Tuesday, September 04, 2012

Scattered Soakings Greet You Today

Temperatures are generally in the lower half of the 70's to start Tuesday, with areas of heavy rain scattered around the Delaware Valley early this morning as well.  Rains are slowly nudging north and northeast through New Jersey and Southeastern Pennsylvania as a frontal boundary to our south  continues to act as an axis for tropical moisture to squeeze out as it pushes north over the front.  That front will slowly lift north through parts of the area today, which will result in a bit of a temperature differential for highs from north to south as rains will continue north of the south, and some tropical temperatures are possible south of the front.

Modeling suggests the front does slip past Philly but guidance varies on how far north it gets from there.  The NAM's high resolution model doesn't push it much past the city, with the GFS and the "traditonal" NAM nudging the front up the coast and a little bit through Southeast Pennsylvania. As a result, temperatures north and west of the boundary will struggle to get to 80 this afternoon and those of you in the Lehigh Valley, Central PA and North Jersey will stand a better chance for heavy rain and thunder than the city or points south.  There could be a few hour break in the activity in between the stuff around us this morning and what moves through late this afternoon and this evening.  That said, everyone runs the risk for soaking downpours, especially this morning, and a few scattered thunderstorms this afternoon (better chances for soaking this afternoon is north of town). 

Rainfall in any downpour will be locally soaking and possibly induce some flooding on local streams and streets.  We're under a flash flood watch in the region today and tomorrow -- the potential for several inches of rain over the next two days does exist as Isaac's remnant moisture pushes east for tonight and tomorrow morning.