Note: This will be my last post until Monday, October 14 or Tuesday, October 15

Summary: The cold frontal squall line came through Berkshire County slightly earlier than expected yesterday with a burst of heavy rain and gusty winds between 4 and 4:30 pm. The BCC weather station reported a maximum gust of 39 mph at 4 pm. Other gusts reported were 40 mph at the Pittsfield airport and 40 mph in Peru. This, however, was enough to bring down a few trees across the county. Interestingly, by the time the squall line reached Berkshire, since we did not have much in the way of surface layer heating (sunshine), there was not even enough instability to generate much in the way of lightning and thunder. The Storm Prediction Center had numerous reports of wind damage across the Northeast but NO hail or tornado reports. Although there were some pre-frontal rain showers (some came through here early to mid afternoon), no supercell thunderstorms (most tornadoes form in this type of storm) formed in advance of the squall line. All of the wind damage was from “straight-line” winds from the frontal squall line. Just to note, tornadoes are relatively rare in these squall lines, and when they develop they are usually weak (EF0, EF1). Rainfall totaled 0.41″ at the BCC weather station and also 0.41″ at the Lanesboro mesonet station but all other reported rainfall totals were between 0.50″ (Savoy) and 0.95″ (Alford).

Surface high pressure is building into the region today following the frontal passage resulting in clear skies and more seasonable temperatures and dewpoints. As mentioned yesterday, this high pressure system will try to hold its own against a pesky surface low pressure system which is developing off the Carolina coast along a stalled portion of the cold front (same one that barreled through here). [Some of the moisture wrapped up in this low is actually remnants from TS Karen]. This low will try to advance north into the Northeast but will probably be held at bay by the high pressure system building over the Northeast. If it weren’t for this little storm we would see clear blue skies from now through the weekend. Instead, it appears the storm will spread a layer of high and mid-level clouds over us Thursday and Friday so that skies may become relatively cloudy during the afternoon Thursday and through Friday morning. The U.S. mid/long-range forecast model (GFS) keeps us relatively dry, with the precipitation staying to our south for the most part, but the European model (ECMWF) has widespread showers spreading over Berkshire County Thursday afternoon into Friday morning. Therefore, it is not a high confidence forecast for that period, particularly since the low will be spinning around without much in the way of steering currents. At this point, I would keep at least the chance of showers in the forecast for Thursday afternoon through Friday, particularly for South County. Right now, it appears that the storm will begin to dissipate and drift out to sea and surface high pressure will build back in from the north, allowing sunny skies to return for most of Columbus Day weekend.

Tuesday Night

Mostly clear, calm and cold with frost in many locations.

Low temperatures in the low to mid 30s. The coldest temperatures and greatest risk for frost is in elevated valley locations.

Calm winds.

Wednesday

The sun will be dimmed at times by afternoon high clouds, otherwise mostly sunny.

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

Easterly winds at 5-10 mph.

Wednesday Night

Increasing clouds.

Low temperatures in the low 40s.

Calm winds.

Thursday

Mostly cloudy with a chance of showers late in the day. Probability of precipitation 30%.

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

Light northeasterly winds.

Thursday Night

Mostly cloudy with a chance of showers, particularly over South County. Probability of precipitation 50%.

Low temperature in the mid to upper 40s.

Light northeasterly winds.

Friday

Mostly cloudy with a chance of showers in the morning, partly sunny in the afternoon. A little milder, with high temperatures averaging in the mid 60s.

Note: Underlined red text indicates links to various weather maps.

Summary: Two important developments: 1) Tropical Storm Karen has stalled and is dissipating over the Gulf of Mexico so we will not be receiving any enhanced rainfall due to the moisture from its remnants; 2) The jet stream trough (upper-level cold pool) will not become completely “cut-off” from the jet stream flow so it will progress through New England more rapidly and the cold front at its leading edge will move through late Monday afternoon and evening instead of Tuesday. This will allow surface high pressure to build in behind the front on Tuesday and give us a beautiful sunny, autumn day on Tuesday.

Once again, as has been the pattern this fall, a sprawling ridge in the jet stream wave pattern and its associated broad surface high pressure system appears as if it will stall over the region and give us a prolonged period of fair weather through the remainder of the work week, and probably next weekend as well. One bug in the long-range forecast is that the computer models are generating a weak coastal storm (in response to an upper-level disturbance imbedded in the ridge) later in the week which may move close enough to New England to bring some clouds and possibly even a few showers into Berkshire County on Thursday night into Friday but….that is a long way off and I have my doubts about this scenario.

Until then, the warm front MAY finally move through tonight and Monday and give us a BRIEF period in the “warm sector” of the surface cyclone (low pressure system) moving by to our north in eastern Canada on Monday. This will result in a warm and muggy day on Monday before the surface low drags its strong cold front through with a band of steady rain late Monday afternoon and evening. There may be some pre-frontal showers and even thunderstorms during the afternoon before the frontal band moves through around dinner time. With increasing instability with the heating of the day and developing low-level wind shear the Storm Prediction Center has indicated that there is the slight risk (15% chance) of severe thunderstorms (wind in excess of 55 mph, hail > 1″ OR a tornado) tomorrow. From what I can see now I think that this is unlikely unless we get large amounts of sunshine to destabilize the atmosphere tomorrow. In particular, I think there is virtually no chance of a tornado. Check back tomorrow for an update on this possibility….

