Monday was a pretty much average day across the region with sunshine giving way to high clouds in the afternoon; with a southeast wind Philadelphia International Airport reached a high of 85 in the early afternoon after a morning low of 66. The clouds are associated with a cold front that will be progressing eastward on Tuesday so overnight we will have a mostly cloudy sky with lows just around 70.
Tuesday will remain cloudy with showers and thunderstorms by mid-morning north and west, but after lunchtime elsewhere. Highs will just be in the middle and upper 70s with a continued southeasterly wind; there will be warm front across the Mason-Dixon Line so it is possible that southern areas could get into the 80s if the front pushes northward, but that will be more of a "nowcasting" ordeal Tuesday morning and afternoon. As for the showers and thunderstorms there will be possibly heavy rain with 1-3" possible further north and west along the I-81 corridor. Overnight showers and thunderstorms will continue with lows in the lower 70s while clouds give way to late afternoon clearing on Wednesday with highs in the middle 80s before falling in the late afternoon once the front clears and the wind shifts.
Now behind the cold front there will be an upper level low pinwheeling across Southern Canada so both Thursday and Friday will be unseasonably cool with highs in the upper 70s and overnight lows in the upper 50s; there will be clouds popping up in the afternoon as well, but showers and thunderstorms should stay well to the north(if one isolated shower pops up at least I warned you!). We'll also stay dry through the weekend despite a disturbance pushing through as highs will range from the lower to 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.