonington picked up 2.5" of snow as of 7 a.m. with only 0.10" of liquid. A more typical snow:liquid ratio in New London County is 10:1!

Now our attention turns to tomorrow. The European model jogged west my a good amount overnight bringing more significant snow in eastern Connecticut while our other models remain a bit more tempered.

This is a tough forecast! 3-6" of snow seems possible now along the I-395 corridor with 1-3" on the I-91 corridor. I expect that this could change quite a bit in either direction given the difficulty our computer models have had with this storm. 


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<![CDATA[Morning Fluffy Snow ]]>Thu, 05 Jan 2017 20:07:14 -0500https://media.nbcconnecticut.com/images/213*120/C1VyrQEXEAAd5u6.jpg

Get excited for it - a coating to 2 inches of snow is on the way! It's about as unimpressive of a storm as you can get. A more apt way to describe it is an atmospheric burp. But that burp is going to manage to squeeze out a period of light snow tomorrow morning during the commute.

One of the reasons I'm expecting some accumulation is the fact there will be a very deep layer of moisture in the atmosphere where the cloud temperatures are around -15C. This is an exciting temperature for winter lovers. Between -12C and -18C snow flakes grow with great efficiency and the favored type of crystal are ornate dendrites. This forecast sounding off the GFS for Hartford shows a deep layer of cloud around -15C (it's shaded in yellow) with some lift. That should lead to a period of fluffy snow flakes that could accumulate to an inch or two in some towns even if we only pick up less than a tenth of an inch of liquid precipitation. 

Beyond tomorrow morning's little snow we're watching an offshore storm for Saturday afternoon. While there has been a shift of this storm closer to the coast I'm not sure if it will track any farther west. I do expect a period of snow for parts of Connecticut - especially eastern Connecticut - but significant snow is unlikely. The 51-member European Ensemble has only a 10-20 percent chance of more than 3" of snow in far southeastern Connecticut - but a 50% chance of >1" of snow. 

We'll be watching Saturday's system closely but it appears to be a much bigger system for the Cape than it will be here in Connecticut. 


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<![CDATA[Snow for Friday]]>Wed, 04 Jan 2017 18:59:15 -0500https://media.nbcconnecticut.com/images/213*120/C1VyrQEXEAAd5u6.jpg

Gusty winds will usher in colder temperatures tonight and by Friday we'll have some snow flakes in the air. There is not much of a storm on our way - it's more of a ripple in the atmosphere that results in enough "lift" to squeeze out a period of snow. 

The 51 european ensembles show the best odds of more than 1" of snow in southeastern Connecticut with lower odds to the northwest of there. This seems pretty reasonable.

We're not going to pick up much from this storm but there will be a bit of a fluff factor. What do I mean by that? Essentially most of the lift in the atmosphere will occur in the clouds where the temperature is near -15C which is the temperature at which dendrites - those beautiful ornate snow flakes that can pile up quickly - are able to form. Additionally, this is the temperature at which snow flakes form most efficiently. This model sounding off the NAM in Groton shows modest lift centered right near this magic temperature Friday morningh. 

Getting lift in the "dendritic growth zone" as we like to call it can result in snow:liquid ratios that exceed the typical 10:1. For example, normally around here we get about 10" of snow for every 1" of liquid. When dendrites are the preferred ice crystal they grow quite rapidly and efficiently and also pile up quickly when they land on the ground. It's not unusual to squeeze out 20 or 30 inches of snow per 1 inch of water if you're looking at all or mainly dendrites. So while we'll struggle to get a tenth of an inch of liquid - getting 1-2" of snow would be a possibility in some areas. 

So expect a few fluffy flakes Friday morning during the commute with a bit of accumulation. A coating to a half inch or so around Hartford seems reasonable with a few pockets of up to 2 inches near the shoreline. 


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<![CDATA[Dropping Temperatures - Any Snow? ]]>Tue, 03 Jan 2017 19:31:18 -0500https://media.nbcconnecticut.com/images/213*120/C1Rb3vGUsAEEKqL.jpg

A blast of cold weather is on the way to southern New England by Thursday but will we have any snow to go along with it? Don't get too excited just yet. 

There are two systems we'll be watching - one on Friday and another later Saturday. Most of our computer models show misses. As the cold builds in the jet stream is going to sink south and effectively keep the storm track well south and east of us. While we could see a few flurries or a period of light snow on Friday the storm to watch is over the weekend.

The European model is the most amplified with the Saturday system. Taken at face value the European model would deliver up to 6" of snow to Cape Cod and a bit of accumulation to southeastern Connecticut. This solution is an outlier, however. The European ensembles show a range of solutions including a total miss to some minor accumulation. If we look at all 51 computer model solutions off the European Ensembles about 1 in 4 of them produce over 1" of snow - not exactly big odds but enough to watch it. The odds of over 3" of snow are closer to 1 in 10. 

While snow is less than certain we are certain of a big temperature drop. Nothing record breaking or unusual for January but it will turn pretty chilly. Both the European and GFS models show a stretch below freezing for a good 72 or 96 hours. 


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<![CDATA[A Rainy and Slushy Thursday]]>Thu, 29 Dec 2016 14:25:38 -0500https://media.nbcconnecticut.com/images/160*143/snowacc_mean_f036_NE.png

Afternoon Update: The forecast appears to be on track across the state. I've made a couple tweaks to the snow map to show a sharper gradient from the valley to the hill towns. We're expecting a change back to snow in many of the hilltowns as the storm winds up and pulls away from Connecticut. The Rapid Refresh model shows this pretty well with a few snow flakes as far south as Colchester with cold air filtering in. 

Previous Discussion: 

A powerful storm is going to develop near Connecticut today but it will be a bit too late for a significant impact here. Still, some slushy snow accumulation is likely in the hills and up to an inch of rain for the rest of the state. The NCAR ensemble mean snowfall shown above shows snow totals >2" restricted to the hills of northwestern Connecticut. The NCAR ensemble is one of my favorite pieces of model data to use in the short term!

Almost all of our computer models now agree with little if any accumulation in Hartford with the potential for a couple inches of slush in the hills. The one thing that we'll have to watch is a band of heavy precipitation that will develop on the northwest side of the strengthening low. If this develops far enough south it could clip some of the hill towns. The latest Canadian Regional model (RGEM) shows this happening with a few inches of snow accumulating in some of the northeast hill towns. While we're not forecasting that now it is something we'll have to watch today as the rain attempts to transition back to snow.

The forecast seems good right now - snow and rain overspreading the state through 11 a.m. and quickly changing to all rain in most areas. Expect marginally cold temperatures to linger in the hills keeping the precipitation a rain/snow mix up that way. 


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<![CDATA[Why Thursday's Storm Won't Be a Big One]]>Wed, 28 Dec 2016 14:49:56 -0500https://media.nbcconnecticut.com/images/160*120/hires_ptype_neng_43.png

Afternoon Update: Our midday suite of computer guidance has come in and looks even less impressive for tomorrow. The storm develops a bit later - which keeps the strongest lift up to the north and subsequently keeps the lower levels of the atmosphere a bit milder. The GFS solution for tomorrow shows only a slushy 1"-3" in the hills with little if any accumulation in the valley. While we're not going to go this low yet that appears to be the direction things are going. The good news is that most of us will pick up a beneficial inch of rain or so.

Previous discussion below...

When a nor'easter is going to crush Connecticut with heavy snow you generally need a couple ingredients in place. The storm should track near Cape Cod (there is some wiggle room here) and you want a cold and dry high pressure system to the north over Quebec. Thursday's storm doesn't check those boxes.

The first issue for many of us snow lovers will be the track of the storm. Most of our computer models tuck the storm in close to the coast - closer to say Block Island than Chatham, MA. This tends to allow warm air to surge inland a bit as the storm organizes. 

The second issue this storm has is that that the antecedent airmass over New England is pretty ugly. There's no cold/dry high pressure to the north and we've only got some lingering stale cold air to play with. While this would be enough for the hill towns it likely will not be for the valley. 

You can see how this looks at the height of the storm on the NAM computer model for Bradley Airport and Norfolk, CT. The low level warmth on the NAM is quite impressive in the valley and would result in a mainly rain storm around Hartford while it's just cold enough in the hills for snow. 

So the bottom line is while this storm may still be impressive for the hill towns it's going to struggle for most of the state with a fair amount of rain. Temperatures will just be too warm for a substantial storm. 

 

  • Snow begins Thursday morning and transitions to rain in most areas besides the hills.
  • 6" of snow is still possible in the highest hilltowns of northwest and northeast Connecticut.
  • As the storm pulls away the rain should change back to snow during the evening commute around Hartford. There could be a bit of accumulation here but probably not more than a 1"-3" kind of deal. Still, a period of slippery travel is possible.
  • The brunt of this storm will miss us to the north - it should be great for ski country in northern New England.
  • Mainly or all rain is expected for the southerly third of the state.
So not a big storm for us - just doesn't check enough of the boxes - but many towns will pick up at least some snow on Thursday. 


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<![CDATA[Late Blooming Nor'Easter on Thursday]]>Tue, 27 Dec 2016 15:33:33 -0500https://media.nbcconnecticut.com/images/160*123/ecmwf_apcp_f60_ne.png

Things are going to get pretty interesting around here Thursday afternoon and evening! A pretty classic late developing nor’easter will approach southern New England on Thursday. Significant snow is possible for parts of Connecticut - especially the northwest and northeast hills.

What this storm is missing, however, is a cold high pressure to the north. If we had one we’d be expecting substantial snow down to the shoreline. This storm will be working with marginal and stale cold air - there’s not much room for error! 

All of our models agree in a late-blooming nor’easter as a powerful piece of upper level energy swings toward the coast. The question is really how quickly the storm develops with a range of scenarios on the table. The GFS, for instance, is the weakest and the last to develop the storm while the European model is substantially stronger and develops the low very quickly. The latter would allow for heavier snow here in Connecticut while to former would result in very little accumulation outside of thr hills. The Euro is probably a bit overdone with how quickly it's developing this storm while the GFS is probably underdone. Regardless, I feel fairly confident that the real "jackpot" from this nor'easter will be north of us in portions of New Hampshire and Maine.

So - what’s most likely here? At this point it seems as if more than 6” of snow is a good bet in the higher elevations of Northwestern Connecticut and also some of the high towns in northeastern Connecticut. A bit of elevation will go a long way in a borderline temperature scenario. The European ensembles show a 50% probability of 6"+ of snow for only the Litchfield Hills - the probabilities drop off quickly southeast of there. 

In the Hartford area things are really tough to pin down but at least a portion of the storm (if not a large portion) will be rain or a mix of rain and snow. This is the GFS solution (below) which shows temperatures >32F for the lowest 3 or 4,000 feet of the atmosphere at Bradley Airport as the storm gets going. Not a great look for snow-lovers. While the GFS is the weakest (and therefore the warmest solution) it does show the challenge here with such a borderline airmass. The Hartford area will be the battleground with the rain/snow line!

At this point I'd say a couple inches of snow is the most likely scenario around Hartford but it really will depend on how quickly the storm develops. A slower and weaker solution (like the GFS) would result in little accumulation while something closer to the Euro would mean a few inches - both are reasonable solutions and I'd probably go with a 75% Euro/25% GFS blend.

Along the shoreline I wouldn’t expect much at this point but I will say there is one concern. If the storm really “bombs out” quickly and one of the stronger model solutions were to verify (like the Euro or NAM shows) there is the possibility of a flip from rain to snow with a substantial accumulation in a relatively brief period of time. This is going to be very, very tough to forecast much more than 24 hours ahead of time so we’ll see.

The bottom line is that significant snow is a decent bet in the hills but in the valley and along the shoreline significant snow is much less certain - in fact along the shoreline it's quite unlikely. We'll be able to pin things down with much more certainty by tomorrow morning.


