Wednesday, March 17, 2021

Burst of Moderate-to-Heavy Snow Thursday Night (March 18, 2021)

 A strong Arctic cold front arriving from the northwest moves across Connecticut early Thursday evening. Meanwhile a low pressure system (responsible for the ongoing tornado outbreak across the deep South) approaches from the southwest Thursday morning. As the low pressure approaches, heavy rain pushes into the state early Thursday afternoon. The combination of the approaching cold front and strong Arctic high pressure behind the front helps to push the approaching surface low south of the state Thursday evening.

By early Thursday evening, the Arctic cold front rapidly pushes through the state resulting in much colder temperatures quickly overspreading the state. Despite the cold front moving through the state, lift will remain rather strong (thanks to the surface low passing south of the state) and ample moisture will be thrown into the colder airmass. This results in rain changing over to a period of moderate-to-heavy snow by late evening Thursday before exiting during the late overnight or early pre-dawn hours Friday. 

Forecast models indicate some pretty strong lift across the state during the early overnight hours Thursday night with forecast soundings showing a thermal profile favorable for snow:



Breakdown of what to expect:

  • Heavy rain moves into the state early Thursday afternoon.
  • Temperatures get into the lower 40's, but during the evening begin to drop rather quickly with increasing winds as the cold front moves through. Wind gusts of 30-40 mph are possible overnight Thursday 
  • Snow begins to transition to rain during the mid-to-late evening Thursday with the changeover occurring more quickly across the northwest hills. 
  • Snow end during the late overnight or early pre-dawn hours Friday morning. Some parts of the hills could see as much as 4-5' of snow.
  • Majority of the snowfall accumulations occurs on the grassy/colder surfaces, however, roads will become slick, especially as temperatures drop below-freezing. Give yourself extra time for the Friday morning commute.
  • Sun comes out through Friday morning, but a cold/breezy day with temperatures only into the 30's.
  • Snowfall Forecast: