After a very dry April, we will end the month with more rain in 3 days than most areas got in 27. The first round of rain has started in Southern PA and will continue through Saturday afternoon.
Then a break before more rain begins Sunday morning, lasting into Monday morning. This graphic goes through Sunday evening, so totals will be slightly higher by Monday, especially in Eastern PA.
A very interesting setup as well, with easterly winds making for upsloping (enhanced precip) on east-facing mountains, and downsloping (weakened precip) in the valleys just west of the ridges. That explains why there are the strangely oriented bullseyes.