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<![CDATA[Merry Christmas - A Little Snow on the Way?]]>Sun, 25 Dec 2016 09:20:18 -0500https://media.nbcconnecticut.com/images/160*120/eps_snow24_1_neng_21.png

Good morning and Merry Christmas! There was some hellacious black ice out there last night and this morning across the state but things are looking up for the rest of today. 

A couple things to watch going forward. One issue is the potential for some really light freezing rain tomorrow in a couple of northwest hilltowns. The odds of this happening are fairly low, however.

There's a better chance for some snow on Thursday, however. The details aren't particularly clear but the European Ensemble is showing decent odds of >1" of snow across inland Connecticut (see graphic above). Temperatures will likely be borderline so this will likely favor the hills over the valleys and shoreline. This doesn't look like a big storm but rather a nuisance.  

Otherwise it's looking fairly quiet this week - hope you enjoy a great holiday!

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<![CDATA[Thursday Snow Showers]]>Wed, 21 Dec 2016 13:17:10 -0500https://media.nbcconnecticut.com/images/213*120/C0OAmcmWQAAFbdq.jpg

A bit of a tough forecast for Thursday across the state. Spread between our computer models has opened up for tomorrow. A weak upper level system is going to swing through New England and produce a period of "lift" in the atmosphere. That would argue for a period of precipitation but it's never that simple.

The question is will there be enough moisture for a period of moderate rain and snow across the state during the morning or will there be too much dry air? Our models offer up two different depictions. 

Here's the NAM's depiction of how the atmosphere will look at 7 a.m. Thursday. Notice where the green line juts to the left several thousand feet above our heads? This is very dry air and would lead to a quick and painless death for snowflakes falling from the clouds. The RGEM, on the other hand, moistens that layer up quickly and brings in a burst of precipitation between 7 a.m. and noon - nearly 0.2" of liquid. 

So which is right? While the RGEM and our in-house RPM models would argue for some minor accumulation in the hills (around an inch) this is likely overdone. The GFS and the European models both agree on a drier scenario along with all but 1 of the 20 member Short Range Ensemble. Given marginal temperatures and marginal precipitation rates we're going with little or no accumulation tomorrow. Speaking of which... here's the forecast:


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<![CDATA[Cool Christmas Expected]]>Tue, 20 Dec 2016 21:29:03 -0500https://media.nbcconnecticut.com/images/160*120/gfs_t2max_neng_22.png

This year it doesn't look like Santa Claus will be confused. Last year Christmas Day was exceptionally warm with highs in the 60s - 64F in New Haven and 62F in Hartford. Christmas Eve? An incredible torch! The temperature reached 69F in Windsor Locks and 70F in Willimantic!

Christmas 2016 looks decidedly more normal. The GFS pictured above has a strong high pressure moving across southern Quebec with a nice surge of low level cold nosing south. This would mean temperatures in the 30s to near 40 degrees across the state. Christmas-like!

Unfortunately, for most of Connecticut there will not be a white Christmas. In the hills there is a few inches of snow on the ground and that may be able to last for the next couple days. Elsewhere it's not looking good.

There is one possible Christmas miracle scenario. The European model has a period of light/moderate snow on Christmas Eve with up to 2" in Litchfield County. Could this include other parts of the state? Maybe but not likely. In fact the European Ensembles show only a less than 10 percent chance of getting an inch of snow in the hills so the Euro's snowy solution is definitely an outlier. 

At least Santa won't be wearing shorts this year!


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<![CDATA[A Break From Winter]]>Mon, 19 Dec 2016 09:10:09 -0500https://media.nbcconnecticut.com/images/160*120/gefs_t850a_noram_27.png

As we approach the winter solstice the weather pattern is becoming decidedly less wintry. For many of us it will be a green Christmas with no sign of significant snow over the next several days and a general warming trend.

Check out the forecast temperature departures at 850mb by Christmas - you can see a real surge of warmth across the eastern half of the country with a pronounced ridge of high pressure over the southeastern United States.

Beyond Christmas there's really no sign of a good push of Arctic air either. The jet stream will take a dip over the northwestern U.S. and the infamous Polar Vortex is going to gain strength over the North Pole which generally keeps the cold bottled up north of the Arctic Circle.

Still, there could be a few opportunities for snow and/or ice beyond 12/25. It's not a great pattern for snow lovers but it's not a hideous pattern either.

Unfortunately, it appears that a white Christmas is out of the cards for Hartford and New Haven. The Litchfield Hills, on the other hand, may maintain just enough snow cover to last for Christmas. Here's a look at some of the snow depth reports this morning in the towns that still have a few inches left...

 

  • New Hartford - 6.0"
  • Collinsville - 5.0"
  • North Canton - 5.0"
  • Enfield - 4.0"
  • North Granby - 3.8"


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<![CDATA[Thump of Snow Followed by Ice]]>Sat, 17 Dec 2016 13:52:54 -0500https://media.nbcconnecticut.com/images/160*120/Cz4_Vc1UQAEiz8Fa.jpg

Afternoon Update: The storm is now over. The impressive thump of snow behaved pretty much as expected with moderate to heavy snow across the state. The colder solutions on our models verified - and then some - effectively delaying the changeover to ice until the storm was over. In West Hartford I had 6.7" of snow/sleet but I would say maybe only 0.1" of that was sleet and there was no glaze of freezing rain. 

The colder trend allowed the shoreline to cash in (around 5" on the shoreline near New Haven) and allowed the Hartford area to perform a bit better than expected. 

The jackpot amounts were up in the Litchfield Hills where a small area of 7"-8" occured in places like Burlington, Harwinton, Riverton, New Hartford and Hartland. 

A bit of freezing drizzle will make things slick tonight so take it easy on the roads. 

Morning Update #2: Snow is quickly changing over to mix and ice on the shoreline. As expected we got a nasty thump right around 8:00 a.m. on the nose of that stronger low level jet. 

One thing to watch is freezing rain over the next few hours as warm air moves in aloft and begins to melting the snowflakes totally above our heads. The cold near the ground is impressive and is not going to be dislodged any time soon. Icy!!!!

Morning Update #1: No big changes to the forecast this morning other than to upgrade the snow forecast along the shoreline by a category. Cold air will hold on for the New Haven area a bit long as I thought was possible yesterday. 4" or 5" for metro New Haven now seems like a pretty good bet.

More to come...

There has undoubtedly been a trend today for a colder storm on Saturday. The result? More snow in many areas and an icy Saturday afternoon as temperatures struggle to reach 32 degrees.

The biggest part of the storm is going to be a thump of snow between 7 a.m. and 11 a.m. across the state. We will be on the nose of a strong low level jet streak (about 5,000 feet above our heads) which will result in strong lift and a burst of heavy snow of 1 inch per hour. 

This storm won't last long but I do expect it to be pretty impactful in the morning with a good burst! This sounding for Hartford illustrates what I'm talking about - a deep layer of moisture with good lift in the snow growth zone (around -15C). 

The biggest change to the forecast has been to hang on to cold temperature longer in the day on Saturday. Along the Massachusetts border I think we'll go straight from snow to freezing drizzle and pick up about 6" of accumulation. Elsewhere a period of heavier freezing rain is possible. The reason? A cold tuck as I like to call it behind a weak little mesolow that develops off Long Island. This results in a northerly wind and prevents warm from the south from moving in. 

The RGEM pictured above shows the 32F line (in red) straddling the shoreline as late as 1 p.m. on Saturday. A period of freezing drizzle will keep untreated surfaces slick through the afternoon and maybe into a portion of the evening. The heavy stuff will be done by 1 p.m. or so but light freezing drizzle will continue. You can also see that potential on this sounding in the Hartford area off the NAM. Warmer temperatures aloft but a subfreezing layer right near the ground. 

Our snowfall map is in pretty good shape this evening. This SREF plume for Bradley shows good clusting around 4"-6" of snow. I have two areas that have the potential to "bust" a bit. One is in the Litchfield Hills where a colder solution will keep things just about all snow. I can't rule out a 7" total up here. The New Haven are up through Middletown and Colchester is also a tough one. With a lot of the precipitation coming in a short period of time it would only take another slightly colder tick to result in the 4"-6" band needing to come south into these areas. We'll reevaluate in the morning. 

Sunday still looks rainy and torchy. Check out the SREF temperature forecast - almost all of the members bring temperatures into the 50s. A lot of melting after a chilly day on Saturday.

Enjoy the snow!


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<![CDATA[Wind, Cold, and a Winter Storm]]>Thu, 15 Dec 2016 20:01:23 -0500https://media.nbcconnecticut.com/images/213*120/CzwCvEtXUAAtW1x.jpg

Another strong Arctic cold front to our north is making its way into Connecticut. Strong winds and snow squalls are expected as the front moves in tonight. So far winds have behaved today but as the front approaches the wind will pick up and the snow will redevelop. As of 7 p.m. the Arctic front stretched from southern New Hampshire into Vermont and near Albany, NY. 

The concern for tonight is the wind that will pick up as the front moves in. The atmosphere will be very well mixed from the ground up to about 7,000 feet above our heads where the winds are near hurricane force! While 65 knots of wind won't make it down to the ground - even 75 percent of this would produce some powerful gusts and scattered power outages. 

So far the winds behind the front haven't been too bad - the highest gust I've seen in Vermont is 40 knots in Barre-Montpelier. However, given the strength of the winds at the top of the mixed layer and the front and sharp pressure rises behind it moving in the threat for 60 mph winds remains.

We'll also have to deal with snow squalls as a long and impressive lake effect snow plume - which stretches from Lake Superior to Lake Huron to Lake Ontario teams up with the Arctic front and approaches from the north. A coating to an inch and a brief period of heavy snow is a good bet in at least some areas.

Tomorrow morning will be cold but not exceedingly so. Temperatures will generally be above zero and wind chills around -15F for many inland areas. While this is pretty cold for sure it's something we deal with a few times a winter - at least!

After tonight our focus shifts to our Saturday winter storm. Our computer models have been in great agreement for a couple days with this storm with a pretty consistent solution since Monday. Right now our European Ensemble  model shows a 90% chance of more than 3" of snow along and northwest of I-84. Around New London not one of the 51 ensemble member delivers 3" of snow! 

The GFS solution is a bit less robust with snowfall maxing out at 3" or 4" across the state. 

One thing that is still to be figured out is how fast low level warmth streams in from the south. Some of our super high resolution models - like the new 3km NAM - keeps an impressive cold tuck over southern New England on Saturday as winds out of the north develop with a weak low tracking over southeastern Massachusetts.

This would result in a period of icy travel after the snow ends Saturday afternoon across most of Connecticut with temperatures struggling above 32F. The high-res NAM is the only model to show this so right now it's worth watching but is not the most likely scenario. 

At this points we're expecting 4"-6" of snow north of I-84, 2"-4" from Hartford south to New Haven, and 1"-2" around New London. The heaviest of the snow will be right around daybreak with a transition to ice (freezing rain) and rain along the shoreline. Should be sloppy!


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<![CDATA[Arctic Blast with Damaging Wind, Cold, and Snow]]>Wed, 14 Dec 2016 21:16:47 -0500https://media.nbcconnecticut.com/images/213*120/Czp-HmfXUAAn9g2.jpg

An anomalous weather pattern is setting up across New England over the next 72 hours. When anomalous patterns occur high impact weather frequently follows. There are a number of issues we're going to have to contend with including damaging wind, cold, and several chances for snow. 

A lobe of the tropospheric polar vortex will swing across New England later Thursday and Friday. An impressive blast of cold will accompany this.  

As the core of the cold moves in the tropopause drops to 700mb or about 10,000 feet above our heads. The tropopause (the start of the stratosphere) is normally substantially higher but can drop dramatically during these Arctic intrusions. So why do we care? 

