Restarting Blog

Due to the impending storm, I have decided to restart posting to this blog today. There will be a post by around 3:00 today. As in the past, I will generally post every other day when the weather is relatively inactive, daily if there is active weather and updates over the course of the day as warranted if a storm is approaching or occurring.

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.

 

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

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.

Sunday, Feb. 2 Update

The latest model runs and what I see on radar suggest the northern edge of the precipitation shield tomorrow may be further north than I indicated. I have updated the snowfall totals as follows: 40% chance of snow in North County with a dusting possible, 50% chance in central Berkshire with a dusting to 1/2″ and, 70% chance of snow in South County with around 1″ accumulation.

I have decided to temporarily suspend posting any forecasts. I just to not have the couple of hours each day that it requires to make and compose an accurate (I hope….) forecast at the present time. Forecasts will definitely return in the autumn when the students in the Introduction to Meteorology course start forecasting as part of their lab work. If I free up some more time then I will start forecasting again before autumn but for now forecasts are on hold…..

Here are the snowfall totals for Berkshire County reported to the National Weather Service:

North Otis     22.0

Alford     20.0

Peru     18.7

Lenox     12.1

Lanesborough     11.0

Great Barrington     11.0

Housatonic     10.0

Pittsfield     10.0

Williamstown     10.0

We definitely escaped the worst of this storm. Snowfall totals in south-central and eastern New England ranged between 2 and 3 feet. Portland, ME has already broken its snowfall record with 29.3″ and it is still snowing heavily there. Thunder snow was reported at numerous locations in CT and central and eastern MA. Snowfall rates reached 5 inches per hour in some locations in CT where a band of incredibly heavy snow and thunder snow developed as the two jet stream disturbances merged and environmental instability and vertical velocities (upward motion in the atmosphere) exploded rapidly during the evening. Milford, CT along the southern coast of CT measured 38 inches and received 12.7 inches in a 3 hour period.

I will be submitting my next forecast tomorrow. For those of you who are new to this “blog”, apparently there are many, I started this website to give a platform to the student’s in my Introduction to Meteorology course to post forecasts (with my help) as part of lab work for that class. I teach this class each fall semester and the forecasts are posted on Monday, Wednesday and Friday afternoons. As a service to the Berkshire County community, I post forecasts, on average about 3 days a week, during the rest of the year. During the spring semester this year I am trying to post on Sundays, Tuesdays and Thursdays, giving forecasts that go out 2-3 days. If there is an important weather event, such as our recent snowstorm, I try to update the forecast at least once a day. I usually post the forecasts after 2 pm, when all of the computer forecast model data has come in. You will also notice that in the summary I frequently discuss the physical processes behind the weather as a teaching tool to my students (I am teaching an Extreme Weather class this spring) and as an educational tool for anyone who is interested.

In addition, you will notice that there are links to my class webpages and a link to a “weather links” page at the top of the forecast (blog home) page. Feel free to help yourself to any of this information.