Berkshire County Forecast-Wednesday, January 23

Summary: BRUTAL!! Sorry, that’s the first thing that popped into my head after coming in from outside….

A very deep trough in the jet stream wave pattern continues to be centered over the eastern U.S., allowing arctic air to plummet southward over our region. This air mass will remain centered over us for the next 36 hours or so and we will continue to have very cold temperatures. Tonight will be generally clear. In addition, surface high pressure will crest over the region so winds will become light to calm. These conditions, together with a snow cover and a very low dewpoint (-9 deg right now) will give us very good radiational cooling conditions. As a result, temperatures will plummet overnight to their lowest levels of the season. I expect most locations to bottom out between -5 to -10 although some valley locations, particularly “depressions” and low points in the elevated terrain could drop below -10.

Over the next few days, disturbances in the jet stream will rotate around the base of the trough and generate weak surface lows that will move by to our south and then move northeast off the coast, following the jet stream. On Thursday, a surface low will move by way to our south and we will not even be within its cloud shield. However, this low will impact our weather as it develops off the coast and tightens the pressure gradient over us (between the low and the arctic high just to our northwest) and increase wind speeds considerably. As a result, Thursday will be much like today with very cold temperatures and brutal wind chill temperatures. Temperatures Thursday night should, once again, be below zero but probably not as cold as tonight since a breeze will persist. However, wind chill temperatures will be extremely low.

On Friday, the trough will begin to flatten out a bit, allowing the coldest air to begin to lift out of our region. Temperatures should finally reach the teens (yipee!). Another disturbance will rotate through the base of the trough. However, the slight shift (flattening) in the jet stream will enable the surface low which develops to our south to move closer than the previous one. Even though earlier this week it looked like we would get more significant accumulations from this “storm”, it now looks like the low will be weaker and move quickly out to sea. We will probably only get an inch or two at best Friday night. Surface high pressure will rebuild behind the departing low giving us a tranquil, albeit still cold, weekend. A trough will dig into the western U.S. early next week (snowstorm for the Rockies) and this shift in the jet stream pattern will enable a ridge to develop over the eastern U.S., allowing much milder air to flood into the region. We will likely see temperatures in the 40s by Wednesday. So, if the cold air is getting you down, relief is in sight…..

Wednesday Night

Mostly clear and extremely cold.

Low temperatures will be between -5 and -10 in most locations with a few of the colder valley locations, particularly “depressions” and low points over the elevated terrain between -10 and -15.

West-northwest winds at 5-10 mph this evening, becoming light to calm after midnight.

Thursday

Mostly sunny and very cold. Becoming very breezy, with brutal wind chills, particularly later in the afternoon.

High temperatures will be near 10 in Pittsfield, Adams, North Adams and Williamstown, the low teens in Great Barrington and Sheffield, and mid single digits over the elevated terrain and hilltowns. However, wind chill temperatures will be very low, from -5 to -20.

Northwesterly winds at 5-10 mph early will increase to 10 to 15 mph during the late morning hours. West-northwesterly winds will increase to 15-20 mph during the afternoon, 20-25 mph over the elevated terrain, with gusts of 30-40 mph.

Thursday Night

Mostly clear. There will be an increase in thin mid to high level clouds toward daybreak.

Temperatures will again drop below zero. Low temperatures will likely be between -2 and -8. However, wind chill temperatures will be dangerously low, between -20 and -30 at times.

West-northwesterly winds of 15-20 mph in the evening, decreasing to 10-15 mph after midnight.

Friday

The sun will be dimmed by mid and high level clouds during the morning. Clouds will thicken and lower during the afternoon. There is a chance of a little light snow or a snow shower late. Probability of precipitation 30%. No accumulation expected.

High temperature in the mid teens in Pittsfield, mid to upper teens in Adams, North Adams and Williamstown, upper teens in Great Barrington and Sheffield, and low teens in the elevated terrain and hilltowns.

West-northwesterly winds at 10-15 mph early, diminishing to 5-10 mph late morning to early afternoon and then becoming light later in the afternoon.