5:40PM

Quiet & cold will be 2 words that aptly describe the weather  in southern New England for the week about to commence. A general west northwest flow will dominate around the base of a mean trough in eastern Canada. There is some Arctic cold up there in Canada. Though it does not look like we’re in for a direct blow, full-force, of this kind of air, there will be small pieces grabbed by passing disturbances and pulled into the region, resulting in the colder week overall. Peak cold shots should come at midweek and again reinforced over the weekend.

Forecast for southern NH, eastern MA, and RI…

TONIGHT: Mostly clear. Lows 15-20. Wind  NW 10-20 MPH gusting around 30 MPH.

MONDAY: Mostly sunny. Highs 30-35. Wind W 5-15 MPH.

MONDAY NIGHT – NEW YEAR’S EVE: Variably cloudy. Lows 25-30. Wind WSW 5-15 MPH.

TUESDAY – NEW YEAR’S DAY: Partly cloudy early then sunny. Highs 33-38. Wind W 10-20 MPH gusting around 25 MPH.

WEDNESDAY: Mostly sunny. Low 9. High 22.

THURSDAY: Mostly sunny. Low 8. High 26.

FRIDAY: Partly cloudy. Chance of snow showers at night. Low 18. High 34.

SATURDAY: Mostly sunny. Low 11. High 25.

SUNDAY: Mostly sunny. Low 12. High 32.

2:33AM

The series of storms that came through this week has, as expected, completed the transition from the mild pattern of December to what will be a colder, fairly dry pattern heading into the first month of 2013.

Quick review of the storm that just ended: A few surprises, especially the rain hanging tough at the coast and even getting inland a bit first over southeastern MA then even along the North Shore of MA for a while. Cold air made it back to Cape Cod before the North Shore, due to the orientation of the rapidly deepening low pressure area just off Cape Cod. Ocean water temperatures running 4 to 5 degrees above normal was the main reason for the rain/snow line being stubborn, but also the low pressure center itself was a touch further north than expected and this changed the positioning just enough to throw the forecast off in a very small area, but this had significant impact since the coast is a high population area. In most areas, amounts were generally what was expected. I am glad I did up the totals from my original estimates. Those were underdone in most locations. A bit of last minute forecasting is sometimes very necessary, especially with quickly changing conditions, i.e., a rapidly deepening storm.

Now, onto looking at the next several days. This update will go through Saturday. This evening a new blog will be posted that will look through next Sunday. It looks like a largely cold/dry pattern this week. Though the timing may change, look for weak systems to produce minor snow shower threats about Tuesday, Thursday, and Saturday.

Updated forecast for eastern MA, RI, and southern NH…

TODAY: Partly to mostly sunny. Highs 30-35. Wind NW 15-25 MPH with higher gusts. Blowing snow at times.

TONIGHT: Mostly clear. Lows 10-15 inland cold spots to lower 20s across coastal areas. Wind NW to W 5-15 MPH.

MONDAY: Sunny to partly cloudy. Highs 33-38. Wind W 5-15 MPH.

MONDAY NIGHT – NEW YEAR’S EVE: Mostly cloudy. Lows 23-28. Wind WSW 5-15 MPH.

TUESDAY – NEW YEAR’S DAY: Mostly cloudy to partly sunny. Chance of snow showers. Highs 33-38. Wind WSW 10-20 MPH.

WEDNESDAY: Mostly sunny. Low 14. High 27.

THURSDAY: Variably cloudy. Chance of snow showers. Low 16. High 30.

FRIDAY: Mostly sunny. Low 8. High 26.

SATURDAY: Partly sunny. Chance of snow showers. Low 10. High 30.

2:47PM

EDIT AT 6:00PM to remove THIS AFTERNOON and tweak final snow amounts…

Updated forecast for eastern MA, RI, and southern NH…

TONIGHT: Snow of varying intensity, heaviest in eastern MA and interior southeastern MA to northern RI. Rain/mix from just south of Boston along the coast through Plymouth  County and over the eastern half of Cape Cod with these areas eventually turning to snow. Snow tapering off west to east after midnight. Revised total snowfall now that we can see the coastal front and precipitation banding setting up around the intensifying low pressure area…3-6 inches north central MA to south central NH, 4-8 inches much of eastern MA except a few locally higher amounts of 9 or 10 inches in interior southeastern MA higher elevations into northern RI, then down to a 2-4 inch band in areas that have seen rain or mix (maybe toward the lower end of this in areas that are last to turn back to snow), even lower with 1-2 inches outer Cape Cod and Islands. Lows around 30 Cape Cod and South Coast, 20s elsewhere. Wind NE to N increasing to 10-20 MPH inland and 20-30 MPH coast with higher gusts. Visibility may be very limited at times from blowing snow.

