DAYS 1-5 (SEPTEMBER 8-12)
The September hot spell peaked yesterday with many areas cracking 90, including Boston’s Logan Airport, adding their 5th 90+ day to the short list this summer (there have been several more in general over inland areas). But now we’re going to turn the heat down over the next few days, but keep the humidity high, as a low pressure trough moves in from the west, slowly, and an accompanying frontal system approaches. This will increase the shower and thunderstorm chances as we head into and through the weekend, probably peaking on Monday as the actual front moves through. Yup, it’s a slow process as things are not moving along swiftly in the regional atmosphere right now. Last evening, some showers and storms made it into the far western / northwestern reaches of the WHW forecast area as was expected to be at least possible. As we go through the next few days, this area expands eastward ever-so-slowly, with today’s activity later on still expected to be mostly north of I-90 but west of I-495. The I-495 belt is more included in Saturday’s threat while I-95 eastward may remain free of the threat. But Sunday, include more of the region including the I-95 belt, while southeastern MA escapes the chance, at least for a part of the day, and then I believe it’s a regionwide threat with highest coverage on Monday. Finally, a break should come Tuesday as the front/trough pull to the east. While we’re not going to dive back into any autumn-like coolness during the next 5 days, when we get to Tuesday we’ll at least lose some of the humidity.
TODAY: Partial sun. A late-day shower or t-storm may visit central MA or southwestern NH. Highs 83-90. Dew point hovering around 70. Wind S 5-15 MPH.
TONIGHT: Variably cloudy. A shower or thunderstorm potential in the evening, especially north and west of Boston. Areas of fog. Lows 64-71. Dew point similar. Wind S up to 10 MPH.
SATURDAY: Partly sunny. A passing shower or thunderstorm possible in the afternoon mainly eastern CT, central and northeastern MA, southwestern and south central NH. Highs 81-88. Dew point near 70. Wind S 5-15 MPH.
SATURDAY NIGHT: Partly cloudy. Patchy fog. Lows 63-70. Dew point 60s. Wind SW-S up to 10 MPH.
SUNDAY: Variably cloudy. Occasional showers and thunderstorms likely, favoring the I-95 belt westward. Highs 78-85. Dew point 60s. Wind S 5-15 MPH.
SUNDAY NIGHT: Mostly cloudy. Areas of fog. Scattered showers and a possible thunderstorm. Lows 65-72. Dew point 60s. Wind S up to 10 MPH.
MONDAY: Mostly cloudy. Showers likely. Chance of thunderstorms. Areas of fog early. Highs 73-80. Dew point near 70. Wind S to variable up to 10 MPH.
MONDAY NIGHT: Showers/storms end, clouds remain, patchy fog forms. Lows 60-67. Dew point 60s. Wind variable to W up to 10 MPH.
TUESDAY: Clouds break for sun. Highs 70-77. Dew point near 60. Wind W 5-15 MPH.
DAYS 6-10 (SEPTEMBER 13-17)
Three things to watch. 1) Hurricane Lee in the western Atlantic basin, with best odds favoring an offshore track between Bermuda and the US East Coast, closest pass to New England around mid period with primary impact being rough surf / large swells. Note: Lee should weaken a little more quickly than climatology would indicate due to a lingering wake cool pool from recent Hurricane Franklin, but it will still likely be quite powerful as it tracks through that area. 2) Trough of low pressure from the west, instrumental in helping keep Lee to the east of the US Mainland. But this system will likely bring high humidity and showery weather to our region during the first half of this period. 3) The exit of the trough allowing a cooler/dry air mass to visit from Canada later in the period.
DAYS 11-15 (SEPTEMBER 18-22)
As we head through the final 5 full days of summer just prior to the autumnal equinox, the strongest indications are for a drier pattern with high pressure being more dominant, keeping most unsettled weather to the south and/or west of our region.