No real change in the overnight forecast with some questions still remaining. The National Weather Service upgraded parts of coastal Connecticut to a blizzard warning – though I expect they will fall short of blizzard warning criteria (wind will be there but visibility won’t be under 1/4 mile). The more I look at this storm the more I get the feeling it will come in 2 parts with a sizable lull in between.
Part 1 will be this afternoon and this evening with a gusty southerly wind (right of the Sound) as the bitterly cold air from this morning is replaced by milder air from the ocean.
I wouldn’t be surprised to see this overperform in areas with a few inches of snow falling in a relatively short period of time later today. There’s a bit of instability and temperatures above the lifted condensation layer are quite cold and in the dendritic growth zone (that means efficient snowflake production – AND snow flakes that are able to accumulate easily).
Most of our computer models show a lull after the first burst of snow this afternoon and evening and then another period of snow in the pre dawn hours tomorrow. There’s a high amount of uncertainty here.
The GFS keeps the snow going all night as an “inverted trough” sets up northwest of the offshore low. Notice the precipitation from Connecticut back toward the Finger Lakes of NY along that kink of the isobars? Our high resolution RPM model also agrees with this output.
If this is correct we will have a fabulous bust in snowfall totals with many areas picking up over 10″ of snow. Most computer models, however, have a much weaker feature like this, some keep it over New York City, and others don’t have it at all. The typically Teflon Euro model bears little resemblance to this forecast and the regional Canadian model (RGEM) has nothing remotely like this (the RGEM has had one hell of a winter too).
The HRRR which is our very high resolution and near-term computer model shows a similar setup to the above mentioned models with a heavy band of snow along the inverted trough and another up with the mid level forcing toward Maine. In between there’s one heck of a sucker hole over northeastern areas and parts of Massachusetts.
So bottom line is watch this one. I think it has a few tricks up its sleeve.