DAYS 1-6 (MAY 26-31)
A one-day shot of heat and higher humidity today as high pressure sits offshore and a cold front approaches from the west. The timing of this front and its associated moisture means the shower and thunderstorm threat from it will hold off until about 6 p.m. or later for the region. The greatest threat for storms both in coverage and intensity, as far as the WHW forecast area goes, will be southwestern and south central NH and north central MA, or areas that have little or no stabilizing influence from a southwest wind, which at this time of year is passing over relatively cool ocean water on its way into New England. This tends to stabilize the air and make it more difficult to develop storms, or to sustain storms that already exist and are moving into these areas. Where the storms do occur, there is a threat of damaging wind gusts, which includes a very small risk of a small tornado should any of the storms be isolated and take on super cell characteristics. Again, this is a low, but not zero, probability so we should pay attention. Otherwise, the typical threats of brief heavy rain, possible small hail, and lightning will be present with any storms. Again, not a widespread event by any stretch, as most people will see activity far less than the maximum potential. Once we are by this threat, another high pressure area moves in for a nice Thursday, warm but dry. As high pressure builds across eastern Canada Friday, a low pressure disturbance will make a run at New England, the brunt of it passing south of the region Friday night and early Saturday, but close enough to put some rainfall into the region at least for several hours. The high to the north will be strong enough to push this away Saturday, which may start wet in eastern and southern areas but will dry out, and be quite cool. Sunday looks dry with only a tiny bit of temperature moderation as a general easterly air flow will continue off the still-cool Atlantic waters. Since this is also the long Memorial Day Weekend, we’ll look at Monday in this section, and it looks like the high pressure area will continue to hold with fair weather, but the center of the high may slip east enough for a more southerly air flow which will allow a bit more warming.
TODAY: Partly cloudy early, then mostly sunny before clouds return late, however clouds may dominate much of the day along the South Coast. Highs ranging widely from 65-72 South Coast with coolest Cape Cod area to 85-92 most areas with a sharp gradient in between these zones. Dew point rising to the middle 60s. Wind SW 10-20 MPH, higher gusts possible.
TONIGHT: Mostly cloudy with a fair to good chance of showers and thunderstorms north and west of Boston early through mid evening and a fair to slight chance of showers and possibly a thunderstorm Boston southward mid to late evening. Clearing overnight. Lows 52-59. Humid evening, drying overnight with dew point falling from the 60s to the 40s. Wind SW 5-15 MPH shifting to NW but may be variable with locally moderate to strong gusts around any showers/storms.
THURSDAY: Mostly sunny. Highs 77-84. Wind NW 5-15 MPH.
THURSDAY NIGHT: Mostly clear. Lows 51-58. Wind N under 10 MPH.
FRIDAY: Increasing clouds. Chance of rain by late in the day. Highs 62-69. Wind NE up to 10 MPH.
FRIDAY NIGHT: Cloudy. Periods of rain. Lows 48-55. Wind E 5-15 MPH.
SATURDAY: Cloudy with a chance of rain or drizzle to start, then a sun/cloud mix. Highs 55-62. Wind NE 10-20 MPH.
SATURDAY NIGHT: Partly cloudy. Lows 47-54. Wind NE 5-15 MPH.
SUNDAY: Partly cloudy. Highs 60-67, coolest coast. Wind E 5-15 MPH.
SUNDAY NIGHT: Mostly clear. Lows 46-53. Wind SE up to 10 MPH.
MONDAY (MEMORIAL DAY): Mostly sunny. Highs 68-75. Wind S 5-15 MPH.
DAYS 7-10 (JUNE 1-4)
The first few days of June are expected to feature seasonable warmth and slightly higher humidity as a couple disturbances move through the region, but with limited chances for showers and a few thunderstorms. This may be followed by a shot of cooler air from Canada at the end of the period but I’ve low confidence on the timing.
DAYS 11-15 (JUNE 5-9)
Warmer air may try to come back early in the period with a shower threat. After that we may be near the border of air masses with additional shower threats but no signs of any widespread beneficial rainfall at this time, and no extreme temperatures.