With a cold front on the doorstep, the Storm Prediction Center has placed Central Pennsylvania under a Tornado Watch. The watch includes the Lehigh Valley, Chester County, and further to the west. This does not include Bucks, Montgomery or Philadelphia counties, or parts east. This particular Tornado Watch is in effect until 11pm and is one of a longer line of watches along the Appalachian Mountain range. The storms in association with the front should be into the Philadelphia metro between 8pm and 10pm, possibly effecting the Phillies game tonight.
The showers and thunderstorms could be strong to even severe in nature, even after traveling across the state. With highs today near the 80's and a strong gradient behind the front, the atmosphere could destabilize quickly. Lows tonight could dip into the upper 40's to lower 50's. Winds will be pumping the warm air from the south at 10 to 20 mph, until the front passes, where it'll switch to the northwest. Showers should taper off and move completely out of the area by 3am Saturday. Behind the cold front, we'll see cooler and breezy conditions, with skies gradually clearing throughout the day. High will be in the lower 60's throughout the area, expect far northern area might not get out of the upper 50's. Winds will be from the west-northwest at 10 to 20 mph.
Sunday looks cooler still but under mostly sunny skies. Highs both Sunday and Monday only into the upper 50's. Monday will see increasing clouds with the chance of showers late as a new system could be moving up the coast. This system will stick around for a few days, making next week damp and dreary. Tuesday, highs will be in the lower 60's with mostly cloudy skies. Wednesday looks slightly warmer, with cloudy skies and the chance for scattered showers. More showers are possible Thursday, with highs in the lower 60's. Finally, by Friday, we'll break the clouds and see some sun with high's in the mid-60's.