SUNDAY: Clearing west to east. Highs 30-35. Wind NW 10-20 MPH with higher gusts.

SUNDAY NIGHT: Clear. Lows 10-15 inland valleys to 20-25 along the coast. Wind NW diminishing to 5-15 MPH.

MONDAY – NEW YEAR’S EVE: Mostly sunny. Highs 35-40. Wind variable 5-10 MPH. First Night Forecast – Clouds move in, temperature cools toward 30, light wind.

TUESDAY – NEW YEAR’S DAY: Mostly cloudy. Chance of a few rain or snow showers PM. Low 30. High 42.

WEDNESDAY: Mostly sunny. Low 22. High 34.

THURSDAY: Variably cloudy. Chance of snow showers. Low 22. High 32.

FRIDAY: Mostly sunny and windy. Low 10. High 25.

3:06AM

The last 3 days of 2012 will feature a variety of winter weather from snow/mix today to a windy and cold Sunday to a chilly & breezy New Year’s Eve. The details of these days…

Today: Low pressure will rapidly develop and intensify while passing southeast of New England. Snow will break out except mix/rain over Cape Cod and possible mix along the New England South Coast and immediate South Shore of MA due to milder ocean water. The mix/rain areas will see snow later at night as cold air finally takes over. Factors that favor snow accumulation include the rapid deepening of the storm and a potential coastal front setting up over southeastern MA (it often snows heavy in an area just west of one of these features as milder ocean air rides up over very cold air just to the west of the boundary). Factors that limit snow accumulation include the track of the storm being south of the “benchmark” for big storms of 40N latitude & 70W longitude, and the very rapid movement of the developing low, pulling precipitation out of the region rather quickly late Saturday night. So I will up the amounts slightly from the previous forecast but remain somewhat conservative just the same.

Sunday: All of the precipitation will be offshore and moving away, but the explosive deepening of the storm as it moves through Nova Scotia Canada on its way toward the North Atlantic will result in a gusty wind as high pressure also tries to build in from the west.

Monday: Fair and chilly weather will dominate as high pressure slides to the south of New England but a gusty breeze will keep up as well.  Some clouds may  move in at night but no precipitation is expected for  First Night and the air will not be all that cold.

Looking ahead to the first few days of 2012…

Tuesday: An approaching cold front will bring lots of clouds and milder air with a few rain or snow showers possible for the first day of the new year.

Wednesday: Dry & chilly as high pressure dominates.

Thursday: A small low pressure system from south central Canada crosses the Great Lakes then pushes across New England. With colder air in place, snow showers will be possible.

Friday: Shot of arctic air with a bright, windy, and very cold day expected.

Updated forecast for eastern MA, southern NH, and RI…

TODAY: Overcast. Snow developing southwest to northeast midday through afternoon, but mixed rain/snow South Coast and immediate South Shore and rain or mix Cape Cod. Highs from the upper 20s southern NH to the upper 30s along the South Coast and Cape. Wind NE 10-15 MPH.

TONIGHT: Cloudy. Snow except mix/rain changing to snow in southeastern coastal areas and over Cape cod, all tapering off west to east by dawn. Snow accumulation ranging from 2-4 inches over far northern MA and southern NH to 4-6 inches over the remainder of MA southward into northern RI except 1-4 inches due to mixing along the South Coast, immediate South Shore, and Cape Cod. Isolated amounts of 7 or 8 inches can occur in higher elevations away from the coast southwest and south of Boston.

SUNDAY: Clearing. Highs 30-35. Wind NW 10-20 MPH with higher gusts.

SUNDAY NIGHT: Clear. Lows 10-15 inland valleys to 20-25 along the coast. Wind NW diminishing to 5-15 MPH.

MONDAY – NEW YEAR’S EVE: Mostly sunny. Highs 35-40. Wind variable 5-10 MPH. First Night Forecast – Clouds move in, temperature cools toward 30, light wind.

