Wednesday, December 26, 2012

Updating This Evening's Rains

A rather stark temperature contrast across the region this evening as the brunt of the storm will be felt over the next several hours.  Temperatures range from 50 in Southern Delaware as of 4 PM to the 20's in the Poconos where snow and sleet continue to fall.  The city has predominately had rain today but some sleet and light snow fell initially at the very front end of the storm.  However, milder air aloft has done a number on transitioning many of our locations from snow to icy rain and sleet or over to just rain.

Even though temperatures are safely above freezing in the city, it's not warm out by any stretch as gusty east winds have been blowing and gusting to over 30 mph around the region.  Wind chills are in the 20's north and west of I-295 as we work into the evening.

Low pressure over Kentucky is transitioning its energy to a secondary area of low pressure in Virginia, which will intensify and become the dominant low later tonight.  This low will push northeast, intensifying and increasing the wind field on the north side of the storm.  Needless to say, winds will be an issue for all but the "worst of worst" for gusty winds tonight will be across Central and North Jersey, where winds could gust to over 50 mph this evening and tonight with the storm.  Inland parts of NJ and along I-95 could see 40-45 mph wind gusts at peak before things taper off a bit later on tonight.

As for precip type, most of Southeastern Pennsylvania is getting rain at this point regardless of temperature. Those areas still below freezing will moderate above 32, with rain becoming heavy and remaining heavy over the next several hours.  The evening hours will feature the heaviest of rains with this storm as a line of wind and rain in Virginia and near DC pushes northeast up I-95 and along the coastal plain.  This line will push through between 8 PM and Midnight from southwest to northeast, with rain tapering off to showers and drizzle afterwards.   With low pressure intensifying in Virginia, the 32 degree line's northward progression probably halts in the Poconos, with sleet and freezing rain possible up to near Scranton for a time.  A transition back to snow is possible over the areas in the Poconos that change over to non-snow.  That transition to snow is not likely around Southeast Pennsylvania, Philly, or in South Jersey as it's simply too warm.  I don't think the Lehigh Valley transitions back to snow but you may have a struggle getting much above 32 this evening.

Once the back edge line of precipitation moves through later tonight, drizzle and showers are possible but the steadiest rains will exit...not before the region picks up a general one to two inches of rain.