The forecast for the upcoming “storm” has not changed greatly from Friday. However, I would like to give a detailed forecast for the timeline of events as I see it…..

It looks like the precipitation should move in a little earlier than it appeared a few days ago, with snow developing from south to north between 1 and 3 am tonight. It looks like we should get a quick “burst” of snow that lasts for an hour or two, which then changes to rain and freezing rain between about 3 and 6 am from south to north. It looks like we should get a fairly widespread snow accumulation of around 1″ with perhaps only a coating in parts of South County where the changeover to liquid precipitation will likely occur sooner. There could be as much as 2″ in a few spots over the elevated terrain, in North County in particular. There most likely will only be intermittent light rain and freezing rain or drizzle from between around 6 or 7 am til around 9 or 10 am. Temperatures should remain fairly close to freezing during this period. It will likely be at or just above freezing in the lower elevations and at, or just below freezing in spots over the elevated terrain. I suspect the roads during the morning will just have a bit of slush on them due to the combination of snow with a little freezing rain on top over the elevated terrain and they may just be wet if the road surfaces are treated, which I suspect they will be given the “Winter Weather Advisory” which has been issued by the National Weather Service. At lower elevations the main roads will probably just be wet, with a little slush on the secondary roads. Given that snow will fall first, it is unlikely that an icy glaze will form, particularly this early in the season, even though it has been quite cold lately.

The precipitation should change to plain rain everywhere in the county by noon or 1 pm and temperatures will likely rise into the 40s from late afternoon into the evening. Rain will fall, moderate at times, from late morning through late afternoon, and then taper off and end during the evening. Temperatures will begin to plummet late in the evening, once the surface low passes and drags its cold front through. However, precipitation should end well before temperatures fall back below freezing. Hopefully, roads will have a chance to dry a good deal before the drop in temperatures but there could be some icy spots on Tuesday morning. A band of lake-effect snow showers will likely set up over the county on Tuesday morning so there could be a dusting of snow in spots as well. However, the main story for Tuesday, and on through Wednesday as well, will be the unusual cold for this time of year. Temperatures should hold steady in the 20s during the day on Tuesday, with winds picking up to 15-25 mph. During the afternoon, the temperatures will begin to fall through the 20s and into the teens by evening with wind chill temperatures falling into the single digits.

Sunday Night

Overcast with snow developing from south to north between about 1 and 3 am. A quick “burst” of snow is likely before a changeover to rain and freezing rain from south to north between about 3 and 6 am. Rain, freezing rain and/or drizzle becoming light and intermittent by 7 am. Probability of precipitation 90%. Likely snowfall totals before the changeover generally about 1″ with only a coating in some parts of South County and as much as 2″ in spots over the elevated terrain in central and northern Berkshire. 0.10″ or less of icing.

Low temperatures in the upper 20s.

Light south-southwesterly winds, shifting to east-southeasterly after midnight.

Monday

Light and intermittent rain, freezing rain and drizzle until between about 9 and 11 am. Temperatures will be close to freezing, likely at or just above in the lower elevations and at or just below over the elevated terrain during this period. Rain becoming moderate at times from late morning through the remainder of the day. Precipitation becoming plain rain countywide by early afternoon. Probability of precipitation near 100%. Likely rainfall totals around 0.50″. Up to 0.10″ of icing possible in spots over the elevated terrain.

Temperatures near freezing during the morning, rising through the 30s and into the 40s during the afternoon and into the evening.

East-southeasterly winds at 5-10 mph, shifting to south-southwesterly during the afternoon.

Monday Night

A few lingering rain showers and mild during the evening, then mostly cloudy, becoming breezy and sharply colder. A few scattered snow showers and flurries are possible after midnight. There could be a dusting in spots.

Low temperatures in the mid 20s, low 20s over the elevated terrain.

West-southwesterly winds at 5-10 mph early becoming west-northwesterly and increasing to 10-15 mph after midnight.

