11:20PM
The weather is trying to remember that it’s wintertime, and making some minor progress. 🙂
A dusting to around 1 inch (isolated areas) of snow fell almost by surprise early Tuesday morning as a disturbance coming out of New York held together well enough and in cold enough air to put down just enough snow to slick up a few roads for the morning commute. All of that melted as it turned milder during the day Tuesday, and it’s now a memory. We have a quiet but chilly day coming up Wednesday as high pressure builds to the north of New England and a storm system approaches from the southwest, though still far enough away that we will see a fair amount of sun during the day.
The storm, carrying plenty of warm air with it, will bump into some chilly air in place as it arrives in the early hours of Thursday, so this may mean that precipitation starts as snow in some areas, especially north and west of Boston, where minor accumulations of snow are possible. Meaningful snow from this system should be confined to the mountains of New Hampshire and Maine, with some ski areas picking up significant accumulation during Thursday. Up to a couple inches of slushy accumulation may occur in the higher elevations of Worcester County, but no significant accumulation is expected from around 495 south and east, including Boston. The Thursday storm will be a quick-mover too, so once the warm air is established and it’s raining in the Boston area, the back edge of the steady precipitation will already be approaching and should cross the region from southwest to northeast by early or mid afternoon, with only lingering drizzle after.
As far as the unsettled weather goes, this will not be the end of the story, as this is a dual storm system. The main upper level trough still has to swing through the region Friday into Saturday, and waves of energy will produce additional precipitation in bands, first in the form of rain as we remain in relatively mild air through Friday morning. It may even be unstable enough for thunder to occur in a heavier band of rain showers sometime Friday morning. Once we get to the afternoon, any rain showers will change to snow showers as colder air moves in, but they should be scattered in nature. Only a slight risk of a line of snow showers or squalls exists for Friday evening as one more trough crosses the region from west to east.
Saturday will be a tranquil but colder day. The cold air gets reinforced by another disturbance crossing the region Sunday. This disturbance may result in snow showers, but no organized widespread snow is expected. This should be gone so that MLK Jr. Day is a dry but cold one. But as has been the case for weeks up to this point, the cold will not be sustained and we’ll already be back into mild air by Tuesday of next week as high pressure slides offshore and low pressure heads for the Great Lakes.
A note on the medium range: My opinion is that we will be unable to sustain cold air for more than a couple of days at a time at least during the next 10 to 15 days. The things working against sustained cold weather in the eastern US:Â Lack of high pressure ridge in western North America, too much west to east flow and Pacific air. Lack of snow cover over much of south central Canada and the US Lower 48, which allows air masses to modify more quickly than they would if they were traveling over snow-covered ground. Also, the configuration of the upper level pattern over Alaska and the Bering Sea is unfavorable for a colder setup here in this area. A rule of thumb: When Alaska is colder than normal, we usually don’t stay cold for long, if at all. We’re getting the colder shots of air at times now, but they are not staying. Getting snow in this pattern will depend on timing of disturbances. We’ll deal with those as they come along.
Enough babble, now to the detailed forecast for the Boston Area…
OVERNIGHT: Bright moonlight in a clear sky. Low 18-23. Wind N around 10 MPH.
WEDNESDAY: Partly sunny. High 34-39. Wind N under 10 MPH.
WEDNESDAY NIGHT: Clouding over. Precipitation arriving from southwest to northeast between 3AM and 6AM, rain south of Boston, rain or mix in Boston, mix or snow north and west of Boston at the start. Low 29-34. Wind NE up to 10 MPH.
THURSDAY: Overcast. Snow/mix in the 495 belt may accumulate up to a slushy inch before turning to rain. Elsewhere, just rain, which may fall heavily for a brief time late in the morning. Steady rain ends southwest to northeast between 1PM and 3PM, with lingering drizzle and areas of fog after. High ranging from near 40 in the Merrimack Valley to near 50 from Boston south, being reached late in the day. Wind NE 10-20 MPH with higher gusts, shifting more E to SE then diminishing somewhat later in the day.
THURSDAY NIGHT: Drizzle ends, areas of fog remain, but clouds may break at times. Temperature steady in the 40s. Wind SE to S up to 10 MPH.
FRIDAY: Mostly cloudy in the morning with a band of rain showers and possible thunder moving from southwest to northeast across the region. Intervals of clouds and sun in the afternoon with a couple periods of rain or snow showers. High 45-50 in the morning, then cooling through the 40s into the 30s during the afternoon. Wind SW 10-20 MPH with higher gusts, shifting to W. Passing snow showers and possibly a snow squall at night.
SATURDAY: Mostly sunny. Low 22. High 33. Patriots vs. Broncos at night in Foxboro will be played under a mostly clear sky with a temperature falling from the middle 20s at kick-off to the upper 10s by game’s end, with light to moderate N wind.
SUNDAY: Variably cloudy. Chance of snow showers. Low 15. High 27.
MONDAY – MLK JR DAY: Partly cloudy. Low 11. High 30.
TUESDAY: Partly sunny. Low 22. High 44.