Tuesday, November 26, 2013

Flood Watch Overnight Tonight

A flood watch has been issued by the National Weather Service for tonight for the Delaware Valley and the counties roughly parallel to I-95 from Wilmington northeast to North Jersey.

There isn't a dramatic shift in thinking but the general consensus of heavy rain moving through tonight, with the prospect of two inches of rain for a number of locations in a ten hour or so timeframe, does yield enough of a threat for minor flooding in the region that a flood watch was issued by the NWS.

The watch starts at 7 PM and continues through midday tomorrow.  The bulk of heavy rains are still to come, with rain falling as far back as South Carolina and Georgia as of 4 PM. We'll be in the steady rains for much of the night, with rainfall increasing in intensity as we march through the evening hours.

Modeling suggests that the bulk of rain tonight falls along I-95. The axis of heaviest rains has waffled through the past couple of days but has generally aligned itself along I-95 and to the east. A general two inch rainfall is the most common expectation for many locations, with some spots picking upwards of three inches of rain tonight. That quantity of rain in a short period of time will result in poor drainage areas getting beat up and some roadway flooding. The areas that typically flood could run the risk of some minor flooding as well overnight.

Heaviest rains should be expected in the 11 PM to 5 AM timeframe. Some of the rainfall in this range could approach an inch per hour in the heaviest rainfall zones. It wouldn't shock me if a few rumbles of thunder occurred south of the city as well.

In addition to the heavy rain, winds will pick up to the east of the frontal zone and low track, with gusty winds into Philadelphia, Bucks County, and east into New Jersey. Winds could gust to 40 miles per hour inland, 50 miles per hour at the Shore.

More: Current Weather Page