Fire Rages in San Francisco After Gas Line Explosion
Today's high at Bradley Internation Airport was an astounding 77 degrees.
The record hightemperature for the day in Hartford fell by 14 degrees. The all-time February high temperature record fell by 4 degrees. Of the 6 times the Hartford area has reached 70F in February - 3 of them have occured in the last year. This was the warmest temperature recorded in the Hartford area during meteorological winter. By any metric the warmth today was remarkable.
From a meteorological perspective what we saw was unprecedented. One of the most common things we display on weather maps is something called geopotential height. Geopotential height (GPH) is the height above sea level a certain pressure level is found in the atmosphere. The higher the GPH the warmer the atmosphere below that level as warm air is less dense than cold air. Warmer air effectively takes up more space. Using GPH is useful since it is all relative to sea level - otherwise the height of a pressure level above the ground would be more closely related to elevation of the ground than the atmosphere's warmth.
During last night's weather balloon launch on Long Island the height of the 500mb level was an absolutely astounding 5880 meters. That would be a "warm" value for the dead of summer. Seeing that in the winter is simply unheard of. It just doesn't happen. We broke the previous record by nearly 100 meters which is a HUGE margin.
The question becomes was today's record shattering warmth caused by climate change? Having 3 of the 6 warmest February days occur in the last year is pretty odd! The answer, of course, is complex.
Extreme heat (compared to normal) is becoming more common as the climate warms. We are seeing this year after year in Connecticut. Winters are warming and they're also shrinking duration. Since 1970 the typical "frost-free" season has grown by weeks with the first frost coming later and the last freeze coming earlier. Winters have warmed by nearly 4F.
Of course, day-to-day weather is full of extremes and ups and downs. Was it possible for a day to be this warm 500 years ago? Sure. Are days like this more likely now? Absolutely. Will they be more likely in future winters? Yes. We're effectively loading the dice toward warmer weather patterns and more extreme heat. We see this as record high temperatures already dramatically outpace record cold temperatures.
There's a lot we don't know about how a warming world will specifically impact Connecticut. The atmosphere doesn't act linearly and feedback loops with a warmer ocean to our south and record heat over the Arctic to the north are capable of doing all sorts of wonky things. What we do know is that winters are getting warmer and extreme warmth is becoming something we should expect to see more and more.