The atmosphere will be well mixed from the tropopause right on down to the ground. A well mixed boundary layer allows momentum to be transferred from higher altitudes to the ground. Friction near the ground reduces this somewhat but a good rule of thumb is about 80% of the momentum from the top of the boundary layer can mix down to the ground. The NAM is showing 71 knots of wind at the top of the boundary layer! Yikes. If this were to verify I would expect locally damaging wind gusts in excess of 60 mph. 

This sounding also strongly suggests scattered snow squalls tomorrow evening that could result in localized heavy bursts of snow and a bit of accumulation given a fair amount of moisture. With powerful winds this could be a problem in some spots. 

One minor change to the forecast over the past few days is that the core of the cold appears to be tracking a bit farther north. Instead of temperatures near 0 it may wind up a few degrees warmer. Not a big deal but we should fall well short of records.

Beyond the Thursday/Friday wind, squall, and cold blast we're tracking a winter storm on Saturday. I'm not going to dig into this too much right now other than to say our confidence is higher than average for a 48-60 hour forecast. At this point I expect 2"-4" of snow across most of the state with 4"-6" in the hills and a bit less in southeastern areas. 

With a high sliding to our east there won't be anything to stop warmth from surging in above our heads so I do expect a transition from snow to ice to rain. Still, it will be quite cold as the storm begins and we'll get a good thump of snow before the change over. The GFS depiction of a couple inches of snow makes good sense to me and closely agrees with the European model. In fact the two models have been in agreement and very steady in their predictions over the past couple days. The 51 member European Ensemble has more than 90% of its members forecasting more than 3" of snow for Litchfield County and only a handful giving New London County more than 3" of snow. 

Stay warm over the next few days and try to sleep in a bit and enjoy the snow falling on Saturday morning. If you have plans on Saturday evening or night - don't worry at all! The storm will wind down around midday and temperatures will climb above freezing statewide by afternoon. 


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<![CDATA[The Polar Vortex is Back – Ugh]]>Tue, 13 Dec 2016 15:15:44 -0500https://media.nbcconnecticut.com/images/213*120/PolarVortex.gif

The dreaded polar vortex – it’s back! Or is it????

I can't think of a meteorological phrase that has entered into our everyday lexicon that bothers me more than polar vortex.

With a blast of cold air moving across the United States the term has been used countless times over the past week or so. Temperatures in Connecticut by Friday morning will approach 0 degrees - with the wind chill it will feel even colder than that! 

Undoubtedly you've heard about the polar vortex roaring down from the North Pole – probably even right here on NBC Connecticut – but it’s not exactly the best way to describe intrusions of Arctic air. I asked Assistant Professor of Meteorology Jason Furtado of the University of Oklahoma, one of the world’s polar vortex experts, to share his thoughts on what the polar vortex is and what it isn’t.

“The polar vortex is an area of low pressure that forms at the high latitudes and is strongest during the winter months when the air is the coldest and hence can create the larger temperature differences between the Arctic and low latitudes, Furtado said. “The vortex is the most well-defined and strongest in the stratosphere, the layer of the atmosphere above the troposphere – i.e., the layer in which we live and where the weather happens.”

The key here is that this is happening up in the stratosphere – or 10 to 20 miles above our heads! What happens below that – in the troposphere – where we live is a bit more complex and is what matters to us.

“There is a polar vortex in the troposphere as well, which we call the tropospheric polar vortex, and it has similar characteristics to its stratospheric counterpart. However, the tropospheric polar vortex most often not as circular or confined, and it has ‘lobes’ that can extend out into the mid-latitudes and bring cold air southward, sometimes with big storms. It is this latter polar vortex (the ‘tropospheric polar vortex’) that is used to characterize these cold air outbreaks and big storms,” according to Furtado.

As it turns out it’s not really the polar vortex diving south into New England that brings bitterly cold air. More accurately a lobe of the tropospheric polar vortex is going to swing through and bring cold air south. That doesn’t sound nearly as sexy, does it?

Furtado thinks the proliferation of the term is a bit much. “The term ‘polar vortex’ has been used and abused over the past few winters. As a scientist, I always think it is important to be accurate without having to be overly technical. I think it is important to understand that cold air outbreaks do not mean that the actual tropospheric polar vortex comes south.”

Another important item to note is that when the polar vortex is stronger – cold air effectively remains trapped over the Arctic. A more accurate headline to describe the science behind and Arctic outbreak would be: ‘The polar vortex is weakening sending Arctic cold south’

The polar vortex in the stratosphere does break down occasionally which can lead to Arctic intrusions as the stratospheric and tropospheric vortexes are coupled. This is something we see every winter and every blast of cold air from Canada is a ripple or lobe of the tropospheric polar vortex that skirts along the U.S./Canadian border with great regularity every winter.

I’m a stickler for science and getting the terminology right. The producers here at the station know that “polar vortex” is one of the phrases they can throw into a script to get a rise out of me. They love to annoy the cranky weather guy! The polar vortex isn’t new and it’s not really enveloping New England on Friday. Yes a lobe of the tropospheric polar vortex is coming south but to say it’s the “polar vortex” isn’t really correct. Unfortunately the term, and the term’s misuse, isn’t really going anywhere.

Thanks to Professor Jason Furtado for sharing his thoughts on the polar vortex. Now… get off my lawn!


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<![CDATA[A Wintry Week ]]>Mon, 12 Dec 2016 19:28:15 -0500https://media.nbcconnecticut.com/images/213*120/15492397_1386313648068928_1206033468317034573_n.jpg

There's a lot going on this week! A few chances for light snow along with a blast are remarkably cold air for Thursday and Friday that is becoming more and more likely.

The big story is going to be the very cold air that comes south from the North Pole Thursday and Friday. Our computer guidance is printing out some ridiculous numbers. For example, the GFS is showing 850mb (about 5,000 feet up) temperatures of -25 to -28C around dawn Friday. The European model is even more impressive with temperatures of -30C. This would be a big headline in January or February - but to get it in mid December is very impressive. 

I looked at Albany and the coldest pre-Christmas 850mb temperature I can find is -25C from their twice daily weather balloon launches. Flirting with -30C shows you that this kind of airmass is extremely unusual this time of year.

On thing that's a bit odd is that if you're just using the metric of low temperature here on the ground the 0F we're forecasting for Windsor Locks won't look all that impressive. In terms of records it's going to be tough to beat the daily record of -4F in the Hartford area. In fact, the temperature has reached 0F or lower 56 times prior to Christmas in the Hartford area with the last time being -2F on December 17, 2013.

So what's the big deal about this cold snap? A lot of those <0F lows are from nights with radiational cooling where winds were dead calm. 0F and no wind isn't as impressive as 0F with 40 mph gusts! The last 0F this early on 12/17/2013 featured clear skies and calm winds (followed by 4.2" of snow later in the day). One notable exception to this is one of our most epic cold shots of all time on Christmas Day of 1980. 

Friday's cold will feature a gusty northwesterly wind we're looking at wind chills between -10F and -20F across the state. Friday morning will be unpleasant if you're stuck outside for any period of time. 

With cold northwesterly winds we'll have to watch for some super Lake Effect Snow bands making it into Connecticut Thursday, Thursday night, and Friday morning. Extreme instability will develop off the Great Lakes given the unusually cold air mass so some of these snow streamers may have more longevity than normal.

After the cold blast we have another storm that looks like it will track west of us allowing the cold to leave and our snow to transition over to a mix and eventually to rain. Still, this storm has the potential to drop a couple inches of snow - especially early Saturday - across Connecticut. The GFS ensembles show good agreement for 1"-2" of snow in Hartford - in fact remarkable agreement for 5 days out while the European Ensembles show a 90% chance of >1" of snow in Connecticut. At least some accumulation on Saturday is a very good bet.

Stay warm later this week - and we'll keep you posted on our little snow threats as the week goes on. 


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<![CDATA[Snow Underway]]>Sun, 11 Dec 2016 20:31:41 -0500https://media.nbcconnecticut.com/images/160*128/rgem_snow_acc_boston_13.png

Evening Update: No big changes to the forecast though I have lowered the accumulation forecast for central Connecticut to 1"-2" and 2"-5" in the far northern part of the state. While we won't pick up much accumulation we're going to have to watch temperatures closely tomorrow morning as a burst of heavier precipitation comes in.

The HRRR model insists on temepratures remaining quite cold in the lowest few hundred feet of the atmosphere which would result in a period of heavier freezing frain - creating a glaze on any untreated surface. The east slopes of the Litchfield Hills and the Connecticut River Valley around and just north of Hartford would be most suscepitable to this. 

Morning Update: After a cold morning across Connecticut we'll see flakes in the air by the evening across Connecticut. This storm isn't going to produce a lot of snow but it is going to be messy later this evening and especially early tomorrow morning. 

The storm is going to come in two parts - and there may even be a brief break or lull in between. The first part is this evening. Snow will overspread all of Connecticut - even down to the beaches - and a minor fluffy accumulation of an inch (maybe 2) is expected. The snow will not be heavy but it will be steady. One reason we're expecting accumulation from just a minor amount of precipitation will be the efficiency of snowflake production.

This is a temperature sounding off one of our computer models for New Haven valid around 10 p.m. this evening. A few things to note. One is that temperatures are below freezing from the ground all the way up through the clouds - that means no melting. The second is that most of the lift is occuring where temperatures are around -15C. Why does this matter? This is the temperature where snowflakes form the most effiiciently AND the favored snowflake is a dendrite. These tend to pile up quickly - think "fluff factor". That's what we'll have this evening even down to the shoreline. While it's not the most likely scenario - I can't rule out an inch or two even down to the beaches.

After midnight we get a brief break before the brunt of the storm moves in.  As it does warm air will be flooding north as well - first a few thousand feet above our heads and more slowly near the ground (with the exception of the coast - where every layer warms quickly). The reason the cold is not going to hang tough is because we don't really have a well positioned high pressure to the north to deliver a steady supply of cold and dry air. There were a few computer model runs on Thursday that showed this - but since then that feature has gone away with the high really scooting to the east of us. This will make it easier for southerly flow to develop and bring in the warmth.

The question will be how quickly does it warm up? This is key for the morning commute. In these scenarios the Connecticut River Valley near and north of Hartford can rot around 32F for a while before the cold that's trapped in the valley can mix out. Initially, I think we'll see a period of snow and/or freezing rain when round 2 develops prior to dawn that quickly flips to all freezing rain and eventually rain. By 7 a..m I expect Hartford to be close to or above freezing while the suburbs north and west of the city remain just below.

So the bottom line is we get some snow this evening... and then inland areas get a predawn burst of wintry mix. By the morning commute we'll be all rain south of I-84 and the valley around and north of Hartford will be transitioning quickly from freezing rain to rain. This won't be an "ice storm" but temperatures near or below 32F will keep things slick and slushy around daybreak. By mid-morning roads should be fine as temperatures soar into the middle 40s for most locations melting whatever we had.

More to come later!


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<![CDATA[Snow & Mix on the Way]]>Fri, 09 Dec 2016 23:23:41 -0500https://media.nbcconnecticut.com/images/213*120/CzSa0sGXUAAvIe8.jpg

11 p.m. Update: Well I've changed my mind :) With a tick colder of the latest GFS and a rather chilly looking Canadian RGEM model I feel just confident enough to throw out some preliminary numbers. We still have two camps with the colder Euro and the warmer GFS. More often than not the truth lies in the middle and that's where our forecast is with 1"-3" for most - <1" at the shore and 3"-5" in far northern Connecticut. We certainly may see some changes to this in either direction if we see a jump toward the GFS or Euro.

Have a great weekend! 

Evening Update: My plan tonight was to draw up a snowfall map for the 11 p.m. news - but as of right now I'm planning on holding off. The reason is that while it appeared our computer models were beginning to converge on a solutuion earlier today they've begun to diverge with two very different outcomes.

One of the best ways to illustrate this is to look at the GFS and European ensembles. Bascially, the computer models are run a number of different times to produce a set of reasonable possible solutions. The GFS is run 21 times and the European is run 51 times - all with slightly different initial conditions and model physics. When the ensembles are tightly clustered it means there's high confidence in the forecast. When the ensembles are all over the place it means there's low confidence. 

