Berkshire County Forecast-Friday, Feb. 14S

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

SummarySnowfall totals reported to the National Weather Service are as follows: Stockbridge – 8.5″, Clarksburg – 9.5″, Pittsfield – 10″, Adams – 14.7″, Williamstown – 15″, Lanesborough – 16″ and Becket – 21″. Savoy reported 12.5″ but that was yesterday at 11 pm last night so I suspect they recieved closer to 18″. As expected, the heaviest band of snow overnight set up just to our west, over western Columbia and eastern Greene and Albany counties, as well as northern Ulster and Duchess counties. Snowfall totals in these regions were in the 18-27″ range. Fortunately (or I guess unfortunately if you are a snow lover) this band of heavy precipitation rotated through here fairly quickly, moving southeast to northwest, between around 11 pm and 1 am before setting up to our west. Most of that precipitation fell here as heavy sleet until the atmospheric column cooled enough to change the sleet to snow around 12:15 or so. It then snowed heavily for an hour or so before the band moved west. The snow did fall heavily at times after that, but not the persistent 1-3″/hour that they received in the strong “frontogenesis” band to our west.

As that surface low rockets away through the Canadian Maritime today another jet stream disturbance is rotating through the base of the same persistent jet stream trough. This upper-level disturbance is generating a weak surface low over Kentucky that is spreading a band of moderate snow into the Ohio Valley. As this low hits the Mid-Atlantic Coast tomorrow, it will intensify rapidly as it moves up the coast to the east of Cape Cod by tomorrow evening. By this point, it will be to far to the east to have too much of an impact on us, although eastern MA is likely to get another dumping of snow. We will see a fairly prolonged period of mostly light snow but should only get on the order of 2-4″ as the low slips by to our south from late morning through the evening tomorrow.

As this low departs, surface high pressure will build into the region in its wake for the remainder of the 3 day weekend. As a result, both Sunday and Monday should have some sunshine, with the greatest amounts on Monday. The sun is feeling pretty warm this time of year, which should help, but air temperatures will be quite cold as the northwest flow behind the departing surface low drags the cold axis of the upper-level trough directly over us. Therefore, temperatures will struggle to get out of the teens both days. In addition, the pressure gradient between the strong departing surface low and the incoming surface high pressure system will generate strong winds for Sunday so wind chills will be pretty low. The wind should die down on Monday so that will probably be the nicer of the 2 days.

The trough will begin to lift out to our northeast on Monday and the jet stream will temporarily become quite flat (zonally oriented) on Tuesday and Wednesday. As a result, a disturbance in the jet stream will have trouble producing much in the way of upward motion as it generates a weak surface low. That low will move directly over us on Tuesday with more snow but it should only be a minor event, possibly a few inches.

Once that low passes by, the jet stream will undergo a bit of a pattern shift that has been quite uncharacteristic for the past month. A trough will dig into the western U.S. and a ridge will build over the eastern U.S.. As a result, a warm front should move through here on Thursday and bring much milder weather for the end of the week and into next weekend. In fact, we could reach 50 degrees! Enjoy it while you can though since the long-range models are suggesting the jet stream may revert to its usual pattern (cold trough over the east) for the following week.

Friday Night

Partly cloudy and breezy this evening. Becoming mostly cloudy with light winds after midnight.

Low temperatures in the mid to upper teens.

Westerly winds at 10-15 mph this evening, becoming light after midnight and calm by morning.

Saturday

Overcast with snow developing mid to late morning and continuing through the afternoon. The snow should be mostly light, although there may be a few moderate bursts. Probability of precipitation 90%. Likely snowfall accumulations 1-3″ by evening.

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

Light easterly winds in the morning, shifting to northeasterly and then northerly at 5-10 mph during the afternoon.

Saturday Night

Snow through the evening, diminishing and ending by midnight. Probability of precipitation 80%. An additional inch of snow is likely with total accumulations of 2-4″ likely. The greater accumulations are more likely in the elevated terrain with the lesser amounts more likely in the lower elevations. Clearing skies, windy and becoming much colder after midnight.

Low temperatures near 10, single digits over the elevated terrain. Wind chill temperatures as low as -10.

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

Sunday

Partly cloudy, windy and much colder.

