DAYS 1-5 (APRIL 20-24)

Very pleasant spring days start and end this 5-day forecast period. In between, we have some spring volatility to go through. First, we begin with high pressure centered to the south of New England and a nice mild air mass in place today. But a cold front will be charging eastward trailing from low pressure moving across southeastern Canada. But this front is running out of steam and will be sputtering out as it moves into New England this afternoon and early evening, only bringing us some clouds and the slight chance of a few rain showers into the region, especially northwest of I-95. This frontal boundary will then pull back to the north as a warm front early Wednesday as low pressure forms in the Upper Ohio Valley and western Pennsylvania and then travels northeastward into northern New England. This will bring one more push of mild air into our region Wednesday but with an increased rain shower threat as this frontal boundary gets pulled eastward from this second low pressure area. The front by then will have quite a sharp temperature contrast across it, with snow on the back side. But that snow is destined for northern New England, not the WHW forecast area in southeastern New England. However once the rain showers (and possibly a thunderstorm) cross this area later Wednesday, the cold air behind the front will waste no time getting in here, along with plenty of wind. So as we observe Earth Day on Thursday, we will do so with a cold air mass in place, a gusty wind, and probably sun followed by lots of clouds. I do think rain and snow showers will be confined mostly to the mountains west and north of this area, but can’t rule out one or two wandering into this area later in the day or during the evening. By Friday, the cold relaxes a little as the wind goes more westerly around northern side of high pressure which will be sliding eastward across the Mid Atlantic States. By Saturday, this high will be offshore and we’ll be in a warmer southwesterly air flow with the timing of the next trough slow enough that while we may end up seeing cloudiness moving in, it should stay rain-free, making it quite the nice start to the weekend.

TODAY: Sunny start, then a sun/cloud mix. A passing rain shower possible mainly west and north of Boston during the afternoon to early evening. Highs 57-64 South Coast region, 65-72 elsewhere. Wind SW 5-15 MPH with higher gusts.

TONIGHT: Variably cloudy. Slight chance of a rain shower, mainly southern NH and northern MA early. Lows 41-48 I-95 belt northwestward, 49-54 elsewhere. Wind SW 5-15 MPH shifting to W-NW then becoming variable.

WEDNESDAY: Variably cloudy with isolated rain showers through mid afternoon. Mostly cloudy with rain showers and possible thunderstorms arriving west to east later in the day. Highs 63-70 except 55-62 South Coast. Wind SW 10-20 MPH, higher gusts.

WEDNESDAY NIGHT: Mostly cloudy evening with rain showers ending west to east. Clearing overnight. Lows 32-39. Wind NW 15-25 MPH, gusts 30-40 MPH.

THURSDAY: Sunny start, then lots of clouds. Highs 43-50. Wind NW 15-25 MPH, gusts 30-40 MPH.

THURSDAY NIGHT: Variably cloudy. Slight chance of a rain or snow shower. Lows 31-38. Wind W 10-20 MPH and gusty.

FRIDAY: Partly sunny. Highs 50-57. Wind W 10-20 MPH and gusty.

FRIDAY NIGHT: Mostly clear. Lows 40-47. Wind SW 5-15 MPH.

SATURDAY: Increasing clouds. Highs 65-72, cooler South Coast. Wind SW 5-15 MPH.

DAYS 6-10 (APRIL 25-29)

Expecting mostly zonal (west to east) flow in the large scale pattern… Significant rain event is possible for April 25 due to passing low pressure along with below normal temperatures. Turning mostly dry as high pressure builds in for several days after, a warming temperature trend but very likely cooler at the coast most of those days.

DAYS 11-15 (APRIL 30 – MAY 4)

Pattern may evolve into a blocking set-up again with trough western US, ridge east central US, and trough off the US East Coast. The idea in this pattern would be for cool / dry overall. Not high confidence, but something to watch as several influences still have to be considered.