The storm prediction center has issued a TORNADO WATCH for most of Virginia through Washington DC and recently expanded them through all of eastern PA
Areas in yellow are in a tornado watch, we have had a good amount of sunshine today that has destabilized the atmosphere just enough to raise the chance of severe weather slightly , and there is now sufficient wind shear for an isolated tornado threat. Instability is still lacking though so the severe threat I believe will be isolated and the tornado threat will be very isolated.
Heavy rain and thunderstorms have developed rapidly along the front over the past 2 hours, this line will intensify until sunset than weaken some once it comes east of the Delaware river, hits a more stable air mass and as we begin to lose daytime heating but heavy rain and thunderstorms are expected fo the whole area, the severe threat will be best over eastern PA and especially southeastern PA into Maryland and down through Virginia.
Peak timing will be from 8pm through 4 am from west to east , the main line of storms will come through between 8 pm west to 11 pm east.