Wednesday was a mild one despite sunshine giving way to some showers and thunderstorms in the afternoon; the high at Philadelphia International Airport was a seasonable 86 after a warm and overcast morning low of 71. As previously mentioned there were some showers and thunderstorms that pushed through before sunset in response to a short wave to the west, but no measureable rain was reported at the airport.
Overnight will remain mostly cloudy with lows ranging from the upper 60s in the suburbs to around 70 in Center City; Thursday will be partly sunny with another short wave pushing through by the afternoon. This in return will spawn off more showers and thunderstorms with highs in the middle 80s and a continued easterly wind. The trade-off here is that with that onshore flow if you were go east of the Delaware River into New Jersey the shower threat will lessen as that easterly wind acts like a stabilizer to the atmosphere(and hence storms fall apart).
The fun part is that the short wave pretty much falls apart so although Friday will still be mostly cloudy there will be that persistent onshore flow thanks to high pressure sitting across New England; this in return suppresses everything to the south and west of us so we stay dry throughout the weekend and unseasonably cool as well with highs just in the middle and upper 70s! That's almost ten degrees below average while the Plains and Deep South get stuck with the hot and humid 90s(hey, I'm not complaining!).
Going to back to work on Monday we still have high pressure parked on top of the region so highs will be a bit warmer into the upper 70s and then lower 80s for Tuesday(still over five degrees below average); there will be a sunshine and cloud mix both afternoons, but come Wednesday there will be increasing clouds in the late afternoon ahead of a cold front as highs climb back to the more seasonable middle 80s.
Don't forget that you can check out the 7-day forecast(as well as obtain radar and satellite maps) any time at www.scottderekwx.com/forecast.html.