Friday Forecast

7:32AM

DAYS 1-5 (DECEMBER 15-19)
Two pieces of energy try to phase up as low pressure develops off the Mid Atlantic Coast later today and passes southeast of New England tonight. This phasing takes place too late for a big storm but soon enough for a brief shot of snow this evening. The next system approaches late Sunday into Monday but looks fairly weak with a bit of light snow/mix Sunday night into Monday. A brief warm up follows this Tuesday but a cold front will already be charging toward the region. Forecast details…
TODAY: Increasing clouds. Highs 24-31. Wind light variable.
TONIGHT: Cloudy. A period of snow accumulating 1/2 to 2 1/2 inches along and southeast of a line from northeastern CT to Boston MA, and less than 1/2 inch elsewhere. Lows 17-24. Wind light variable.
SATURDAY: Clearing. Highs 28-35. Wind NW 10-20 MPH with higher gusts.
SATURDAY NIGHT: Clear. Lows 16-23. Wind NW 10-20 MPH, diminishing late.
SUNDAY: Increasing clouds. Chance of light snow at night. Highs 30-37. Wind light variable.
MONDAY: Mostly cloudy. Chance of light snow/mix mainly early. Temperatures steady in the 30s.
TUESDAY: Variably cloudy. Chance of late day rain showers. Lows in the 30s. Highs in the 40s.

DAYS 6-10 (DECEMBER 20-24)
A few snow showers possible December 20 otherwise fair and cold December 20-21. Unsettled weather possible in the December 22-24 period but the track of low pressure is highly uncertain this far in advance.

DAYS 11-15 (DECEMBER 25-29)
The region will likely be near the border between warmer weather in the southeastern US and very cold weather in Canada with a tendency for the cold to win out here. A few mix/snow events are possible with fast-moving weather systems.

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Thursday Forecast

7:35AM

DAYS 1-5 (DECEMBER 14-18)
The “South Coast Special” snow event will wind down soon and the dry/cold will return to the region for the balance of the day. Another system makes a quiet run at the region late Friday but stays in 2 pieces instead of merging. This limits the impact to just a little light snow or flurries Friday night. A similar disjointed system passes through Monday after fair weather weekend.
Detailed forecast…
TODAY: Mainly cloudy with lingering snow South Coast through Cape Cod early then clearing. Highs 26-33. Wind W 5-15 MPH with higher gusts.
TONIGHT: Clear. Lows 12-19. Wind NW 5-15 MPH.
FRIDAY: Increasing clouds. A period of snow possible at night. Highs 26-33. Wind light N to NE.
SATURDAY: Partly cloudy. Lows from the upper 10s to middle 20s. Highs in the 30s.
SUNDAY: Mostly sunny then increasing clouds late. Lows in the 20s. Highs from the upper 30s to lower 40s.
MONDAY: Mostly cloudy with a little light snow/mix possible. Lows from the lower to middle 30s. Highs from the upper 30s to lower 40s.

DAYS 6-10 (DECEMBER 19-23)
Near the borderline of a warmer air mass to the south and very cold air in Canada starting out with fair weather but turning unsettled later in the period.

DAYS 11-15 (DECEMBER 24-28)
Again near the borderline of mild to the south and much colder to the north. Uncertain on precipitation events at this time.