TUESDAY – NEW YEAR’S DAY: Mostly cloudy. Chance of a few rain or snow showers PM. Low 30. High 42.

WEDNESDAY: Mostly sunny. Low 22. High 34.

THURSDAY: Variably cloudy. Chance of snow showers. Low 22. High 32.

FRIDAY: Mostly sunny and windy. Low 10. High 25.

10:49PM

The complex storm is about history. We all know how it went with the big snow in the mountains and significant snow inland southern New England with mostly rain coast. Though some areas that missed out on the main snow were coated with snow from back-lash snow showers during Thursday evening. In the next several days, we’ll deal with cold weather and a snow threat. Friday will be a bright, windy, chilly day. Low pressure moving out of the eastern Ohio Valley will redevelop off the Middle Atlantic Coast Saturday and track northeastward, close enough to throw some snow at southern New England but probably too far out to result in a big storm. This will be due to a very progressive system not really getting fully organized until it’s beyond the region. The window of opportunity for snow will be over about a 12 hour period from noon Saturday to midnight Saturday night/Sunday morning. What this low pressure area will do is help to drag down more cold air for Sunday as the pattern changes to a cold/dry one, as has been expected to take place for some time. A couple shots of Arctic air will welcome the New Year next week.

Updated forecast for eastern MA, RI, and southern NH…

OVERNIGHT: Partly cloudy. Isolated snow showers lingering. Icy areas on untreated surfaces. Lows from the lower 20s southern NH to upper 20s Boston to Cape Cod. Wind NW 10-20 MPH.

FRIDAY: Mostly sunny. Highs 32-37. Wind NW 15-25 MPH.

FRIDAY NIGHT: Increasing clouds. Lows 20-25. Wind N 5-15 MPH.

SATURDAY: Cloudy. Snow developing midday and afternoon from southwest to northeast. Highs upper 20s to lower 30s from north to south.  Wind NE 5-15 MPH.

SATURDAY NIGHT: Mostly cloudy. Snow tapering off from southwest to northeast by midnight. Snow accumulation of up to a few to several inches possible especially in eastern MA and RI. Lows 20-25.  Wind NW 5-15 MPH.

SUNDAY: Partly cloudy. Highs 30-35. Wind NW 15-25 MPH.

MONDAY – NEW YEAR’S EVE: Mostly sunny day. Variably cloudy with snow showers night. Low 18. High 33.

TUESDAY – NEW YEAR’S DAY: Mostly sunny. Low 13. High 27.

WEDNESDAY: Partly cloudy. Low 8. High 27.

THURSDAY: Mostly cloudy. Snow showers likely. Low 18. High 31.

11:43PM

Low pressure has redeveloped in the Mid Atlantic and will move northeastward across southeastern New England through Thursday. This will continue to throw a complex package of precipitation into southern New England with snow inland and rain at the coast, a wavering rain/snow line with some sleet, which will eventually push further northwestward during the early hours of Thursday. Precipitation will taper off during the day Thursday as the low pressure area moves just northeast of the region.

Here are the major factors with the storm…

Wind: From the east 25-35 MPH gusting 40-60 MPH along the coast especially south of Boston during the morning hours of Thursday. Minor wind damage possible.

Coastal flooding: Astronomical tides are not too high, but some minor flooding and splash over is possible during the mid to late morning Thursday.

Snowfall: Amounts are expected to range from nothing across southeastern MA and Cape Cod to slushy coatings to 1 inch or so from Boston north and west into the immediate suburbs, building up to a few inches in the 495 belt north of the Mass Pike, building further to 6-10 inches in higher elevations of north central MA into southern NH.

Behind the system as colder air starts to filter in, some snow showers may dust the ground in areas that did not see much during the storm.

Looking ahead… A chilly/drier day Friday behind the storm. Another low pressure area moves off the Mid Atlantic Coast Saturday and it will be cold enough to snow in all areas here, but the track of the storm may be too far south and east of New England to produce much in the way of significant snow. Another chilly day Sunday as dry weather returns.

Peaking at the end of 2012 and the start of 2013: Arctic cold front will bring the coldest air of the early winter so far, probably around Tuesday which is the 1st day of January. This will be the beginning of a chilly/dry pattern which is expected to dominate the first month of the New Year.

