A Clipper And A Classic?

7:59PM

** EDITED FOR A SLIGHT DOWNGRADE TO SNOW AMOUNTS **

Firstly, let me answer the question posed in the blog title: Yes, and no.

Secondly, allow me to give my reasoning for both answers, leading to a First Night forecast, and my attempt to describe why the late-week snow event will not likely be a classic “northeaster”, as some like to call them, but in some ways may resemble one, for at least parts of the region: An Arctic cold front passed through the region during Monday, with less fanfare than might be expected from such a boundary. Nevertheless, it’s through, and the Arctic air may not be blasting in via the Montreal Express, but it is oozing into the region like a cloud of dry ice, and once it is in place, it will be hanging around for a while. The clipper system will be rather small and of light to moderate strength, as far as such systems go, and will track across central and northern New England Tuesday afternoon and evening. A northerly track of a system like this generally produces little in the way of precipitation (snow in this case) for southeastern New England, but some snow shower activity is expected, mainly along the leading edge of a boundary which will serve to reinforce the Arctic air as we count down the final hours of 2013. When we flip the calendar to 2014, it’ll be very cold but dry and with a gusty breeze, air temperatures in the teens and wind chill values being driven down toward zero at times. If you plan to be outside, please dress appropriately…

…As many people are sleeping off the results of their late-night on New Year’s Day (Wednesday), the cold will be firmly established, setting the stage for the next event. As is often the case, the various computer models offer a variety of solutions when trying to come up with how this event will unfold. The most in-common thing between them all is the cold remains in place, and snow falls in the region during a prolonged period that starts as early as Wednesday night (more likely early Thursday morning) and ends sometime Friday. The majority of the models depict a variation of my initial thoughts on this system, a stretched out area of low pressure, possibly with more than one center, tracking south of where most of your classic storms would track. One model has been a little more aggressive in predicting a stronger, dominant low, taking the classic track for a big time snowstorm. It must be noted that even though I am not on board with the classic set up, the model forecasting it has a decent track record and the solution cannot be completely ignored. I do feel that an outcome more like the other models is what eventually takes place. However, that does not mean that we hardly get any snow. This particular set up, with a strong Arctic high to the north, plenty of cold air, a boundary nearby, some instability at mid levels of the atmosphere lifting into the region, and a long fetch of east to northeast winds from the ocean between the low to the south and the high to the north, all combine to still produce significant snowfall amounts through most of the region (significant being 4 inches or more in a fairly widespread fashion). With the cold air dominating, snow to water ratios will be fairly high, so it will not take a lot of liquid equivalent precipitation to pile up a good amount of snow, which will be very low water content. A difference between this set up and one like we saw on December 17 will be that the accumulation with the upcoming event occurs over nearly 2 days’ time, versus the 3 to 4 hour week-before-Christmas rush-hour dumping of snow we saw on December 17. This will lessen the overall impact of the snow, though will not render it insignificant, so caution still must be practiced.

In case you had difficulty staying awake during the description above, allow me to summarize where we have gone so far, before we move on…

*Tuesday: Fairly weak clipper system, few snow showers for the early part of First Night activities, no significant accumulation, then clearing, windy, and very cold for the countdown to midnight.

*Longer-duration snow event begins overnight Wednesday night and lasts into early Friday.

*Snow amounts of at least 4 inches are very possible over most of the region, with an early call on highest amounts being in northeastern MA and southern NH (based on where I think a heavier snow band may set up from air lifting over a boundary), and along the eastern coast of MA (due to ocean-enhanced snowfall).

*Snow impact much less than December 17 because of the more drawn-out event and possibly lower amounts.

*I have not mentioned this yet, but may need to watch for minor coastal flooding at high tide times because of a long-fetch east to northeast wind.

After it’s done: Bitterly cold Arctic air pours into the region Friday afternoon and night with strong winds and very low wind chill values. Coldest air of the season so far lingers into Saturday. Temperatures moderate Sunday ahead of the next weather system, though timing of it is uncertain. For now will hold it off until Monday when there will be a chance of rain or snow.