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Wednesday Forecast

1:53AM

DAYS 1-5 (DECEMBER 13-17)
And now that we are beyond that December 10 marker and the pattern has had a chance to readjust, the cold has arrived. This cold pattern will be good for this 5 day period with the coldest days being the first 3, today through Friday, and slow moderation over the weekend. Behind our departed low pressure area of yesterday comes a fast-moving clipper system which now appears it will be far enough north to bring a light snowfall to southern areas in the early hours of Thursday. A second system will make a run at the region Friday night with a shot at snow, again favoring southern areas, departing Saturday at which time high pressure will build in for the balance of the weekend. We still have to keep an eye on the late Friday system as it still has the potential to grab extra moisture and throw it at us here. Detailed forecast…
TODAY: Partly cloudy. Isolated snow showers possible. Highs 24-31. Wind W 15-25 MPH gusting 30-45 MPH at times. Wind chill below 20 at times.
TONIGHT: Increasing clouds. A period of snow especially near and south of I-90 overnight with a coating to 1 inch possible in these areas and just a little very light snow with no accumulation to the north. Lows 17-23. Wind W 10-20 MPH gusting 25-35 MPH, diminishing overnight.
THURSDAY: Mainly cloudy with lingering snow possible Cape Cod early then clearing. Highs 26-33. Wind W 5-15 MPH with higher gusts.
THURSDAY NIGHT: Clear. Lows 12-19. Wind NW 5-15 MPH.
FRIDAY: Increasing clouds. A period of snow possible at night. Highs 26-33. Wind light N to NE.
SATURDAY: Partly cloudy. Slight chance of snow showers. Lows from the upper 10s to middle 20s. Highs in the 30s.
SUNDAY: Mostly sunny then increasing clouds late. Lows in the 20s. Highs from the upper 30s to lower 40s.

DAYS 6-10 (DECEMBER 18-22)
Briefly milder to start the period then a weak system comes through with a minor precipitation event and colder air then returns. There may be a clipper system around December 21 or 22 with a snow threat but not confident of this at this time.

DAYS 11-15 (DECEMBER 23-27)
The cold is likely to win out along with a couple snow/mix chances but far too early to really time or detail anything.

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Tuesday Forecast

7:31AM

DAYS 1-5 (DECEMBER 12-16)
Low pressure will move across south central New England today, with a track far enough north to allow mild enough air in for a mainly rain event in much of the forecast area with snow that accumulates confined to north central MA and southwestern NH with a hint of accumulation slightly south and east of there. This will be the mildest day for a while as a very cold airmass awaits behind this system to move in for the middle of the week. This may be accompanied by some snow showers as temperatures fall and winds pick up on Wednesday. A wave of low pressure will rapidly move southeast then east, passing south of New England on Thursday. A little snow from this may skirt the South Coast but the bulk of the precipitation shield with the low will stay south of the region. Another disturbance will dive southeastward and ignite another storm on the boundary well to the south of New England by Friday and this new low may make a run far enough north to bring a snow shield into at least a portion of southern New England Friday night, moving out by Saturday. Confidence on this part of the forecast is low. Forecast details…
TODAY: Cloudy. Snow with up to an inch and locally 2 inches higher elevations north central MA and southwestern NH mixing with and changing to freezing rain then rain, snow with up to 1/2 inch before changing to rain with pockets of freezing rain briefly in the I-495 belt north of I-90, brief snow/mix to rain I-95 belt, rain elsewhere. Band of heaviest precipitation will be rain all areas first half of afternoon and may include thunder. Highs 35-42 north central MA and southern NH, 43-50 elsewhere with mildest in southeastern MA and RI. Wind SE 5-15 MPH, shifting to S late.
TONIGHT: Mostly cloudy with scattered rain showers evening. Variably cloudy with scattered snow showers overnight. Watch for patchy icy areas overnight. Lows 22-28. Wind SW 10-20 MPH evening, W 10-20 MPH with higher gusts overnight. Wind chill falling below 20 overnight.
WEDNESDAY: Partly sunny. Isolated snow showers. Temperatures steady 22-28. Wind W 10-20 MPH, higher gusts. Wind chill below 20.
WEDNESDAY NIGHT: Mostly clear. Lows 12-18. Wind W 5-15 MPH, higher gusts. Wind chill near to below 10 at times.
THURSDAY: Filtered sun and a period of heavier clouds and a slight chance of snow near the South Coast. Highs 22-28. Wind W 5-15 MPH.
FRIDAY: Increasing clouds. Chance of snow late-day or night. Lows from the middle 0s to lower 10s. Highs in the 20s.
SATURDAY: Clearing. Lows in the 20s. Highs in the 30s.

