Yesterday, we talked about how the upcoming heat event is pretty significant despite a pretty decent chance that it may end up only a two day event in duration. Even if we coax a 90 degree high on Friday to get a heat wave designation (for "official" purposes), the core of the heat will be on Wednesday and Thursday...and its core will be pretty impressive and intense for this time of the year.
Excessive heat watches are out for the Delaware Valley for both Wednesday and Thursday as the combination of heat and humidity will lead to heat index values that approach or exceed 100 degrees in the Delaware Valley. It would not surprise if those 100 degree heat indexes are also felt outside that area -- and I think some heat advisories will probably get issued for some other portions of the region as we approach the event. While both days will be hot, Thursday looks to be the worst of the two as temperatures could approach the upper 90's if everything breaks right and we get full sunshine. The region could see some records approached or hit as well. Thursday's records are below.
In addition to Thursday's records, Wednesday does feature the possibility of a record high at Atlantic City (95, set in 2010) and Mount Pocono (89, set in 1953). Some of the records on Wednesday are over 100 degrees and probably a good bit out of reach for folks in Allentown and Reading...but Thursday's are a bit closer. Even if we don't set a record, it's gonna be hot those two afternoons.
The cool front that was also talked about for Thursday night and Friday is still on track to pass through during that time -- one of the models still shows a chance of some thunder (GFS) but the Euro still pushes a dry frontal passage through the region overnight.