Potential Dry Spell Buster On Tap Today

It's going to be a busy weather day in some parts of the Delaware Valley today as thunderstorms are poised to develop along a stalled out frontal boundary.   Given a rather moist atmosphere, the sufficient trigger in place, and the enhancement of a weak surface low moving along the frontal boundary and you have a recipe for a healthy couple of rounds of storms to fire up.  Additionally, the upper levels are stagnant (not a lot of wind aloft) so any storms that do develop will move pretty slowly this afternoon.   Factored together, the stage is set for not only some strong/severe thunderstorms (gusty winds are the likely culprit) but very heavy rainfall in some of those storms could yield quick rising streams and ponding of water on roadways.

A slight risk of severe is in place south of a line from Sandy Hook, NJ to York, PA -- including Philly and most of suburban Southeastern Pennsylvania for those gusty winds in the stronger of storms.   Also, a flash flood watch is out for the counties shaded in green on the map below, including Philly and its suburbs, Trenton, AC, and Wilmington.

Radar this morning already has some shower and storm activity -- as the day progresses the numbers of thunderstorms will increase and with the weak surface low tracking along the stalled front, we could see the potential for a widespread round of thunder breaking out along and south of the front this afternoon.  The highest odds for thunderstorms to track this afternoon are along and south of the PA Turnpike and I-195.   Timing suggests the brunt of the storminess occurs between 2 and 11 PM in/around the city, 3-Midnight in New Jersey and points south.  It might not storm the entire time but it is the time frame with the best chances of thunder.

The higher resolution modeling (below) suggests two rounds around the region -- the first in the 3-6 PM range (see above) with the weak surface low getting agitated by daytime heating, and the second round from activity in West Virginia and Virginia in the late afternoon tracking across New Jersey and Delaware in the late evening (9-Midnight).   The other computer modeling out there suggests a slightly different placement on thunderstorms but in general they all suggest a late afternoon/evening/early overnight time frame for activity.

The heaviest of thunderstorms could bring 2-4" of rain in isolated locations...others will probably not get anything, especially if you are farther north of the city.   The strongest of storms could bring wind gusts over 50 mph as well.

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