Forecast for southeastern New England (southern NH, eastern MA, and RI)…

TONIGHT: Clouds hang on southeastern areas, then more arrive from the west by dawn. Lows 8-18, coldest interior valleys. Wind NW up to 10 MPH.

TUESDAY: Variably cloudy. Scattered snow showers mainly during the afternoon hours. Highs 22-30, coldest interior hills. Wind W 10-20 MPH.

TUESDAY NIGHT – NEW YEAR’S EVE: Variably cloudy with scattered snow showers early, but no significant snow accumulation, only brief dustings possible. Clearing later. Lows 10-18. Wind NW 10-20 MPH gusting 25-30 MPH. Wind chill frequently below 10.

WEDNESDAY –  NEW YEAR’S DAY: Bright sunny start, overcast grey sky conclusion. Highs 18-25. Wind W 10-15 MPH early, diminishing to near calm.

THURSDAY: Overcast. Periods of snow. Low 10. High 20.

FRIDAY: Cloudy with periods of snow into midday. Breaking clouds afternoon. Winds increase. Low 8. High 15.

SATURDAY: Mostly sunny. Low -4. High 18.

SUNDAY: Variably cloudy. Low 16. High 36.

MONDAY: Mostly cloudy. Chance of rain or snow. Low 32. High 40.

The Week Ahead

6:47PM

With the Sunday storm wrapping up , it’s time to look ahead to the coming week’s weather, but before we go there, just a few loose ends to tie up with the current storm…

*Low pressure crosses Cape Cod early tonight and accelerates away to the northeast.

*Precipitation ends from southwest to northeast across the region between 7:30PM and 10:00PM, as rain in most areas, but with a little icing ongoing in higher elevations of east central MA and interior NH and a flip to snow in these areas with up to a slushy inch of accumulation.

*Temperatures dropping below freezing interior MA, northern RI, and southern NH overnight. Wet areas that to not dry out from increasing wind will freeze, creating some walking and driving hazard for the early morning hours. Temperatures should remain above freezing along coastal areas and over most of southern RI and Cape Cod and the Islands.

Looking ahead…

Transition Monday: A couple cold fronts will move through the region, but with very little weather associated with them – just a few clouds. Temperatures will reach their highest points for the day before noon then drop off during the day.

Cold New Year’s Eve, few flakes?: A very weak disturbance will approach from the west into newly delivered but slightly modified arctic air on Tuesday, bringing clouds and some risk of snow showers. No significant accumulation will take place from this event, and many areas will see only clouds, but not any snow. For  First Night activities, expect it to be breezy and very cold with a temperature falling into the teens! Bundle up if you plan to be out there anywhere!

2014 starts with a snow threat and some very cold weather: What is known is that the Polar Vortex (large area of low pressure in the middle and upper atmosphere), often the core of the coldest air, will be wobbling around eastern Canada during the coming week. This will deliver some arctic air to the region for the first few days of the new year. What is less certain (still) is how an area of moisture and energy moving into the northeastern US will interact with this and impact the weather here. There have been all kinds of scenarios depicted on various runs of the computer guidance. The best idea I can come up with at this point is that we will not see one single powerful storm clobber the region with a big snowstorm, but rather a more strung-out area of energy and moisture, being stretched by strong westerly winds around the southern side of the Polar Vortex. Timing also remains uncertain, but for now I will go with the snow threat being in the Wednesday night and Friday morning time frame. It is too early to talk about potential amounts. I will monitor this and update as needed.

If the timing I expect does indeed work out, watch for another push of arctic air Friday into Saturday, with moderating temperatures by the end of next weekend.

