Winter storm to bring heavy snow, sleet, freezing rain, and rain to the region tonight

Hello everyone!

While this is a pretty run of the mill storm for the area, that’s not to say it’s not without impacts. Precip is moving into the region from the west right now and a significant amount of virga is showing up on radar. Virga is the technical term for precip that evaporates before reaching the ground because of dry air.

Temperatures (Blue numbers) and Dew Points (purple numbers) showing very dry air across the area this evening. Observations current as of 4:15 PM.
Temperatures (Blue numbers) and Dew Points (purple numbers) showing very dry air across the area this evening. Observations current as of 4:15 PM.

With such dry air in place, we’ll have to be a little patient before the first flakes will fall. By 7PM, everyone will be seeing precip with RI/CT rain, MA rain and snow, and NH/ME snow.

With such bitter cold the past few days, the temperatures on the road surfaces are well below freezing so when snow starts, we won’t have to wait long before travel becomes hazardous. With only two to three hours of snow, areas of MA and CT are already seeing very bad road conditions with snow piling up. Expect the snow and the poor road conditions to move north the next few hours.

gfs vert velo
12Z GFS valid 1AM Tomorrow Showing Intense Upward Motion Causing Heavy Precip.

 

This image looks very confusing but it boils down to how much air is moving up in the atmosphere as well as how fast it is moving up. The more air that moves up, and the more quickly it does so, the heavier the precip will be. This image shows well the potential for a very heavy band of snow/sleet/rain late tonight and very early tomorrow morning.

snow map 1-3

Here is the updated snow map with a few important changes. First, I have increased the mountains to 8-12 because precip wraps up around 7AM and I do not see the warm air making it up there in time for a changeover to mixed precip. I also backed off on the areal extent of the ice since mixed precip in the foothills will be more of a mix of sleet and freezing rain rather than just freezing rain.

I reduced amounts slightly for the very immediate coast since the proximity to the ocean should aid in the transition fro snow to rain. that being said, even an hour extra of snow would deliver an extra 1-2″ of snow while an hour earlier in the changeover would do the opposite. This is a fairly uncertain forecast for the coast so be prepared for a little more and know that there is the possibility for a little less.

mesolow

One important feature I should make note of which is a little bit of a wild card is a low pressure area that is developing off the Carolina coast. This is developing a little farther south and a little more quickly than anticipated which could have significant consequences down the road. This low will help turn winds more northerly and will thus help lock in the cold air across the region at least at the lower levels of the atmosphere.

As far as timing goes, some light snowflakes are being reported around the area now with heavier snow back towards MA/CT/RI. Expect snow to develop quickly from here on out and become steady and moderate. The recent cold has left roads and sidewalks very chilly so as soon as snow starts falling expect slick roads. We have seen very bad road conditions in this snow band across MA and CT. As the band moves northeast, expect the bad road conditions to as well.

The heaviest snow will occur between 10PM and 4AM tapering off as we get closer to dawn. Scattered drizzle, both liquid and frozen, will last a little longer before finally dissipating midday tomorrow. Temps will warm right up tomorrow as we sit in the warm sector of the low so expect highs in the 30’s and 40’s. Temps crash Monday with brutal cold returning next week. The coldest day looks to be thursday with highs struggling to get above 5 degrees. The mountains of ME and NH look to see highs remaining below zero. More details on that in the coming days.

-Jack

One thought on “Winter storm to bring heavy snow, sleet, freezing rain, and rain to the region tonight”

  1. Jack: FYI, we’ve had about an inch of new snow so far this evening and it continues to fall. Don’t know how much we’ll have before things get messy tomorrow. Gramps.

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