Low pressure over Pennsylvania this evening will track to the east. As it does so, any leftover showers will move south out of the region. They should be gone by midnight. Meanwhile, there is plenty of dry air and clear skies to the north of Lake Ontario. As that air tries to move south overnight there should at least be partial clearing.
An area of high pressure stretching from the Ohio Valley into the Northeast will bring a nice start to the weekend. While it may be rather cloudy for a while to start the day we should average out to a mix of sun and clouds. The air mass over us tomorrow is fairly typical for mid July so we expect mid 80s by afternoon.
By Sunday our wind will turn into the west-southwest. That will help import warm air and our temperatures will rise accordingly, perhaps even reaching 90 degrees again. Along with the warm air will come an increase in moisture. It should feel a bit more humid and with an approaching cold front there will likely be a few scattered afternoon thunderstorms.
This first cold front will weaken and fall apart Monday leaving us in a hot and humid until early Tuesday. On Tuesday, a second, stronger cold front will move through with the chance for a few showers and thunderstorms.