Berkshire County Forecast-Friday, September 5

It will remain uncomfortably warm and humid overnight tonight (one of the warmest and muggiest nights of the summer) and during much of the day Saturday. However, a fairly strong cold front, at the leading edge of a trough in the jet stream wave pattern, will pass through the county, from northwest to southeast, between 5 and 7 pm on Saturday. This will result in a marked drop in temperature and humidity as a continental polar surface high pressure system from the upper midwest replaces the warm and humid air mass, resulting from the maritime tropical “Bermuda High”, which is presently in control of our weather.

The cold frontal passage will generate fairly widespread thunderstorms during the afternoon and evening on Saturday, as the cooler air behind the front lifts the warm, moist, unstable air over the region. The air will become even more unstable as we will likely get enough sunshine through midday to drive surface temperatures to, and probably, exceeding 80 degrees. The Storm Prediction Center has issued a forecast of a “slight” chance of “severe” thunderstorms (15% probability within 25 miles of any point). However, the risk is primarily for damaging “straight-line” wind gusts. It does not appear that there will be enough wind shear to generate significant supercell (rotating) thunderstorms that could spawn tornadoes. Some of the high-resolution models are generating a “prefrontal” band of thunderstorms which would move through the county from northwest to southeast during the early afternoon. I think this is a likely scenario. A second band of thunderstorms, accompanying the frontal passage, will likely pass through the county between 5 and 7 pm. I believe most places in the county will experience a thunderstorm at some point on Saturday, possibly in the early afternoon, but more likely during the late afternoon to evening period as the front passes.

Temperatures will plummet from the 80s to the 60s as the thunderstorms move through, then into the 50s during the evening. Temperatures will continue to drop overnight Saturday, falling to near 50 by Sunday morning. It will be mostly sunny both Sunday and Monday as surface high pressure re-establishes control of our weather. Temperatures will return to seasonal levels, with highs in the low 70s on average and it will be much drier, with dewpoints in the upper 40s, compared with the low 70s of today. This high pressure system should maintain control of our weather into mid-week as it drifts slowly off the coast. Another, much more amplified, trough in the jet stream wave pattern will likely develop over central portions of the continent during the week next week and propagate through our region late in the week and through next weekend. It looks like this trough will contain much cooler air from Canada and could give us our first taste of Autumn, with temperatures struggling to get out of the 50s (?) next weekend.

Friday Night

Mostly clear. Unseasonably warm and humid.

Low temperatures generally in the upper 60s to near 70 with some low 70s in South County.

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

Saturday

Mostly sunny to partly cloudy into early afternoon. Very warm and humid. Thunderstorms likely in the afternoon into early evening, with a band of thunderstorms possible in the early afternoon, and a second band more likely between 5 and 7 pm. Gusty winds and heavy downpours will likely accompany some of these storms. Probability of precipitation 80%.

High temperatures in the low 80s in Adams, North Adams, Williamstown and over the elevated terrain; low to mid 80s in Pittsfield, Lee and Stockbridge; and mid 80s in Great Barrington and Sheffield.

South-southwesterly winds at 5-10 mph in the morning, becoming southwesterly and increasing to 10-15 mph in the afternoon, and then shifting to west-northwesterly between 5 and 7 pm. Strong gusts likely in thunderstorms.

Saturday Night

A few lingering showers early, then clearing skies and much cooler and drier.

Temperatures falling through the 60s and into the 50s during the evening. Low temperatures near 50 to low 50s by morning.

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

Sunday

Mostly sunny, with seasonable temperatures and low humidity.

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

Northwesterly winds at 5-10 mph.

Sunday Night and Monday

Mostly clear overnight and mostly sunny on Monday. Seasonable temperatures and low humidity, with overnight lows averaging in the mid to upper 40s with highs in the low 70s.

Berkshire County Forecast, Wednesday, September 3

Now that the fall semester has begun, I will once again be providing forecasts for Berkshire County. I will post a new forecast every other day, on average, but provide updates for any significant changes. Once winter weather events begin to occur, as was the case last year, I will give more frequent updates as needed. The students in the Introduction to Meteorology class (ATM-145) will begin making forecasts with me sometime in October. Real-time weather data from the BCC Weather Station can be found by clicking on the “BCC Weather Station” link (rainwise.net/weather/bcc) on the bottom blue strip of the BCC web homepage (www.berkshirecc.edu).