Forecast for southeastern New England…

TONIGHT: Storm ends as rain most areas by 10PM but a period of snow higher elevations north central MA into interior southern NH with minor snow accumulation. Clearing later. Lows 25-35 from northwest to southeast across the region. Wind variable becoming mostly NW to W 10-20 MPH with higher gusts.

MONDAY: Mostly sunny. Highs from near 32 in the higher elevations northwest of Boston to near 40 Cape Cod by midday then falling back to the 20s in the afternoon. Wind W to NW 10-20 MPH with higher gusts.

MONDAY NIGHT:  Clear. Lows 10-20, least cold along the South Coast. Wind NNW 10-20 MPH.

TUESDAY: Increasing clouds. Chance of snow showers mainly midday and afternoon. No significant accumulation. Highs 20-27. Wind variable 5-15 MPH.

WEDNESDAY: Increasing clouds. Chance of snow at night. Low 10. High 19.

THURSDAY: Cloudy. Chance of snow. Low 10. High 18.

FRIDAY: Chance of snow early. Clearing. Low 8. High 16.

SATURDAY: Mostly sunny. Low 0. High 22.

SUNDAY: Partly sunny. Low 11. High 33.

Sunday Storm, Arctic Air Arrives After

10:43AM

A rather benign weather day today, probably welcomed by everybody, as temperatures go above freezing allowing more of the melt/refreeze ice to melt away and dry up. It’s not the brightest day as of the writing of this blog, as cloudiness formed by advancing warmer air aloft are blotting out the sun in much of southeastern New England, and will continue to do so through the middle of the day, before decreasing. Had we had the benefit of full sun today, the temperature may have gone into the 45-50 range, but the lack of sun and the still-short sunlight day means that a 40-45 range will be more accurate for most of the region (thought it is already 45 on Martha’s Vineyard as of 10AM).

Turning attention to Sunday’s storm, which will be a rainstorm for the WHW forecast area of southern NH, eastern MA, and RI, it will be the result of a low pressure area moving rapidly north northeastward from the Gulf of Mexico today to crossing southeastern MA by Sunday evening. In an already mild air mass, and with more mild air coming up with the storm, the only place that will be cold enough for snow during the heart of the storm will be the mountains of western and northern New England. As the low passes the region and starts to wrap some colder air in, a mix/change line will try to charge southeastward, but will probably be beaten by the end of the precipitation, which should clear the region by midnight, if not before. If it does snow in some of the higher elevations of southwestern NH and north central MA, accumulations would be minor. Other aspects of the storm: Rainfall totals of 1 to 1.5 inch, which will fall over a relatively short period of time, resulting in flooding of poor drainage areas; Wind gusts of 40-50 MPH on Cape Cod and the Islands from the SE in advance of the low center, with some minor damage and a few power outages possible.

Beyond the storm: Monday will be a transition day with mixed sun and clouds. Two fronts or boundaries will come through, one around midday to early afternoon, the other in the early evening, from northwest to southeast. This will send us down a proverbial flight of stairs into the deep freeze, which will settle in at night. At this time it looks like both boundaries will come through devoid of snow shower activity, but never completely count out a flurry or squall with the passage of such boundaries.

Arctic cold takes hold: Tuesday, the final day of 2013, and Wednesday-Friday, the first few days of 2014, will likely be dominated by Arctic air. That is the more certain part of the forecast. The less certain part is whether or not any snow will occur at some point during that time. To make a long story short, computer guidance will have trouble “figuring out” what to do with the boundary of the cold air and milder air to the south, and its interaction with pieces of energy moving along it, born of the remains of Pacific weather systems. Scenarios can range from dry weather to one or two near-misses, to a brushing or two with minor snow systems, to a major winter storm. It is just too early to be sure.

