Tuesday, November 26, 2013

Updating The Incoming Storm System

Tonight's storm system is organizing across the Deep South and is beginning to lift northeast towards us. We will see precipitation begin to work into the region later today, with some sleet pellets and snowflakes on the front end before transitioning to a cold rain for much of the region. With temperatures dropping to near freezing along and north of I-78, some of that rain may freeze on untreated surfaces late this afternoon plus snow may linger a bit longer before transitioning to icy rain or rain in the Poconos.

Accumulations in the Poconos should only get to about an inch on the snow side, plus some icy crust, before temperatures warm above freezing and allow for the wintry slop to melt.

Locally, any sleet pellets or snowflakes will not last long as milder air pushes in with the incoming storm system. Low pressure will track roughly from near the Gulf of Mexico to Charlotte to west of Richmond to just west of Philadelphia through the next 24 hours, drawing milder air northward. While it will take until tonight for that milder air to work up the coast, we will have about six hours or so where temperatures will be pretty mild locally. In fact, modeling from the NAM and GFS suggest 60 degrees is not out of the question for the city and points east overnight and early tomorrow morning. Areas west of the low track probably struggle to get much above 40 during the storm, which results in a sharp temperature gradient through the region later tonight.

With a robust storm system coming north up the coast and a 60-70 mile per hour low level jet, winds will increase later tonight and become rather gusty for those east of the low track. We could see 40 to 50 mile per hour gusts along the coast after Midnight, which is why there is a Wind Advisory out along the Shore overnight. Winds could reach 40 or so inland as well while rains fall.

The bulk of rain falls tonight from about 8 PM through 6 AM tomorrow, with the region picking up generally around two inches of rain from the storm system. Some spots pick up more than that...the best chances of anyone getting three inches of rain will be just west of the low track across some of the hills in Southeast Pennsylvania.

Essentially, no real changes in thinking with today and tonight's portion of the event -- rain for the majority of us for the majority of the event, some icy travel on the front end in the Poconos.  As for Wednesday, a second piece of energy will pivot through during the afternoon. Across the Poconos and areas north of I-78, showers will fall mostly as snow and some coating accumulations may occur. Around here, rain looks to be the dominant precipitation type although snowflakes will certainly to mix in towards the end. We'll update this a bit more as we work into tomorrow but the second piece of energy does not look to be a big deal.

More: Current Weather Page