Friday will be the final day of this stretch for the heat and humidity before some cooler and drier weather arrives by the weekend. A strong cold front will march across Pennsylvania tonight and that will lead to more thunderstorm development.
Hazy sun could boil up a few stray storms this afternoon, some of which could be severe. A lot of places will actually stay dry during the daylight hours, however, before the front actually moves in tonight. A line of gusty thunderstorms is projected to move across the viewing area from 9 p.m. to 3 a.m. overnight.
Expect gusty winds and heavy rain. There could also be an isolated tornado warning both from the stray storms this afternoon and/or from the line that blows through tonight.
Clouds begin to clear Saturday morning as cool air takes over behind the departing front. Our highs this weekend only will be in the upper 70s to lower 80s as a result of this pattern change. We also see a bit of an unsettled forecast to start out next week with the cooler conditions remaining in place.