Scattered thunderstorms will pop up this afternoon to our west (out towards Johnstown, State College, Altoona) and will gradually push east and northeast through the balance of the afternoon and into the evening hours. A slight risk of severe weather is out (just updated as of 12:15 PM) for Eastern/Central PA, pretty much along/northwest of I-95.
Additionally, heavy rainfall can't be ruled out in any stronger storm that fires up later on. The key in today's storms is scattered, not widespread. Philly should make it to the dinner hour without any thunder threat and perhaps make it through tonight as well because of the scattered nature of the thunderstorms that should pop up later. Our part of the world should see some of these storms move through after 6 PM, closer to 6 west and later on in the evening the farther east one is.