Sunday Night

Overcast and damp with patchy fog and scattered drizzle and sprinkles. No significant showers or rainfall is expected.

Temperatures holding steady this evening and then rising gradually after midnight, reaching the low 60s by morning.

Easterly winds at 5-10 mph this evening, veering to southeasterly and then south-southeasterly by morning.

Monday

Partly sunny, breezy, warm and muggy. There is the chance of a few scattered showers and even a thunderstorm early to mid-afternoon in possible pre-frontal convective bands. A more continuous band of rain and/or thunderstorms will move through, most likely, between 5-8 pm. Rain will be heavy at times. Probability of precipitation 90%. Most likely rainfall totals between 0.50″ and 1.00″.

High temperatures in the low 70s in Pittsfield, North Adams, Adams and Williamstown; low to mid 70s in Lee, Stockbridge, Great Barrington and Sheffield and; near 70 over the elevated terrain and hilltowns.

South-southeasterly winds increasing to 10-20 mph with gusts to 30 mph.

Monday Night

Rain will end in the early evening followed by clearing skies. It will still be somewhat breezy, particularly over the elevated terrain, and turning much cooler and drier.

Low temperatures in the low 40s, near 40 over the elevated terrain.

West-northwesterly winds at 5-15 mph.

Tuesday

Mostly sunny, breezy and seasonably cool.

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

Northwest winds at 10-15 mph, with gusts over 20 mph, particularly over the elevated terrain.

Tuesday Night

Clear, calm and cold. Low temperatures in the mid to upper 30s.

Wednesday

Mostly sunny. High temperatures averaging in the mid 60s.

Summary: The warm front, which served as a focus for this mornings showers, has stalled over the Mass Pike, with sunny skies and 70 degree temperatures in South County and a low overcast and near 60 degrees in the rest of the county. This front, now a stationary front, will waver slightly north and south over the county through Saturday. From this afternoon’s conditions it is clear that the exact location of the front at any time tomorrow, which is very difficult to predict, will have a large impact on the weather conditions across the county. However, it appears that most of the county will remain overcast for most of the day Saturday with occasional drizzle and a few sprinkles and temperatures holding in the low to mid 60s. In parts of South County the sun may break through the clouds at times during the afternoon which would result, once again, in temperatures approaching or exceeding 70 degrees.

In any case, the front will finally make its move through the county and to the north late Saturday night and during the day on Sunday. This movement, along with a developing disturbance along the front, will likely generate more shower activity (and even some rumbles of thunder) across the county late Saturday night and during the day on Sunday. This will keep temperatures in the 60s across the entire county.

It now appears that the trough in the jet stream wave pattern developing over the Midwest will slow down its forward progress and become a bit “cut-off” from the rest of the jet stream. This will delay the passage of the cold front at the trough’s leading edge (trailing south from a surface low-pressure center being generated by the trough over the Great Lakes) until this “cut-off” gets picked-up by the jet stream again on Tuesday. As a result, we will break into the “warm sector” of the surface cyclone, between the warm and cold fronts, on Monday, giving us a partly cloudy, very warm and humid (almost tropical) day.  This delay will also likely allow the remnants of Tropical Storm Karen to be picked-up and funneled north by the cold front. Karen’s tropical moisture would then enhance the frontal rain band as it passes through our region, giving us fairly pronounced rainfall totals Tuesday into Wednesday.

Friday Night

Mostly cloudy and mild for this time of year. There is the chance of a few scattered showers, and even some rumbles of thunder, this evening. Probability of precipitation 30%. Rainfall totals will be highly variable, but there could be as much as 0.10 to 0.25″ in any showers that fall. Patchy fog and drizzle may develop after midnight.

Low temperatures in the mid to upper 50s.

Calm winds.

Saturday

Generally overcast, although some breaks of sun are possible during the afternoon in South County. Nothing more in the way of precipitation than some spotty drizzle and sprinkles.

High temperatures in the low to mid 60s in Pittsfield, North Adams, Adams and Williamstown; mid to upper 60s in Lee and Stockbridge; near 70 in Great Barrington and Sheffield and; low 60s over the elevated terrain and hilltowns.

Light winds veering from westerly in the morning to northerly by sunset.

Saturday Night

Mostly cloudy and mild. Some patchy fog and drizzle is again possible. There is a good chance of showers toward morning. Probability of precipitation 50%. Rainfall amounts 0.10″ or less.

Low temperatures in the mid to upper 50s.

Calm winds, becoming southeasterly at 5-10 mph by morning.

Sunday

Mostly cloudy with showers likely. There may be a few embedded rumbles of thunder as well. Probability of precipitation 70%. Rainfall totals around 0.25″.

High temperatures in the mid 60s in most locations, low 60s over the elevated terrain.

Southeast winds at 5-10 mph.

