Wed 09:42 PM Forecast Review — Not all models were onboard with very heavy rain tonight. I think the GFS overdid the rain forecast for tonight. But most models agree with a forecast for periods of heavy rain starting Thursday afternoon, 1-3 PM.  

Updated Wed 3:32 PM with precip map

A quick post here….As described in my previous post, a front will move through and stall just south of the Philadelphia area.

Some scattered pop-activity possible late this afternoon.

The main frontal activity will move in this evening (Wednesday evening). Latest models have storms affecting immediate PHL area from about 8 PM through midnight, starting in far northwestern suburbs earlier. Severe activity possible far northwestern suburbs; heavy activity here.

GFS Accumulated Rain forecast at 1 AM Thurs morning. Note that the GFS is forecasting additional 1-2 inches of rain in some areas Thursday afternoon into Friday. Please note that weather models cannot exactly predict precise location and amounts of rain, but it gives an idea of the general quantity. (Click on image for a larger view.)

Not all models are on-board with the above GFS forecast of excessive rain.

Main event appears to be Thursday mid-afternoon (2-3 PM) into night with additional heavy rain/storms.

Stay tuned for updates.