Today's heat is the peak of the warmth that we'll get ahead of the next frontal boundary passage that comes at us from the west. Thanks to a bit of an onshore influence tomorrow, temperatures will not be as warm (still at or above average though for many of us)....and thanks to the approach of this stronger front from the west, temperatures will hang near 80 or just above it on Tuesday afternoon with clouds increasing and storms moving in late in the day.
The front could take the better part of Tuesday night and Wednesday to move through the region according to computer modeling from this morning. The front itself doesn't have a strong push of colder air behind it but it does have a good deal of moisture to work with. Thunderstorms will have the potential of dropping heavier rainfall as they approach on Tuesday and pass overhead Tuesday night into Wednesday. The heaviest rainfall threat will be to our west on Tuesday and Tuesday evening, overhead Tuesday night into early Wednesday morning, and in New Jersey on Wednesday.
Rainfall by the time Wednesday evening ends could exceed two inches in parts of the region...the GFS computer model hints at the possibility that some of us (north and south of the city) could see at least that much rainfall...with perhaps the rest of us picking up over an inch of rainfall. The Euro does not paint as aggressive of a scenario for us but does paint the potential that a large chunk of the region picks up an inch plus (generally north of a Wilmington-Atlantic City line) of rainfall for this same timeframe.
As the front clears the coast, some wraparound energy does get tossed back into the area on Thursday, which could result in a few afternoon showers and storms popping up. It doesn't look like a huge event but could add a bit of an insult to the heavier rainfall that may fall on Tuesday night or Wednesday.
As always, we will update this more as we get closer...but be forewarned that we could see some heavier rains Tuesday night and Wednesday around the Delaware Valley.