Wednesday started off with a few clouds(which actually prevented widespread temperatures in the 50s) and then sunshine prevailed before fair weather cumulus clouds popped up in the afternoon. The low temperature at Philadelphia International Airport was 62 around 5:30am while the high reached a cool 80 degrees just before 4pm(the average high is 87).
There were showers and thunderstorms well west of Center City(west of I-81 to be exact), but as we have stable air on top of us the storms will a) never reach us as well as b) lack of daytime heating is causing the storms to collapse. Overnight lows will be in the lower 60s with a mostly clear sky. Thursday will feature sunshine and then clouds in the afternoon once we reach our convective temperature(the estimated temperature that the surface must reach in order for clouds to develop). Highs will approach the middle 80s.
After lows around the middle 60s highs on Friday will be in the lower 80s with sunshine giving clouds in the late afternoon as a frontal boundary offshore begins to retrograde closer to the coast; overnight into Saturday there will be some showers and thunderstorms(especially along the coast) with highs close to the middle 80s. Come Sunday that front is still nearby, but there will be a lesser chance of rain(more of the isolated variety) as a second wave of low pressure riding along the front passes by to the east of the shoreline with highs in the middle 80s.
Remember that you can check out the rest of the 7-day forecast(any time) at www.scottderekwx.com/forecast.html.