Friday, March 02, 2012

Tracking Tonight's Rainfall

Rain is moving into Delaware as of 5:30 this evening and is a couple of hours to perhaps three hours away from crossing through the whole of the Philadelphia metro.  Tonight's rains may total a half inch to three quarter inch across a chunk of the region, with the highest rainfall totals south of Philadelphia compared to north.   This initial shot of rain should work through over the evening hours, perhaps with a rumble of thunder. Steadier and heavier rainfall is likely later overnight as the severe weather over the Ohio Valley and Midwest works east and weakens into areas of rain and thunder as they push east at a rapid rate.   We'll probably see our thunder threat greatest between Midnight and daybreak but we will not see severe weather across the Philadelphia area.  Some gustier thunderstorms could linger into the Delmarva but odds favor no severe over any severe whatsoever.

By tomorrow morning, the frontal boundary will be approaching the region and steadier rains will be about to depart.  The NAM, below, shows a lingering line of rain and thunder through the region around 7 AM.  The NAM suggests rains will push off the coast by 10 or 11 AM tomorrow, with the GFS slowing the end of the rain into early afternoon (the GFS is the slowest on having the rains exit stage right).  In any case, the morning will feature a bit more rainfall than after midday and in fact some sunshine is certainly possible after midday tomorrow across the region from Philly on west in the latter afternoon hours in Jersey.


The Storm Prediction Center still highlights the potential for severe weather across Western Pennsylvania later on tonight and a severe thunderstorm watch is certainly possible out near Pittsburgh later on tonight as the line of thunderstorms and wind-whipped rain in Ohio works east.