Forecast for eastern MA, southern NH, RI…

OVERNIGHT: Rain Cape Cod, SE MA, coastal MA, mix just inland eastern MA, RI, NH Sea Coast, snow further inland (see accumulations above). Rain/snow line pushing further northwest toward dawn. Lows from near 30 far NW of Boston to near 40 Cape Cod area. Wind E increasing to 20-30 MPH with gusts 40-60 MPH coastal areas especially south of Boston, NE-N 10-20 MPH elsewhere.

THURSDAY: Overcast. Lighter precipitation mainly rain/drizzle except mix far northwest, tapering and becoming intermittent in the afternoon. Highs from 35 far NW to 45-50 Cape Cod. Wind variable from SE to S then W 10-20 MPH over SE MA and RI, variable to N and eventually NW at similar speeds elsewhere.

THURSDAY NIGHT: Variably cloudy with scattered rain/snow showers becoming all snow showers with a few scattered dustings. Lows 25-30. Wind NW 10-15 MPH gusting over 20 MPH.

FRIDAY: Mostly sunny. Highs 32-37. Wind NW 10-20 MPH.

SATURDAY: Mostly cloudy. PM snow or snow showers. Low 18. High 30.

SUNDAY: Partly sunny and windy. Low 18. High 30.

MONDAY – NEW YEAR’S EVE: Partly cloudy. Snow showers late. Low 21. High 34.

TUESDAY – NEW YEAR’S DAY: Mostly sunny. Low 8. High 18.

WEDNESDAY: Mostly sunny. Low 5. High 24.

2:02AM

A strong storm will track up the East Coast today through Thursday with the center likely passing close to Cape Cod MA early Thursday. This storm will be progressive and move away quickly later Thursday, but during its passage it will produce a variety of precipitation along with some strong wind. Cold air in place to start with will allow for snow to occur in much of the region at the onset (though milder ocean area will have already made it warm enough for mix/rain along the South Coast and Cape Cod). How quickly the snow comes in will determine how fast it can accumulate before milder air from the ocean changes it to mix and then rain along the East Coast then pushing inland possibly as far as the 495 belt, even north of the Mass Pike. There will likely be a very sharp gradient in this region from very little snow to a rapid buildup to significant accumulation. It all winds down Thursday, though some of the heaviest precipitation may be around during the morning commute (rain coast and some distance inland, mix/snow far inland). Strongest winds from the east may also occur early Thursday morning with some coastal flooding and minor wind damage possible. Everything winds down later Thursday. Friday is a quieter and colder day behind the storm, setting the stage for a weekend snow threat as another low pressure area moves up and off the East Coast. Early indications are that this low will be further south and east and may take its heavier precipitation offshore with it, but it’s far enough way that confidence is low and this system needs to be watched.

Updated forecast for eastern MA, RI, and southern NH…

TODAY: Sunshine gives way to clouds. Snow possible by late afternoon south and west of Boston except mix South Coast. Highs 33-38. Wind NE 5-15 MPH.

WEDNESDAY NIGHT: Overcast. Snow developing all areas except mix to rain south of Boston eventually working north and northwest into the 95 belt. Up to a few inches of snow possible before the change over, especially north and west of Boston. Several inches of snow may accumulate in the 495 belt north of the Mass Pike. Lows 28-33 early then rising slowly. Wind NE-E 10-20 MPH gusting to 30 MPH in some eastern coastal areas.

THURSDAY: Cloudy with rain except some mix still possible in interior southern NH and north central MA, tapering off later in the day. Highs 35-45 from northwest to southeast. Wind E 20-30 MPH with higher gusts, shifting to N.

FRIDAY: Partly cloudy. Low 26. High 38.

SATURDAY: Mostly cloudy. PM snow. Low 22. High 31.

SUNDAY: Mostly cloudy. AM snow. Low 25. High 30.

MONDAY: Mostly sunny. Low 16. High 30.

12:05PM

The small snow (mix/rain for some) event is about over. A touch less snow fell than expected as the energy split in 2 and one area went rapidly eastward across far southern New England overnight and a second area went north of southern New England during the morning. But some snow did fall, and much of central and northern MA, some areas to the south, and also southern NH did see at least a heavy dusting of snow.