Tuesday

More clouds than sun, windy and unseasonably cold. A few scattered snow showers and flurries are possible in the morning. Probability of precipitation 30%. There could be a dusting in spots.

Temperatures will hold steady into the afternoon with high temperatures in the mid 20s in Pittsfield, Lee, Stockbridge, Adams, North Adams and Williamstown; mid to upper 20s in Great Barrington and Sheffield and; low 20s over the elevated terrain. Temperatures will fall through the 20s over the course of the afternoon and into the teens by evening with wind chill temperatures falling into the single digits.

Westerly winds at 10-20 mph, with gusts to 30-35 mph.

 

There is no student forecast today…..

The tail end of some lake-effect snow bands will rotate north to through the county this evening. These will give us nothing more than the chance of a few scattered flurries/light snow showers. After these pass through, skies will begin to clear overnight as a sprawling surface high pressure system presently centered over the Midwest, moves eastward and becomes centered over the East Coast during the day on Saturday. This will result in a good amount of sunshine but unseasonably cold temperatures for Saturday.

As the surface high moves to our east Saturday night and Sunday, southwesterly flow around the backside of the high will drive warmer air from the south up and over the cold air here at the surface. This broad area of rising air will result in a building cloud cover later Saturday night and a mostly cloudy day on Sunday. Essentially, what will be happening is that the polar front, which passed through our area as a cold front last night, will begin moving back to the north as a warm front. It will be slightly milder Sunday, but temperatures will still be below average.

In the meantime, as the broad, unseasonably cold, trough in the jet stream wave pattern that has been covering a good part of North America, begins to flatten out over the weekend (why the front is moving back to the north) and temperatures moderate, a bit, across the country, another pool of arctic air will begin to descend southward into the base of the trough. This pool of cold air will plunge into the base of the trough over the central U.S. on Sunday and Sunday night. This will serve to amplify the trough and develop surface low pressure along the Gulf Coast, along the southeastern edge of the trough Sunday night. This surface low will then ride rapidly northeastward along the stalled polar front directly toward Berkshire County during the day on Monday. Right now, it looks like the low will pass directly over southern New England and into the Gulf of Maine by Monday night. With this track, the low will likely draw enough “overriding” warm air (aloft) inland to turn the majority of precipitation to liquid form.

The most likely scenario for this “storm” is that snow will develop sometime Monday morning. We may get an inch or two (or three) of snow before it changes to freezing rain and then rain during the afternoon. Rain should end during the evening hours. There could be enough cold air locked in at the surface that freezing rain may persist for awhile during the afternoon, particularly over the elevated terrain to the north, so that will be something to keep an eye on. I will try to update this forecast on Sunday…..

After the low passes, the cold pool previously discussed, will shift eastward, becoming centered just to our west on Tuesday. In addition, the low which passed through on Monday will intensify as it moves into the Canadian Maritime region. The strong pressure gradient between this departing low and strong high pressure building into the eastern U.S. will generate very strong winds over us. Bottom line….if you think this is bad, wait until Tuesday and Wednesday, when we are likely to see lows in the teens and highs in the 20s and wind chills in the single digits (help!! its too early for this….).

Friday Night

Chance of a few scattered snow flurries this evening, particularly in central and northern Berkshire. Scattered flurries could persist past midnight in North County. Probability of precipitation 30%.  No accumulation expected. Clearing skies after midnight in South County and partial clearing to the north.

Low temperatures near 20, upper teens over the elevated terrain.

West-northwesterly winds at 5-10 mph this evening, becoming light.

Saturday

Mostly sunny but cold.

High temperatures in the low 30s in Pittsfield; low to mid 30s in Lee, Stockbridge, Adams, North Adams, and Williamstown; mid 30s in Great Barrington and Sheffield and; upper 20s to near 30 over the elevated terrain.

West-northwesterly winds at 5-10 mph.