In this case the GFS ensembles are insisting on only minor snowfall accumulations before a transition to ice. Of the 21 ensemble members no member produces over 2" of snow in Hartford. However, more than 50% of the European ensemble members show more than 3" of snow! This shows there are two distinct and different camps - all of it seems to be due to the strength of the low pressure to our west. The stronger the low (like the GFS) the more warmth that floods north.

Regardless of which set of ensembles is right the morning commute on Monday looks icky with some snow transitioning to ice and eventually rain (unless the colder European model solution is right). Until we see some type of agreement it's hard to pin down one solution as the right one as I don't see anything that really argues one way or another. Normally I would hedge toward the European solution - but our short range models such as the NAM and various WRFs show a warmer scenario too like the GFS making it tough to toss out. 

Previous Update: Our overnight computer models have come into better agreement and it's becoming more clear the kind of storm we'll be dealing with later Sunday and Monday. Yesterday, I wrote about the sizable differences between our two main sets of models - the GFS and the Euro. Now, there's only a much smaller difference between the two.

We've found some common ground here and it appears the odds of a significant snowstorm >6" have come down quite a bit. What does seem most likely is a period of snow (a couple of inches still possible) before we transition to an icy mix right before or during the Monday morning commute. Icky.

The GFS model which is notorious for bringing in low level warmth too quickly when there's a high pressure lurking to the north and east even keeps temperatures around or just below 32F Monday at 7 a.m. during the height of the storm. 

While I'm becoming more confident that this won't be a big storm - the timing for what we do get looks unfortunate. The best bet right now is an icy mix for the morning commute. Could this change? Yes, it is possible that the storm comes a bit farther north and we wind up with a warmer scenario (faster change to rain). 

More details through the day!


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<![CDATA[Winter Storm Possible Monday]]>Thu, 08 Dec 2016 20:29:56 -0500https://media.nbcconnecticut.com/images/213*120/CzMAVGpXcAY91kZ.jpg

Things are starting to get interesting for those of us who enjoy winter weather. Our computer models are now starting to show a rising chance for accumulating snow and ice Sunday night and Monday. While it's too far out to get into the specifcs I want to dig into this store and take a look at what scenarios are most likely and which are not. 

Right off the bat I should mention that a period of light snow is possible on Sunday. A bit of moisture and cold temperatures may be just enough to squeeze out some off and on snow. This won't be a big deal but don't be surprised to see some "mood flakes" in the air. One thing our models are showing is quite a bit of moisture above our heads where the temperature is around -15C which can produce fluffy snowflakes with even the most modest lift. 

Now on to the fun stuff - at least for a meteorologist like me :)

There's two main scenarios for the Sunday night and Monday storm. The GFS model has a stronger storm that's farther inland which would mean a real mess of a storm from snow to ice to rain. The European (ECMWF) model on the other hand has a much weaker storm with a surface low that tracks just south of us. This scenario would be mainly snow - even around New Haven. You can see the difference here comparing the two model solutions. Ironically, the weaker storm is the one that would be the most snowy for us. 

The ECMWF solution is a weak 1008mb low near Erie, PA with redevelopment south of Connecticut while the GFS is a 992mb low over Detroit, MI. This is a big difference! The latter would flood us with warm air changing any snow and mix to rain. What is important to note is that either solution would provide us with at least a period wintry weather given the cold high north.

So which is most likely? One of the things we like to look at are the ensembles of these 2 models. Basically we take the model (GFS or Euro) and make small tweaks to the initial conditions and model physics and run the model a bunch of times. In the case of the GFS we run it 21 times and the Euro 51 times. Ideally, this gives us a spread of possible solutions. Here's a look at the 21 GFS ensemble members predicted snowfall through Tuesday morning. While the numbers aren't particularly instructive - the spread or range of solutions is useful to look at. 

The stronger solutions (like the strong low over Detroit and Toronto) generally produce less snow while the weaker solutions like the ECMWF produce more snow.

Another way of looking at these ensembles is figure out the probability of a certain weather variable occuring. For example, of the 21 GFS ensembles (GEFS) how many of them show >3" of snow. Is it 20 of the 21 or 3 of the 21? The GEFS show about a 60% chance of >3" of snow in the far Northwest Corner and a 10% chance in the southeast corner. There are clearly a lot of milder solutions of the 21 ensemble members indicating a snow/mix/rain solution. The European ensembles (EPS) are much colder with a better than 50% chance of >3" of snow around New Haven and a 70% chance in the hills. Definitely a colder set of solutions. 

With all of the above in mind it's fair to say a winter storm is a pretty good bet across the state later Sunday and especially Monday. How much snow we get is still an open question. There's a substantial spread in our models AND in the ensembles with the strength and track of the low to our west. However, there is a fair amount of cold at the onset with a nice looking high to the north - this should guarantee at least some wintry precipitation.

Worst case scenario (if the ECMWF is right) this is a 6"+ kind of storm across a good chunk of southern New England. If the GFS is right and we see warmth flooding in expect a 1"-3" kind of deal to sleet/freezing rain and then over to rain. Both are reasonable possibilities at this point and both would make a mess of the Monday morning commute.

Stay tuned!


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<![CDATA[Arctic Outbreak - Big Cold on the Way]]>Wed, 07 Dec 2016 19:46:33 -0500https://media.nbcconnecticut.com/images/160*120/gefs_t850a_noram_33.png

Last December shattered records for its remarkable warmth. This December will not. One blast of Arctic air moves in this weekend - and then a more sizable blast of cold air next week. 

The reason for this isn't the Polar Vortex (though you'll hear it incorrectly used ad nauseum over the next 10 days) but rather a weaker Polar Vortex over the North Pole and a cross polar flow. What do I mean by that? Check out the surge of cold coming south from the Arctic with streamlines (wind direction) superimposed on top. You can see the origin of this cold is on the other side of the North Pole coming right down into North America.

So just how cold will it get? Right now we're predicting 4 days below 32F next Wednesday through Saturday which is pretty impressive for days 7 through 10 this time of year. The downscaled GFS ensembles have mean high temperatures in the mid 20s later next week - wow! Getting mean temperatures that low so far out is quite impressive.

The other question that we'll have to dive into is what exactly will happen Sunday and Monday. There are a number of dramatically different scenarios showing up on our models with an active jet stream with several different pockets of energy rotating through. To be honest - besides saying there's a threat for some snow, mix, and rain it's a very low confidence forecast Sunday and Monday. Timing, strength, and track questions very much remain. 


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<![CDATA[Wintry Mix in the Hills]]>Tue, 06 Dec 2016 19:43:30 -0500https://media.nbcconnecticut.com/images/213*120/CzBNrCbXEAAkLgK.jpg

A storm that looked fairly impressive earlier today to our southwest is falling apart as it moves into Connecticut - as we expected. This evening and tonight as the leftover lift and moisture moves in we'll see rain and some mix in the hilltowns.

The latest High Resolution Rapid Refresh model (HRRR) shows a sharp gradient from nearly a half inch of liquid precipitation tonight around Greenwich to barely a few hundreths of an inch around Hartford. The western part of the state stands the best chance to get a period of steady precipitation - and in the hills a bit of snow - before the storm really bites the dust. 

With marginal cold air around and only light precipitation in most areas we will struggle to get any appreciable wintry precipitation. This forecast of 2-meter temperatures off the HRRR at 11 p.m. shows temperatures close to freezing around Waterbury and in the hills of western Connecticut - but temperatures in the mid and upper 30s in the Connecticut River valley and along the shoreline. 

So the bottom line is don't expect a whole lot out of this system. A bit of light rain for the shoreline and the valley (a bit more precipitation - up to a 1/4" down toward Stamford) and a light mix in the hills. Temperatures will be just marginal enough that some towns in western Connecticut may scrape together an inch or two of snow if the heavier precipitation can make it across the New York border.


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<![CDATA[Tyler's Take: Surge of Cold]]>Mon, 05 Dec 2016 14:53:20 -0500https://media.nbcconnecticut.com/images/160*123/m850ta_f132_bg_US.png

Ready for a taste of winter cold? It's coming. Ryan's off today, so I'll take the reins and update the blog with "Tyler's Take."

After a quick coating to an inch of snow this morning, the active pattern isn’t going to quit anytime soon. Roads across Connecticut were relatively problem-free when compared to New Hampshire, which saw snow cover even the biggest highways during the height of the morning commute. A few accidents were reported here in Connecticut. No doubt, the pretreatment paid off.

Our next focus is a bout of rain and snow Tuesday night into Wednesday morning. Without even digging into the details, the timing is conducive for snow to stick. But while high pressure will be overhead beforehand, the setup looks unimpressive in terms of cold air.

Dew points will be around 32 degrees Tuesday night, meaning temperatures won’t fall much below freezing. The atmosphere will be within a degree or two below freezing in the lowest few thousand feet, so the consistency of the snow will likely be wet.

Given this marginal temperature profile, the precipitation will likely be predominately rain along the shoreline, with the hill towns seeing snow and the valley experiencing a mix of rain and snow. There isn’t a ton of moisture to work with, so like this morning’s event, a coating to an inch or two of snow is in the cards for the hills of northwest and northeast Connecticut.

An event like this demands greater intensity precipitation in order to cool the atmosphere, but that doesn’t look to be the case this time around. Thus, most roads will likely stay wet, but could turn icy given the hour of day and temperatures close to freezing.

The other story is cold air. A big surge of cold air arrives Thursday and high temperatures fall going into the weekend.

The European model consensus is temperatures about 10 degrees below average, which results in highs barely cracking freezing on Saturday. This weekend, morning low temperatures could plunge into the teens.

What about record low temperatures? Not even close. Take Saturday, for example. The record low temperature is 1 degree, set back in 1964, and the record low maximum is 16 degrees, set back in 1917. Very old records!

It’s likely that a number of southern New England ski areas begin making snow late this week.


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<![CDATA[Signs of Winter]]>Thu, 01 Dec 2016 12:55:12 -0500https://media.nbcconnecticut.com/images/160*120/gefs_t850a_5d_noram_55.png

Today marks the beginning of meteorological winter. November wasn't particularly warm - but it was above average with Bradley Airport coming in 1.4 degrees above normal and (of course) 0.83" below normal in terms of precipitation. That is a bit misleading, however, as most of the state received substantially more rain than BDL.

Looking forward things get a bit more interesting for those of us who like the threat for wintry weather. The 8-14 day temperature outlook from the National Weather Service got a lot of attention yesterday as it shows almost the entire country (including Alaska) below normal for the second week of December. 

The reason for the cold is that the weather pattern across the Northern Hemisphere is going to go through a major change. Both the GFS and European models develop an anomalous ridge over Alaska and eastern Russia that pokes up toward the North Pole. This should send a sizable chunk of Arctic air south into North America with a "cross polar flow".

Of course what we really care about is what happens in our backyard in Connecticut - and at this time range it's impossible to start talking specifics. That said, it's a pretty good bet that we'll be dealing with a stretch of colder than normal winter weather before long with the coldest air across central and western North America. Whether we can get a favorable storm track for snow remains to be seen. 


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<![CDATA[Round 2 of Rain is Here]]>Wed, 30 Nov 2016 13:22:23 -0500https://media.nbcconnecticut.com/images/213*120/Cyh5CIWWEAAXkOp.jpg

Yesterday's rain was awesome. A much needed and steady soaking that dropped anywhere between 2/3" and 2 1/2" of rain across Connecticut. As expected the heaviest rain set up just inland from Long Island Sound where a narrow band of rain around or just over 2 inches occured. 

The setup for today's rain isn't too dissimilar from yesterday. An upper level disturbance swinging around a large cut-off low to our west will force a surface low to develop near Southern New England. A strong low level jet will transport moisture north and promote strong long level convergence (resulting in rising air) across Connecticut.

