The following forecast is provided by Ryan Vandervoort and Amanda Kerswell  as part of lab work for the Introduction to Meteorology course (ATM-145) under faculty (Joe Kravitz) supervision. The forecast discussion is mine (JK) ……

The polar front and associated jet stream are aligned across the northern U.S., and Berkshire County, in a fairly zonal (flat, west-east configuration). As a result, relatively weak systems will move through fairly quickly, with alternating surface high and low pressure systems through Monday. Monday night into Tuesday and amplifying trough in the jet stream wave pattern will be digging to our west. This will create a significant change to our weather for next week. Surface low pressure will likely develop off the Mid-Atlantic coast in response to this trough. The trough in the wave pattern will then become so amplified that that the wave will “break” and low pressure will become “cut-off” from the main jet stream flow to our north. With this cut-off low over us, essentially what we will have is a cold pool of air aloft spinning counterclockwise (upper-level low pressure) and the surface low which developed in response to this upper-level process stalling somewhere from New York city to Long Island or off the southern New England coast and then weakening and moving slowly northeast. Since the ECMWF (European) model has been consistent with this event, as well as our last storm on Thanksgiving, I am, once again, inclined to believe this model’s scenario, which goes as follows….The low develops off the Mid-Atlantic coast Tuesday morning and moves north and stalls for a time over Long Island/NYC Tuesday night. The low then weakens and moves SLOWLY northeast over the next few days, not reaching the Gulf of Maine until during the day Thursday or Thursday night. It is still too early to tell precipitation type or amounts, in particular since we will be near the rain/snow line and this will be a very complicated system. However, there is the possibility of a heavy snow event, particularly over the elevated terrain sometime from Tuesday through Wednesday. Obviously, I will update this forecast on Monday…..

That being said, we also have some weather issues in the near term. Surface high pressure is departing to our east and a weak surface low pressure system and its associated warm front are approaching from the Midwest. There is cold air at the surface and as the warmer air associated the the warm front overrides this cold air we will receive a mixture of precipitation overnight tonight. After a few scattered light snow showers early this evening, steady precipitation should begin around 8 pm or so. The precipitation should start as snow but turn, fairly rapidly to freezing rain in the lower elevations, where only a coating to an inch (at most) of snow should accumulate. 1-2″ is possible over the elevated terrain to the east where it will likely stay snow a bit longer. After the changeover, freezing rain will change to plain rain in the lower elevations by midnight or so but will likely continue over the elevated terrain. There could be a light coating of ice in the lower elevations before the changeover, with around 0.10″ over the elevated terrain. Since snow will fall first, the roads should be mostly slushy, as opposed to glazed, and there should not be enough ice for widespread power outages. Rain/freezing rain will taper off sometime between 3 and 5 am and there will be a relative pause in the precipitation until it becomes steady again around 9 or 10 am. By that point, temperatures should be above freezing everywhere and we will have off an on rain for most of the day Saturday. Rain may mix with and then change to snow briefly before ending Saturday evening as colder air comes in behind the departing low, but there should only be a coating to perhaps as much as an inch over the elevated terrain. It will then turn breezy and colder and surface high pressure will move in for Sunday, making the second half of the weekend sunny but fairly cold.

Friday Night

A few scattered snow showers early, then a burst of steady snow arriving around 8 pm or so. Snow will change to freezing rain within a few hours. Snow accumulations a coating to 1″ in the lower elevations and up to 2″ over the elevated terrain. Freezing rain will likely change to rain in the lower elevations by the early morning hours but will likely continue over the elevated terrain. Significant ice accumulation is not expected in the lower elevations but about 0.10″ is likely over the elevated terrain. Rain/freezing rain will taper off between 3 and 5 am. Probability of precipitation near 100%. Likely total rainfall (liquid equivalent) 0.25″-0.40″.

Temperatures near freezing this evening will rise above freezing in the lower elevations by midnight or so and low to mid 30s by morning. Temperatures will remain at or near freezing over the elevated terrain.

Easterly winds at 5-10 mph this evening, becoming light southeasterly after midnight.

Saturday

A few scattered light rain showers or drizzle early. Steadier off and on rain developing around 9 or 10 am and continuing throughout the day. Probability of precipitation near 100%. Likely rainfall totals 0.25″-0.50″.

High temperatures in the upper 30s in Pittsfield, Lee, Stockbridge, Adams, North Adams, and Williamstown; near 40 in Great Barrington and Sheffield and; mid 30s over the elevated terrain.

Light winds veering from southeasterly early to northwesterly during the afternoon.

Saturday Night

Rain may mix with and briefly change to snow before ending during the evening. A coating of accumulation is possible, with as much as 1″ over the elevated terrain. Skies will remain mostly cloudy, clearing around daybreak, and it will turn breezy and colder.

Low temperatures in the low to mid 20s.

North-northwesterly winds at 5-10 mph in the evening, increasing to 10-15 mph after midnight.

Sunday

Sunny but a bit breezy and rather cold.

High temperatures in the upper 20s to near 30 in Pittsfield, Lee, Stockbridge, Adams, North Adams and Williamstown; near 30 to low 30s in Great Barrington and Sheffield and; mid 20s over the elevated terrain.

North-northwesterly wind at 10-15 mph, decreasing to 5-10 mph during the afternoon.