DAYS 6-10 (DECEMBER 17-21)
Colder than normal pattern with a risk of a couple passing systems in a general west northwest flow. Will fine-tune.

DAYS 11-15 (DECEMBER 22-26)
Brief moderation may occur but overall the same general pattern is expected.

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Monday Forecast

7:35AM

DAYS 1-5 (DECEMBER 11-15)
A disturbance exits the region this morning. A clipper system crosses the region Tuesday, too far north for all of the region to see snow but not far enough for all of the area to escape it, redeveloping over Maine then exiting via Canada. As it intensifies it will drag down the coldest air of the season for the middle of this week ahead of the next clipper system that brings a chance of snow Friday. Details…
TODAY: Mostly cloudy with passing snow showers possible early, then mostly sunny. Highs 33-40. Wind W 10-20 MPH.
TONIGHT: Clouding over. Precipitation arriving pre-dawn as snow or mix northwest of a Boston-Providence line, mix or rain to the southeast. Lows 28-35. Wind light SE.
TUESDAY: Cloudy morning with snow central MA into southern NH, rain southeastern MA and RI, snow to rain in between. Snow accumulation 1-3 inches outside of I-495 and north of I-90 but 3-6 inches higher elevations north central MA and southwestern NH, and less than an inch to the southeast. Mostly cloudy afternoon with a few rain showers possible. Highs 38-45. Wind variable 5-15 MPH, higher gusts.
WEDNESDAY: Partly cloudy. Windy. Temperatures fall to the 20s early then remain there.
THURSDAY: Sunshine then late clouds. Lows from the upper 0s to middle 10s. Highs in the 20s.
FRIDAY: Cloudy. Chance of snow. Lows in the 10s. Highs from the middle 20s to lower 30s.

DAYS 6-10 (DECEMBER 16-20)
The pattern will feature near to below normal temperatures in a general northwesterly flow with a series of clipper systems passing through. Current timing brings them through about December 17 and 20.

DAYS 11-15 (DECEMBER 21-25)
The pattern is expected to continue generally the same. There is a slight chance of brief temperature moderation at some point during this period but not enough evidence for me to be confident of it.

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Sunday Forecast

11:50AM

STORM SUMMARY
Just a quick look back on our first widespread snowfall of the 2017-2018 season. This was the first of what I believe will be several snow events from now until mid January during a pattern that is overall colder than normal, and a pattern in which we may get greater than half of our snow for the season. Right or wrong about the long range, this first system delivered nicely for most of the region, except for the expected areas discussed in yesterday’s forecast. My error was similar to many I have made in having difficulty forecasting the intensity of banding and therefore my top number of 6 should have been 7 or 8. But overall the storm did not throw any real surprises at us, and occurring on a weekend eliminated the issue of a “work day” commuting nightmare, at least for the vast majority of people. Here at the WHW headquarters, my final total was 6.6 inches.