A brief note to anyone who is interested….A new Atmospheric Science 2 year A.A. program has been established at BCC starting this year. An articulation agreement has been reached with SUNY Albany (University at Albany) so that, upon completion of BCC’s program, students can transfer directly into the 3rd year of their Atmospheric Science B.S. program (one of the best in the country). As a result, Berkshire County students interested in a career in Meteorology or Climate Science can complete the first 2 years of a B.S. degree in Atmospheric Science in a local community college setting at a markedly reduced cost compared to a 4 yr. school. Anyone who is interested, feel free to contact me at: jkravitz@berkshirecc.edu.

On to the weather….. A cold front passed through Berkshire County yesterday afternoon and evening resulting in scattered thunderstorms during the afternoon in the unstable air in advance of the front, followed by a period of steady rain with the actual frontal passage during the late evening hours. Cooler and much drier air moved in behind the front today. Most notably, dewpoints were much more comfortable, near 60, today compared with almost unbearable dewpoints, near 70, on Monday and Tuesday. The lower dewpoints and light winds will permit significant radiational cooling tonight, with temperatures falling well down into the 50s. The “Bermuda High” (semi-permanent subtropical high pressure system located off the Atlantic Coast) will re-establish its control over our weather over the next few days, with temperatures increasing and moisture levels rising through Friday. Skies should remain relatively clear over the next few days, however, with surface high pressure in control.

Cold air is beginning to build over northern Canada and will push far enough south to generate a trough in the jet stream wave pattern over the western U.S. late this week. This trough will propagate eastward, with a cold front along the leading edge of the trough reaching Berkshire County on Saturday. As the cool air plows into, and lifts, the unstable unseasonably warm and humid air over the Northeast, a line of thunderstorms, possibly severe, will likely develop over New York and then move through Berkshire County sometime on Saturday. Once the cold front moves through, a much cooler continental Polar (cP) airmass (surface high pressure system) will build in and dominate our weather into midweek next week. There should be plenty of sun, and the air will be much drier, but temperatures will struggle to get out of the 60s on both Sunday and Monday.

Wednesday Night

Clear, calm and comfortable.

Low temperatures in the low to mid 50s.

Light westerly winds this evening, becoming calm after midnight.

Thursday

Clear and sunny in the morning. Remaining mostly sunny in the afternoon, with some build up of fair-weather cumulus clouds, particularly over the elevated terrain. It will be unseasonably warm, but humidity will remain low.

High temperatures in the low 80s in Pittsfield, Adams, North Adams, Williamstown, Lee and Stockbridge; low to mid 80s in Great Barrington and Sheffield and; near 80 over the elevated terrain.

Winds light and variable in the morning, becoming southwesterly at 5-10 mph in the afternoon.

Thursday Night

Clear, calm and seasonably cool.

Low temperatures in the mid 50s.

Calm winds.

Friday

Mostly sunny, unseasonably warm and becoming muggy.

High temperatures in the low to mid 80s in Pittsfield, Adams, North Adams, Williamstown, Lee and Stockbridge; mid 80s in Great Barrington and Sheffield and; low 80s over the elevated terrain.

South-southwesterly winds at 8-12 mph.

 

Berkshire County Forecast-Tuesday, March 25

Note: Clicking on underlined red text provides links to various weather maps.

Summary: A weak surface low pressure system, presently located off the Carolina Coast, will deepen rapidly as it moves northeast to the east of Cape over the next 24 hours. Fortunately for us, the low center will be well off the coast and we will not see anything more than scattered snow showers and snow flurries. However, the low will be so deep that the pressure gradient will be very strong over Berkshire County tomorrow so it will likely be quite windy and unseasonably cold.