Saturday Night

Mostly clear in the evening, then increasing clouds after midnight.

Low temperatures in the low to mid 20s.

Light westerly winds becoming southwesterly after midnight.

Sunday

Although there may be a few sunnier periods, particularly during the mid to late morning, skies should be mostly cloudy for the majority of the day. It will become a bit breezy in the afternoon.

It will be a bit milder, but still fairly cold for mid November. High temperatures in the mid to upper 30s in Pittsfield; upper 30s in Lee, Stockbridge, Adams, North Adams and Williamstown; upper 30s to near 40 in Great Barrington and Sheffield and; low to mid 30s over the elevated terrain.

South-southwesterly winds at 5-10 mph, increasing to 10-15 mph in the afternoon.

Sunday Night and Monday

Becoming overcast Sunday night, with snow developing Monday morning. Snow will likely change to freezing rain and then rain during the afternoon. Pockets of freezing rain could persist, particularly over the elevated terrain to the north. Snow accumulations 1-3″. Possible icing over the elevated terrain. Rain and freezing rain ending during the evening.

It now appears that the surface low pressure system developing along the arctic front that was mentioned in yesterday’s forecast is developing more rapidly and closer to the coast. Therefore, it now looks like a fairly continuous period of, mostly light, snow will develop this evening around 8pm and continue til around 2am. Temperatures will, initially be above freezing in the lower elevations, so it will have trouble “sticking” at first. However, the southern track of the storm means locations in South County will get a greater liquid equivalent. The most likely snow accumulations should be 1-2″ in South County, with the higher amounts over the elevated terrain, where as much as 3″ could fall in some of the favored locations, such as Becket and Otis. In central Berkshire, 1/2″-2″ is likely, with the higher amounts over the elevated terrain. In North County, a coating to 1″ is most likely, with as much as 2″ in some spots over the elevated terrain to the east (e.g. Savoy, Florida).

The following forecast is provided by Shai Lev as part of lab work for the Introduction to Meteorology course (ATM-145) under faculty (Joe Kravitz) supervision. The forecast discussion is mine (JK) ……

A cold front at the leading edge of a deep trough in the jet stream wave pattern moved through today with a few showers accompanied by a steep drop in temperatures from about 60°F to 42°F within a 2 hour period late morning into early afternoon. As this cold trough moves over the region our temperatures will fall and remain below average through the weekend. Temperatures tonight will fall into the mid 20s with highs tomorrow generally in the low 40s. As the coldest pool of air within the trough approaches Thursday, a second “arctic” cold front at its leading edge will plow through Thursday evening with a line of snow showers and snow squalls. Expected accumulations are a dusting in most places, to as much as an inch in some heavier squalls over the elevated terrain. After this front passes, a weak surface low will develop along it. However, this low should pass off the coast well to our east and will likely not impact us.

Once this “arctic” front passes through, temperatures will turn even colder, with highs in the 30s Friday through Sunday and overnight lows near 20. On Monday, it looks like a stronger surface low will develop along the eastern margin of the trough and ride northeastward toward Berkshire County. The computer models have been struggling with consistency with this storm, however, it looks to me like we are most likely to get a mixture of precipitation, probably mostly rain as the low passes right over us, or at least very close to the coast, allowing “milder” air to move in off the ocean. However, this event is still 5 days away so I will update this with my Friday forecast.

Wednesday Night

Mostly clear and colder. Some cloudiness will build in toward daybreak.

Low temperatures in the mid 20s, some low 20s over the elevated terrain.

Northwesterly winds at 5-10 mph, becoming light after midnight.

Thursday

Partly cloudy early, then increasing clouds and cooler than previous days.

High temperatures near 40 to the low 40s in Pittsfield, Lee, Stockbridge, Adams, North Adams, and Williamstown; low 40s in Great Barrington and Sheffield and; upper 30s over the elevated terrain.

