DAYS 1-5 (MARCH 10-14)
Today we get a preview of mid spring with a healthy southwesterly air flow due to high pressure to the south and low pressure passing through the Great Lakes into southeastern Canada. This air flow off the ocean water to the south of New England of course will keep the South Coast / Cape Cod / Islands cooler than areas that experience a true land breeze, which is typical and notable for this time of the year – and you’ll see that reflected in the wide-ranging specifics on the temperature expectations for today. Abundant sunshine can be enjoyed by all, regardless of air temperature at your specific location, but don’t get used to this weather because changes are coming, and quickly. Tonight, clouds increase both from the west associated with the approach of the trough that drives the low pressure area mentioned in the first line of this discussion. At the same time, the front attached to the low, which by tonight will be well east of our longitude, will be pushed southward and pivot southwestward via the Gulf of Maine, thanks to high pressure build into east central Canada behind it, and will cross our region as a back-door cold front overnight. This sets up a cloudy and uniformly chilly day on Wednesday. The region’s high temperatures for the day will occur at about midnight tonight, after which it’ll be in the 40s everywhere, with no big temperature range, no sun, and patchy drizzle along with the chance of a passing rain shower. Another low pressure area will be moving through the Great Lakes at that time, and it will serve to pull that frontal boundary back to the northeast at night, when the temperature will start to rise again from southwest to northeast into Thursday morning, when that day’s high temperatures will occur. One band of showers can come through Wednesday late evening with a trough, and the main band of precipitation will come through on Thursday morning and midday from west to east with a cold front. This boundary has a sharp enough temperature contrast with it so that what falls as mainly rain showers can end mixed with wet snow from west to east across the region during the day late morning to early afternoon Thursday. I don’t expect much of any clearing that afternoon as chilly air arrives, but any that does occur will be brief and mainly at night, before the next low pressure system dives our way via the Great Lakes on Friday with clouds re-thickening and a chance of some rain, mix, and snow arriving from west to east. This system passes through and departs Saturday with a trend back to drier weather after an unsettled start.
TODAY: Mostly sunny. Highs 68-75 Boston west southwestward to northeastern CT and northwestward through interior northeastern MA, central MA, and interior southern NH, ranging down a narrow band of 60-67 between that and 53-60 tip of Cape Ann MA and across the South Coast and Upper Cape Cod with 45-52 Lower Cape Cod and Islands. Wind SW 5-15 MPH.
TONIGHT: Clouding over. Patchy drizzle NH Seacoast and eastern MA coastal areas by morning. Lows 38-45 except 43-50 south central MA to eastern CT. Wind SW shifting to NE 5-15 MPH from northeast to southwest.
WEDNESDAY: Mostly cloudy. Patchy drizzle. Chance of rain showers, especially during the afternoon. Highs 43-50, mildest southwest of Boston. Wind NE 5-15 MPH.
WEDNESDAY NIGHT: Cloudy. Rain showers likely. Areas of fog. Temperatures rise to 50-57. Wind shifting to S 5-15 MPH.
THURSDAY: Cloudy. Rain showers likely in the morning, may mix with or change to wet snow especially higher elevations of southern NH and central MA during the afternoon. Highs 52-59 early, then falling. Wind S shifting to NW 5-15 MPH with higher gusts.
THURSDAY NIGHT: Mostly to partly cloudy. Lows 31-38. Wind N 5-15 MPH.
FRIDAY: Partly sunny to mostly cloudy. Late day or evening mix / snow possible from west to east. Highs 38-45. Wind variable up to 10 MPH.
FRIDAY NIGHT: Cloudy. Occasional rain / mix / snow likely. Lows 30-37. Wind variable up to 10 MPH.
SATURDAY: Cloudy start with a chance of rain / mix, then breaking clouds. Highs 43-50. Wind SW to W 5-15 MPH.
DAYS 6-10 (MARCH 15-19)
Additional unsettled weather opportunities which can include some mix / frozen precipitation as the pattern is somewhat colder.
DAYS 11-15 (MARCH 20-24)
The vernal equinox (start of spring) occurs at 10:46 a.m. EDT on Friday March 20. A volatile weather pattern with up and down temps and unsettled weather on frequent occasion will mark its early days.