Summary: After a warm front moved through this morning with about 0.60 inches of rain, we broke into the warm sector of its associated mid-latitude cyclone (surface low pressure system), which is moving through the Great Lakes, this afternoon. As the sun came out, temperatures shot into the 60s countywide and even approached 70 in South County (68 in Great Barrington). Seemed strange after our hard freeze on Saturday morning (21.6 deg. F. at BCC and 24 deg. at PSF [Pittsfield airport], which was a record low for the date) but such is the roller-coaster ride that we frequently experience in New England this time of year as the sun progresses south of the equator and the meridional (north-south) temperature gradient steepens across the Northern Hemisphere. Just a note about our first killing frost/freeze. Even though the long-term average killing frost/freeze for Berkshire County is mid to late September (exact date depending on location), anyone with a garden knows that the average for the past ten years has been mid to late October. More evidence, albeit anecdotal, of global climate change’s local impact on Berkshire County.

As the mid-latitude cyclone continues its trek to the northeast over the next 24 hours, it will finally drag its associated cold front through Berkshire County late Monday afternoon and evening. The front will lift the very moist air for this time of year causing a band of rain or showers to develop and move through the region. This precipitation will be enhanced by a secondary surface low pressure system developing along the front as it moves slowly to our east. This low will move northeast from the Del Marva Peninsula to the Gulf of Maine tomorrow night. However, most of the heavier rain associated with this low should stay to our south and east. This will allow a high pressure system to build in from the west with a cooler but drier day on Tuesday. As the source region of the approaching air mass (high pressure system) is the Midwest instead of Canada, it will not get nearly as cold as with our last cold front passage on Friday night. As the high moves over the region and then to our east, the return flow around the high (south/southwest winds) will result in fair and progressively milder weather on Wednesday and Thursday until the next cold front passage sometime on Friday. Temperatures are likely to reach well into the 60s again by Thursday.

Sunday Night

Clear early. Increasing cloudiness after midnight.

Despite the clear skies early, a persistent southerly wind and high dewpoints in the 50s will prevent much radiational cooling. The increasing cloud cover will prevent any further cooling. Low temperatures will only fall into the upper 50s.

South-southwesterly winds at 8-12 mph.

Monday

As the cold front approaches from the west it will become increasingly cloudy, becoming mostly cloudy during the morning (75-90% cloud cover) and then overcast during the afternoon. There is a good chance of scattered light rain showers from late morning through most of the afternoon. Probability of precipitation before 3 pm is 50%. Any precipitation during this period should be less than 0.05 inches. A more solid band of rain or showers will likely move through from late afternoon through the evening hours. Probability of precipitation is 80%. There is a slight chance of some imbedded thunder within the band of rain. Rainfall amounts should average about 0.25 inches but up to 0.50 inches in a few isolated heavier showers.

High temperatures will climb into the mid 60s in most of the county.

South-southwest winds at 10-15 mph.

Monday Night

Any rain or showers should end well before midnight but it will remain mostly cloudy.

It will feel much cooler as dewpoints and temperatures drop through the night. Temperatures will fall into the low to mid 40s countywide by daybreak.

Southwest winds early shifting to northwest at 8-12 mph.

Tuesday

Decreasing clouds throughout the day. Mostly cloudy at daybreak but becoming mostly sunny during the afternoon. Becoming very breezy and much cooler than Monday.

High temperatures in the low 50s in Pittsfield and North Adams, mid 50s in Great Barrington and upper 40s over elevated terrain and the hilltowns.

Northwest winds increasing to 15-20 mph during the afternoon with gusts to 30 mph.