Our models show an additional inch of rainfall is very likely - with pockets of up to 2 inches possible in some locations. This plume diagram of the NCAR ensembles (which I am a huge fan of) shows a range of possible rainfall totals for Windsor Locks - 1.5" of rain for the mean isn't bad!

It appears that the rain will come in two waves. The first wave will be this afternoon and evening with a warm front over Long Island Sound and a surge in the aforementioned Low Level Jet. This should be a soaking for the evening commute in some areas. You can see the enhanced reflectivity/precip rates on the HRRR model just north of that front valid at 5 p.m. today.

The second batch of rain scoots through after midnight - and before dawn - as a cold front swings in from the west. Behind this - drier air and better weather moves in for Thursday.


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<![CDATA[Much Needed Tuesday Rain]]>Tue, 29 Nov 2016 20:08:43 -0500https://media.nbcconnecticut.com/images/213*120/radarmorning112916.jpg

Evening Update: The rain is pretty much done across the state and now we wait for round 2 to move into Connecticut tomorrow. The rain pretty much met our expectations with a band of heavier totals near the Connecticut shoreline (most of our high resolution models have been showing this) and slightly less rain around and northeast of Hartford. Here's some selected rainfall totals from our automated stations as of 8 p.m. across Connecticut.

  • Bridgeport - 1.69"
  • Groton - 1.65" 
  • New Haven - 1.21"
  • Windsor Locks - 1.11"
  • Meriden - 1.08"
  • Danbury - 1.07" 
  • Willimantic - 0.92"
  • Hartford - 0.65"

Our next rain event is already taking shape in the Deep South with a severe weather and tornado outbreak across portions of Mississippi. Most models show 0.5"-1.0" tomorrow across Connecticut - it will come in waves (won't rain the whole time) and it could be locally heavy. Our Short Range Ensemble Forecast shows about an additional 3/4" of rain at Bradley Airport which seems reasonable.

More rain - let's fill up those reservoirs! 

Afternoon Update: Let me geek out for a second about the warm front that's moving through the Hartford area right now. There's a very, very shallow wedge of cold air stuck in the Connecticut River Valley north of Hartford. This is nothing unusual and it happens almost all the time we get a storm like this in the cold season. Warmer air is surging north and causing this shallow wedge of cold to mix out - and the temperature jump behind the warm front is substantial. These are mesonet obs across the Hartford area and you can see the difference. It's currently 55F at Brainard Airport but only 44F downtown. Along Rt 44 in the North End it's only 42F! In West Hartford and Newington the difference is dramatic as the temperature goes from 55F in Newington Center to 45F in Elmwood up Rt 173. Always cool to see these really small-scale features evolve. One other update is the back edge of the rain is moving in a bit earlier than forecast - the heavy rain will likely end from west to east across the state between 4 p.m. and 7 p.m. This may limit totals a bit in some areas though a widespread 1"+ is still expected. I'm no longer expecting a band of >2" of rain.

Midday Update: So far the rain has been light to moderate across the state though it is expected to increase in intensity this afternoon. The latest High Resolution Rapid Refresh model or HRRR brings in pockets of very heavy rain (hourly totals of 0.3" to 0.5") right during the evening commute between 4 p.m. and 7 p.m. Our current forecast of 1"-2" of rain with localized amounts of 2"-3" seems on track. One trend we've also noticed is that tomorrow's rain may wind up less impressive - but still beneficial. More on that soon.

Morning Update: No change to our morning computer guidance with respect to today's rain. Our high resolution computer models continue to highlight southern Connecticut as the area most susceptible to the heaviest rain (>2") today.

What's amazing is the amount of agreement there is between our high-resolution computer models. The SUNY Stony Brook WRF, the 4km NMM & ARW, and the NCAR WRF Ensemble all show that band of 2" just inland from Long Island Sound across the southern half of the state.

What is the cause of this? Like I discussed yesterday the biggest forcing mechanism for today's rain will be low level convergence at the nose of a powerful low level jet a few thousand feet above our heads. Additionally, low level frictional convergence in the Boundary Layer (strong winds over the ocean and Sound decelerate over land) will aid in this low level forcing coupled with a warm front that sets up right over the coastal plain. This is a classic setup for heavy rain in Connecticut. 

Putting it all together we're still on track for 1"-2" of rain with the rain picking up across the state through the day. There will be a narrow band of heavier rain (2"-3") - which appears most likely to happen in the southern half of the state. The HRRR time lagged ensemble shows good probabilities of over an inch of rain in 6 hours statewide.

Even with all this rain - flooding is unlikely given the very low river levels and streamflows. While the rain will be heavy this is all good news for the state due to our ongoing drought.



Photo Credit: NBC Connecticut
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<![CDATA[On Ryan's Radar: A Soaker This Week!]]>Mon, 28 Nov 2016 13:58:53 -0500https://media.nbcconnecticut.com/images/160*120/gfs_tprecip_boston_20.png

Is anyone else as excited as I am for some heavy rain!? This has all the makings of a soaker here in Connecticut. The GFS model (pictured above) is most impressive with over 4" of rain in spots! The European model (not shown) shows 1"-3" across the state - not quite as wet as the GFS but still quite a bit of water.

Two bursts of heavy rain - one tomorrow and another Wednesday afternoon and Wednesday night - will be very, very welcome across our dry state. So why are we looking at all this rain? We have two upper level disturbances that will swing through and each force a response with developing low pressure near southern New England.

One way to visualize this is to look at what we call the low level jet (LLJ) which is approximately 5,000 feet above our heads tomorrow. While the winds will be quite light here on earth just a few thousand feet up with wind will be whipping over hurricane force! The nose of that LLJ will tickle the coast of southern New England putting Connecticut in a favorable area for heavy rain. Think of it like this - strong winds blowing 60-80 mph are forced to rapidly decelerate over New England (to 30 or 40 mph). That forces air to converge and pile up forcing the air to rise. This convergent signature is a great signal for heavy rain.

So how much rain are we looking at? A fair forecast is 1"-3" of rain coming in two waves - one tomorrow and another later Wednesday. It's possible that some areas could receive 4" or 5" of rain where thunderstorms or banding develops. The 1"-3" range fits in well with the spread shown on the SREF models. This plume diagram shows the 21 members of the Short Range Ensembles for Hartford with most in that 1"-3" camp.

This is pretty much all good news with 1-hour flash flood guidance (how much rain needs to fall to produce flash flooding) values of around 2" across the state and 6-hour values between 2.5" and 3.0". We should generally be below these thresholds.

In case you're wondering how much rain we need to extricate ourselves from this drought? The National Weather Service estimates we'd be eliminated from any drought outlook if we picked up somewhere between 6" and 12" of rain. While we don't need it all at once we'll take what we can get!


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<![CDATA[Much Needed Soaking Rain on the Way]]>Sun, 27 Nov 2016 11:37:41 -0500https://media.nbcconnecticut.com/images/160*120/wpc_total_precip_neng_18.png

Finally - a solid chance at a heavy rainstorm across most of the state. We've needed this for a while! This won't end the drought but it may very well put a dent in it. The WPC forecast has a bullseye of 3" over parts of Connecticut - that would be sweet!

The weather setup remains the same as it has looked for the last few days of computer model runs. A giant cut-off low over Minnesota with different spokes of energy rotating around the low. We get two such spokes to deal with - one on Tuesday and another later Wednesday into Thursday. 

Initially I was concerned about a bit of icing at the onset on Tuesday but that seems like it will be a very minor deal. Can't rule it out but I'm not expecting any major issues.

How much rain we get still is a bit of an open question. Odds are very, very high of more than an inch or rain across the state. The European Ensemble is not as bullish with excessive 2"+ rainfall amounts (in fact has a <10% chance of seeing that in the Hartford area) but the GFS ensembles are.

The difference between the European and GFS solutions appears to be with whether or not a secondary low develops near the coast and how far north the warm front/triple point gets. Still a lot of time to work out the details but at this point it's fair to say 1"-2" of rain is a very good bet across the state with a lower risk for 2"+. It should all wind down around midday Thursday. 


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<![CDATA[A Rainy Storm - Finally!]]>Fri, 25 Nov 2016 21:33:22 -0500https://media.nbcconnecticut.com/images/160*123/ecmwf_apcp_f144_ne.png

With our ongoing drought it's easy to get excited about a rainstorm. A two-part rain event is on its way to the state with decent odds of more than an inch of rain. Here's the setup for next week. There will be a big upper level low cut off from the jet stream over the upper Midwest that will dominate the lower 48's weather.

Two disturbances spinning around the larger low in Minnesota (think of spokes in a bicycle tire) will bring us rain. The first one is on Tuesday. The upper level energy moves over the northeast and forces surface low to form nearby. The same thing will happen on Wednesday and Thursday as that piece of energy over Arizona and New Mexico ejects northeast toward us.

So what does it mean? Our medium range computer models are in pretty good agreement for two rounds of rain. The GFS ensembles show the 2-part rain event with most of the 21 members printing out between 1" and 3" by the time it all winds down. The European Ensemble shows odds of >1" of rain in the 2nd part of the storm Wednesday/Thursday of about 1 in 3 - good odds!

These two rounds of rain won't be blockbusters but they'll do a bit to help the ongoing drought. Every little bit helps before the winter snow comes. With such dry conditions right now no flooding is anticipated besides the typical leaf-clogged storm drain or low-lying railroad underpass.

As I mentioned yesterday, the onset of the rain on Tuesday could be a bit icy in some of the hilltowns with a bit of lingering low level cold, but at this point it doesn't seem like a huge deal. Additionally, depending on the track and eventual strength of this storm there is the potential for strong gusty winds but at this point the confidence in that is quite low. 


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<![CDATA[On Ryan's Radar: Midweek Storm?]]>Thu, 24 Nov 2016 23:14:57 -0500https://media.nbcconnecticut.com/images/160*120/GFSNE_prec_prec_162.png

Happy Thanksgiving! It's a quiet night in the weather office after a rainy evening and an amazing Thanksgiving feast at my coworkers Kate Rayner's house. As I fight off the tryptophan and try to stay awake the forecast next week appears to be getting more and more interesting.

There's good model agreement that there will be a sizable storm next week. The specifics are very much up in the air. Tuesday is a good example of the model discrepancy. The GFS computer model keeps Tuesday dry with a storm cutting to our west - with most of the lift and moisture well west. The European model, on the other hand, brings in a good slug of lift and moisture with a warm front holding south of New England. 

The European model solution is a bit interesting as it does keep a relatively cold and dry high pressure anchored to our north over Quebec which could support a period of mixed precipitation. In fact, temperatures near the ground are right around 32 degrees on the European model which makes sense given the location and strength of the high to the north.

Could this turn more wintry? Possibly but not much more. The atmosphere out ahead of this system is awfully mild - there's not much Arctic air around. The European ensembles (a version of the European model run 51 different times to produce a reasonable spread of possible solutions) shows a 10-20 percent chance of >1" of snow - with the highest odds in Litchfield County This seems reasonable to me.

In order for this to turn into a period of ice and snow a few things need to happen. The evolution has to be closer to the ECMWF than the GFS - the storm needs to make it in here on Tuesday! The second requirement is that the high pressure to the north needs to trend stronger and colder. This can happen and is why I'll be watching it closely. I'd say there's about a 1 in 4 shot of some wintry weather on Tuesday especially in the hills. 

Regardless of what happens Tuesday - this storm has the potential to produce heavy rain which is something we desparately need. The 18z GFS has nearly 4" of rain in Hartford!!!! This is likely quite overdone but many of the GFS ensemble members show between 1" and 3" across the state which is a good signal for a storm 5 days out. 

Let's hope for rain and I hope you have an amazing Thanksgiving!