High temperatures in the mid to upper teens in Pittsfield; upper teens in Lee, Stockbridge, Adams, North Adams and Williamstown; near 20 in Great Barrington and Sheffield and; low to mid teens over the elevated terrain. Wind chill temperatures in the single digits below zero at times.

West-northwest winds at 10-20 mph with gusts to 30 mph.

Sunday Night and Monday

Clear skies and very cold overnight. Mostly sunny on Monday, still cold but with lighter winds than Sunday.

Low temperatures in the single digits below zero Sunday night. High temperatures ranging from mid teens over the elevated terrain to low 20s in the lower elevations of South County.

Northwest winds at 10-15 mph Sunday evening lightening to 5-10 through Monday morning, becoming light during the afternoon.

Berkshire County Forecast-Thursday, Feb. 13

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

SummaryStill don’t see much change in the forecast. Things are pretty much progressing as expected. The dry slot which has rotated into the center of the storm is now moving over Berkshire County (4:30 pm) and the last band of heavy snow is moving south to north through the county. Precipitation should pretty much shut down within the next hour. There will be intermittent spotty mixed precipitation, mostly sleet (ice pellets) through the evening hours. Between 10 pm and midnight the band of precipitation wrapping around the back of the low will begin to move into the county. Right now, this feature is represented by an area of heavy snow and rain over Virginia, Maryland and Delaware. It still looks like the heaviest of this precipitation should stay just to our west. Precipitation will become steady and increase in intensity between 10 pm and midnight. The precipitation should start as sleet and we may see 1/2″ to 1″ of ice pellets accumulate before the sleet changes to snow between midnight and 1 am. Snow will continue, varying in intensity, for the remainder of the night and begin to taper off around daybreak. Most likely additional snow accumulations for this period will be 3-6″. In contrast to today’s snow, the heaviest amounts overnight are most likely in the northwestern parts of the county. Light snow may persist for a good part of the morning as the wrap around moisture is lifted by the elevated terrain. In fact, intermittent snow showers and/or flurries may persist into the afternoon. An additional dusting to 1″ of snow may fall during the day. Most likely storm total snow accumulations will be 10-16″.

Believe it or not, we will only get a brief break from the snow. After this storm departs, another jet stream disturbance will quickly follow, rotating through the base of the same trough. As a result, a much weaker surface low pressure system will scoot off the coast to our south on Saturday. A period of light snow is likely from mid-morning to mid-afternoon. Likely accumulations will be 1-3″.

Thursday Night

Overcast and breezy. Intermittent and spotty light mixed precipitation, mostly sleet until sometime between 10 pm and midnight. Sleet will then become steady and increase in intensity before changing to snow by midnight to 1 am. Snow, varying in intensity, for the remainder of the night. Snow will begin to taper off by daybreak. Probability of precipitation near 100%. Likely sleet accumulation of 1/2″ to 1″. Likely additional snowfall 3-6″, with the greatest amounts in northern and western portions of the county.

Temperatures will remain steady for most of the night and then drop a few degrees late. Low temperatures generally in the low 20s, near 20 over the elevated terrain.

Northeasterly winds at 10-20 mph, with gusts 30-35 mph, shifting to northwesterly after midnight.

Friday

Mostly cloudy and windy with light snow likely continuing off and on through most of the morning, scattered snow showers or flurries possible into the afternoon. Partial clearing late. Probability of precipitation 60%. Additional snowfall a dusting to 1″. Most likely storm total snow accumulation 10-16″.

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

West-northwesterly winds at 15-25 mph with gusts up to 35-40 mph.

Friday Night

Partly cloudy with diminishing winds in the evening, becoming overcast after midnight.

Low temperatures in the mid teens, low teens over the elevated terrain.

Westerly winds at 5-10 mph during the evening, becoming calm after midnight.

Saturday

Overcast with light snow likely, developing early to mid morning and continuing through mid-afternoon. Probability of precipitation 70%. Likely snowfall accumulations 1-3″.

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

Light northeasterly winds in the morning, shifting to northwesterly at 5-10 mph in the afternoon.

