Area Discussion |
SYNOPSIS ... Arctic high pressure will continue to bring frigid temperatures to the region through the weekend into Monday morning. An area of low pressure will bring widespread light snow to the region Monday night into Tuesday. Seasonably cold and quiet conditions return for the rest of the week with high pressure in place across the Northeastern United States.NEAR TERM /THROUGH MONDAY/... As of 1211 PM EST Sunday...We`ve got some diamond dust (very small snow flakes) falling out of yet another lake effect band off of Lake Champlain across Chittenden and Addison Counties. We could see minor snow accumulations of .1 to .2 inches but given the lack of any appreciable moisture and the size of the snowflakes, no significant accumulation is expected. As skies clear this morning and afternoon, these flurries will dissipate leading to the coldest night of the season thus far and possibly the coldest since February of 2023. Previous Discussion...A strong Arctic surface high centered over the Great Lakes will shift eastward over the region, continuing to bring bitterly cold conditions through the weekend. After a cold start with lows overnight plummeting into the single digits above and below zero, temperatures will continue to unseasonably cold. Daytime temperatures will struggle to warm, with the broader valleys climbing into the low teens and elsewhere only reaching single digits for high temperatures. Despite the bitter cold, some blue skies and sunshine will make an appearance under the high pressure. With the high directly overhead, ideal radiational cooling conditions are expected for Sunday night, especially with many locations receiving a fresh snowpack although the potential of some cloud cover may limit how much some locations are able to radiate out. Outside of the Champlain Valley, most places will drop below zero, with temperatures of -5 to -15 expected across portions of the Northeast Kingdom and the Adirondacks. There is a chance that BTV may reach or drop below zero for the first time since February of 2023. Winds will be light and terrain driven overnight with the center of the high overhead, which will keep apparent temperatures Monday will start out dry with high pressure shifting eastward, with increasing cloud cover through the day as our next system approaches the region. Temperatures will continue to be below normal, but will be warmer compared to Sunday, with daytime highs climbing into the teens and lower 20s. Chances for precipitation will gradually increase throughout the morning, with snow showers reaching the St. Lawrence Valley by Monday evening.SHORT TERM /MONDAY NIGHT THROUGH TUESDAY/... As of 410 AM EST Sunday...A clipper type system will sweep through the North Country Monday night through Tuesday bringing some breezes along the boundary, potential for a snow squall or two, and accumulating snow ranging 2- 4 inches. Progged strength of 850mb jet is around 50kts and will track across over Monday night into early Tuesday morning. This timing could mitigate some impacts to holiday travelers, but those out and about could run into bursts of snow. It`s not the best set up for long lived squalls with some parameters not quite reaching necessary thresholds, but details can change between now and Monday night. The bulk of the precipitation is expected just behind the front supporting widespread accumulations of 1 to 2 inches and better chances of 2-4 inches along slopes and higher terrain. Central Vermont could end up being the "winner" with higher elevations potentially seeing up to 6 inches of powdery snow. Will need to see how this system evolves; winds could produce lower valley shadowing and/or shatter dendrites, so timing of lljet will be key. Otherwise, cooler than average temperatures will linger through Tuesday with some warming over recent conditions into the upper 20s to around 30 degrees.LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/... As of 410 AM EST Sunday...Model signals remain for a large high pressure to settle over the Northeast Christmas Day through the end of the week. Model guidance is attempting to warm profiles quite a bit through Friday, but my suspicion is that recent low level snowpack is not being taken much into account. 925mb temperatures remain several degrees below freezing and without strong warm air advection any thermal gains will initially be offset by melting of low level snow. High temperatures should warm to around averages slightly above freezing. Models diverge wildly heading into the weekend with some globals moving the omega pattern east quickly - likely a result of model biases. Gave a nod to these more progressive solutions, but could see a stubborn ridge persisting through the weekend. Should the progressive models win out, some chances of mixed precipitation will be possible as southerly flow deepens and as an upstream system approaches. .AVIATION /17Z SUNDAY THROUGH FRIDAY/... Through 18Z Monday...Mainly VFR conditions are occurring and expected through the TAF period. The one exception is across the Champlain Valley and northern Vermont where ceilings range from 1800 to 2200 ft. This is mainly in response to a lake cloud off of Lake Champlain and will likely continue through 21Z to 22Z. At KBTV, we will see light snow continue through 21-22Z before tapering off with just a few tenths of accumulation. Winds will go light and variable overnight and begin shifting to the south after 12Z on Monday. Outlook... Monday Night: Mainly VFR, with areas MVFR and IFR possible. Definite SN. Tuesday: Mainly MVFR, with areas VFR possible. Chance SN, Chance SHSN. Tuesday Night: VFR. NO SIG WX. Christmas Day: VFR. NO SIG WX. Wednesday Night: VFR. NO SIG WX. Thursday: VFR. NO SIG WX. Thursday Night: VFR. NO SIG WX. Friday: VFR. NO SIG WX. . |
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