Northwesterly winds at 5-10 mph in the morning, becoming light west-northwesterly in the afternoon.

Thursday Night

Mostly cloudy and seasonably cold. A band of snow showers with some embedded snow squalls is likely late in the evening. The most likely time period is between 9 pm and 1 am. Probability of precipitation 70%. Likely snowfall totals a dusting to 1″. Some clearing toward daybreak.

Low temperatures in the mid 20s.

Northwesterly winds at 5-10 mph.

Friday

A mix of clouds and sun and cold.

High temperatures in the mid 30s in Pittsfield, Lee and Stockbridge, Adams, North Adams and Williamstown; mid to upper 30s in Great Barrington and Sheffield and; low 30s over the elevated terrain. 

West-northwesterly winds at 5-10 mph.

There is no student forecast today…..

Two more mild days and then the weather in Berkshire County will turn decidedly wintry, probably for an extended period. Interestingly, this distinct change in the weather pattern all starts with a tropical system in the western Pacific Ocean. Super typhoon Nuri has undergone what is called an “extratropical transition” whereby it looses its tropical characteristics and takes on the characteristics of a midlatitude storm as it moves north out of the tropics and begins to interact with the jet stream. This interaction with the jet stream is greatly amplifying the jet stream wave pattern and this amplification is propagating eastward over North America. It is like Nuri is yanking on a rope (the jet stream) which generates a wave along the rope that travels down the rope (you can try this at home!!??). This process is called “downstream development”. The warm tropical air and cyclonic flow around Nuri, presently in the North Pacific, is generating a very strong ridge in the jet stream wave pattern over the eastern Pacific that is extending way north into the Arctic. As a result, a very deep trough is plunging south into the U.S., bringing cold arctic air with it. It appears that once this wave pattern becomes established, it is likely to take on a “standing wave” configuration where the amplified wave is maintained over a long period as the pattern itself generates storms that continually reinforce the overall jet stream pattern and prevent the wave from propagating eastward. Bottom line….it looks like temperatures will drop below average on Thursday and stay that way for the next 7-10 days as the cold trough sets up over the eastern U.S. and stays there. 

As disturbances drop into the base of the trough and generate surface low pressure systems along the eastern side of the trough we will be under the threat that they could move up the coast close enough to us to give us snow. The first of these will be on Thursday night but the disturbance and resulting low will be weak and it looks like a dusting to 1″ would be a likely accumulation if the low passes close enough to the coast. A stronger coastal storm is possible in the Sunday/Monday time period but it is too early to determine the track or strength of that low.

For the more immediate time period, as the previously mentioned trough begins to dive into the central U.S. today it has resulted in a warm ridge developing (part of the “downstream development” I mentioned) over the Northeast. As a result, temperatures surpassed 50 today and will likely surge well into the 50s on Tuesday. There may be some low clouds tomorrow as a moist southeasterly low-level flow off the ocean develops around an ocean storm well to our east. We are likely to see some, mostly light, rain showers early Wednesday as this moist flow interacts with an approaching strong cold front (signifying the eastern edge of the trough). As the front passes through Wednesday morning, temperatures will likely drop slowly in the afternoon from morning highs in the 50s. Temperatures will drop into the 20s Wednesday night and then struggle to reach 40 on Thursday. High temperatures will then not exceed the 30s from Friday through Sunday.

Monday Night

Mostly clear. Some low cloudiness developing toward morning.

Low temperatures in the low to mid 30s.

Light south-southeasterly winds.

Tuesday

A mix of sun and clouds and unseasonably mild.

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

South-southeasterly winds at 5-10 mph.

Tuesday Night

Mostly cloudy and unseasonably mild. There is the chance of a shower, mostly light, toward morning. Probability of precipitation 40%. Likely rainfall totals 0.05″ or less.

Low temperatures near 50.

Light southeasterly winds.

Wednesday

Mostly cloudy and mild, with scattered showers likely in the morning, mostly light. Mostly cloudy and turning breezy and noticeably cooler during the afternoon. Probability of precipitation 60%. Likely rainfall totals 0.10″ or less. 

High temperatures will likely occur during the morning with highs in the mid 50s in Pittsfield, Lee and Stockbridge, Adams, North Adams and Williamstown; mid to upper 50s in Great Barrington and Sheffield and; low 50s over the elevated terrain. Temperatures will then drop into and through the 40s over the course of the afternoon.

Light southeasterly winds in the morning, shifting to northwesterly and increasing to 10-15 mph in the afternoon.

There is no student forecast today…..

Weak surface high pressure will build in overnight tonight and for the day on Saturday. This will lead to clearing skies tonight and a partly cloudy day on Saturday. Clouds will be on the increase late in the day as a weak cold front extending well south of a surface low pressure system over Hudson Bay in Canada approaches. As it passes through overnight Saturday it will not generate much “lift” in the atmosphere and there is only a chance of a light rain or snow shower. Any light precipitation that falls will likely be rain in the lower elevations and, possibly, wet snow over the elevated terrain. However, anywhere that precipitation does fall it should only be enough to moisten the ground, with no significant rain or snow expected.

The jet stream will then lift northward and surface high pressure will build in for Sunday through Tuesday so there will likely be a good deal of sunshine and moderating temperatures during that period. Temperatures may reach 50 on Monday and into the 50s on Tuesday. A strong cold front will likely move through on Wednesday with a few showers and then colder air will move in for the end of the week. It looks like the really cold arctic air won’t sink as far south as it looked earlier this week so, even though it will be colder, it should not be anything out of the ordinary for November. It also does not look like we are in line for any significant snow anytime in the near future……

Friday Night

Mostly cloudy with a lingering flurry possible this evening, then clearing skies and cold overnight.

Low temperatures in the mid 20s.

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

Saturday

A mix of sun and clouds and still fairly cold, increasing clouds late.

High temperatures in the low to mid 40s in Pittsfield, Lee, Stockbridge, Adams, North Adams, and Williamstown; mid 40s in Great Barrington and Sheffield and; upper 30s over the elevated terrain.

Westerly winds at 5-10 mph, shifting to southwesterly in the afternoon.

Saturday Night

Mostly cloudy with just a chance of a light rain or snow shower. Any precipitation that falls will likely be rain at the lower elevations but could be wet snow over the elevated terrain. Probability of precipitation 30%. Any rainfall will likely be less than 0.05″. No snow accumulation expected.

Low temperatures in the low 30s.

Light south-southwesterly winds.

Sunday

Mostly cloudy in the morning with decreasing clouds in the afternoon.

High temperatures in the mid 40s in Pittsfield, Lee and Stockbridge, Adams, North Adams and Williamstown; mid to upper 40s in Great Barrington and Sheffield and; near 40 to low 40s over the elevated terrain.

West-northwesterly winds at 5-10 mph.

Sunday Night and Monday

Partly cloudy with seasonable temperatures. Overnight low in the upper 20s and Monday’s highs averaging in the upper 40s.

There is no student forecast today…..Remember that clicking on underlined blue font will take you to weather maps that the text is describing.

A cold front weakened as it moved through this morning and then stalled just to our south during the day. In the mean time, a weak surface low pressure system is developing over the upper Midwest in response to an amplifying trough in the jet stream wave pattern. This low will strengthen as it moves southeastward overnight, reaching Ohio by Thursday morning. It will then re-develop along the stalled front along the southern New England coast Thursday afternoon and evening and then deepen rapidly as it moves into the Gulf of Maine and then the Canadian Maritime region Thursday night and Friday.

As the low shifts to the coast, rain and showers will spread across Berkshire County from south to north during the late morning into early afternoon. Rain and showers should then continue off and on for the remainder of the afternoon. Rainfall should be generally light to occasionally moderate with likely rainfall totals between 0.25″ to 0.40″. Any steady rain should taper off to scattered light showers during the evening. Overnight, as the low moves into the Gulf of Maine, moisture will rotate counterclockwise around the low and be lifted by our elevated terrain. This will result in scattered, off an on, light showers. As colder air moves in the rain showers will turn to snow showers well after midnight. By the morning commute there could be a light coating/dusting of snow on grassy surfaces in spots, particularly over the elevated terrain to the north. Over the course of the day on Friday it will remain mostly cloudy and turn breezy and remain fairly cold, with temperatures remaining in the 30s in most locations. Off and on snow flurries and showers are possible, particularly in northern and central Berkshire and are most likely over the elevated terrain there. The snow shower activity may be enhanced during the afternoon as a cold pocket aloft rotates into the trough over us and destabilizes the atmosphere further. This may generate a few snow squalls that could leave a coating in places with even up to 1-2″ or so over the higher terrain in North County.

Surface high pressure will build in briefly on Saturday so we will have on “dry” day. It will remain fairly cold, with temperatures once again struggling to get out of the 30s, despite some sunshine. Another weak cold front will move through Saturday night into Sunday morning with a period of light rain or snow showers. The jet stream will then, temporarily, lift northward, allowing a “warmer” ridge and accompanying surface high pressure to build in on Monday and Tuesday and we will likely see temperatures “soar” back into the 50s. However, don’t get too used to it because the ridge will building in advance of an amplifying trough that will likely plow into our region on Wednesday. Cold arctic air will dive out of Canada into this trough and into our region and it looks like it could get quite cold, colder than anything we have seen thus far, during the late week and possibly into the following weekend.

Wednesday Night

Increasing and thickening clouds.

Low temperatures in the upper 30s to near 40.

Light southwesterly winds this evening, becoming calm after midnight.

Thursday

Overcast and cool. Rain or rain showers spreading over the county from south to north from late morning into early afternoon. Rain/showers will continue off and on throughout the afternoon. The rain should be mostly light to occasionally moderate. Probability of precipitation 90%. Likely rainfall totals 0.25″ to 0.40″.

High temperatures in the mid 40s in Pittsfield, Lee, Stockbridge, Adams, North Adams, and Williamstown; mid to upper 40s in Great Barrington and Sheffield and; low 40s over the elevated terrain.

Light easterly winds in the morning, increasing to 5-10 mph in the afternoon.

Thursday Night

Mostly cloudy with scattered rain showers, mostly light, turning to scattered snow showers by morning. Probability of precipitation 70%. Likely rainfall totals 0.10″ or less. There may be a coating of snow on grassy surfaces in spots by morning, particularly over the elevated terrain. It will become breezy toward morning.

Low temperatures in the mid 30s, low 30s over the elevated terrain.

Light northeasterly winds early, shifting to northwesterly during the evening, and increasing to 10-15 mph by morning.

Friday

Mostly cloudy, breezy and cold. A bit more sunshine is possible in South County. Scattered snow flurries and showers are likely in central and northern Berkshire, particularly early in the morning and then later in the afternoon. There may be a few heavier squalls, particularly in North County later in the afternoon. Probability of precipitation 60%. Likely snow accumulation, a dusting in spots with up to 1-2″ in any heavier squalls over the elevated terrain to the north.

High temperatures in the mid to upper 30s in Pittsfield, Lee and Stockbridge, Adams, North Adams and Williamstown; near 40 in Great Barrington and Sheffield and; low to mid 30s over the elevated terrain.

Northwesterly winds at 10-20 mph with higher gusts, particularly in any snow squalls.