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<![CDATA[Rain Moves in On Thanksgiving Day]]>Thu, 24 Nov 2016 08:53:21 -0500https://media.nbcconnecticut.com/images/213*120/Cx90a6NXAAgEI4D.jpg

A bit of good news for people who need to travel on Thanksgiving. Yesterday, it appeared that we'd have a bit of snow first thing Thanksgiving morning across the state. That chance for snow has evaporated (or sublimated in this case) thanks to a weaker storm and a tenacious bubble of dry air near the ground.

This sounding off the NAM model (previously the most bullish with the snow chance) shows why. There's a decent bit of moisture in the mid levels of the atmosphere (where the green and red lines are close to one another implies humidity near 100%) but in the lowest 5,000 feet of the atmosphere it's a different story. There's a pronounced layer of dry air around 875mb and that will be enough to prevent any snow of consequence.

Still, we're not necessarily out of the woods for all of Thanksgiving. Up in the hills of Litchfield County temperatures will be very close to freezing as a wave of moisture moves in during the late afternoon and early evening. 

Most of our computer models are on the line between rain and snow/mix above 1,000 feet in the Northwest Hills. The RGEM shows a little burst of precipitation between 4 p.m. and 7 p.m. in the hills and temperatures awfully close to freezing (the blue line is 35F). This is pretty similar to most of our computer models. Farther north, in the Berkshires and southern Green Mountains, an inch or two of snow is likely to accumulate. 

The bottom line is that most of the state isn't going to see much at all. A bit of rain in the afternoon and evening. In a few of the hilltowns we're very close to seeing a brief period of wintry mix so we'll be watching that closely.


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<![CDATA[Thanksgiving Issues?]]>Tue, 22 Nov 2016 13:27:31 -0500https://media.nbcconnecticut.com/images/213*120/Cx4t72eWIAACB8h.jpg

A weak weather system (about as weak as it gets) is going to scoot into New England on Thanksgiving. This is an incredibly minor system but its timing could cause some issues. 

Several of our computer models are showing some light precipitation around daybreak Thanksgiving and it looks cold enough for snow in many areas. This sounding from the NAM valid at 8 a.m. Thursday at BDL shows temperatures below 32F from the ground up through the clouds. Plenty of moisture is seen on this sounding as well. The GFS model is drier and would indicate mainly flurries or a period of non-accumulating light snow. 

The most likely scenario is a coating of snow in some towns and maybe a bit of slick travel around daybreak through noon or so. The worst case scenario would be about an inch or so of snow. The best case scenario (which is certainly possible) is little if any snow because the lowest levels of the atmosphere are too dry or if the "storm" manages to weaken anymore. 

Lots of clouds stick around through the day on Thursday with the potential for some light rain showers during the afternoon and evening. There is one exception to this and that's in the Litchfield Hills where temperatures will be around 32 degrees (the 4km NAM-WRF from SUNY Stony Brook is shown above). It's conceivable a period of light freezing rain or drizzle could occur in some of the elevated towns Thanksgiving afternoon and evening and require some treatment of roads.

Overall this isn't something to be concerned about - just something to keep an eye out for on Thursday.


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<![CDATA[Unusual Snowstorm Clobbers Litchfield County]]>Mon, 21 Nov 2016 13:37:50 -0500https://media.nbcconnecticut.com/images/213*120/Cxy9R2OVEAIG72u.jpg

To say this storm was a surprise for a few towns in Litchfield County would be an understatement. The hill towns got clobbered! This was an unusual storm in many respects and turned out to be a shockingly prolific snow producer.

Large snowfall differences between the valleys andhills aren't unusual. How many storms produce a foot of snow in Norfolk and barely anything in Winsted? A lot! What was different was the mechanism that produced this snow. 

Besides the few inches of snow that fell Sunday morning this storm was almost exclusively due to "upslope" - or snow that developed due to air being forced up and over the hills in Litchfield County. This phenomenon is why the ski areas in Vermont get so much snow but rarely produces big totals here. The reason is that the hills in Connecticut just aren't that high - about 1,500 feet from Norfolk to Warren compared to 4,000 feet in northern Vermont!

What made this storm so prolific when most setups like this aren't? I believe there are several reasons. One, is that this upper level low had an unusual moisture connection from the subtropics. On the water vapor loop you can see moisture streaming north from Bermuda into southeast Canada and back to the south into southern New England. The more moisture in the lowest levels of the atmosphere the less it needs to be lifted for clouds and precipitation to form.

The second reason is likely the unusually warm Great Lakes. Northwesterly winds blowing from Lake Ontario were able to effectively "pick up" more moisture than they ordinarily would be able to. 

The third reason is that the upper level low stalled just to our north - producing a persistent band of snow for nearly an entire day. That persistent flow kept the snow machine cranking.

In retrospect I should have picked up on some of these signals. Our most bullish model (the high res NAM) started showing 6"-8" of snow for the higher elevations in Litchfield County by Friday night but more often than not the high resolution NAM is quite overdone with these setup. 

After talking with Bob Maxon in the weather office this morning - neither of us can another upslope event quite like this!

What was forecast well was the snow showers across the valley and shoreline locations this morning. New London picked up a half inch and Southington picked up a little over an inch. As early of Thursday I was talking about scattered snow showers Sunday night and Monday morning that could put down a quick coating of snow on the roads.  That happened right on schedule and unfortunately resulted in a number of accidents. 

Snow totals so far...

 

  • Goshen - 16.0"
  • Norfolk - 14.2" (official)
  • Warren - 12.3"
  • Colebrook - 9.0"
  • Colebrook - 5.7"
  • New Hartford - 1.7"
  • Bristol - 1.3"
  • Prospect - 1.2"
  • Southington - 1.0"
  • New London - 0.5"
  • Collinsville - 0.5"
  • Staffordville - 0.5" (official)
  • Mystic - 0.4"
  • No. Granby - 0.1"
  • Moosup - 0.1"
  • West Hartford - Trace
  • Windsor Locks - Trace (official)
  • Bridgeport - Trace (official)


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<![CDATA[On Ryan's Radar: Snowstorm in the Hills]]>Sun, 20 Nov 2016 20:43:43 -0500https://media.nbcconnecticut.com/images/160*120/CxtFvTWUQAAUG0A.jpg

Evening Update

Wow! What a storm this has been in the Litchfield Hills. This morning's 3"-5" in some of the higher elevations has continued with a remarkable "upslope" snowstorm into this evening. Basically, cold and moist air is being forced up over the ridges/hills in Litchfield County and dumping an additional 3"-5"+ in towns like Warren, Goshen, and Norfolk. There is also a second maxima right along the New York border in Lakeville and Sharon with a local minima in places like Cornwall and Falls Village. 

There were some signals for bursts of moderate snow through the day and evening but I did not expect this! This is the most impressive "upslope" storm I can remember in Connecticut - it's generally really hard to get more than an inch or two around here on the backside of a low. 

There's a HUGE gradient here. Less than an inch of snow has fallen in Torrington and Winsted and just a few miles away on the ridge in Goshen and Norfolk there's been 10". While "upslope" helps the hill towns the opposite effect - downsloping - forces air to sink and result in little precipitation along the Route 8 corridor in the Valley.

As always these storms are fascinating as a weather geek to witness, frustrating as a weather geek (I barely got a flake), and humbling as a meteorologist. 

Earlier Update

As expected, snow is accumulating in the Northwest Hills this morning from a dynamic little storm and colder air filtering in from the west. We've seen reports of 1"-3" of snow this morning in the higher elevations and the heavier snow is beginning to wind down. 

In Norfolk cooperative observer Russell Russ reported 4.8" of snow at 1,600 feet at the Great Mountain Forest! It appears that there's a zone of 3"-5" of accumulation on the ridge in Norfolk and Goshen. In the valley around Winsted only 1" of snow accumulated and even eastern Colebrook only reported 1.3" this morning at 7 a.m. 

While I'm not shocked that Norfolk managed nearly 5" of snow (there were some hints of this heavy burst on the models) it definitely managed to overperform a bit. 

This mornings snow over the Hills came as an upper level low closed off and drifted over Litchfield County. You can see that here on the 6-hour GFS forecast valid at 7 a.m.. As the low drifts north into Berkshire County, Massachusetts through the day today the snow will shift north as the best lift in the atmosphere is featured along and north of the upper level low. Generally, you want to be under or just on the left side of one of these strengthening upper level lows to get significant precipitation. 

That said, snow showers will continue off and on through the day and tonight in the Northwest Hills due to upsloping. What's upsloping? Northwesterly wind over the Hudson Valley in New York will be forced to rise over the Litchfield Hills. As the air is forced up and over the change in elevation clouds form and precipitation can fall. Think of it this way - as air blows toward a mountain it can't blow into the ground - it has nowhere to go but up! 

It's unusual for this to produce heavy snow in Connecticut - but it appears there's just enough moisture for this upslope snow to continue in the hills. I wouldn't be surprised to see an additional 1"-3" in some towns above 1,000 feet through Monday morning. Farther north, upsloping is how the spine of the Green Mountains in Vermont gets the majority of their snow - cold, moist air being forced up and over the 4,000 foot peaks. 

While Litchfield County gets their own personal snowstorm the rest of the state is not looking at much snow at all. Occasional snow showers are possible tonight and into tomorrow morning.

The one thing the I'm concerned about, however, is lake effect snow coming off Lake Ontario. Once in a while these plumes can make it all the way into Hartford or New Haven and can cause some brief accumulation. It's almost impossible to forecast this ahead of time but it's something I'm watching for. 

Wind will become an issue later today, tonight, and Monday. Model soundings indicate gusts of 40-50 mph will be widespread. This may result in scattered tree damage and power outages. The above model sounding for New Haven valid tomorrow afternoon shows winds of 55mph at 5,000 feet above our heads. With a well mixed atmosphere a large chunk of this will be able to be mixed to the ground. 


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<![CDATA[Cold, Wind, and Snow]]>Sat, 19 Nov 2016 07:13:10 -0500https://media.nbcconnecticut.com/images/213*120/Cxj85aGVQAAVz3y.jpg

Saturday morning update: Good morning! No real change to note in our overnight computer models. We're still on track for a bit of accumulating snow in the high elevations of Litchfield County tomorrow morning (maybe 1" or 2"?) and occasional rain/snow showers through the day and into Sunday night and Monday. The biggest question is how widespread the snow showers will be across the rest of the state Sunday night and Monday - I'm thinking the coverage is relatively scattered - but still can't rule out a few heavier bands resulting in a burst or two of snow even around Hartford and New Haven.

Previous Friday update: Sunday will be unpleasant. Cold, windy, and showery with snowflakes across parts of Connecticut. In fact, it looks cold enough that there will be some snow accumulation across the Litchfield Hills on Sunday - talk about a change from the 60s today!

Here's the weather setup across the region. A strengthening low pressure will "close off" in the upper levels of the atmosphere. Effectively, it will get cut itself off from the jet stream. This happens with a fair amount of regularity this time of year with varying impacts across the region. There are a number of possible impacts to watch.

Daybreak Sunday - A flip to snow in the hills

A powerful cold front will sweep east causing temperatures to drop from near 50 at midnight Sunday morning into the 30s by daybreak in the hills. Strong lift in the atmosphere will produce a quick period of downpours statewide between 2 a.m. and 6 a.m. and in Litchfield County it looks like the cold air will arrive in time for a change to snow and even a bit of accumulation.

Below is a sounding showing temperature and dew point through the atmosphere valid 4 a.m. Sunday in Canaan up at about 1,000 feet. You can see plenty of moisture in the low levels of the atmosphere (temperature and dew point...red line/green line...next to each other implying relative humidity near 100%) and lift in the atmosphere (the farther the thin white line juts to the left the stronger the upward motion of air is). 

This setup could produce a quick inch of snow in some of the hilltowns right around daybreak and is something to watch closely. In the valley locations and along the shoreline it should be a bit too mild for a much in the way of accumulation though a few stray wet snow flakes around daybreak are still possible. While temperatures in the hills will drop to around freezing it will be milder in the valley. You can see this at 1 p.m. in Hartford on Sunday with temperatures near the ground in the low 40s. This is not a snow sounding.