DAYS 1-5 (DECEMBER 10-14)
We get a break today with the clouds having departed and sunshine dominant for the several short hours it is up at this time of the year. Tonight and early Monday, a disturbance will cross the region and may produce a few snow showers, and then along comes a fairly potent clipper system for Tuesday, the track of which will be extremely critical in determining where and how long an initial period of snow is. At the moment, anyone along and northwest of a Boston-to-Providence line can expect to see this start as snow as best I can tell. A rain/snow line will likely advance rapidly northwestward but just as that happens the precipitation may cut off, especially if the storm center is moving just north of the region (across northern New England) before it redevelops in the Gulf of Maine. So during the next day I will be trying to pinpoint this, as even a quick inch or two of snow can cause travel issues, and this is certainly possible somewhere early Tuesday. Regardless of how the details of that clipper system play out, what is much more certain is the arctic air mass that will arrive for the middle of the week. Along with wind, especially Wednesday, it’s going to have a bite to it. We’ll already be watching the approach of the next clipper system by late Thursday with clouds advancing into the region. On to the forecast details…
THIS AFTERNOON: Mostly sunny. Highs 35-42. Wind W 5-15 MPH.
TONIGHT: Variably cloudy. Scattered snow showers mainly after 10PM. Lows 24-31. Wind SW 5-15 MPH.
MONDAY: Mostly cloudy with passing snow showers possible early, then mostly sunny. Highs 33-40. Wind W 10-20 MPH.
MONDAY NIGHT: Clouding over. Precipitation arriving pre-dawn as snow or mix northwest of a Boston-Providence line, mix or rain to the southeast. Lows 28-35. Wind light SE.
TUESDAY: Cloudy morning with snow and a minor accumulation likely from eastern CT through central MA and southern NH except the coast, snow/mix/rain with minor snow accumulation possible NH coast down the I-495 and I-95 belts, and rain likely to the southeast. Variably cloudy afternoon with a few rain showers possible. Highs 38-45. Wind variable 5-15 MPH, higher gusts.
WEDNESDAY: Partly cloudy. Windy. Temperatures fall to the 20s early then remain there.
THURSDAY: Sunshine then late clouds. Lows from the upper 0s to middle 10s. Highs in the 20s.

DAYS 6-10 (DECEMBER 15-19)
The pattern will feature near to below normal temperatures in a general northwesterly flow with a series of clipper systems passing through. Current timing brings them through December 15 and December 17/18. The first one has a shot at producing widespread snow. Too early for details on the follow-up.

DAYS 11-15 (DECEMBER 20-24)
The pattern is expected to continue generally the same. There is a slight chance of brief temperature moderation at some point during this period but not enough evidence for me to be confident of it.

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Saturday Forecast

9:12AM

DAYS 1-5 (DECEMBER 9-13)
Here comes the first widespread snow event to include most of the region, and it will be the result of a wave of low pressure moving along a cold front offshore. This wave of low pressure is wave #2 of 2 that we’d been eyeing, with #1 having gone by overnight with a few raindrops reaching Nantucket during the night. But that rain is important. It tells us that it is warm enough for rain somewhere, and without a ton of cold air draining in it also tells us that it will remain warm enough for rain somewhere, so this does not become a measurable snow event for all. But we’ll get back to that in a moment. Just to go back briefly and touch upon why this and many forecasts leading to an event are not so clear cut. We’ve been eyeing a batch of energy diving out of Canada and into the upper Midwest and Great Lakes. The timing of this was key to whether or not one of these offshore waves would evolve more and come close enough to deliver precipitation to everyone. One theory for the difficulty in timing this a few days ago outside of normal model uncertainty is the fact that there is less data coming out of Alaska available for models, i.e., fewer upper air soundings. How much of a roll this may have played is not really known, but it will be interesting to see if similar situations occur going forward. Also, as a little fun fact, it seems that December 9 and 17 have become favorable dates for snow over the years. Looking back in history, and I won’t list a bunch of dates here at this point, there have been quite a few events of one type of another on these 2 dates. Today will be no exception. Once upon a time I thought today’s event would occur but would be placed far enough northwest for a lot of the region to have rain. This turned out to be a medium range forecasting error. So today we will once again attempt to foretell the future with minimal errors! Basically the forecast from my perspective is not really changed since yesterday so there is not much to say other than recapping we’ll have precipitation expanding across the region today, first with just spotty areas of very light snow except rain Cape Cod during this morning, becoming more steady from south to north later in the morning through midday and peaking during the afternoon and evening before ending west to east tonight. The rain/snow line will start out around Cape Cod and progress west northwest to at least to a Plymouth / New Bedford line. It will also bend up to include parts of Cape Ann where a northerly wind comes off a warmer ocean surface. It will likely expand to include most of the South Shore and possibly mix right up to near Boston. As everything winds down this rain/snow line will head back to the east. For road impact, look for moderate impact due to snow especially this afternoon into tonight where it is all snow, and less impact with mainly wet roads from the South Shore through Cape Cod. Overnight and early Sunday look for some icy areas on untreated surfaces. Looking ahead, a disturbance may produce a few snow showers Sunday and a lingering trough will keep some cloudiness around and maybe even a few additional flurries on Monday. The early call on the next system is a clipper that tracks over southern New England and redevelops to the east but too far north to give a significant snow event to the WHW forecast area. Still more details to iron out on this. Time for forecast details…
TODAY: Overcast. Spotty light snow except rain Cape Cod this morning. Steadier precipitation advancing northward late morning and midday mainly as snow except rain Cape Cod and a change from snow to rain into the South Shore towns of MA as well as Cape Ann MA. Highs 30-40, coldest in north central MA and southwestern NH and mildest South Shore to Cape Cod MA. Wind light N.
TONIGHT: Overcast evening with snow except rain South Shore to Cape Cod, then breaking clouds with snow tapering off west to east and rain changing to snow before ending South Shore to Cape Cod. Lows 25-32. Wind N to NW 5-15 MPH. Snow accumulation for this event: Under 1 inch Cape Cod, 1-3 inches Cape Ann and MA South Shore, 3-6 inches elsewhere.
SUNDAY: Variably cloudy. Scattered snow showers. Highs 32-39. Wind NW 10-20 MPH with higher gusts.
SUNDAY NIGHT: Partly cloudy. Lows 22-29. Wind NW 10-20 MPH with higher gusts, diminishing overnight.
MONDAY: Variably cloudy. Slight chance of snow showers. Highs 33-40. Wind W up to 10 MPH.
TUESDAY: Cloudy. AM snow to mix/rain. PM rain showers. Evening snow showers. Lows in the 20s. Highs from the upper 30s to lower 40s.
WEDNESDAY: Partly cloudy and windy. Lows in the 10s. Highs in the 20s.