The following forecast is provided by Keiland Cross as part of lab work for the Introduction to Meteorology course (ATM-145) under my supervision. The forecast discussion is mine……

The amplified trough responsible for generating a rapidly developing coastal storm off the New England coast yesterday, which was responsible for over one foot of heavy wet snow in parts of Maine, is lifting rapidly to our northeast and is being replaced by a warm ridge, as the jet stream, temporarily, shifts northward. As a result, temperatures will be above normal for the next few days. At the surface, sprawling surface high pressure centered to our southwest will move slowly eastward and keep our weather dry for the next few days. The next approaching trough will generate surface low pressure well north of the Great Lakes on Tuesday. This low will have little affect on our weather aside from some clouds on Tuesday as a weak warm front, extending well south and east of the low moves through. As the low lifts northeast over Hudson Bay on Tuesday night it will attempt to drag its cold front across our region. However, the front will weaken and dissipate to our northwest, over upstate New York, and we will once again likely only see some cloudiness late Tuesday night into Wednesday morning, but should remain dry.

The jet stream will once again shift southward, and as a result, our weather will become more active, later in the week. A trough in the jet stream will amplify as it moves over the eastern U.S. on Wednesday and Thursday. A surface low will develop over the Great Lakes in response to this deepening trough on Wednesday night and then move into the Ohio Valley Thursday morning. The surface low will deepen rapidly as it moves directly over Berkshire County on Thursday evening. With strong forcing/lifting associated with the low, and plenty of moisture feeding into the system from our south and east, we are likely to get substantial rain Thursday afternoon and night, possibly upward of 1″.

As the cold trough moves over us on Friday and the deepening low departs, it will turn windy and much cooler, with some lingering showers still possible. Surface high pressure will build in briefly to give us some sunshine and still cool temperatures on Saturday before the next storm arrives on Sunday. It looks like we may get substantial rain from this storm as well. However, that is still almost a week away, so that forecast scenario may change……

Monday Night

Partly cloudy and seasonably cold.

Low temperatures near 30.

Light westerly winds.

Tuesday

A mix of sun and clouds and mild, with more sun than clouds in the morning and more clouds than sun in the afternoon.

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

Light southwesterly winds in the morning, becoming south-southwesterly at 5-10 mph in the afternoon.

Tuesday Night

Partly cloudy in the evening, becoming mostly cloudy after midnight. There is the slight chance of a sprinkle or light shower in North County toward daybreak. Probability of precipitation 20%.

Low temperatures in the low 40s.

South-southwesterly winds at 5-10 mph, becoming light toward morning.

Wednesday

Mostly cloudy in the morning, with the slight chance of a sprinkle or light shower, then partly cloudy and mild in the afternoon.

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

West-southwesterly winds at 5-10 mph.

It looks like the low is tracking a little closer to the coast. Rain still looks to begin early afternoon. Snow changeover times also look unchanged. However, precipitation will be more continuous and heavier than it appeared yesterday with liquid equivalents between 0.25″ and 0.50″, with greatest amounts over the elevated terrain to the east, and wet snow will likely continue through the evening, ending around midnight. Likely wet snow accumulations, a coating to 1″ in the lower elevations and 1-3″ over the elevated terrain to the east.

The following forecast is provided by Allen Chague as part of lab work for the Introduction to Meteorology course (ATM-145) under my supervision. The forecast discussion is mine…….

An amplified trough in the jet stream wave pattern is centered to our west with a stalled frontal boundary along its eastern edge, aligned southwest to northeast, just off the East Coast. A series of mid/upper-level disturbances (three in total) will rotate through the base of the trough over the next few days. Each of these will generate a surface low pressure system that will ride northeastward along the front. The first of these is presently generating a very weak low pressure system well off the Mid-Atlantic Coast that will move out to sea and dissipate. The second, somewhat stronger disturbance will generate a slightly more significant low pressure system, although still fairly weak, off the Mid-Atlantic Coast on Saturday that will move northeastward, by Cape Cod and into the Gulf of Maine, Saturday night. Berkshire County will be on the western edge of the precipitation shield of this “storm” during Saturday afternoon and into the evening. I think we are likely to see a period of light precipitation or showers during the afternoon and into the early evening on Saturday. Whether we will get snow or rain is also a tough call. Temperatures aloft are cold enough to support snow but the boundary layer is still fairly warm. I think that early afternoon any precipitation that falls will likely be rain everywhere. By mid afternoon the rain may change to snow over the elevated terrain and then by 5 or 6 pm any precipitation that falls will likely be snow everywhere. It looks like precipitation totals will likely be about 0.10″ liquid equivalent, possibly as much as 0.20″ over the hill towns to the east, so I wouldn’t expect to see anything more than a light coating of wet snow on grassy surfaces, predominantly over the elevated terrain and hill towns to the east (Windsor, Peru, Savoy, etc.).