A few rain or snow showers are possible during the day Sunday across the state - especially in Litchfield County. Minor additional accumulation is possible in the hills.

Sunday Night & Monday Morning - Snow even in the valleys

By Sunday evening temperatures will be cold enough to support snow even down to the valley floors and along the shoreline. Cold air from the northwest will advect (be pushed by the wind) in all day. Most of our computer models show 850mb (around 5,000 feet up) dropping to -8C by 7 p.m. Sunday - definitely cold enough for snow.

The question always is with these setups will there be enough moisture to support precipitation? Frequently the answer is no - but in this case it may be different. Remnant streamers of lake effect snow may make their way south from Lake Ontario. A strong northwesterly wind and low level moisture will aid in producing some "upslope" in the hills - basically the wind forces air up and over the ridges which can result in an enhancement of clouds and sometimes precipitation. Also, on the backside of this upper level low there appears to be an unusually high amount of low level moisture in southern New England - we're not drying out as quickly as we normally do.

You can see that robust moisture with relative humidity of near 100% about 5,000 feet up across the state. While it won't snow the whole time periods of snow showers appear likely. In the hills - where there is a bit of an assist from that "upslope" effect I can't rule out some additional accumulation. Elsewhere, patches of accumulation are possible under heavier bands. This is very much like a summer thunderstorm where some towns get it and others don't.

This continues through Monday morning. This sounding for Canaan valid at 10 a.m. Monday shows a favorable setup for snow with a deep layer of moisture (high relative humidity around -15C which supports dendrite production) and temperatures well below freezing from the clouds to the ground. Of course, it is not as favorable in the valley and along the shoreline but you get the idea.

Strong, gusty winds

Every town will have to deal with strong gusty winds. Computer models support wind gusts of 40-50 mph which, when coupled with temperatures in the 30s, will result in unusually cold wind chill values. A few isolated tree and power line issues are possible.

The bottom line

Most of the state along the I-91 and I-95 corridors can expect to see cold, wind, and scattered snow showers Sunday night and Monday morning. A few towns may even pick up some accumulation - though it won't be everywhere. 

In the hills, particularly in Litchfield County, enough pieces are coming together where 1"-3" of snow is possible in the higher elevations. There will likely be a few different times of snow - one around daybreak Sunday morning and another window Sunday evening through Monday morning. Expect some areas of slippery travel.

It's definitely not a big storm but a good reminder that the calendar says it is mid November and it will finally feel like it!

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<![CDATA[Perspective on the Drought]]>Thu, 17 Nov 2016 13:37:52 -0500https://media.nbcconnecticut.com/images/160*120/nepaug1.JPG

This morning about 40 percent of the state was upgraded from severe drought to extreme drought. With rainfall deficits of nearly 20 inches since January 1, 2015 across parts of north central Connecticut this classification is not a surprise. 

Extreme drought has all sorts of problems associated with it. People with shallow wells are without water, cities and towns with small reservoir systems are beginning to run low on water, farmers are dealing with crop losses due to the unusually dry soil conditions.

While it's fair to say this is the worst drought in decades it pales in comparison to the big drought of 1962-1966. The drought in the mid-1960s remains the most significant on record. Take the Metropolitan District Commission reservoir system that serves greater Hartford as an example. The Barkhamsted and Nepaug Reservoirs are currently at 76.2% but in 1965 they dipped to 46%. For a reservoir system with a capacity of 40 billion gallons this is a big difference!

Another way tolook at this in a quantitative way is to use the Palmer Drought Severity Index. Currently the PDSI is <-4.00 across the state which puts our three climate divisions in extreme drought.. 

The current -4.15 PDSI in Litchfield County is a bit worse than the 2002 drought which spiked at -3.82 in 2002. But between 1964 and 1966 the PDSI was <4.00 (extreme drought) for an extended period of time. From March 1965 through August 1966 we were in extreme drought continuously- with values approaching -5 several months (it did reach -5 in other parts of northern Connecticut which is considered exceptional drought). We've had 1 month of extreme drought - the 1960s extreme drought lasted for 17 months!

Of course, there's nothing to say that this drought won't continue to get worse. The estimate is that we would need approximately 10" of rain to get out of any kind of drought classification. It's hard to make up a lot of ground in the winter (our climatologically driest season) but you never know. Hope for rain and help conserve water!

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<![CDATA[Unseasonable Warmth (For Now)]]>Thu, 17 Nov 2016 09:53:50 -0500https://media.nbcconnecticut.com/images/160*123/ecmwf_apcp_f108_ne.png

November is always a big transition month in southern New England as we close out meteorological fall and usher in meteorological winter on December 1st. Unsurprisingly, the evolving weather pattern shows quite a bit more winter than we've seen lately.

Through Saturday we're looking at a truly gorgeous stretch of weather. Plenty of sunshine and above normal temperatures will be the rule for today, tomorrow, and Saturday. Highs around 60 - and possibly into the middle 60s by Saturday - will be a full 10 degrees above normal. Not bad for November!

But it's not going to last. A developing low over New England and eastern Canada on Sunday will send a blast of sharply colder air southeast into Connecticut. This storm becomes a large and powerful cut-off low with unseasonably cold air over our part of the country. 

So what can we expect? Rain showers are likely Sunday morning as the strengthening low passes over us. Clouds linger on Sunday with a few scattered showers and temperatures that slowly drop through the 40s. 

Monday will be quite cold for the time of years with temperatures struggling out of the 30s. It's possible a few towns could see flurries but the bigger story will be the cold and the wind - wind chills will be stuck in the 20s all day.

From 10 to 15 degrees above normal to 10 to 15 degrees below normal will be a pretty sizable drop. 


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<![CDATA[Little Drought Relief but a Stormier Pattern Ahead]]>Wed, 16 Nov 2016 12:55:37 -0500https://media.nbcconnecticut.com/images/213*120/CxZklwCWgAE6RNJ.jpg

Between 1/2 and 1 1/2 inches of rain yesterday was a welcome sight after a nearly 2 year stretch of dry weather - but we haven't kicked this drought yet. The rainfall deficit since January 1, 2015 in Windsor Locks is still a staggering 19"!

There are some signs of hope looking forward. The weather pattern is evolving and does look a bit stormier in the long term. Nothing epic - but looking a bit more interesting with several chances for rain (and maybe some mixed precipitation). The 8 to 14 day outlook from NOAA shows this with below normal temperatures and near normal precipitation. A big change from weeks of above normal temperatures and below normal rainfall.

Of course, the winter lovers who are desperate for any flake of snow this time of year, really care about whether or not we have any snow in our future. In the near future the answer is maybe a few flakes but don't get too excited. A strong storm is expected to develop overhead and behind it gusty northwesterly winds will bring in colder air. With an upper level low overhead a few rain or snow showers seem possible on Monday but that's the extent of it.

In the more distant future one can envision a more interesting pattern after Thanksgiving. The GFS ensembles (the GFS model run 20 different times with slightly different tweaks to represent a reasonable spread of possible solutions) show a substantially negative North Atlantic Oscillation developing (-NAO). See all the orange and red over Greenland? That's a strong signal for jet stream blocking upstream of us.

A -NAO helps keeps storms underneath southern New England and can promote wintry solutions. We'll see what happens - nothing to get excited about now but it's the first "interesting" window we've seen in a few weeks.

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<![CDATA[On Ryan's Radar: The King Tide]]>Mon, 14 Nov 2016 15:46:53 -0500https://media.nbcconnecticut.com/images/160*120/14991835_1349837131716580_2033566142400568014_n.jpg

Last night's supermoon was hard to miss. The brightest and biggest full moon since 1948 lit up the night sky across Connecticut. Today and tomorrow we'll see the supermoon's impact in a different way - the King Tide.

The height of high tide varies through the year because of differences in the gravitational pull of the moon and sun. When the earth, sun and moon line up the amplitude of the tides is greatest - we call this a spring tide. The gravitational pull of the moon and sun act together to create higher high tides and lower low tides.

When the moon is at first quarter or third quarter the sun and moon are at 90 degrees. This results in lower high tides and higher low tides as the gravitational pull of the sun and earth are not working in tandem -  we call this a neap tide.

In New Haven the difference between a neap tide and spring tide is big! On November 7th when we had a one quarter moon the highest tide was 6.0ft MLLW. Today's high tide following the supermoon was 8.0ft MLLW - that's a difference of 2 feet! 

But what the heck is a king tide? The moon's orbit around the earth is elliptical and the distance between the earth and the moon changes through its orbit. When the moon is farthest from the earth it is at apogee and when it is closest to the earth it is at perigee. The closer the moon is to the earth the stronger the gravitational pull will be.

When the spring tide aligns with perigee you get a perigean spring tide or what we like to call the King Tide. When there's a supermoon you can expect the tide to be higher than normal!

That's exactly what we'll have today and tomorrow. Here in Connecticut this will be the second highest tide of the year. The high astronomical tide combined with an onshore wind ahead of a storm will result in widespread minor to locally moderate flooding. This won't be a big deal but it will be nuisance flooding in the typically vulnerable towns on the Sound. 

Flooding from King Tides is becoming more and more common these days thanks the sea level rise. What is known as "sunny day" flooding has increased substantially over the last 10 years as ocean levels climb. The latest research indicates more than 50% of nuisance flood days can be attributed to human caused sea level rise in New London. When these king tides occur during a storm serious coastal flooding can be the result.

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Photo Credit: Eweather
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<![CDATA[Ryan's Take: Unseasonable November Warmth Moves In]]>Wed, 16 Nov 2016 17:17:21 -0500https://media.nbcconnecticut.com/images/213*120/CwNKGxVVYAEXBGw.jpg

From a hard freeze to near 70 degrees. That's November in New England for you! Even though temperatures will warm we will be well short of a record for Wednesday and Thursday with records of 83 and 78, respectively. It will be mild but definitely not unprecedented for November. 

The mild air doesn't last too long. An upper level disturbance swings through bringing with it a period of rain and a cold front. Behind it temperatures will drop in a hurry with highs struggling above 50F on Friday.

What's really a bummer as we look forward through day 10 is that there's really no sign of a prolonged wet weather pattern. Let's look at the European Ensembles through November 10th. The European Ensemble is a somewhat lower resolution of the vaunted European model that is run 51 separate times with slightly different initial conditions and model physics to represent a reasonable spread of possible outcomes.  The more ensemble members that show any given solution the more likely it is to occur. 

Through November 10th there's less than a 10 percent chance of more than 0.5" of precipitation in Connecticut! Put another way, less than 5 of those 51 ensemble members show more than 1/2 inch of rain. Those are bad odds.

While temperatures here in New England don't appear to be too warm past Thursday the weather pattern across most of North America looks incredibly warm. A +EPO (East Pacific Oscillation) should flood the United States and Canada with maritime Pacific air over the next week or so but most of that warmth should remain to the west. 

The bottom line is that while we have some warmer on the way through Thursday the weather through day 10 looks mainly dry with temperatures relatively close to normal - especially compared to extreme warmth from the Great Lakes to the west coast.


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<![CDATA[Ryan's Take: Our Drought Continues]]>Thu, 17 Nov 2016 09:55:16 -0500https://media.nbcconnecticut.com/images/200*120/14642019_10210886060968949_971759458207119416_n.jpg

A drought is about the worst kind of weather for a weather geek like myself to cover. The absence of precipitation is about as dull as it gets! Even though droughts aren't as sexy as big thunderstorms or nor'easters for meteorologists they have very real impacts - for agriculture, for people's wells, and even for public drinking water supplies.

Connecticut is generally pretty blessed when it comes to rainfall. Even our "bad" droughts aren't nearly as bad as in other parts of the country as we get quite a bit of water most years. That said, our 2-year drought across the state is pretty impressive. 