Looking ahead, still seeing 2 storms coming along during the remainder of this week. Wednesday/Thursday: Track of low should be near Cape Cod with snow/mix to start in most areas, some accumulation, then warm air taking over with a switch to rain in the Route 95 belt with a mix further west and north. Saturday/Sunday: Jury’s out still but colder air in place should support snow. Track of low is a question. It may be a little further south and east which would mean lighter snow but at least some chance this one tracks close enough to drop significant snow on parts of southern New England. Stay tuned…

Updated forecast for eastern MA, southern NH, and RI…

THIS AFTERNOON: Mostly cloudy but a few breaks of sun possible. Highs 35-40. Wind N under 10 MPH.

TONIGHT: Partly cloudy. Lows 25-30. Wind N under 10 MPH.

WEDNESDAY: Mostly cloudy. Snow possible by late afternoon south and west of Boston except mix  South Coast. Highs 33-38. Wind NE 5-15 MPH.

WEDNESDAY NIGHT: Overcast. Snow developing all areas except mix to rain south of Boston eventually working north and northwest into the 95 belt. Up to a few inches of snow possible before the change over, especially north and west of Boston. Several inches of snow may accumulate in the 495 belt north of the Mass Pike. Lows 28-33 early then rising slowly. Wind NE-E 10-20 MPH gusting to 30 MPH in some eastern coastal areas.

THURSDAY: Cloudy with rain except some mix still possible in interior southern NH and north central MA, tapering off later in the day. Highs 35-45 from northwest to southeast. Wind E 10-20 MPH with higher gusts, shifting to N.

FRIDAY: Partly cloudy. Low 26. High 38.

SATURDAY: Mostly cloudy. PM snow. Low 22. High 31.

SUNDAY: Mostly cloudy. AM snow. Low 25. High 30.

MONDAY: Mostly sunny. Low 16. High 30.

8:48AM

My focus on this entry and forecast is for the first of 3 likely events upcoming, the first being the Christmas snow/mix event, the second being the post-Christmas or midweek storm, the third being a storm threat on the weekend.

Cold air is in place. It may not be frigid, but it’s cold enough to support snow in most of southern New England when a low pressure wave comes along from the southwest later tonight and Christmas Day. It will be a progressive low pressure wave, moving right along, but will produce enough precipitation to put down anywhere from a coating to 2 inches of snow and locally up to 3 inches in a few areas. Enough mild air will be involved to change snow to sleet/freezing rain (cold air still trapped near surface) over interior southeastern MA and parts of RI, and possibly a period of liquid rain along the South Coast and Cape Cod, so any accumulation there may be very limited.

Hardly a break early Wednesday before a stronger low pressure area roars up the East Coast Wednesday night and Thursday. This should start as snow for much of southern New England except a mix/rain South Coast, but this time the track of the storm looks closer, and that combined with a stronger east wind and milder air aloft will change any snow/mix to rain over the region. Some accumulation of snow is possible before the rain, however, and I’ll put some #’s on this as it gets just a touch closer.

Another break later Thursday and Friday as cold air comes back, setting the stage for another storm threat on the weekend. Timing is suspect, but an early leaning is more for late Saturday or Sunday, and with colder air in place the odds favor snow. I also have a slight leaning toward this one being a little further south and therefor being a less prolific precipitation producer. But again this is far away and there will be many details to work out.

In the mean time, the forecast for eastern MA, southern NH, and RI…

TODAY: Sunshine, some high clouds moving in late. Highs 35-40. Wind N up to 10 MPH.

TONIGHT – CHRISTMAS EVE: Clouding up. Snow developing from southwest to northeast, mainly after midnight, mixing with sleet/rain/freezing rain near the South Coast. Lows 25-30. Wind light NE.

TUESDAY – CHRISTMAS DAY: Cloudy with snow except freezing rain/sleet/rain RI, SE MA, and Cape Cod, in the morning. Clearing in the afternoon. Snow accumulation from a coating to 2 inches but a 3 inch snow amount possible in a few locations. Highs 33-38. Wind N to NW 5-15 MPH.

WEDNESDAY: Sun then clouds. Snow to rain overnight. Low 23. High 38.

THURSDAY: Cloudy with rain morning. Breaking clouds afternoon. Low 32. High 41.

FRIDAY: Mostly sunny. Low 22. High 33.

SATURDAY: Partly sunny. Low 17. High 33.

SUNDAY: Cloudy. Chance of snow. Low 20. High 30.

1:01PM

A big storm pulling away but large in size will be responsible for a variably cloudy & windy Saturday and as high pressure tries to build in Sunday there will be more sunshine, but wind will still be a factor due to the contrast between the departing low and the arriving high. This weekend will also be on the chilly side, feeling more like December. This chilly air will set the stage for what may be a white Christmas for southern New England. Cold high pressure will hold on Monday, Christmas Eve Day, with plenty of sun and cold air. Low pressure moving out of the Ohio Valley is expected to take a track just south of New England Tuesday, Christmas Day, producing a swath of snow across southern New England. There may be some rain involved along the South Coast and Cape Cod due to mild ocean temperatures. This will not be a big storm but does have the potential to put down up to a few inches of snow in some locations. Looking ahead a little, there is still the potential for a larger storm of some sort at midweek next week. The track is still uncertain, so details will be left out for now.

Updated forecast for eastern MA, southern NH, and RI…

THIS AFTERNOON: Mostly cloudy. Isolated rain and snow showers. Highs around 40. Wind W 15-25 MPH gusting over 30 MPH.

TONIGHT: Partly cloudy. Lows in the 20s. Wind WNW 10-20 MPH with higher gusts.

SUNDAY: Mostly sunny. Highs in the 30s. Wind NW 15-25 MPH with higher gusts.

SUNDAY NIGHT: Clear. Lows from the middle 10s inland valleys to middle 20s coastal and urban areas. Wind N 5-15 MPH.

MONDAY: Mostly sunny. Highs 35-40. Wind N 5-10 MPH.

MONDAY NIGHT – CHRISTMAS EVE: Increasing clouds. Snow developing. Lows 22-27. Wind NE 5-10 MPH.

TUESDAY – CHRISTMAS DAY:  Cloudy. Snow, except rain or snow South Coast & Cape Cod, ending in the afternoon. Snow accumulation up to a few inches possible. Highs in the 30s. Wind NE 10-15 MPH.

WEDNESDAY: Mostly cloudy. PM snow or rain. Low 25. High 35.

THURSDAY: Cloudy. Snow or rain. Low 32. High 40.

FRIDAY: Clearing and windy. Low 28. High 38.

8:37AM

A bit more spring-feeling today, even though the Winter Solstice occurred at 6:12AM. This will be due to a strong low pressure area winding up and passing well northwest of our region into Canada. A swath of rain, some heavy, will cross southern New England today. The heaviest band of rain is expected to move southwest to northeast across the forecast area between noon and 3PM. Winds will be the bigger story as gusts of 45 to 55 MPH may occur with winds shifting from E and SE to S and SW during the day. A slot of drier and behind it may result in a few breaks of sunshine before it sets. Tonight, colder air will really start to flow in around the back side of the low pressure system, and the coming weekend will be a chilly one. A few snow and rain showers may occur Saturday as an upper level low pressure area is still spinning around the region. Sunday will be a brighter day.

The Christmas Eve & Christmas Day period will be on the cold side and dry at least to start. The weather for later at night on Christmas Eve and for Christmas Day hinges on the track of a wave of low pressure passing south of New England.  It may be close enough to throw a swath of snow at least in to RI and parts of eastern MA. Would that be enough for a “white Christmas” for some areas? Time will tell.

Looking ahead, another storm threat exists for the middle of next week, but computer models have been all over the place with the track, as is not only normal for something that far out in time, but also normal for a pattern that is transitioning, as this one is (from mild and slightly wetter to colder and somewhat drier).

Forecast for eastern MA, RI, and southern NH…

TODAY: Cloudy with rain through early afternoon including a band or 2 of heavier rain and possible thunder. Breaks in clouds mid to late afternoon may yield a bit of sun before sunset in some areas. Highs around 50. Winds E to SE 15-25 MPH shifting to S and SW, gusting as high as 45-55 MPH, relaxing a bit later in the day.

TONIGHT: Mostly cloudy with scattered rain showers early changing to snow showers late. Lows around 30. Wind SW 10-20 MPH with higher gusts, shifting to WNW.

SATURDAY: Mostly cloudy with scattered snow or rain showers. Highs 40-45. Wind W 5-15 MPH.

SATURDAY NIGHT: Partly cloudy. Lows 22-27. Wind NW 5-15 MPH.

SUNDAY: Mostly sunny. Highs 33-38. Wind NW 10-20 MPH.

MONDAY – CHRISTMAS EVE: Mostly sunny day. Clouds move in with a chance of light snow late at night. Low 18. High 34.

TUESDAY – CHRISTMAS DAY: Mostly cloudy. Chance of light snow in the morning. Low 21. High 35.

WEDNESDAY: Sunshine then clouds. Low 17. High 35.

THURSDAY: Chance of snow or rain. Low 30. High 40.

8:37PM

The transitional pattern continues…

Short term: Low pressure offshore to the east of southern New England has taken its time getting out of here, and one lobe of moisture may bring some rain showers to the South Shore of MA and parts of Cape Cod tonight.

Thursday & Friday split pair: Narrow high pressure will bring a slice of nice weather Thursday, though a bit cool. Low pressure will track northeastward from the Midwest into NY then down the St. Lawrence Valley Friday, redeveloping Friday night just east of New England. Ahead of the initial storm will come a period of rain which may be mixed with snow in some interior areas as cold air hangs on in the early stages of the storm Friday morning. By Friday noontime the warm sector will have enveloped all of southern New England. During this time a period of strong southeast to south winds will take place with the potential for some wind damage. As a cold front charges eastward across southern New England on Friday afternoon, a band of heavier rain and possible thunderstorms will take place, and may result in some additional wind damage and local flooding. Once this is by, a rush of drier and colder air will come in from the west Friday night.

Weekend: This colder air will make it possible for some wrap around moisture to produce snow showers Saturday. Weak high pressure should bring dry conditions and chilly air to the region on Sunday.

Christmas Eve & Christmas Day: It is far away, but the previous dry/cold outlook has to be replaced with a threat of a period of snow as a wave of low pressure passing just to the south of the region may be enough to throw some moisture into some cold air in place for a period of snow in some areas. Will this be enough for a white Christmas (defined as 1 inch or more of snow on the ground)? We’ll see.

In the mean time, the updated forecast for eastern MA, southern NH, and RI…

TONIGHT: Variably cloudy. A few rain showers along the South Shore of MA and over Cape Cod early. Lows 35-40. Wind W 5-15 MPH.

THURSDAY: Mostly sunny. Highs around 40. Wind W 5-15 MPH, diminishing.

THURSDAY NIGHT: Clouding over. Light rain and snow possible before dawn. Lows 30-35. Wind light variable to E.

FRIDAY: Mostly cloudy. A touch of light rain/snow early, a few rain showers later morning-midday, then a band of rain and possible thunderstorms pushing west to east through the region in the afternoon. Highs from the middle 40s well to the northwest to the middle 50s over Cape Cod. Wind E 10-20 MPH with higher gusts, shifting to south and increasing to 15-35 MPH with gusts over 40 MPH especially late morning through early afternoon, then shifting to SW 10-20 MPH in the afternoon, then W 15-25 MPH by sunset.

SATURDAY: Mostly cloudy with rain and snow showers. Low 30. High 40.

SUNDAY: Mostly sunny. Low 22. High 36.

MONDAY – CHRISTMAS EVE: Partly sunny. Chance of snow at night. Low 18. High 34.

TUESDAY – CHRISTMAS DAY: Mostly cloudy. Chance of snow in the morning. Low 20. High 33.

WEDNESDAY: Cloudy. Chance of snow or rain. Low 27. High 37.

10:34PM

The transitional pattern will continue for the next 7 days, through Christmas Day. Computer model solutions will likely be somewhat unstable during this time. My best guess at the pattern is that we will see drier and cooler air move in through early Thursday. Another low pressure area will traverse the region Thursday night and Friday. Some of the chilly air may be hard to scour out and make precipitation type issues for the forecast. Right now the thinking is that we may see some areas, especially north and west of Boston, start out as some snow late Thursday night into Friday before the warm sector blasts into the region and everyone ends up mild and wet. But as the low pressure area passes, colder air will wrap back in from the north and west. A race between the cold and the end of the precipitation makes it uncertain as to whether or not a period of snow will occur Friday night. Either way, we may see additional periods of snow on Saturday as an upper low pressure area comes across the region in a newly arrived cold air mass, with a surface low sitting just offshore. This should clear out on Sunday, and early next week (Christmas Eve & Christmas Day) should also be cold and mainly dry, though we will need to watch the orientation of the wind field as an ocean wind may set up and bring in ocean effect snow showers. There are many days to fine tune this.