For you more model-savvy folks, it’s a well known fact that operational runs of computer guidance will often miss the details so far in advance, while ensemble runs of the same models will pick up on storm threats. Such is the case this time, where the ensembles have been hinting more loudly of a storm threat somewhere along the East Coast in the January 1-4 period, where some of the operational runs have shown nothing, or hinted at something only to take it away on successive runs. These operational models are now starting to hint more at “something happening”. And more detail will come as we get closer to the event. Even with this much known, there is nowhere near enough confidence to forecast a storm of any kind for this area. It’s better to just keep that part of things on the back burner for another day or so, until the energy responsible for the threat is in a place where models start to handle it a little more accurately. So instead of trying to make it seem like I have a confident clue of the outcome up here in southeastern New England, you’ll find a low confidence generic-worded forecast for January 1-3 at the end of this update…

Southeastern New England Forecast…

TODAY: Lots of clouds through early afternoon, increasing sun west to east thereafter. Highs 39-46. Wind SW 10-20 MPH.

TONIGHT: Mostly clear in the evening followed by increasing cloudiness later at night. Lows 25-32. Wind SW 5-15 MPH, diminishing.

SUNDAY: Thickening overcast morning. Rain develops rapidly from south to north during the first half of the afternoon and grows heavier during the second half of the afternoon. Heaviest rain early evening, including the chance of thunderstorms Cape Cod & Islands. Rain ending south to north by midnight, but may end as mix/snow in higher elevations of southwestern NH and north central MA where some minor accumulations are possible. Highs in the 40s, may break 50 Cape Cod & Islands, then falling back to the 30s at night. Wind E to SE 10-20 MPH, increasing to 20-30 MPH coastal areas and Cape Cod/Islands, shifting more to the S and SW there toward evening and variable over southeastern MA (where the low tracks), then backing to NE and eventually NW over most of the region, NW to W over the South Coast region. Top wind gusts may reach 30 MPH anywhere near the coast and in higher elevations, and 40-50 MPH Cape Cod & Islands, lighter elsewhere.

MONDAY: Variably cloudy. Lows in the 20s. Highs around 30 midday but dropping after.

TUESDAY: Partly cloudy. Highs in the 20s but falling through the 10s for New Year’s Eve. Gusty winds develop and create very cold wind chill values.

WEDNESDAY-FRIDAY: Periods of cloudiness and some threat of snow, timing uncertain. Very cold with lows commonly 0-10, highs 10-20, possibly a little higher South Coast.

Dry & Cool Today, Milder Weekend, Cold New Year

7:44AM

High pressure builds in today with bright and cool weather. Watch for black ice early in the day as partially melted snow from Thursday re-froze overnight.

Warm front brings some clouds and milder air in for Saturday, then Sunday turns overcast and ends wet as a low pressure area coming out of the Gulf of Mexico rides up the East Coast and brings a slug of rain to southeastern New England.  This system is likely to be rain instead of snow because of the lack of cold air in place and a low track very close to the coast (probably over southeastern MA) during Sunday night. We’ll have to watch the hills outside of I-495 for some mixing.

An arctic cold front will come through on Monday and bring some significant cold to the region for the final day of 2013 and the start of 2014. We’ll have to watch for a couple clipper systems that may threaten the region with a bit of snow from time to time during the first couple days of the New Year.

Forecast for southeastern New England (southern NH, eastern MA, and RI)…

TODAY: Mostly sunny. Areas of black ice early. Highs 33-40 from northwest to southeast. Wind NW 10-20 MPH.

TONIGHT: Mostly clear. Lows in the 20s, some 10s inland valleys. Wind light variable.

SATURDAY: Increasing clouds. Highs 35-40. Wind SE 5-15 MPH.

SATURDAY NIGHT: Mostly cloudy. Lows around 30-35. Wind SE-E 5-15 MPH.

SUNDAY: Overcast. Rain developing south to north in the afternoon, may mix with snow interior southern NH and north central MA, mainly higher elevations at night with a bit of a mix trying to expand eastward as rain ends overnight. Highs 38-45, mildest southeastern areas. Wind E to NE 10-20 MPH, gust over 30 MPH coastal areas and higher elevations.