Forecast Update-Thursday, Feb. 13 – 11:00 AM

The storm is progressing as forecast. Snow will be heaviest between 11 am and 4 pm today (as forecast) with snowfall rates 1-3″ per hour at times. Expect 6-12″ of accumulation by evening, with heaviest totals in southern and eastern portions. By 5 pm, the snow will lighten up and change to light sleet and/or light freezing rain and drizzle. It now looks like the entire county will see this changeover. This light icy precipitation will continue off and on until 10 or 11 pm tonight. The sleet/freezing rain will then become steady and increase in intensity. We will likely get a total of 1″ or so of icy sleet from 5 pm to midnight. Around midnight the precipitation should change to all snow. Snow will then continue, varying in intensity, for the remainder of the night, ending in the early morning. It still looks like the heaviest portion of the “frontogenesis” band will be located just to our west during this “backlash” period after midnight. In those locations snowfall rates will be 1-3″ per hour. Even though the band will be focused to our west most of the time, portions of it may rotate through parts of the county (mostly north and west portions) during early and late parts of the period. Otherwise, snowfall will be light to moderate in Berkshire County during this period. I think we may get a little more than my forecast 2-4″ during the after midnight period, perhaps 3-6″. In contrast to our daytime snowfall, the highest totals during this period will likely be in the northwestern parts of the county. By the time all of the snow and ice is totaled up expect widespread 10-16″ totals.

I will post another update by 5 pm……

Berkshire County Forecast-Wednesday, Feb. 12

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

Summary: We are in for a prolonged, and possibly, a large impact snow event. Snowfall totals could exceed 12″ in some locations. Also, in contrast to previous recent snowfalls, the snow will have a heavier consistency (higher water content), and winds will be stronger, so there will be greater potential for damage to trees and even possible power outages.

The models are still struggling with the details of what will be a complex and, eventually, very deep surface low pressure system hugging the Atlantic Coast. The difficulty in forecasting snowfall totals accurately with this storm lies in the smaller scale (mesoscale) structure within the overall storm. The models struggle with these small scale features and their location and intensity is difficult to predict. In particular, the precipitation is likely to vary in intensity in “bands” so that if you are located within a heavy band for any length of time snow may be falling at 1-3″ and hour so that you will receive a much higher accumulation than areas not within one of these bands. This will have the largest impact Thursday night when a band of heavy snow forms to the west of the surface low pressure center as it intensifies rapidly as it moves over eastern Long Island and Cape Cod. In my experience, this type of band, which forms in an area of strong “frontogenesis” (a region of low level convergence  where warmer, moist air from the ocean is being force up agains cold dense air to the west) tends to form to our west, over Albany and the Catskills. This is where the European Model (ECMWF) is placing it. The U.S. models place it directly over Berkshire County. Therefore, my tendency is to find the ECMWF solution more likely.

Another uncertainty is that a dry and milder wedge of air will likely wrap into the low and lighten the precipitation considerably between about 5 pm and 10 pm. This “wedge” of air will also likely bring above freezing air in aloft, between 5 and 10 thousand feet and change precipitation to light sleet for a time during the period in South County and, possibly, central Berkshire.  I was pretty set on a total snow accumulation of 6-12″ with the reason for the large range being due to the banded precipitation and the dry slot. However, the latest data coming in this afternoon suggests that the storm is carrying more moisture and that the snow tomorrow morning and afternoon will be heavier than it looked earlier. Therefore, I think 8-16″, with highest amounts in the elevated terrain to the east (particularly in North County [e.g. Savory, Florida] where a changeover to sleet is less likely), by the time the storm ends Friday morning is a better estimate.

Here is my take on the timeline for the upcoming storm….

Snow should develop across the county from south to north between 5 and 7 am. Snow should continue fairly continuously moderate to heavy at times through the morning and afternoon. Likely snowfall accumulations are 3-6″ by lunch time (12 or 1) and 6-12″ by 5 pm. Between 5 and 10 pm the precipitation will lighten considerably and even shut down completely as the dry “wedge” of air wraps into the storm and over us. Precipitation is likely to change to light sleet and/or freezing drizzle during that period in South County and central Berkshire. Precipitation should then pick up again about 10 pm and continue, mostly light but possibly with an embedded  period of moderate to heavy snow, from 10 pm until it ends near daybreak or early morning on Friday. The precipitation during this latter period may begin as sleet and/or freezing rain for an hour or two before changing back to snow by midnight. An additional 2-4″ of snow is likely overnight. By Friday morning, I expect likely snowfall accumulation totals to be 8-16″ with the highest totals most likely in the elevated terrain to the east, particularly northeast (e.g. Savoy, Florida). I will try to give updates on this rapidly evolving event as frequently as possibly as things progress…..

