Thursday, December 22, 2011

Tonight's Rains Shouldn't Flood

Tonight's rains will move in over the next several hours -- they are currently tracking through the Ohio Valley and the Southern Appalachians.   This fast moving system should begin to spread rain into the western parts of the region after 9 PM, with the city getting in on the fun around 11 or so tonight.  It is a quick hitting storm system that will bring a solid shot of rain in short fashion -- should be over by 6 AM in many locations, with just lingering showers continuing into the morning hours.   Rainfall estimates from the NAM model (up above) suggest at least an inch of rain across the northern and western suburbs (the dark green shade), with an inch possible as well along the Shore and across parts of Delaware.   Some thunderstorms can't be ruled out later tonight, especially south of the city (south/east of the low track, which is poised to run generally along I-95 through our collective real estate).

Temperatures, as you can tell today, have been quite mild.  They will cool tonight as cooler air tries to filter in during the storm.  However, a changeover of rain to snow is not expected in much of the region.  A few back-edge flakes of snow can't be ruled out in the Poconos or in Central Pennsylvania (along Blue Mountain) but in our region, it's gon' rain tonight.   The "twin tiers" of Pennsylvania and New York will see a changeover from rain to snow, especially on the higher peaks, but not until the latter portions of the event (see the NAM depiction as an example).

The quick hitting inch of rain won't cause flooding problems tonight but will make for a soggy late night around the region -- some of the usual suspect streams might get a bit on the "fuller" side but the region should weather this event relatively well.

More:  Current Weather Page