MONDAY: Partly cloudy. Chance of snow showers late. Lows 20-25. Highs 30-35.

TUESDAY: Mostly sunny. Lows 10-18. Highs 20-28.

NEW YEAR’S EVE OUTLOOK: Increasing clouds. Lows 10-15.

WEDNESDAY – NEW YEAR’S DAY: Mostly cloudy early with a chance of snow, then clearing. Highs 15-20.

THURSDAY: Increasing clouds. Lows 5-13. Highs 18-25.

Winding Wind-Down

7:07PM

The final days of December, and of the year 2013, will feature some changing weather, but not likely any major storms, and some varying temperatures including some very cold air. As 2014 gets underway, we’ll have to watch for a little New Year’s Day snow.

Since there is some model uncertainty with the passage of storm systems, this forecast will be worded cautiously and simply, with low to moderate confidence, and will be fine-tuned over time.

Thursday, a weak area of low pressure will move in from the west and start to redevelop off the coast. Enough mild air should work in for mix to rain over the South Coast of MA and RI, Cape Cod, and the South Shore of MA. Elsewhere, some snow is expected, especially from late morning into late afternoon, with minor accumulations at best.

Friday will be governed by an area of high pressure that will bring dry and chilly weather.

Cloudiness is expected Saturday as warm air comes in at high levels and it also warms somewhat at the surface.

By Sunday, a low pressure area will track up along or just off the Northeast Coast, but with mild air in place, rain is more likely than snow. The timing of the precipitation will depend on the speed of the low pressure area. Not sure how this works out just yet.

The final 2 days of 2013 Monday-Tuesday look quite cold with a blast of Arctic Air. More details to come about the weather for New Year’s Eve, which looks quite cold.

The first day of 2014 looks like it may be a bit white as a clipper system brings a chance of snow.

Detailed forecast for southeastern New England (southern NH, eastern MA, and RI)…

TONIGHT: Mostly cloudy. Lows 10-18. Wind light variable.

THURSDAY: Partial sun eastern MA morning, otherwise mainly cloudy. A period of precipitation late morning through late afternoon, mainly snow NW of Boston, mix/rain to the southeast with greatest rain threat South Coast of MA/RI, Cape Cod, and South Shore of MA. Snow accumulation NW of Boston generally less than 1 inch but a few areas of 1-2 inches possible. Highs 30-35 NW of Boston, 35-40 elsewhere. Wind SE up to 10 MPH.

THURSDAY NIGHT: Slow clearing. Watch for black ice on untreated surfaces. Lows 20-25. Wind variable shifting to NW 10-20 MPH.

FRIDAY: Mostly sunny. Highs 30-35. Wind W 10-20 MPH with higher gusts.

SATURDAY: Mostly cloudy. Low 22. High 44.

SUNDAY: Mostly cloudy. A period of rain, mix far inland. Low 33. High 40.

MONDAY: Partly sunny. Chance of snow showers. Temperature falls to 20s.

TUESDAY: Mostly sunny. Low 10. High 25.

WEDNESDAY – NEW YEAR’S DAY: Cloudy. Chance of snow. Low 18. High 28.

Drier, Colder Pattern Returns

2:45AM

After a brief milder spell, and a transition that featured a major temperature contrast across southeastern New England, we’re heading back into a generally colder and mostly dry pattern as we reach Christmas then head toward the New Year.

The wet weather system that brought rain and a little ice to southern New England but a moderate to major ice storm to parts of northern New England is finally offshore, with only lingering cloudiness from it over southeastern areas this Christmas Eve Morning. As the day goes by, those clouds will continue to slide offshore, but other clouds will develop as a disturbance at high levels of the atmosphere moves across the region from west to east. It looks like any snow shower activity from this disturbance will occur southwest of the region (toward NYC). What won’t miss this area is the cold air, which will arrive in force Christmas Eve during the night and remain in place during Christmas Day Wednesday. Christmas morning will dawn bright, but the day will end with filtered sun as high cloudiness increases from the next disturbance, which will bring some snow and rain showers on Thursday. Behind that, a few dry days are expected, with a chilly Friday and a milder trend over the weekend. The mild air will quickly be replaced with a blast of cold air by the start of next week. This may be the start of a very cold stretch of weather. More on this potential upcoming pattern soon.