Wednesday Night

Increasing clouds with snow developing from south to north between 5 and 7 am.

Low temperatures in the low teens during the evening, then rising slowly to near 20 by morning.

Light southeasterly winds this evening, shifting to northeasterly after midnight.

Thursday

Snow, moderate to heavy at times, through the morning and afternoon, until about 5 pm. Snow should be heaviest from late morning through early to mid afternoon. Breezy. Snow will lighten in intensity and possibly change to light sleet and/or freezing drizzle after 5 pm. Probability of precipitation near 100%. Likely snowfall accumulations 3-6″ by noon or 1 pm and 6-12″ by evening.

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

East-northeasterly winds at 5-10 mph early, increasing to 10-20 mph by afternoon. Winds shifting to north-northeasterly late.

Thursday Night

Intermittent light snow until about 10 pm. Precipitation may be in the form of light sleet and/or freezing drizzle in central and southern Berkshire. Breezy. Precipitation will become more continuous and increase in intensity after 10 pm. Precipitation will change to snow everywhere by midnight. Snow continuing, mostly light, with a possible period of moderate to heavy snow after midnight, ending by daybreak or during the early morning. Probability of precipitation near 100%. Additional likely nighttime snowfall accumulations 2-4″.

Temperatures near steady, falling a few degrees after midnight, with low temperatures in the low to mid 20s by morning, near 20 over the elevated terrain.

North-northeasterly winds at 10-20 mph, shifting to northwesterly after midnight.

Friday

Snow tapering off and ending during the early morning. Likely storm total accumulations 8-16″, with the highest totals in the elevated terrain to the east, particularly where no changeover to sleet occurs (e.g. Savoy, Florida). Mostly cloudy in the morning, becoming partly sunny in the afternoon. Breezy.

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

Westerly winds at 10-20 mph.

Berkshire County Forecast-Tuesday, Feb. 11

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

SummaryEven though the U.S. computer models have been all over the place with Thursday’s storm (or lack there of), they are finally beginning to converge on the solution that the European Model (ECMWF) has been very consistent with for several days now. Therefore, although there are still important difference’s between the models, I am tempted to find the ECMWF solution more reliable at this point. First, let me lay out what all of the models are agreeing upon…..

A weak surface low pressure system, presently developing over the Gulf of Mexico, will drift slowly northeastward to a location along the southeast U.S. coast Wednesday evening. The low will then drift more northerly to a position right over Cape Hatteras, NC by Thursday morning. At this point, the low will still be fairly weak with a central pressure near 1000 mb. However, it will be carrying loads of moisture from the Gulf of Mexico and Gulf Stream so it will have already wreaked havoc on the Southeastern states with large amounts of wintertime precipitation that they are unaccustomed to (hopefully lessons will have been learned from the snow “storm” in Georgia a few weeks ago). In particular, the southern Appalachians will likely receive over a foot of heavy wet snow during this time.

During the period from now until Thursday morning the trough in the jet stream configuration responsible for generating this surface low will become more amplified and during the day on Thursday it will become “negatively tilted”. This configuration will create a large amount of “divergence” of the jet stream winds above the surface low that will enhance the upward motion and deepen the surface low. As a result, the storm will undergo rapid development as it moves northeastward along the Mid-Atlantic and New England coast, attaining a very low central pressure around 970 mb by the time it reaches the Gulf of Maine Friday morning.  Therefore, precipitation will become heavy, winds will strengthen, particularly along the coast, and there will likely be some coastal flooding Thursday and Thursday night in the Mid-Atlantic states and New England.

The million dollar question is…where will the heaviest precipitation fall and it what form? This is where there are important differences between models. There will be a band of heavy snowfall which will have a very sharp northwestern margin with a changeover to sleet and freezing rain to the southeast of the band. The U.S. models track the surface low off the coast, moving southeast of Cape Cod. These models also move the low relatively quickly so that precipitation will begin here near daybreak but end during the evening on Thursday.  This track would keep most of New England cold enough at all levels of the atmosphere so that snow would fall everywhere except Cape Cod. In this scenario, the band of heaviest snow, over one foot and possibly well over, would fall to the southeast of Berkshire County. In addition, the northwestern edge of the heavier snow would lie right across Berkshire County for much of the storm. If this scenario was realized, the northwest corner of the county (e.g. Williamstown) would receive about 4-6″ of snow and the elevated terrain to the southeast (e.g. Otis, Becket, Sandisfield) would receive near 12″ with amounts elsewhere in the county increasing in amount from northwest to southeast between these two locations.

