An incredible weather day is now in the books. We reached 78 in Boston in the sunshine, only slightly below normal considering the early fall feel, temps were able to climb into the mid-upper 70’s in spots in the full afternoon sunshine. High pressure is cresting over New England tonight with clear skies, diminishing wind, and extremely dry air. This will set the stage for good radiational cooling for this time of year with lows dropping into the 40’s in many suburbs and low lying areas and valleys. Temps will remain in the 50’s in more urban locations and along the coast.
High pressure will be pulling off the coast Tuesday with a more southerly wind at the surface. Sunshine with highs in the 70’s and lwr 80’s likely inland with a seabreeze at the coast keeping most beaches in the 70’s. A few afternoon clouds may try to push through during the midday into the afternoon. High pressure will remain close enough to us on Wednesday to squeeze out another good day with sunny to partly sunny skies. Dewpoints will still be in the 50’s Highs still near 80. Some high clouds will be start to increase a bit during the afternoon ahead of our next approaching front.
The upper level trough which has been so persistent so far this August is lifting out temporarily. This is allowing for a weak upper level ridge starting to build into the northeast by the midweek. This will help to keep us dry, with some warming temps and some building humidity. Another upper low (accompanied with cooler air) will strengthen from Canada and push into the Great Lakes. The contrast of the cool and warm airmasses separating the north from the south will energize the Jetstream and force a piece of energy into the upper SW flow and head into the northeast. This will be a cold front which will likely trigger a round of showers with maybe some embedded thunderstorms on Thursday. After a quiet Thursday night, In the flat upper flow, the front will stall near or over SNE. Another wave of low pressure will ride along this front and through New England Friday and Friday night with another round of showers and a few T’storms. Friday will hold the better chance for thunderstorms. Some may contain heavier downpour with the potential for up to and inch or more of rain for some of the heavier spots.
The low will be pulling off the coast Saturday morning. The weekend could start off damp with a few lingering showers, with skies becoming partly sunny and warm in the 80’s by afternoon as the low pulls away. Drier, cooler NW winds will shift in Sunday and Monday with temps in the 70’s and Lwr 80’s and low humidity returning back into the Northeast