Updated forecast for southeastern New England…

TODAY: Lots of clouds Eastern MA and Seacoast NH  giving way to more sun during midday and afternoon. Elsewhere, more sun to start then variably cloudy. Highs 30-35. Wind NW 10-20 MPH.

TONIGHT – CHRISTMAS EVE: Variably cloudy early then clearing overnight. Lows 13-18. Wind NW 10-15 MPH gusting 20-25 MPH.

WEDNESDAY – CHRISTMAS DAY: Bright sun in the morning. Filtered afternoon sun. Highs 23-28. Wind N 10-20 MPH diminishing during the day.

WEDNESDAY NIGHT: Thickening clouds. Lows 15-20. Wind variable 5-15 MPH.

THURSDAY: Mostly cloudy. Snow and rain showers in the afternoon, best chance of rain South Coast, best chance of snow showers elsewhere but only minor accumulation at best. Highs 32-37. Wind variable 5-15 MPH.

FRIDAY: Partly cloudy. Low 22. High 35.

SATURDAY: Mostly sunny. Low 22. High 40.

SUNDAY: Partly sunny. Low 26. High 47.

MONDAY: Partly cloudy. AM snow showers. Low 22. High 29.

The Week Ahead

4:40PM

It’s Christmas Week. Maybe 2 weekends included in it, with the holiday itself being on Wednesday. There is a lot to cover, but most importantly are the events ongoing now through Monday, because some areas of southern New Hampshire and even valley areas of north central and northeastern Massachusetts will see some icing issues. The low level cold air that has been advertised arrived from the north pretty much on schedule, from New Hampshire into Massachusetts, with a boundary between this as a very warm air mass to the south setting up somewhere south and southwest of Boston Sunday afternoon. Precipitation has been confined mostly to northern New England, where it is much colder, with moderate to major icing, causing some damage and power outages. Here in southeastern New England, there are areas of fog and drizzle and a few areas of rain, but the bigger story has been the contrast of temperatures from the 30s in northeastern MA right into Boston, to the 60s in much of interior southeastern MA and RI. This boundary will not move too much through early Monday, other than to sink a bit further to the south. On Monday, a stronger cold front from the west will sweep through the region, though with slow to moderate pace, so rain and valley icing will still be a likely occurrence before everything ends from west to east, possibly as some snow showers when colder air comes back in aloft.

Once we get to Tuesday (Christmas Eve), the cold air will be established again, and a trough of low pressure moving through the region from west to east will likely bring cloudiness and the threat of some snow shower activity. A cold and dry Christmas Day is expected Wednesday, as the timing of the next system that I thought may arrive that day will be pushed back until around Thursday, with some snow showers again possible then. Another dry and bright day is expected Friday as high pressure moves in. A warm front may produce some cloudiness but not likely any meaningful precipitation for Saturday, before an Arctic cold front brings yet another chance of snow showers and a blast of colder air about next Sunday.

Forecast for southeastern New England…

TONIGHT: Overcast. Areas of dense fog. Periods of rain, especially north of the Mass Pike, with icing likely interior valleys of east central and northeastern MA and southern NH. Lows around 30 interior valleys to middle 30s most areas except 40-50 far southern areas. Wind light N-NE most areas, calm at times, except SW 5-15 MPH near the South Coast.

MONDAY: Cloudy. Areas of fog. Periods of rain except freezing rain interior valleys of MA and NH in the morning. Highs 35-40 most areas except falling through the 40s in southern areas. Wind variable 5-15 MPH becoming mostly N to NW.

