The following forecast is provided by Allen Chague as part of lab work for the Introduction to Meteorology course (ATM-145) under my supervision. The forecast discussion is mine…….
An amplified trough in the jet stream wave pattern is centered to our west with a stalled frontal boundary along its eastern edge, aligned southwest to northeast, just off the East Coast. A series of mid/upper-level disturbances (three in total) will rotate through the base of the trough over the next few days. Each of these will generate a surface low pressure system that will ride northeastward along the front. The first of these is presently generating a very weak low pressure system well off the Mid-Atlantic Coast that will move out to sea and dissipate. The second, somewhat stronger disturbance will generate a slightly more significant low pressure system, although still fairly weak, off the Mid-Atlantic Coast on Saturday that will move northeastward, by Cape Cod and into the Gulf of Maine, Saturday night. Berkshire County will be on the western edge of the precipitation shield of this “storm” during Saturday afternoon and into the evening. I think we are likely to see a period of light precipitation or showers during the afternoon and into the early evening on Saturday. Whether we will get snow or rain is also a tough call. Temperatures aloft are cold enough to support snow but the boundary layer is still fairly warm. I think that early afternoon any precipitation that falls will likely be rain everywhere. By mid afternoon the rain may change to snow over the elevated terrain and then by 5 or 6 pm any precipitation that falls will likely be snow everywhere. It looks like precipitation totals will likely be about 0.10″ liquid equivalent, possibly as much as 0.20″ over the hill towns to the east, so I wouldn’t expect to see anything more than a light coating of wet snow on grassy surfaces, predominantly over the elevated terrain and hill towns to the east (Windsor, Peru, Savoy, etc.).
A much more vigorous disturbance (cold pool aloft), that is responsible for the amplification of the trough, will rotate through the base of the trough Saturday night and Sunday and generate a much deeper surface low off the coast. However, this low should track well to our east as the movement of the disturbance through the trough generates enough momentum to finally drag the axis of the trough eastward. As a result, we should not receive any precipitation in Berkshire County from this low. However, the axis of this very cold trough (for this time of year) will be centered over us on Sunday so, despite sunshine during the afternoon, temperatures will struggle to reach 40. In addition, the pressure gradient being generated by the strengthening low off the coast and strong high pressure moving in from the west will result in fairly strong winds, 15-25 mph (stronger gusts) during the day Sunday so it will feel even colder (wind chills). Temperatures will plummet Sunday night, possibly reaching a low of 20 in some places. It should remain breezy as well so wind chills are likely to drop into the single digits by Monday morning. Surface high pressure will crest to our southwest on Monday as the trough finally begins to lift out. Monday should turn out mostly sunny, but it will still be somewhat breezy and cool but it looks like temperatures will be slightly milder, reaching into the 40s in most locations.
Friday Night
Partly to mostly cloudy and seasonably cold.
Low temperatures in the mid 30s, upper 30s in South County.
East-northeasterly winds at 5-10 mph, shifting to northeasterly after midnight.
Saturday
Mostly cloudy early, becoming overcast by mid-morning. A period of light precipitation or showers likely developing during the early afternoon and continuing off and on into the evening. Rain is likely in the lower elevations during the afternoon, with any precipitation turning to wet snow by 5 or 6 pm. The changeover to wet snow will likely occur during the mid afternoon over the elevated terrain. Probability of precipitation 70%. Likely rainfall equivalent totals 0.10″, to as much as 0.20″ over the elevated terrain to the east. Likely snowfall totals, a coating of wet snow on grassy surfaces, predominantly in the higher terrain to the east.
High temperatures in the low 40s in Pittsfield, Lee, Stockbridge, Adams, North Adams, and Williamstown; low to mid 40s in Great Barrington and Sheffield and; upper 30s to near 40 over the elevated terrain. Temperatures falling into the 30s everywhere by evening.
Northeasterly winds at 5-10 mph in the morning, shifting to northerly in the afternoon.
Saturday Night
A few lingering wet snow showers early, then mostly cloudy and seasonably cold, becoming breezy after midnight.
Low temperatures near 30.
North-northwesterly winds at 5-10 mph, increasing to 10-15 mph after midnight.
Sunday
Mostly cloudy in the morning, clearing skies in the afternoon. Windy and cold.
High temperatures upper 30s to near 40 in Pittsfield, Lee, Stockbridge, Adams, North Adams and Williamstown; near 40 to low 40s in Great Barrington and Sheffield and; mid to upper 30s over the elevated terrain. Wind chill temperatures in the 20s.
Northwesterly winds at 15-25 mph with gusts 30-40 mph.
Sunday Night and Monday
Mostly clear, breezy, and very cold overnight with low temperatures near 20, wind chills falling to the single digits at times. Mostly sunny and still breezy Monday, slightly milder, with highs averaging in the mid 40s.