Berkshire County Forecast-Wednesday, October 30

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SummaryIt looks like we may get our first significant precipitation since October 7 tomorrow night into Friday morning as a surface low pressure system presently developing over the Great Plains deepens rapidly, moves through the Great Lakes, and drags its trailing strong cold front through Berkshire County. As the storm moves northeast on Thursday, it will first drag its attendant warm front through our region during the afternoon. Most of the forcing with this front will be to our north and west but we will still likely get some scattered rain showers during the afternoon as the front passes. This frontal passage will open the door to subtropical air in the “warm sector” of the cyclone. Temperatures will rise into the upper 50s during the afternoon and then continue to rise slowly overnight, reaching the low 60s by morning. Even more notable may be the “mugginess” of the air as dewpoints soar to close to 60. After the warm front passes we will have scattered showers during the evening until the cold front approaches with a band of heavier rain and showers after midnight and into Friday morning. Temperatures will continue to soar on Friday, well into the 60s, before the cold front passes around mid-day or early afternoon. After the front passes, skies should begin to clear and temperatures will drop as the afternoon progresses.

The surface cyclone (low pressure system) will deepen rapidly as it moves over the Great Lakes as a double jet streak pattern develops above it at the tropopause. This will result in marked divergence aloft, with a rapid drop in pressure at the surface, as air is “sucked out” of the atmospheric column by the jet stream. The practical relevance of this for us is that, as central pressures fall to 970 mb, the pressure gradient between the low and a departing high pressure system off the coast will generate very strong southerly winds across the county. Winds will likely reach 15-25 mph on average (strongest over the high terrain) with gusts to 40 mph possible Thursday night.

It still looks like a gradual cooling trend over the weekend as the cold front passes. It should still be in the 50s on Saturday but the coldest air will arrive on Sunday on blustery northwest winds. Temperatures will struggle into the low 40s for highs on Sunday. It should be mostly dry over the weekend aside from a few scattered light lake-effect and instability showers Saturday afternoon.

Wednesday Night

Mostly clear this evening. Clouds will increase after midnight and it will likely be mostly cloudy by daybreak.

Low temperatures in the mid to upper 30s.

Light and variable winds becoming light southerly after midnight.

Thursday

Mostly cloudy in the morning. Becoming overcast during the afternoon with scattered rain showers likely developing. Becoming breezy and mild. Probability of precipitation 60%. Any showers will be generally light, with rainfall totals generally 0.10″ or less.

High temperatures in the upper 50s in Pittsfield, North Adams, Adams and Williamstown; near 60 to low 60s in Lee, Stockbridge, Great Barrington and Sheffield and; mid 50s over the elevated terrain and hilltowns.

Southerly wind increasing to 10-15 mph during the afternoon with some higher gusts, particularly over the elevated terrain.

Thursday Night

Scattered showers likely during the evening. Rain will become steadier and heavier after midnight. It will become quite windy and unseasonably mild. Probability of precipitation near 100%. Rainfall totals near 0.50″ to as much as 0.75″ in spots.

Temperatures will actually rise a few degrees overnight, reaching near 60 over the elevated terrain and the low 60s in most lower elevation locations.

South-southwest winds at 10-15 mph in the evening, increasing to 20-25 mph after midnight. Gusts to 40 mph are possible.

Friday

Rain and showers will taper off over the course of the morning and end by midday. Skies will clear during the afternoon. It will be windy and unseasonably warm in the morning into early afternoon with temperatures dropping during the afternoon after the cold front passes. Probability of precipitation 80%. Most likely rainfall totals between 0.10″ and 0.25″.

High temperatures will be reached around midday to early afternoon and should be in the mid 60s in Pittsfield, North Adams, Adams and Williamstown; mid to upper 60s in Lee and Stockbridge; upper 60s in Great Barrington and Sheffield and; low to mid 60s over the elevated terrain and hilltowns.

It will be windy but winds will tend to diminish somewhat as the day progresses. South-southwesterly winds at 15-25 mph in the morning will shift to southwesterly at 10-20 mph in the afternoon and then westerly at 10-15 mph late. Gusts to 35 mph are possible, particularly during the morning.