Rare Winter Tornado Rips Through Western Massachusetts - NBC Connecticut
On Ryan's Radar

On Ryan's Radar

First Alert Meteorologist Ryan Hanrahan Gives You His Take on Connecticut's Weather

Rare Winter Tornado Rips Through Western Massachusetts

On Ryan's Radar

NBC Connecticut First Alert meteorologist Ryan Hanrahan gives you the science behind the forecast and shares with you an in-depth look at the weather impacting Connecticut.

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Morning Forecast for Oct. 17
Damage in Conway, MA courtesy of Anne Farrell

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.

This 4 panel radar plot from the National Weather Service radar in Albany shows strong rotation in the upper right box. The lower right panel shows normalized rotation approaching 2.00 (very impressive) and the upper left shows a classic and well defined bow echo signature. Just north of the bows apex is an area where brief tornadoes can form and bow echoes themselves are typically associated with strong straight line winds.

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. 

This sounding off the high resolution rapid refresh model reveals only meager instability - <100 j/kg of CAPE. That said, there is very strong low level shear and there is neutral buoyancy near the ground which wouldn't preclude strong winds from mixing down to the surface.

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. 

Photo credit: Jeff Jumper / Pennsylvania Emergency Management Agency

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.