Updated forecast for eastern MA, RI, and southern NH…

TONIGHT: Mostly cloudy. Scattered rain showers except rain or snow showers in areas well north and west of Boston. Lows 33-38. Wind W increasing to 10-15 MPH.

WEDNESDAY: Partly to mostly sunny. Isolated rain or snow showers. Highs 40-45. Wind NW 10-20 MPH with gusts around 25 MPH.

WEDNESDAY NIGHT: Mostly clear. Lows from the upper 10s inland valleys to middle 20s coast. Wind NW to N decreasing to around 10 MPH.

THURSDAY: Sunny. Highs around 40. Wind light variable.

FRIDAY: Cloudy with mix to rain morning. Mostly cloudy with rain showers afternoon. Variably cloudy with rain showers changing to snow showers at night. Low 32. High 50.

SATURDAY: Cloudy. Periods of snow. Low 24. High 33.

SUNDAY: Partly sunny. Chance of light snow showers. Low 22. High 35.

MONDAY – CHRISTMAS EVE: Partly cloudy. Low 18. High 37.

TUESDAY – CHRISTMAS DAY: Partly sunny. Low 17. High 33.

10:44PM

A week of transition is underway from the mild pattern of December so far to a colder/dry pattern coming in the days ahead. This will take place with the passage of low pressure systems late Tuesday and late Thursday to early Friday. Both of these systems should be largely mild systems with rain for the forecast area. Looking ahead to the end of the week, it looks like it will be colder & mostly dry, but we may have to watch for a couple disturbances that may produce some snow showers.

Forecast for eastern MA, RI, and southern NH…

OVERNIGHT: Overcast. Areas of fog. Periods of rain and drizzle except some freezing rain and sleet in the 495 belt north of the Mass Pike up through southern NH. Lows 30-40 from north to south. Wind NE-E up to 10 MPH.

MONDAY: Overcast. Areas of fog. Periods of rain and drizzle. Highs 40-45. Wind E 5-15 MPH.

MONDAY NIGHT: Overcast. Periods of rain. Lows 35-40. Wind E 5-15 MPH.

TUESDAY: Overcast with periods of rain in the morning. Mostly cloudy with lingering rain showers in the afternoon. Highs 45-50. Wind SE 5-15 MPH in the morning shifting to W in the afternoon.

WEDNESDAY: Mostly cloudy and windy. Isolated rain and snow showers. Low 30. High 40.

THURSDAY: Mostly sunny. Low 25. High 42.

FRIDAY: AM cloudy with rain. PM variably cloudy with rain or snow showers. Low 35. High 43.

SATURDAY: Partly sunny. Low 25. High 38.

SUNDAY: Partly sunny. Low 20. High 36.

12:17PM

Short discussion now, full discussion next update…

The next several days will be a transition period between the mild pattern and the return to the pattern of November. It will feature the passage of 3 low pressure systems during the transition. None of these at the moment look like they have a great chance of putting down snow that will hang around for Christmas, but since that day itself is still 10 days away, we absolutely cannot discount the possibility of a White Christmas in southern New England, though I would say the percentage chance lies around that of climatology, at best.

Updated forecast for eastern MA, RI, and southern NH…

THIS AFTERNOON: Mostly sunny. Highs around 40. Wind N around 10 MPH.

TONIGHT: Increasing cloudiness. Lows in the 20s. Wind NE under 10 MPH.

SUNDAY:  Cloudy. Snow and sleet developing except some rain near the South Coast. Precipitation changing to rain from south to north late in the day and at night. Minor accumulation of up to 1 or 2 inches may occur especially higher elevations north of the Mass Pike. Highs 35-40. Wind NE to E 10-15 MPH.

MONDAY: Cloudy. Drizzle and patchy fog. Chance of light rain. Low 35. High 45.

TUESDAY: Cloudy. AM rain. PM rain showers. Low 40. High 49.

WEDNESDAY: Variably cloudy. Chance of snow showers. Low 30. High 40.

THURSDAY: Partly sunny. Low 25. High 43.

FRIDAY: Mostly cloudy with rain AM. Variably cloudy with snow showers PM. Temperatures falling from the 40s through the 30s.