MONDAY NIGHT: Mostly cloudy. Chance of rain or snow showers Cape Cod and South Coast, snow showers elsewhere. Lows 25-35, coldest northwest of Boston. Wind NW 10-20 MPH.

TUESDAY: Variably cloudy. Chance of snow showers. Highs 30-35. Wind NW 10-20 MPH.

TUESDAY NIGHT – CHRISTMAS EVE: Partly cloudy. Chance of snow showers. Lows 10-15 except 15-20 South Coast. Wind N 5-15 MPH.

WEDNESDAY – CHRISTMAS DAY: Mostly sunny. Highs in the 20s. Wind N 10-20 MPH.

THURSDAY: Variably cloudy. Chance of snow showers. Lows 10-18. Highs 25-33.

FRIDAY: Mostly sunny. Lows 10-18. Highs 25-33.

SATURDAY: Mostly cloudy. Lows 20-28. Highs 33-40.

SUNDAY: Variably cloudy. Chance of snow showers. Temperatures falling 30s to 20s.

Fine Line

3:16AM

This weekend it’s all about the line between a warm air mass just south of New England, whose northern edge will poke into southern New England with potential record high temperatures, and a very cold air mass in northern New England and southeastern Canada, whose edge will try to push southward and undercut the mild air. For us in southeastern New England, it only makes for a tough temperature forecast, as the bulk of the precipitation that does occur will fall as rain (not ice) and the heaviest and steadiest of which will stay north of the region. How I think it will play out, with the cold air sinking into southern NH and northeastern MA Saturday night and Sunday, will be reflected in the wording in the forecast below. The biggest plague of the weekend may be areas of dense fog that form, especially over areas that have a significant snow cover (mainly Boston area northward). As we get to the start of the new week, a cold front will push all of this offshore, but the transition on Monday may be rather slow, so it will be a day of occasional wet weather and lowering temperatures. By Tuesday (Christmas Eve), a fresh cold air mass will have moved in, and a weak disturbance moving into the region may touch off a few snow showers. Wednesday (Christmas Day) will also be cold, and we’ll have to watch the timing of a weak clipper system, for the potential for a touch of light snow. A slight moderation in temperature should occur later next week, but only back to normal, along with a few more disturbances bringing clouds and a few risks of snow showers.

Updated forecast for southeastern New England…

TODAY: Mostly cloudy. Highs 45-50. Wind SW up to 10 MPH.

TONIGHT: Mostly cloudy. Spotty light rain mainly northern MA and southern NH. Areas of fog. Lows 40-45 but may fall into the 30s southern NH and northeastern MA. Wind SW up to 10 MPH may shift to N in southern NH and northeastern MA.

SUNDAY: Southern NH and northern MA – overcast with areas of fog and drizzle, and a chance of a few periods of light rain, temperatures in the 40s, and light N to NE wind. Southern MA and RI – mostly cloudy, a few rain showers possible, highs in the 50s, and WSW wind up to 10 MPH.

MONDAY: Cloudy. Chance of light rain. Areas of fog. Temperatures fall through 40s.

TUESDAY – CHRISTMAS EVE: Partly cloudy. Isolated snow showers. Lows around 20. Highs around 30.

WEDNESDAY – CHRISTMAS DAY: Variably cloudy. Chance of light snow. Lows in the 10s. Highs around 30.

THURSDAY & FRIDAY: Variably cloudy. Episodes of snow showers. Lows in the 20s. Highs in the 30s.

Cold Loosens Grip, But Not As Warm As Advertised

10:13PM

The coldest of the recent spell has gone by, and it will turn a little milder the remainder of this week. But low level cold air will be lingering just to the north as high pressure will be tending to develop there. With snow cover in much of the region (except closer to the South Coast), this will act like a refrigerator, temporing warm-ups, and making it easy for cold air to drain in from the north. Before all of this happens, a warm front will try to push out the last of the current cold air as it passes by early Friday, but a cold front will approach later Friday into Saturday and sink across the region during the weekend. The position of that front will determine temperatures which may vary widely across parts of the region. There will also be some periods of wet weather, mostly in the form of rain, though not a whole lot of precipitation will likely occur. We’ll also have to watch for the potential for icing over the interior areas depending on how much cold is able to drain into the region later in the weekend.