Since January 1, 2015 the greater Hartford area is running a nearly 18" rainfall deficit. We've picked up about 79% of normal precipitation. 

While this dry spell is bad - this is not unheard of. The drought the peaked in spring of 2002 was worse with 100% of the state in severe drought and 17% in extreme drought (right now we are at 86% and 0%, respectively). In the mid 60s there was a drought that lasted from 1961-1968 and was substantially more impactful.

Over the past year (10/12/15-10/11/16) we've picked up only 33.87" of precipitation in Windsor Locks which ranks as the 7th lowest out of last 111 years. The median rainfall for that period using all 111 years is 43.80" - so we're about 10" below normal. The other years that were a bit worse include 1965 (the big drought - with 1964 and 1963 also in the top 15 driest), 1980 and 1981 (top 3 and 4 driest, respectively) and 2002 (the previous year, 2001, was 8th driest). 

While this kind of dry spell isn't unheard of we still need the rain! Not surprisingly, no big rain is expected over the next 10 days but our luck will change sooner rather than later.



Photo Credit: Fran Lawlor
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<![CDATA[Ryan's Take: A Stormy (and Wintry) Thursday]]>Wed, 16 Nov 2016 17:19:14 -0500https://media.nbcconnecticut.com/images/160*120/NAMNE_prec_prec_036+%282%29.png

After record warmth not too long ago we've got a big change on the way. Our updated computer models continue to show snow, sleet, rain, and thunder across parts of the state on Thursday.

There are still a few questions that remain. The biggest one that I have is whether or not the snow will accumulate. It appears the best chance of that happening is in the hill towns of Litchfield County above 1,000 feet. Temperatures near the ground will be coldest here and snow will begin falling by late morning. One of my favorite high resolution models is the NCAR ensemble. This graphic shows the probability of temperatures remaining below 32F early in the afternoon tomorrow - there's a clear signal of near freezing air in the highest elevations of northwest Connecticut. A slushy 1"-2" is possible for the hills.

Elsewhere in Connecticut there is the chance for some snow and sleet - even down to the shoreline around New Haven. Enough lingering cold air and some dry air that will result in evaporational cooling as the precipitation begins will be sufficient for a few flakes or pellets. You can see the dry air on this sounding valid at 10 a.m. around Hartford.

This dry air will allow the atmosphere to cool - as snow falls through this dry column the air will cool as the atmospher saturates. This could promote a brief period or snow or sleet even down to the New Haven area - but this will be brief. Any accumulating snow will be confined to the hilltowns. 

Temperatures will warm above freezing and any snow will change to rain across the state by late afternoon. The storm will strengthen as it moves into Connecticut with a bit of instability present as well giving us a few thunderstorms and areas of heavy rain are possible. There's an outside chance of a gusty strong storm on the Sound as a bit of surface-based instability tries to work north. The NAM model shown here depicts enough instability for strong thunderstorms over Long Island but not quite enough here in Connecticut. This is worth watching.

With a few flakes in the forecast - how common is October snow? Since 1905 (110 years) snow has been reported in the Hartford area on 45 calendar days but snow has only accumulated 4 times which includes the epic October 2011 snowstorm.

  • October 29, 2011 - 12.3"
  • October 10, 1979 - 1.7"
  • October 19, 1972 - 0.4"
  • October 30, 1925 - 0.1"
  • October 18, 2015 (and 39 previous days) - Trace

In the hills, it's a different story. There was a bit of snow on Saturday in Litchfield County and at the summit of Bear Mountain (over 2,000 feet) Jim Dayton sent in this picture of snow that had accumulated there.

In Norfolk, the Cooperative Weather Station at the Great Mountain Forest has picked up measureable snow 33 times in their 73 years of weather observing. A trace of snow occurs almost every October.

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<![CDATA[Ryan's Take: Does a Snowy October Mean a Snowy Winter?]]>Wed, 16 Nov 2016 17:17:42 -0500https://media.nbcconnecticut.com/images/160*160/sylviamaieli_bolton.jpg

Does a snowy October mean a snowy winter? Are we going to get clobbered after Thursday's snowfall? I have good news for you - don't panic! Brad crunched some of the numbers last night at 11 p.m. and here's some of what he found.

1.5" of snow in the Hartford area (measured at Bradley Airport) yesterday makes this the 3rd snowiest October on record and only the 5th time on record measurable snow has been recorded on or before Halloween. In the hills, where October snow is more common, the 2.5" at the Great Mountain Forest in Norfolk makes 2016 the 6th snowiest winter on record!

At least in the Hartford Area the 2 Octobers that have been snowier have gone on to produce horrible duds for snow lovers like myself. I mean absolutely hideous winters. 2011-2012 managed to drop 26.7" of snow for the whole season! The 12.3" on October 29th was the biggest storm of the season. The 1979-1980 winter was even worse - 16.7" of snow fell making it the 3rd least snowy winter on record. Brutal. 

Of course, this is a very small sample size and there really aren't many conclusions you can draw from it. The two other Octobers with measurable snow - 1972 and 1925 - weren't memorable winters either with 35.2" and 45.7", respectively over the season. 

In Norfolk, where the sample size is larger, the results are more mixed. The 10 snowiest Octobers have gone on to produce near normal winters on average. The long term average in Norfolk is around 90" for the season and the winters following snowy Octobers managed 83.0" on average - with some big duds and above average years in the sample. The 1987-1988 and 1962-1963 dropped 116.4" and 125.2", respectively up in the Icebox of Connecticut. 

So - don't freak out and expect a snowy winter since this October storm dropped an inch or two of snow. But, don't be fooled into thinking this winter will be a cake walk either. The numbers don't really support any argument about how much snow we'll see this season based on one storm in October. More importantly, just be glad you didn't lose power for 11 days after this October snowstorm :-)

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Photo Credit: Sylvia Maieli
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<![CDATA[Ryan's Take: Third Snowiest October Day in Hartford Area]]>Wed, 16 Nov 2016 17:18:07 -0500https://media.nbcconnecticut.com/images/161*120/14523221_10211356176128980_5007557260169087938_n.jpg

Evening update: Today's storm turned out to be a bit of an overperformer across parts of Connecticut! A thump of snow during the middle of the afternoon managed to accumulate on all surfaces (even roads) in the valley locations from Hartford up through the Farmington Valley. Intensity of snow is by far the most important in factor in whether or not snow accumulates on the roads (temperature of the road prior to the snow is almost completely irrelevant if the snow comes down hard enough). Farther northwest, up to 2.9" of snow accumulated in the higher elevations of Colebrook!

That burst of snow around Hartford managed to drop 0.6" at the station in West Hartford, 1.5" at Bradley Airport, and nearly 2" in Coventry and Tolland! The 1.5" in Windsor Locks makes October 2016 the 3rd snowiest October on record (records go back to 1905) and the 2.3" at the Great Mountain Forest in Norfolk is the 9th snowiest October day (records go back to 1942).

These borderline storms are always very tough to pin down. A degree in either direction means the difference between a cold rain mixed with snow flakes and accumulating snow. It's never easy - but I'm happy we gave people several days heads up about the snow!

Midday update: Snow continues to accumulate in the hill towns of western Connecticut where 1"-2" will stick. In the Hartford area a bit of accumulation on the grassy surfaces is possible as temperatures have dropped to near 32F in moderate snow! The snow will gradually change to rain as warmer air moves in just above our heads - and also at the ground! By 5 p.m. most of the state will be seeing rain with the exception of the highest hill towns such as Hartland, Norfolk, and Colebrook. 

Morning update: A few flurries have started already this morning along the New York border and that will gradually spread east as the morning goes on. While this isn't going to be a big storm - some areas will see a bit of slippery travel later today.

The easiest way to explain why we're looking at snow is that we have a significant amount of dry air between the ground and 8,000 feet up. You can see that on this forecast sounding valid at 8 a.m. in Hartford. Notice the separation between the green line (dew point) and red line (temperature) in the lowest part of the graphic? That means you have low relative humidity - or dry air! 

In order to get snow flakes or rain drops to the ground from the clouds above this dry layer will need to disappear. As precipitation falls through and evaporates (or sublimates in the case of snow) - energy is expending by the surrounding air to evaporate the precipitation which causes the air to cool. This is evaporational cooling - and why we'll see a bit of snow today! 

A good way to look at the potential for snow is to look at the temperatures just above our heads. A good level is 925mb - which is approximately 2,500 feet up. Below is the temperature forecast (NAM) valid at 2 p.m. at 925mb which shows a solid area of <0C temperatures - especially northwest of Hartford. The second map shows the previous 3 hours of precipitation valid at 2 p.m. which indicates there is a sizable chunk of precipitation moving in at that time.

Putting it all together, a period of snow or a mix of rain and snow is likely in many towns. This includes the towns around New Haven on shoreline! However, the only places that are in the game for actual accumulation of snow will be the hill towns northwest of I-84 where temperatures near the ground will be just cold enough to see up to an inch of snow. 

This matches up well with the NCAR ensemble (one of my favorite tools as it is a good short range/high resolution set of models) showing a good chance that temperatures will be below 32F in the higher elevations of Litchfield County. Elsewhere in the Northwest Corner, even with temperatures near 33F or 34F, if the snow comes down hard enough there could be accumulation on paved surfaces.

Temperatures will warm later this afternoon and into this evening and any snow changes over to rain. There is a chance for some heavy rain and thunder during the overnight hours - particularly along the shoreline. If the warm sector (think temperatures in the low 60s) is able to move inland past Long Island Sound there is the potential for strong winds - up to 45 or 50 mph on the coast around midnight - particularly with any thunderstorms that develop. The NCAR ensemble has mean QPF (precipitation forecast) of over 1.0" in many locations. A good rain!

With a few flakes in the forecast - how common is October snow? Since 1905 (110 years) snow has been reported in the Hartford area on 45 calendar days but snow has only accumulated 4 times which includes the epic October 2011 snowstorm.

  • October 29, 2011 - 12.3"
  • October 10, 1979 - 1.7"
  • October 19, 1972 - 0.4"
  • October 30, 1925 - 0.1"
  • October 18, 2015 (and 39 previous days) - Trace

In the hills, it's a different story. There was a bit of snow on Saturday in Litchfield County and at the summit of Bear Mountain (over 2,000 feet) Jim Dayton sent in this picture of snow that had accumulated there.

In Norfolk, the Cooperative Weather Station at the Great Mountain Forest has picked up measureable snow 33 times in their 73 years of weather observing. A trace of snow occurs almost every October.

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Photo Credit: Kate Mlodzinski
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<![CDATA[Ryan's Radar: Drought Conditions Continue]]>Wed, 16 Nov 2016 17:16:55 -0500https://media.nbcconnecticut.com/images/213*120/Almanac+Deficit+Surplus_11_2_16.png

Another day with another mainly dry extended forecast - no surprise here! Sure we'll get a little rain Thursday afternoon but certainly not a drought buster! Through yesterday the Hartford area is 18.33" below average since January 1st, 2015! That is a sizable rainfall deficit and something we only see every 10 or 20 years.

That said, Over the last month drought conditions improved significantly in eastern Connecticut with over 8 inches of rain in some towns! The rest of the state the story was more of the same with well below normal precipitation. I expect the updated drought monitor tomorrow to reflect that with a downgrade of the drought conditions along the I-395 corridor.

The updated 8-14 day precipitation forecast from the National Weather Service shows decent odds of below normal precipitation across the northeast in week 2. The GFS Ensembles (An snsemble is a somewhat lower resolution of a typical model that is run multipletimes with slightly different initial conditions and model physics to represent a reasonable spread of possible outcomes) show the dry pattern quite well. Of the 21 ensemble members only about 30 percent show over 1" of rain in the next 16 days!

My concern going forward is that we've wasted what is typically our wettest period of the year - October - without solid rains over a good chunk of the region. These things can change quickly but right now through there's no signal for big rains through the middle of the month.

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