Monday, January 28, 2013

Winter Weather Advisories & Update On Wintry Slop

Winter weather advisories are out for a fair chunk of the region to start today as a shot of wintry slop moves on through over the next several hours. Precipitation will gradually transition over to liquid from snow or light sleet over the next couple of hours as temperatures aloft warm up. However, the surface is cold thanks to nearly a week of subfreezing temperatures and despite air temperatures nudging above 32 it will take a while for the surface to respond to "warmer" air.

Here's the 1 PM NAM temperature profile -- subfreezing is marked in varied shades of blue.  The NAM historically is solid on cold air damming situations in the short term and given it shows a slow retreat in subfreezing temperatures, it could be a slick time of things on sidestreets and untreated roadways into the afternoon hours into the north/west burbs, Lehigh Valley, and Poconos.  It takes until late evening for temperatures into the Poconos to flirt with 32 but given valley areas may be a bit colder advisories were extended up there through tonight.

NAM temp. profile for 1 PM today --

Precipitation will be with us for a fair chunk of the day today -- light freezing rain and then rain as temperatures moderate above freezing through the course of the day.  Even with temperatures climbing above 32 eventually, the ground may be a bit slow to respond to temperatures inching above freezing so side streets, sidewalks, and parking lots that didn't get treated prior to or during the event nor get used a lot could be a bit slick through a good chunk of the day in many parts of the region.

NAM temp. profile at 7 PM tonight.

Much of the day will be stuck in the lower or middle 30's for Philly and points north.  The Shore might brush 40 by this evening.  Drizzle and rain should end by 5 or 6 PM, with clouds lingering through the night.  It's going to be raw, rotten, and miserable around the region.

We will provide an update on two through the day via social media. Utilize twitter and Facebook for more information as the day progresses.