DAYS 6-10 (DECEMBER 14-18)
Fair and very cold December 14. Next clipper brings a risk of snow or snow showers December 15. Fair but not as cold over the weekend of December 16-17 and then another clipper may follow that with a rain/snow risk. Timing obviously uncertain this far in advance.

DAYS 11-15 (DECEMBER 19-23)
Overall temperatures below normal with a couple opportunities for precipitation, favoring snow or snow showers, from passing clippers.

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Friday Forecast

7:27AM

DAYS 1-5 (DECEMBER 8-12)
A wave of low pressure will move up along a front offshore and will come close enough for the region’s first widespread snowfall of the season on Saturday and Saturday night. An upper level disturbance will bring additional snow showers during Sunday. The next storm threat is Tuesday but the track of this one remains uncertain. Detailed forecast…
TODAY: Sun and high clouds. Highs 38-45. Wind light SW.
TONIGHT: Clouding over. Lows 28-35. Wind light variable.
SATURDAY: Cloudy. Snow/rain developing in the afternoon, turning to snow most areas but remaining as mix/rain Cape Ann, immediate South Shore through Cape Cod. Highs 33-40. Wind light N.
SATURDAY NIGHT: Cloudy. Snow likely except mix/rain immediate coast especially outer Cape Ann and Cape Cod. Snow accumulations under 1 inch outer Cape Ann and Cape Cod, 1-3 inches South Shore and Logan Airport, 3-6 inches elsewhere. Lows 25-33. Wind N to NW 5-15 MPH.
SUNDAY: Partly sunny. Scattered snow showers. Highs 33-40. Wind NW 10-20 MPH with higher gusts.
MONDAY: Variably cloudy. Lows in the 20s. Highs in the 30s.
TUESDAY: Overcast. Chance of snow/mix/rain. Lows from the upper 20s to lower 30s. Highs from the middle to upper 30s.

