A stalled frontal boundary is draped across the region extending from a weak wave of low pressure heading out to sea from NJ to a stronger one over southwest OH. That stalled front will give rise to a scattering of showers and thunderstorms this afternoon with northern parts of the viewing area probably being most active.
As the wave from Ohio comes east there will be more widespread showers and thunderstorms tonight and first thing tomorrow and some of the storms could be rather heavy or strong. While some drying is indicated for the afternoon tomorrow there may be another shot of rain tomorrow night (at least according to the latest models).
Saturday is now looking dry for the most part with the next chance for showers coming later in the weekend (best chance probably Sunday afternoon/night) and perhaps into Monday.