10:20PM
A strong disturbance will move into the region Thursday and Thursday night. First, its warm front will slide into New England from the southwest, with a thunderstorm potential ahead of it. This first threat will favor areas along and north of the Mass Turnpike in northern MA and southern NH, but with some limited instability, activity may weaken as it moves eastward. The timing for this threat is between dawn and the end of the morning. Right now, this threat appears to be the weakest of the several upcoming.
The second round comes in the form of clusters of storms that are expected to form near and south of the warm front as it lifts to the north across the region. The most likely areas for these storms are near and south of the Mass Pike, including Rhode Island. Damaging winds, large hail, flash flooding, and even isolated tornadoes cannot be ruled out with these storms, though the tornado potential is highest in areas to the west (western MA, western CT, and eastern NY). This round of potential severe weather can occur any time from early afternoon to early evening.
The third round of threatening weather is expected to occur during a 6-hour window from 9PM Thursday to 3AM Friday across all of the region, with the highest potential in central and southern portions of eastern MA through RI. The main threat with numerous storms moving east and northeast across the forecast area will be damaging winds, with a secondary threat being flash flooding if storms train (develop over the same areas for an extended period of time).
I didn’t mention lightning in any of these threats, but frankly that’s because all thunderstorms produce lightning and all cloud-to-ground lightning is dangerous. Some of these storms, especially in rounds 2 and 3, can produce frequent lightning.
What happens beyond this?
We stay unsettled Friday into the weekend as the frontal boundary remains in the area. The severe weather potential is less on Friday but cannot be completely ruled out, especially from southern MA through RI. Otherwise, look for fairly numerous showers and storms over the region Friday. Saturday and Sunday, the current expectations are that things will shift southward with time, but the boundary will still be close enough to provide the threat of showers and a few thunderstorms.
Early next week looks nicer, but that may not last too long…
Updated forecast for eastern MA, southern NH, and RI…
OVERNIGHT: Increasing clouds. Lows 60-65. Wind light variable to S.
THURSDAY: Mostly cloudy. Chance of showers and thunderstorms mainly north of the Mass Pike in the morning. Showers and thunderstorms likely in the afternoon, with highest potential for severe storms along and south of the Mass Pike. Becoming very humid. Highs upper 70s to middle 80s, warmest southwest of Boston. Wind S to SW 5-15 MPH. Strong, gusty winds near some thunderstorms.
THURSDAY NIGHT: Mostly cloudy. Showers and thunderstorms likely, some storms possibly severe. Lows around 70. Very humid. Wind SW 5-15 MPH. Strong winds possible near storms.
FRIDAY: Mostly cloudy. Showers and thunderstorms most numerous in the morning, more scattered in the afternoon. Humid. Highs in the 70s. Wind variable 5-15 MPH.
SATURDAY: Mostly cloudy. Chance of showers and thunderstorms. Low 62. High 76.
SUNDAY: Mostly cloudy. Chance of showers. Low 62. High 77.
MONDAY: Mostly sunny. Low 63. High 81.
TUESDAY: Partly sunny. Low 63. High 83.
WEDNESDAY: Mostly cloudy. Chance of showers and thunderstorms. Low 66. High 80.