The jet stream pattern with this storm will have a classic “double jet streak” configuration that will create pronounced upper-level divergence, permitting the surface low to deepen very rapidly. In fact, if the models are correct, the central pressure will drop below 960 mb. This is similar to the central pressure in a Category 3 hurricane. This pressure level is also similar to Sandy, as well as the “Superstorm” that wreaked havoc on the eastern third of the U.S. in mid-March 1993, dropping 1-3 feet of snow as far south as Alabama. Luckily for the East Coast, the jet stream trough that is responsible for generating this storm is located further east than those prior events. As a result, the low will track well offshore and carry most of its heavy snow with it. Cape Cod and eastern Maine have blizzard warnings in effect, however, due to a period of heavy snow tomorrow with near hurricane force wind gusts and reduced visibility due to falling and blowing snow. Coastal flood advisories are also in effect there due to an expected storm surge of 3-4 feet (although not even close to the scale of Sandy).

As the storm moves away skies should clear Wednesday night with very cold temperatures (once again). However, the jet stream trough will lift rapidly northeast and a bit of a ridge will build in so there should be a fairly rapid “warming” trend Thursday and Friday, with high temperatures in the 30s Thursday and well into the 40s on Friday. Two low pressure systems will slide by to our north, one on Friday and a second on Saturday night. Precipitation may start as a little light mixed sleet and freezing rain Thursday night with some low-level cold air in place but the precipitation should change fairly quickly to rain Friday morning. Rain should be light on Friday but a bit heavier from late Saturday afternoon into Saturday night.

Tuesday Night

Partly to mostly cloudy.

Not as cold as previous nights, with low temperatures in the upper teens.

Light easterly winds, shifting to northerly and increasing to 5-10 mph after midnight.

Wednesday

Mostly cloudy windy and cold with a chance of a snow shower in the morning. Clearing windy and cold during the afternoon.

High temperatures in the mid to upper 20s in Pittsfield, Adams, North Adams and Williamstown; upper 20s in Lee, Stockbridge, Great Barrington and Sheffield and; low to mid 20s over the elevated terrain, with wind chill temperatures in the single digits.

Northwest winds at 10-20 mph during the morning, increasing to 15-25 mph, with gusts to 40 mph during the afternoon.

Wednesday Night

Mostly clear and unseasonably cold. It will be windy in the evening, with winds diminishing somewhat after midnight.

Low temperatures near 10, with wind chills near zero.

Northwesterly winds at 10-20 mph during the evening, shifting to westerly and diminishing to 8-15 mph after midnight.

Thursday

Mostly sunny in the morning with an increase in clouds during the afternoon. Not as cold.

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

Westerly winds at 8-12 mph, shifting to southwesterly in the afternoon.

Berkshire County Forecast-Wednesday, March 12

Note: Clicking on underlined red text provides links to various weather maps.

Summary: As of 4:30 pm it is raining across the county. Temperatures are generally in the mid to upper 30s, but as low as 33 degrees at the reporting hill towns to the east. Temperatures are above freezing in southern VT and have been for the entire day as well, so there is no sign yet of any changeover to freezing rain. Freezing rain is occurring in the Albany area as northerly winds have been able to drain the dense cold air down the Hudson Valley from the north. This cold air should not be able to be drawn into Berkshire County until the surface low passes by to our east and winds shift to the northwest. This is not likely to occur until sometime around 9 or 10 pm this evening in most locations. However, the changeover could occur as early as 7 pm over the elevated terrain. There should be a fairly rapid changeover to sleet, by 10 or 11 pm, and then to snow by midnight or so, so there is unlikely to be much of an ice accumulation in most locations. However, 0.10″ of ice could accumulate in spots over the higher terrain where the changeover may occur earlier. The heavy precipitation will likely have shifted eastward by the time the precipitation changes to snow. Occasional light snow will continue into the morning, with snow showers lingering until early afternoon. Likely snow accumulations still look to be light, even lighter than yesterdays forecast, on the order of a dusting – 1″ in most locations, with 1″-2″ possible in a few spots over the elevated terrain, particularly in North County.

It still looks like it will turn windy and very cold overnight with temperatures falling into the single digits by morning and only rising into the low to mid teens during the day. Winds will increase to 15-25 mph, with gusts into the 30-40 mph range after midnight and through the day tomorrow. Therefore, wind chills will be below zero at times and as much as the teens below zero after midnight into the early morning.

