Summary: A surface high pressure system centered right over New England gave us a beautiful autumn day today with sunshine only occasionally filtered by high clouds and temperatures several degrees above average. This high pressure system will drift SLOWLY eastward as a trough in the jet stream digs down deep into the Midwest. After one more nice day on Thursday, quite similar to today but even slightly milder, the leading edge of this trough will approach our region Thursday night as a surface cold front. As the trough amplifies and partially cuts off from the jet it will slow up considerably. Therefore, it will take quite a while for the cold front to move through our region. A weak surface low will develop along the front and move slowly north along the front. As a result we will have a fairly prolonged period of rain beginning towards daybreak on Friday and extending through the day. We will likely receive upwards of 1.00 inch of rain from this slow moving cold front and its associated developing surface low pressure system. One computer model moves the tough/cut-off low (upper-level) more slowly and generates two waves of surface low pressure with a pause in the rainfall late Friday and then resuming Friday night and continuing well into Saturday. I find the single low and cold front moving through by sometime Friday evening a more plausible scenario at this time. However, I am still concerned about our weekend because the computer models sometimes lift these cut-off lows (the upper-level low/trough, not the surface low along the cold front) out too fast. This situation will become more clear cut in subsequent model runs. For now, I would say that the rain should end by sometime Friday night with a dry day on Saturday and a nice day on Sunday as the trough/cut-off low lifts to the northeast and surface high pressure begins to build back in to our area. A look at the long-range scenario suggests that the jet stream wave pattern may shift early next week and allow a full thickness (all of the troposphere) ridge to build over the eastern U.S.. This means that warmer air at all levels of the atmosphere will move east and push the jet stream and any storms associated with it to the north.

Wednesday Night

Mostly clear, calm and seasonably cold.

Low temperatures in the mid to upper 30s.

Calm winds.

Thursday

Mostly sunny and unseasonably mild. There may be an increase in high clouds late in the afternoon.

High temperatures in the mid 60s in Pittsfield and North Adams, high 60s in Great Barrington and low 60s over elevated terrain and the hilltowns.

South-southeast winds at 10-15 mph.

Thursday Night

Increasing clouds in the evening, becoming overcast after midnight. Not as cold. Rain will likely develop by daybreak. Probability of precipitation is 70%. Rainfall totals most likely between 0.10 and 0.25 inches.

Low temperatures in the low 50s.

Winds shifting from south-southeast at 5-10 mph in the evening to the east-southeast and increasing to 10-15 mph after midnight.

Friday

Rain, moderate to heavy at times. Rainfall totals will likely exceed 1.00 inch. Probability of precipitation near 100 percent.

High temperatures in the low 60s for most of the county, near 60 for the elevated terrain.

Southeast winds at 10-15 mph.