The ECMWF model scenario differs somewhat. It has consistently tracked the surface low more slowly and had it hugging the coast closely, moving directly over southeast MA. In this scenario, the heaviest band would lie over southeastern parts of Berkshire County during the day Thursday with enough warm air off the ocean overriding the cold air at the surface to possibly change the precipitation to sleet there briefly sometime during the afternoon or evening before changing back to snow. This track could also enable the “dry slot” (dry air wrapping into the low) to move over Berkshire for a time. A band of “backlash” snow would then rotate through the county Thursday night, affecting northern portions of the county to a greater extent, with snow not ending until well after midnight on Thursday night.

So, enough blather, what do you think is going to happen? You’re a meteorologist, make a forecast already!

I think the most likely scenario at this point is that snow will develop across Berkshire County from south to near daybreak Thursday morning. The snow will likely be light at first but become moderate to heavy at times, particularly  in central and southern portions from mid morning through the afternoon. The snow may change to sleet briefly in the south late in the afternoon. I would expect the snow to lighten or end for a time during the evening with mostly light snow, with some heavier bands, redeveloping later in the evening. This backlash should have its greatest impacts over the elevated terrain, particularly in North County. Snow should end sometime after midnight, probably during the early morning hours. Predicting snow fall totals is almost a guess at this point but I think we are in for a substantial snowfall, with 8-12″ likely for most of the county. However, I would not be surprised to see over a foot, maybe well over a foot in the elevated terrain, if the cards all align right (wrong). I will update this forecast late tomorrow afternoon. Hopefully, the forecast will have a higher degree of certainty at that time. However, my gut tells me that we won’t have a definite answer until the snow ends with this one. One thing I do know with a fairly high degree of certainty is that there will be places in the Appalachians and along the east coast that receive more than a foot of snow from this storm.

Tuesday Night

Mostly clear and very cold.

Low temperatures in the single digits below zero. Most locations will be in the mid single digits below zero but some valleys, particularly over the elevated terrain, could fall to -10° F.

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

Wednesday

Sunny skies, except for a thin veil of high clouds at times during the afternoon. Still cold, but not quite as cold as the past few days. In particular, it will feel milder since winds will be light and the sun is fairly strong in mid-February.

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

Winds light and variable.

Wednesday Night

Increasing clouds with snow likely developing from south to north near daybreak. Probability of precipitation 60%. 1″ or less accumulation by 8 am.

Low temperatures in the low to mid teens during the evening, rising to near 20 by daybreak.

Southeast winds at 5-10 mph, shifting to northeast after midnight and increasing to 10-15 mph by morning.

Thursday and Thursday Night

Snow and becoming windy. Snow will likely be moderate to heavy at times from mid-morning into the evening. There may be a brief changeover to sleet in southern portions late afternoon or early evening. Likely snowfall totals by evening 6-10″. Snow will lighten or end for a time during the evening. Light snow with a few moderate bursts will likely re-develop later in the evening ending after midnight. Most likely total snowfall accumulations 8-12″ although greater amounts are possible.

Daytime high temperatures low to mid 20s in most locations, upper 20s over South County and near 20 over the elevated terrain. Temperatures only falling a few degrees overnight, ranging from upper teens to low 20s by morning.

Northeast winds at 10-15 mph during the morning, shifting to northerly and increasing to 15-25 mph during the afternoon, shifting to northwesterly at 15-25 mph during the evening and decreasing to 10-15 mph after midnight.

Berkshire County Forecast-Saturday, Feb. 8

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

SummaryThe last in the series of jet stream disturbances to rotate through the region this weekend looks a little more vigorous than it did yesterday. In fact, it will be vigorous enough to generate a weak and diffuse surface low pressure system that will move rapidly through New England and off the coast Sunday night. As a result, I think snowfall totals, although still relatively light, may be a little greater than I forecast yesterday. Snow will likely develop late in the day Sunday, between about 4 and 6 pm. The snow should be relatively steady through the evening, ending by midnight. Snow should be mostly light, although there may be a few moderate bursts. Most likely accumulation totals will be 1-2″.