The bitterly cold air will linger overnight Thursday, with lows back into the single digits (although winds will lighten), but temperatures will likely rebound into the 30s on Friday and possibly into the 40s on Saturday.

Wednesday Night

Occasional rain, changing to freezing rain around 9 or 10 pm, as early as 7 pm over the elevated terrain. Freezing rain should change to sleet by 10 or 11 pm and then light snow by midnight. Occasional light snow or snow showers after midnight. Probability of precipitation near 100%.  Likely rainfall totals 0.10″-0.20″. The quick changeover of precipitation types should make significant ice accumulations unlikely in most locations. However, as much as 0.10″ of ice could accumulate in spots over the elevated terrain. Likely total snowfall generally a dusting – 1″ with 1″- 2″ in a few spots over the elevated terrain, particularly to the north. It will become windy and much colder as the night progresses.

Temperatures will fall rapidly into and through the 20s before midnight and into the single digits by morning. Low temperatures will reach the upper single digits in most spots, mid single digits over the elevated terrain. Wind chill temperatures in the single digits to teens below zero after midnight.

North-northwest winds at 10-15 mph before midnight, shifting to northwesterly and increasing to 15-25 mph after midnight, with gusts 30-40 mph.

Thursday

Mostly cloudy, windy and very cold, with occasional snow showers and flurries likely into early afternoon. Probability of precipitation 60%. A dusting is possible in spots.

Temperatures will not rise much, with high temperatures in the low teens in Pittsfield; low to mid teens in Adams, North Adams, Williamstown, Lee and Stockbridge; mid teens in Great Barrington and Sheffield and; near 10 over the elevated terrain.

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

Thursday Night

Partly cloudy and very cold with diminishing winds.

Low temperatures in the low to mid single digits.

West-northwesterly winds at 10-20 mph during the evening, diminishing to 5-10 mph after midnight, becoming light by morning.

Friday

Mostly cloudy to partly sunny, breezy and milder.

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

South-southwesterly winds at 10-15 mph.

Berkshire County Forecast-Tuesday, March 11

Note: Clicking on underlined red text provides links to various weather maps.

Summary: It looks like the surface low may track slightly farther south than it appeared yesterday, tracking closer to New York city. However, it does not appear that this will affect the forecast for Berkshire County dramatically. The only changes to yesterday’s forecast that I would make is that 1) I think that we may get more rain, and it may be moderate to heavy at times, during the afternoon and evening tomorrow. Also, 2) surface temperatures will be close to freezing in spots over the elevated terrain, particularly to the north, so there may be some freezing rain there. However, with temperatures close to freezing and the high sun angle during the day, I would not expect a significant ice accumulation during the day. In addition, 3) as the dense cold air wraps in behind the low over the course of Wednesday evening there will likely be a changeover to freezing rain and sleet progressing from north to south. The changeover to freezing rain will likely occur by 8 or 9 pm in North County and central Berkshire, by 10 pm in South County. It will likely have changed to sleet everywhere by 11 pm. There should only be a light coating of ice and a thin (1/4″-1/2″) layer of sleet before precipitation changes to snow by midnight in central and northern parts of the county with the changeover from sleet to snow closer to 1 or 2 am in South County. There may be a burst of heavier snow at the outset, otherwise the snow should generally be light and continue into mid-morning on Thursday. Snow showers will likely linger into the afternoon on Thursday. I still expect 1-3″ snow accumulation by the time it ends, with the lower amounts more likely in South County and the higher amounts in North County and over the elevated terrain to the east. There could be as much as 4″ in a few spots over the elevated terrain in North County (e.g. Savoy, Florida).

Tuesday Night

Increasing clouds this evening. Becoming overcast after midnight with mixed snow and rain showers likely in North County and rain showers elsewhere toward daybreak. Probability of precipitation 70%. Likely snow accumulation, a dusting to 1/2″ in parts of North County by the time any snow showers end around 10 am.

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

Calm winds.