A much more vigorous disturbance (cold pool aloft), that is responsible for the amplification of the trough, will rotate through the base of the trough Saturday night and Sunday and generate a much deeper surface low off the coast. However, this low should track well to our east as the movement of the disturbance through the trough generates enough momentum to finally drag the axis of the trough eastward. As a result, we should not receive any precipitation in Berkshire County from this low. However, the axis of this very cold trough (for this time of year) will be centered over us on Sunday so, despite sunshine during the afternoon, temperatures will struggle to reach 40. In addition, the pressure gradient being generated by the strengthening low off the coast and strong high pressure moving in from the west will result in fairly strong winds, 15-25 mph (stronger gusts) during the day Sunday so it will feel even colder (wind chills). Temperatures will plummet Sunday night, possibly reaching a low of 20 in some places. It should remain breezy as well so wind chills are likely to drop into the single digits by Monday morning. Surface high pressure will crest to our southwest on Monday as the trough finally begins to lift out. Monday should turn out mostly sunny, but it will still be somewhat breezy and cool but it looks like temperatures will be slightly milder, reaching into the 40s in most locations.

Friday Night

Partly to mostly cloudy and seasonably cold.

Low temperatures in the mid 30s, upper 30s in South County.

East-northeasterly winds at 5-10 mph, shifting to northeasterly after midnight.

Saturday

Mostly cloudy early, becoming overcast by mid-morning. A period of light precipitation or showers likely developing during the early afternoon and continuing off and on into the evening. Rain is likely in the lower elevations during the afternoon, with any precipitation turning to wet snow by 5 or 6 pm. The changeover to wet snow will likely occur during the mid afternoon over the elevated terrain. Probability of precipitation 70%. Likely rainfall equivalent totals 0.10″, to as much as 0.20″ over the elevated terrain to the east. Likely snowfall totals, a coating of wet snow on grassy surfaces, predominantly in the higher terrain to the east.

High temperatures in the low 40s in Pittsfield, Lee, Stockbridge, Adams, North Adams, and Williamstown; low to mid 40s in Great Barrington and Sheffield and; upper 30s to near 40 over the elevated terrain. Temperatures falling into the 30s everywhere by evening.

Northeasterly winds at 5-10 mph in the morning, shifting to northerly in the afternoon.

Saturday Night

A few lingering wet snow showers early, then mostly cloudy and seasonably cold, becoming breezy after midnight.

Low temperatures near 30.

North-northwesterly winds at 5-10 mph, increasing to 10-15 mph after midnight.

Sunday

Mostly cloudy in the morning, clearing skies in the afternoon. Windy and cold.

High temperatures upper 30s to near 40 in Pittsfield, Lee, Stockbridge, Adams, North Adams and Williamstown; near 40 to low 40s in Great Barrington and Sheffield and; mid to upper 30s over the elevated terrain. Wind chill temperatures in the 20s.

Northwesterly winds at 15-25 mph with gusts 30-40 mph.

Sunday Night and Monday

Mostly clear, breezy, and very cold overnight with low temperatures near 20, wind chills falling to the single digits at times. Mostly sunny and still breezy Monday, slightly milder, with highs averaging in the mid 40s.