Saturday Night

Mostly cloudy and not quite as cold as previous nights. There is a chance of a snow flurry or snow shower, predominantly after midnight. Probability of precipitation 30%. No accumulation expected.

Low temperatures in the low teens.

Light northwesterly winds.

Sunday

Partly sunny early. Becoming overcast by noon with snow developing between 4 and 6 pm. Continued cold.

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

Light westerly winds, shifting to westerly and then southerly during the afternoon.

Sunday Night

Snow during the evening, ending by midnight. The snow will be mostly light with a few moderate bursts possible. Probability of precipitation 80%. Most likely snowfall accumulations 1-2″. Remaining overcast after midnight, becoming breezy with partial clearing toward daybreak.

Low temperatures in the low to mid teens.

Light southwesterly winds in the evening, shifting to northwesterly and increasing to 10-15 mph after midnight.

Monday

Partly cloudy, breezy and cold.

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

West-northwesterly winds at 10-15 mph.

Berkshire County Forecast-Friday, Feb. 7

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

Summary: The jet stream will remain zonally oriented (“flat” east to west) and to our south for the next four or five days so we should continue to have cold temperatures and no significant storms until at least Thursday of next week. A series of minor jet stream disturbances will be moving through later in the weekend. There is only the chance for a few scattered snow showers and flurries late Saturday night and during the day Sunday. A period of light snow may develop during Sunday evening with any accumulations on the order of a dusting to 1″. Otherwise, it should be a rather uneventful February weekend (weather wise). It will remain fairly cold, with temperatures below average, with highs in the 20s and overnight lows near zero Friday night and in the low teens Saturday night.

Surface high pressure will build back into the region for Monday through Wednesday with generally fair skies. It will remain cold with high temperatures only in the teens and 20s. It is still uncertain if and how a coastal storm on Thursday will impact Berkshire County. Today it is looking a little more disorganized and less intense than it did yesterday and the long-range models are all over the place both from run to run within models, as well as between different models. I suspect there will be more certainty to that forecast by Monday.

Friday Night

Mostly cloudy with the chance of a snow flurry this evening then becoming clear and very cold. Probability of precipitation 20% this evening. No accumulation expected.

Low temperatures near zero.

West-northwesterly winds at 5-10 mph.

Saturday

Mostly sunny in the morning. The sun will be dimmed by increasing high clouds in the afternoon.

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

West-northwesterly winds at 5-10 mph.

Saturday Night

Mostly cloudy and not quite as cold. There is the chance of a snow flurry or snow shower after midnight. Probability of precipitation 20%. No accumulation expected.

Low temperatures in the low teens.

Light northwest winds.

Sunday

Partly sunny in the morning, mostly cloudy in the afternoon. There is the chance of a snow shower or flurry, particularly late in the day. Probability of precipitation 30%. No accumulation expected.

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

Light northwesterly winds.

Sunday Night

There is a good chance that a period of light snow will develop during the evening. Probability of precipitation 50%. Any snowfall accumulations will most likely be a dusting to 1″.

Berkshire County Forecast-Thursday, Feb. 6

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

SummaryAfter yesterday’s storm our weather will be quiet for the next few days as the jet stream wave pattern flattens out and a sprawling surface high pressure system continues to build into and over the central and eastern U.S.. A weak disturbance in the jet stream flow will rotate through the region on Sunday. As a result, clouds will increase during the afternoon on Saturday and Saturday night and snow showers or some off and on light snow become likely after midnight on Saturday and during the day Sunday. It appears that any accumulations will be light, from a dusting to 2″ at most. The long-range models are now consistently indicating another coastal storm may bring us significant precipitation next Wednesday night and Thursday. The projected track of the storm suggests snow or snow changing to mixed frozen precipitation. However, it is too early to draw any conclusions.

Thursday Night

Mostly clear to partly cloudy and cold.

Low temperatures in the low to mid single digits.

Light westerly winds, 5-10 mph over the elevated terrain.

Friday

Mostly sunny and cold.

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

Westerly winds at 8-12 mph.

Friday Night

Mostly clear and cold.

Low temperatures in the low to mid single digits.

Westerly winds at 5-10 mph.

Saturday

Mostly sunny in the morning with increasing cloudiness in the afternoon.