Wednesday

Any mixed rain and snow showers early, predominantly to the north, should end by 10 am. Rain will then re-develop across the county near noon to early afternoon and continue moderate to heavy at times through the afternoon and into the evening. There may be some pockets of freezing rain over the elevated terrain. Probability of precipitation near 100%. Likely rainfall totals 0.50″-0.75″ by the time rain transitions to frozen precipitation during the evening hours. No significant ice accumulation expected during the daylight hours.

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

Easterly winds at 5-10 mph in the morning, shifting to northeasterly at 10-15 mph during the afternoon.

Wednesday Night

Rain, moderate to heavy at times, early in the evening. Rain will likely change to freezing rain and then sleet, with the changeover progressing from northwest to southeast across the county, during the evening. In central and northern Berkshire the changeover to freezing rain will likely occur by 8 or 9 pm and by 10 pm in South County. There should be sleet everywhere by 11 pm. Sleet will likely change to snow by midnight in central and northern sections, by 1 or 2 am in South County. A thin coating of ice is possible in spots (< 0.10″) with a thin layer of sleet (0.25″-0.50″) before the changeover to snow. Occasional snow, mostly light, will likely continue into mid-morning. Likely total snow accumulations 1″-3″ with the least amounts most likely in South County and the greater amounts to the north and over the elevated terrain to the east. There could be as much as 4″ over the elevated terrain to the north (e.g. Savor, Florida). Becoming windy and much colder as the night progresses.

Temperatures will plummet into and through the 20s during the evening and then through the teens after midnight, with low temperatures in the single digits by morning. Wind chill temperatures in the teens below zero at times.

North-northeasterly winds at 10-20 mph in the evening, shifting to northwesterly at 15-25 mph with gusts to 40 mph after midnight.

Thursday

Light snow likely until mid-morning with scattered snow showers lingering into the afternoon. Probability of precipitation 60%. Likely total snow accumulations as stated above (in the Wednesday night forecast). It will be windy and bitterly cold.

Temperatures will not rise much, only reaching the low teens in most locations, near 10 over the elevated terrain. Wind chill temperatures will be in the single digits below zero at times.

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

Berkshire County Forecast-Monday, March 10

Note: Clicking on underlined red text provides links to various weather maps.

SummaryAll of the models have been trending “warmer” with Wednesday’s storm with the surface low tracking over Southern New England, almost directly over Berkshire County. With this path, there will be enough warm air wrapping into the low from off the ocean to drive temperatures in the lower 10,000 feet of the atmosphere above Berkshire County over the freezing point. As a result, most of the precipitation the County receives from this storm should be in liquid form.

After a weak disturbance moves by to our north and gives us the chance of a few mixed snow and rain showers tonight, Tuesday will turn out partly sunny and seasonably mild as we sit in a lull between systems. On Tuesday night a surface low pressure system will develop and strengthen rapidly over the Mid-Mississippi Valley in response to a deepening trough in the jet stream as the flow pattern becomes more amplified, with cold Canadian air diving south and colliding with a warm and moist atmosphere which has been developing over the Southeast. The low will track eastward through the Ohio Valley overnight becoming centered over Ohio by Wednesday morning. When the precipitation shield reaches Berkshire County early Wednesday morning the atmosphere should be just cold enough to support light snow at the outset. The counterclockwise circulation around the low center will push warmer air into the lower levels of the atmosphere as the morning progresses. A changeover to light sleet and then light rain will occur quickly in South County where only a dusting of snow at most is likely to fall. As warmer temperatures stream north, the changeover will occur next in central Berkshire during the mid to late morning and then, eventually, in North County by noon. Likely snowfall before the changeover is a dusting-1/2″ in central Berkshire and 1/2″-1″ in North County.

As the surface low tracks over Pennsylvania and southern NY during the afternoon and almost directly over Berkshire County during the evening there should be occasional rain, moderate at times, over the county. There may be some pockets of freezing rain over the elevated terrain for a time during the afternoon. Rainfall totals are likely to be between 0.25″ and 0.50″ South County and central Berkshire with 0.50″- 0.75″ in North County.

