A cool front will be approaching the region on Tuesday afternoon and will take its time crossing the region, hanging out in the Delaware Valley through Wednesday evening before exiting stage right. With the approach of the cool front on Tuesday into a very warm and humid airmass thunderstorms will be developing in spots during the afternoon. However, based on guidance as of this morning it is possible we see more thunderstorm development on Wednesday as the front is overhead.
Tuesday's threat is higher in Pennsylvania and Northwest New Jersey, Wednesday's would be more likely (if it does indeed come to fruition) in New Jersey. A slight risk for severe weather is out northwest of Philadelphia for Tuesday afternoon as the front approaches the region.
Because dynamics will be "better" to our north, we may not have as much of a severe threat to consider as we will a heavy rain threat tomorrow afternoon and evening. Dew points will be near 70 and the front will be slow moving, which will result in thunderstorms possibly tracking over the same general areas in Pennsylvania and North Jersey...the infamous training precipitation setup. Whether or not that comes to fruition remains to be seen but if it does heavy rainfall and some flooding can't be ruled out on Tuesday afternoon and evening. A couple of inches (or more) of rain can't be ruled out.
We'll have another update tomorrow morning on the potential for a bumpy Tuesday afternoon and evening!