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

Light northwesterly winds.

Saturday Night and Sunday

Increasing clouds Saturday night with a chance of snow showers after midnight. Probability of precipitation 40%. Overcast with snow showers or some off and on light snow likely on Sunday. Probability of precipitation 60%. Any accumulations should be light, a dusting to 1-2″. Low temperatures in the mid to upper teens and high temperatures in the low to mid 20s.

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SummaryThe forecast for tomorrow’s snowstorm is, once again, not significantly changed. The computer models have been very consistent from run to run as well as between models for the last few days so this is a fairly high confidence forecast. One “concern” that I have for the forecast is that the models are suggesting there will be very high snowfall rates tomorrow morning, on the order of 1-2″ per hour and that most of the accumulating snow will fall in a relatively short period, between about 4 or 5 am and noon. Two things; 1) If that scenario occurs travel will be extremely difficult tomorrow morning. 2) However, sometimes with a strong storm a “gravity wave” (not usually picked up by the computer models) develops, which may result in snow completely stopping for a few hours where the “downward” portion of the wave moves through. If this were to occur, since most of the snow is expected to fall during a short period, if the very high snowfall rates are not maintained anywhere in the county during that period, snowfall accumulation forecasts would be way too high. However, I think this scenario is not particularly likely since this type of wave “usually” forms with a low pressure system developing explosively just off the coast, which is not the expected scenario with this storm.

To summarize, the most likely timing of events looks like this: Snow will likely begin between 3 and 5 am. However, do not expect a gradual increase in snowfall intensity. Once the snow begins it should become fairly heavy relatively quickly. It should be snowing heavily during the morning commute with 2-4″ accumulation by 7 or 8 am. Snow should continue heavy at times throughout the morning with snowfall rates occasionally 1-2″ per hour. The majority of the snow accumulation with this storm will have occurred by noon, with 6-10″ of snow and 12″ over the elevated terrain to the east. Around midday, the center of the primary surface low pressure system will be just to our northwest. Drier and milder air wrapping counterclockwise around this low at 5-10 thousand foot elevation will briefly move over the county. As a result, the precipitation will lighten fairly abruptly and may even stop for a short time. As the milder air moves over the cold air at the surface the snow may mix with or change to sleet for a short time in South County. This is not likely to impact snowfall totals much since precipitation will be light at that time. At the same time, jet stream energy will be in the process of being transferred to a developing surface low south of Long Island. This will enable moisture to wrap back into the county so that snowfall will resume, at much lighter intensity, during the remainder of the afternoon and into the evening. An additional 1-3″ of snowfall is likely during this period (noon til 8 or 9 pm) before the snow ends during the evening. Total snowfall will likely be 8-12″ in most locations with more than a foot (12-15″) in a few locations in the elevated terrain to the east (e.g. Windsor, Peru, Savoy).

Tuesday Night

Increasing cloudiness this evening. Overcast after midnight with snow likely developing between 3 and 5 am, then snow, heavy at times until morning. Probability of precipitation 90%. Likely snowfall accumulation 2-4″ by 7 or 8 am.

Low temperatures in the mid to upper teens.

Calm winds, becoming east-northeasterly at 5-10 mph after midnight, increasing to 10-15 mph toward daybreak.

Wednesday

Snow, heavy at times during the morning, with snowfall rates occasionally 1-2″ per hour. Likely snowfall accumulations 6-10″ by noon, with 12″ in some spots in the higher terrain to the east. Precipitation will lighten or stop briefly around midday and may mix with or change to sleet for a time in South County. Light snow will resume during the early afternoon and continue into the evening. An additional accumulation of 1-3″ is likely during this time. Snow should end by 8 or 9 pm. Total accumulations 8-12″, with 12-15″ in some spots in the elevated terrain to the east (e.g. Windsor, Peru, Savoy).

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

East-northeasterly winds at 10-20 mph, shifting to northerly and decreasing to 5-10 mph during the afternoon.

Wednesday Night

Light snow ending during the evening, then remaining overcast, with partial clearing toward morning, and turning colder.

Low temperatures in the mid to upper single digits, low single digits over the elevated terrain.

Northerly winds at 5-10 mph, shifting to northwesterly after midnight.

Thursday

Partly cloudy and cold.

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

West-northwesterly winds at 5-10 mph.