Scattered heavy showers and strong thunderstorms are popping once again and these will affect parts of the Philly metro region over the next several hours. One batch is currently developing rapidly across southern Chester County and it will move northward and affect parts of central Chester County before 4PM. Another batch of showers and storms is developing just east of Philly and it will move northward and affect NE Philly, eastern Montgomery and eastern Bucks Counties before 4PM. Any storm can produce heavy rainfall as they are slow-movers and loaded with moisture. Today's threat will continue well into the evening hours to about 8 or 9PM.
It looks like an even more organized threat will occur from late Sunday through Sunday night with the potential for severe weather. At that time, a strong cool front will combine with energetic upper-level support to generate numerous heavy showers and strong-to-severe storms in the Mid-Atlantic region and much of the Northeast US. We’ll continue to monitor this situation as the weekend progresses.