The jet stream pattern will be typical for a very strong East Coast storm with a “double jet streak” pattern generating substantial upper-level divergence in the wind flow pattern, creating marked ascent in the atmosphere. As a result, the central pressure in the center of the low will likely drop below 980 mb as the low intensifies as it approaches and reaches the coast late on Wednesday and Wednesday evening. In addition, the warming March atmosphere can hold more moisture available for condensation (clouds and precipitation) than a mid-winter scenario so there will be places that get over 2″ of liquid equivalent precipitation.  However, we should avoid the heaviest precipitation since, as is typical with these storms, the strongest ascent and, thus, the heaviest precipitation will fall north and west of the surface low center, with heavy rain in southern Vermont and heavy snow likely in the Adirondacks and central and northern Greens where 2 feet or more could fall in some spots.

The surface low should be centered over Boston by midnight on Wednesday night and as cold air circulates in behind the low our rain should change to snow. However, by that time most of the heavy precipitation will have shifted over NH and Maine. Light snow will likely fall from near midnight until Thursday morning with 1-3″ of accumulation likely by morning. Snow showers should continue during the morning on Thursday with an additional dusting-1″ of snow possible as moisture circulating around the low is lifted by our elevated terrain.

As the low pulls away Wednesday night and Thursday, the pressure gradient between the strong surface low and high pressure building in from the west will strengthen so it will become windy. Temperatures will also plummet as the cold trough in the jet stream that was responsible for generating the storm becomes centered over us. In fact, temperatures will not escape the teens on Thursday with wind chill temperatures below zero. Fortunately, the trough will swing by and temperatures will become more seasonable on Friday and into the weekend.

Monday Night

Overcast with a period of mixed rain and wet snow showers in the lower elevations and wet snow showers over the elevated terrain likely near midnight. Probability of precipitation 60%. There could be a light dusting of snow in a few spots over the elevated terrain. Partial clearing toward morning.

Temperatures will hold fairly steady, with low temperatures in the low to mid 30s over the lower elevations, near 30 to low 30s over the elevated terrain.

Southerly winds at 5-10 mph this evening, shifting to southwesterly and then westerly after midnight.

Tuesday

Partly cloudy, breezy and mild.

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

West-northwesterly wind at 10-15 mph diminishing toward evening.

Tuesday Night

Increasing clouds in the evening, overcast after midnight with a good chance of light snow or a snow shower toward daybreak. Probability of precipitation 50%. A dusting of snow possible in spots.

Low temperatures in the low 30s.

Light and variable winds in the evening, becoming calm overnight.

Wednesday

Light snow likely early, changing to light rain during the morning. Likely snow accumulations before the changeover to rain, none to a dusting in most locations, with as much as 1/2″-1″ in parts of North County. Breezy with rain, moderate at times during the afternoon. There could be a little freezing rain in spots over the elevated terrain early in the afternoon. Rainfall totals generally 0.25″-0.50″. Probability of precipitation 90%.

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

East-southeasterly winds at 10-15 mph.

Wednesday Night and Thursday

Occasional rain and mild during the evening. Rain changing to light snow near midnight. Light snow likely after midnight. Likely accumulations 1-3″ by morning. Snow showers likely during Thursday morning with an additional dusting-1″ possible. It will briefly turn quite mild during the evening with temperatures rising into the 40s. It will turn windy and much colder after midnight. Low temperatures by morning in the low teens with temperatures holding in the teens during the day, with wind chills occasionally below zero.

Berkshire County Forecast-Monday, March 10 (preliminary)

It is now looking like the surface low for Wednesday’s big storm will track almost right over Berkshire County. As a result, we will most likely see predominantly heavy rain from this storm with a big snowstorm to our north and west over the Green and Adirondack Mountains. It looks like precipitation should begin as light snow Wednesday morning, with a fairly rapid changeover to sleet and then rain. We should then see heavy rain Wednesday afternoon and evening, although there may be a few pockets of freezing rain for a time over the elevated terrain. Rain should change back to snow overnight on Wednesday as the storm passes by, however, we are unlikely to see more than a few inches of “backlash” snow by Thursday morning. I will update this forecast in detail around 5 pm today.

Berkshire County Forecast-Friday, March 7

Note: Clicking on underlined red text provides links to various weather maps.