Monday

Partly cloudy, very warm and muggy. High temperatures generally in the 70s.

Summary: I do not see much of a change in the weather scenario since yesterday but there are some slight changes in the outlook from yesterday…..First of all, I think that even though there is the chance of a shower anytime from after midnight tonight right through the weekend, the chance of rain at any given time and place is relatively small. Also, rain amounts should be relatively light. This will all change when a cold front moves through on Monday and Monday night with a bout of more substantial rain. It still appears that it will be fairly bleak and cloudy over the weekend as the warm front previously discussed stalls over New England. Saturday should be the bleakest of the two weekend days, featuring a low overcast and scattered drizzle and light showers, with temperatures in the low 60s at best. The warm front may finally pass through during the day on Sunday so, even though it looks to remain mostly cloudy, it should be a bit milder and there may even be a few breaks of sun during the afternoon (although I wouldn’t count on it). One important feature is newly developed Tropical Storm Karen, presently in the Gulf of Mexico. Although it is projected to briefly become a minimal hurricane, the present forecast track has it making landfall along the Alabama/Florida panhandle during the day on Saturday as a tropical storm. As it moves inland and weakens the track becomes more uncertain. However, its remnants may come through New England with some fairly heavy rainfall on Tuesday or Wednesday…..stay tuned. 

Thursday Night

Becoming mostly cloudy with the chance of a shower after midnight. Probability of precipitation 30%. Any rainfall amounts generally less than 0.05″.

Low temperatures in the low 50s.

Calm winds.

Friday

Mostly cloudy with the chance of a shower. Probability of precipitation 40%. Any rainfall amounts generally 0.05″ or less.

High temperatures in the mid 60s in most locations, low 60s over the elevated terrain.

Winds light and variable.

Friday Night

Mostly cloudy with the chance of a shower. Probability of precipitation 30%. Any rainfall amounts generally 0.05″ or less.

Low temperatures generally in the mid to upper 50s.

Winds light and variable, become southeast at 5-10 mph after midnight.

Saturday

Overcast skies with scattered drizzle and a few sprinkles or light showers possible. Rainfall amounts should be minimal.

High temperatures generally in the low 60s, near 60 over the elevated terrain.

Southeast winds at 5-10 mph, slightly stronger over the elevated terrain.

Sunday

Mostly cloudy, still the chance of a light shower early. A little milder, with high temperatures in the mid to upper 60s.

Summary: A very weak cold front moved through this afternoon, generating nothing more than some cloudiness. Skies will clear out tonight and early Thursday as the front drifts to our south and a weak surface high pressure system builds back into the region. The airmass behind the front is not much different than the one it is replacing so that, even though temperatures will be a few degrees cooler and the air will be drier (dewpoints in the 40s instead of 50s), it will still be warmer than average for this time of year with temperatures averaging in the low 70s.

The front will drift north and back over us on Friday in an attempt to move back through to our north. The front will make for an overcast day on Friday and will likely generate a few showers as well, although rainfall amounts should be relatively light.

A few days ago it looked like the the warm front would push through our region and usher in sunny, warm and even humid weather for the weekend. Unfortunately,  it is starting to look like the front may stall over us on Saturday, then finally start to pull north on Sunday, but leaving us close enough to the front to maintain a low overcast with drizzle and a few sprinkles both days. However, any significant showers or rain are unlikely.

A stronger cold front, at the leading edge of a more amplified trough in the jet stream will bring a more significant rainfall here on Monday. The front then looks likely stall over us while a surface low pressure system develops along the front to our south and then moves north along the front and over us with additional rainfall on Tuesday. Ahhhh, this nice autumn weather couldn’t last forever.

Wednesday Night

Clear and a little cooler.

Low temperatures in the low to mid 40s.

Northwest winds at 5-10 mph this evening, becoming light after midnight.

Thursday

Mostly sunny in the morning. Increasing and thickening high clouds will begin to dim the sun as the afternoon progresses.

Slightly cooler and drier than Wednesday, with high temperatures near 70 to the low 70s in Pittsfield, North Adams, Adams and Williamstown; low 70s in Stockbridge, Great Barrington and Sheffield and; mid to upper 60s over the elevated terrain and hilltowns, depending on elevation.

Light northwesterly winds in the morning, increasing to 5-10 mph and shifting to westerly in the afternoon.

Thursday Night

Increasing clouds with a good chance of a shower toward daybreak. Probability of precipitation 50%. Rainfall amounts 0.10″ or less.

Low temperatures in the low 50s.

Calm winds.

Friday

Mostly cloudy and cooler with scattered showers likely. Probability of precipitation 60%. Rainfall totals around 0.10″.

High temperatures in the mid 60s in most locations, low 60s over the elevated terrain.

Winds light and variable.

Saturday

Low overcast with scattered drizzle and sprinkles. High temperatures in the low 60s.

Sunday

Mostly cloudy, still some scattered drizzle and sprinkles. High temperatures in the mid 60s.

There is no forecast discussion today. I have updated the forecast on the BCC “Weather Station” page. I will do the next forecast discussion tomorrow (Wednesday, October 2).