DAYS 1-5 (DECEMBER 1-5)
We’re going to see an unsettled pattern open the month of December. Despite that, we start today with sun before clouds roll in ahead of a warm front and a weak low pressure wave. This gives us a shot of light rainfall in the region from around sunset to around midnight, and the frontal boundary lifts northward and then hangs there for several hours Saturday. As a result, we have a milder couple days to start the final month of 2023. Some sunshine may even return to at least areas from the South Coast to the I-90 belt for a while Saturday – a more optimistic forecast than I had on my last update. And it also looks like a rain-free day other than the chance of a brief rain shower passing through north central MA and southwestern NH. The frontal boundary will begin to slip back to the south later Saturday, and by Sunday, it’ll sit just to our south again, and we’ll be back in chilly air under a heavier overcast. A low pressure wave with more moisture will then approach and rain will overspread the region from southwest to northeast during Sunday afternoon and especially Sunday night. There may be just enough cold in place for this to begin as a little bit of frozen/mixed precipitation in the higher terrain of southwestern NH and north central MA, but it will fall mainly as rain, before tapering off early Monday, maybe again as a little mix or wet snow in the aforementioned locations. In general, Monday’s’ weather trend will be for drying, with an increasing breeze and chilly air as clouds start to break. Expect dry weather other than a slight chance of a passing snow flurry, and a chilly breeze on Tuesday, as we’ll be in a northerly air flow between low pressure to the east and high pressure to the west of our region.
TODAY: Sun gives way to clouds. Light rain west of Metro Boston late-day. Highs 46-53. Wind S 5-15 MPH.
TONIGHT: Cloudy. Light rain evening. Patchy fog overnight. Lows 38-45. Wind SW up to 10 MPH.
SATURDAY: Areas of fog early. Cloud/sun mix with most sun I-90 south until midday, then clouds dominant later. A possible brief rain shower north central MA to southwestern NH. Highs 48-55. Wind W up to 10 MPH.
SATURDAY NIGHT: Cloudy. Lows 35-42. Wind N up to 10 MPH.
SUNDAY: Cloudy. Rain becomes more likely from southwest to northeast during the course of the day, but may start as a frozen mix in higher elevations of southwestern NH and north central MA. Highs 42-49. Wind NE 5-15 MPH.
SUNDAY NIGHT: Cloudy. Rain likely. Areas of fog. Lows 35-42. Wind NE 5-15 MPH.
MONDAY: Cloudy start with rain ending, possibly as a frozen mix in higher elevations of southwestern NH and north central MA. Highs 40-47 by midday, cooling into the 30s during the afternoon. Wind N 10-20 MPH.
MONDAY NIGHT: Clearing. Lows 23-30. Wind N 5-15 MPH, higher gusts.
TUESDAY: Partly cloudy. A passing snow flurry possible. Highs 33-40. Wind NW 10-20 MPH, higher gusts.
DAYS 6-10 (DECEMBER 6-10)
Chilly northerly air flow but dry weather December 6. A small and fast-moving low may bring brief precipitation episodes late December 7 to early December 8 with generally dry weather to follow. Temperatures variable during mid to late period but averaging close to normal.
DAYS 11-15 (DECEMBER 11-15)
A fairly quick-moving west to east flow pattern is anticipated at mid month. Active in terms of having a couple of passing low pressure systems but no major storms are indicated, nor are major temperatures swings with near to slightly above normal temperatures despite some variability.