A peek into next week: Cold front sinks to the southeast of the region Monday with mild air replaced by cold. Cold high pressure builds in Tuesday with maybe a few Christmas Eve snow showers, and (timing uncertain) watching a potential clipper system for a bit of Christmas Day snow.

Updated forecast for southeastern New England (southern NH, eastern MA, and RI)…

OVERNIGHT: Clear. Watch for icy patches on ground. Lows from near 10 inland valleys to near 20 South Coast. Wind W under 10 MPH.

THURSDAY: Increasing clouds. Highs 30 inland hills to middle 30s South Coast. Wind W 5-15 MPH gusting over 20 MPH.

THURSDAY NIGHT: Mostly cloudy. Lows around 30. Wind variable 5-15 MPH.

FRIDAY: Mostly cloudy. Highs around 40. Wind SW 5-15 MPH.

SATURDAY: Cloudy. Chance of rain showers early. Lows in the middle 30s. Highs in the lower 40s.

SUNDAY: Cloudy. Periods of light rain (ice possible inland valleys). Lows around 30. Highs around 40 north to 50 south daytime, may rise at night.

MONDAY: Mostly cloudy. Chance of rain showers early. Temperatures fall through 40s.

TUESDAY – CHRISTMAS EVE: Partly cloudy. Isolated snow showers. Lows around 20. Highs around 30.

WEDNESDAY – CHRISTMAS DAY: Mostly cloudy. Chance of light snow. Lows around 20. Highs around 30.

Classic Clipper

7:46AM

A clipper storm will move across the region today. A classic one. The phrase classic clipper does not mean a big storm (in this case, snow). It means that a system moving along the northern jet stream, out of Canada, will pass just south of most of New England, probably cutting across Cape Cod or the Islands as it redevelops, then accelerates out to sea while intensifying. This is a perfect track to bring light to moderate snow in this cold set-up. We’ll see that this afternoon and evening, except limited accumulations over Cape Cod and the South Coast due to mixing.

The clipper is gone by tomorrow morning, and we’re left with fair weather, a breezy/cold Wednesday as sun returns and then a chilly but more tranquil Thursday as sun gives way to clouds from an approaching warm front. This leads to a milder end of the week, and also unsettled, Friday-Sunday, as a front moves into then lingers in the area. It’s hard to time any precipitation this far out, but if anything takes place, odds favor rain and rather light amounts. Fine tuning of this will take place as it gets closer.

Forecast for southeastern New England…

TODAY: Clouding over west to east this morning with snow develop west to east early through mid afternoon and continuing. Highs barely to 20 remote NW suburbs of Boston, pushing beyond 30 over Cape Cod. Wind light N to NE except E to SE over Cape Cod and the Islands.

TONIGHT: Cloudy with snow in the evening, except mix/rain parts of the South Coast and Cape Cod. Accumulations less than 3 inches where mix or rain occurs, 3-7 inches elsewhere with isolated 8 inch amounts possible especially northeastern MA and southern NH. Temperatures steady. Wind variable over Cape Cod, NE to N 5-15 MPH elsewhere.

WEDNESDAY: Clearing. Highs around 30. Wind NW 10-20 MPH and gusty.

THURSDAY: Increasing clouds. Low 15. High 33.

FRIDAY: Mostly cloudy. Chance of rain showers. Low 33. High 45.

SATURDAY-SUNDAY: Mostly cloudy. A few periods of precipitation, probably rain, favoring Sunday. Lows 25-35. Highs 35-45.

MONDAY: Variably cloudy. Chance of snow showers. Low 20. High 33.