SummaryOur weather will remain quiet, without any big storms, and temperatures pretty close to average through early next week. The polar front jet stream has weakened, with a fairly zonal orientation and has even shifted slightly to the north, into a more “normal” location for March. The surface high pressure system which has given us fair weather for the past 2 days has shifted to our east and off the coast. The southerly flow around the backside of the high (clockwise circulation) is bringing us the mildest temperatures we have seen in a while with highs well up into the 30s and low 40s today and likely in the low 40s again on Saturday. A surface low has formed to our south along a subtropical branch of the jet stream but is drifting out to sea well to our south and will not impact us.

A weak cold front will pass through our region late Saturday with some cloudiness and just the chance of a snow flurry or snow shower Saturday evening. It will then turn breezy and colder behind the front on Sunday, with temperatures dropping back into the 20s to low 30s. However, as surface high pressure builds in behind the front, there should be abundant sunshine to help diminish the pain. A weak “Alberta Clipper” type surface low will dive south over the Great Lakes Sunday night into Monday but, once again, there is only the chance of a snow flurry or snow shower with this system. After the clipper passes, the zonally oriented jet stream will shift slightly to the north again so that our temperatures will likely soar into the 40s on Tuesday.

Unfortunately, that brief taste of spring may not last. The long range computer model runs for the past few days have consistently amplified the jet stream flow pattern for mid-week, with cold surface high pressure anchored over eastern Canada and the generation of a surface low along the eastern side of the jet stream trough base in the Midwest on Wednesday morning. However, the two long-range models differ significantly in their solutions, which is not unusual 5-6 days out. Both models have been quite consistent in their solutions for the past few days. The European Model (ECMWF) has a more classic New England March snowstorm scenario with the jet stream becoming more amplified, and a much deeper surface low developing. The low center moves through the Ohio Valley on Wednesday and off the DelMarva Peninsula Wednesday night. With this scenario, snow would develop here late in the afternoon or evening on Wednesday and continue heavy at times overnight. The eastward progression of the low is relatively slow, due to the amplified jet stream, with the low only drifting to south of Long Island by Thursday morning. The low then deepens as it moves over the warmer ocean waters and speeds up a bit as it moves over Cape Cod and towards the Canadian Maritime on Thursday. With this scenario, snow would continue, although lighter, through a good part of the day Thursday. If the ECMWF solution was realized, Berkshire County would get a fairly good dumping of snow, possibly a foot or more.

The U.S. GFS model has a less amplified jet stream with the cold trough pushing farther south. Thus, a weaker low is generated over the Tennessee Valley on Wednesday and off the Carolina Coast Wednesday evening. With this “flatter” jet stream scenario, the low does not deepen considerably and moves quickly out to sea, well south of Cape Cod, on Wednesday night. If this solution was realized, Berkshire County would only receive a period of light to moderate snow late Wednesday afternoon and Wednesday night, with only a light snowfall of 2-5″ or so.

Interestingly, until the last one of these scenarios, last Monday, the ECMWF had been more consistent and correct with its solutions for these storms than the GFS. For last Monday’s storm, both models had similar solutions (5-6 days out) to the ones they are generating now. However, the GFS ending up being more correct, with that storm moving out to sea to our south and Berkshire County getting no snow at all. Therefore, a good gambler would probably bet that the GFS will be right again and we will not get a big snow storm. However, my gut is telling me that the ECMWF scenario is more realistic looking and I fear that we could get a classic March snowstorm dump. I hope this is wrong…….I will keep an eye on the situation and post updates.

Friday Night

Mostly clear, calm, and not as cold.

Low temperatures in the low to mid teens.

Calm winds.

Saturday

Mostly sunny to partly cloudy in the morning. Increasing cloudiness and becoming breezy during the afternoon. Seasonably mild. There is the slight chance of a snow flurry late. Probability of precipitation 20%. No accumulation expected.

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

West-northwesterly wind at 5-10 mph during the morning, increasing to 10-15 mph during the afternoon.

Saturday Night

Mostly cloudy with the slight chance of a snow flurry during the evening. Clearing after midnight.

Low temperatures near 20.

Northwesterly winds at 5-10 mph.

Sunday

Mostly sunny, breezy and colder.

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

West-northwesterly winds at 10-20 mph.