DAYS 6-10 (DECEMBER 13-17)
Much colder early in the period, temperatures still below normal but not quite as cold later in the period. Best opportunity for additional snow is around December 15 probably from a clipper type system.

DAYS 11-15 (DECEMBER 18-22)
Still looking for the dominant trough, colder than normal temperatures, and a couple clipper systems.

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Thursday Forecast

7:38AM

DAYS 1-5 (DECEMBER 7-11)
I’ll keep it short and sweet today. We have high pressure in control today for a nice December day. A front sits offshore and will be the “train tracks” for a wave of low pressure that may bring a period of precipitation to southeastern areas Friday night. A second wave of low pressure is expected to pass by Saturday night. Then, an upper level energy will cross the region Sunday bringing a chance of snow showers. Weak elongated upper low pressure may hang in the region Monday with some clouds lingering. On to a detailed forecast…
TODAY: Sunny. Highs 42-48. Wind light SW.
TONIGHT: Clear. Lows 23-29. Wind light W.
FRIDAY: Increasing clouds. Highs 40-46. Wind light N.
FRIDAY NIGHT: Cloudy. A period of rain/mix/snow favoring RI and southeastern MA with some minor snow accumulation possible. Lows 30-36. Wind light N to NE.
SATURDAY: Mostly cloudy. Chance of light snow/mix/rain favoring eastern MA and RI early morning and again late-day and at night with additional minor accumulation of snow possible. Highs 36-42. Wind N 5-15 MPH.
SUNDAY: Variably cloudy. Scattered snow showers. Lows from the middle 20s to lower 30s. Highs from the middle to upper 30s.
MONDAY: Partly sunny. Lows from the middle to upper 20s. Highs from the middle to upper 30s.

DAYS 6-10 (DECEMBER 12-16)
Potential storm of snow/mix/rain December 12 followed by a blast of very cold air during the middle of next week. A weaker system may bring light snow around December 15-16 and a very slight moderation but still cold.

DAYS 11-15 (DECEMBER 17-21)
Trough resides in the northeastern US and a series of clipper type systems will deliver at least opportunities for precipitation and otherwise continue to reinforce cold air.

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Wednesday Forecast

8:00AM

DAYS 1-5 (DECEMBER 6-10)
Cold front pulls offshore today and a seasonable chill enters the region during the next 24 hours then hangs out through this weekend. Continuing to watch the “threats” for late Friday and late Saturday but both look stretched out and more offshore than over this area. Precipitation shield from the Friday night system has a better chance as it looks now of expanding westward enough to perhaps reach the Boston area, but either way, not expecting significant snow. An upper disturbance lagging it all on Sunday may bring some snow showers.
Detailed forecast…
TODAY: Early showers exit. Clouds followed by clearing. Temperatures fall slowly through the 40s. Wind W 10-20 MPH, higher gusts.
TONIGHT: Clear. Lows 22-28. Wind W 5-15 MPH, higher gusts. Wind chill below 20 at times.
THURSDAY: Sunny. Highs 38-45. Wind W 5-15 MPH, higher gusts, diminishing during the day.
THURSDAY NIGHT: Clear. Lows 18-26, coldest interior valleys. Wind light N.
FRIDAY: Increasing clouds. Chance of light rain/mix/snow late-day and night, favoring southeastern MA and RI. Highs 37-43. Wind light N to NE.
SATURDAY: Mostly cloudy. Risk of a period of rain/mix/snow favoring southeastern areas late. Lows from the upper 20s to lower 30s. Highs from the middle 30s to near 40.
SUNDAY: Partly sunny. Chance of snow showers. Lows in the 20s. Highs in the 30s.

DAYS 6-10 (DECEMBER 11-15)
Dry/chilly December 11. Still watching next storm threat for December 12-13 with mix/snow risk – too early for details. Drier or a few snow showers and much colder thereafter.

DAYS 11-15 (DECEMBER 16-20)
A cold pattern with a couple clipper type low pressure areas bringing snow or snow shower risks.

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