Sunday, February 17, 2013

Tuesday's Attempted Push Of Warmth & Precipitation

After this brief shot of cold through tomorrow, a storm system pushes in from the west with moderating temperatures and rainfall. Given we're going to be dealing with a lingering cold airmass in the region we might have some areas that deal with snow or sleet on the front end of the event on Tuesday.

Dry air aloft combined with lingering low level cold could yield the snowy or sleety front end of this event, particularly over the northern edges of the Lehigh Valley and Poconos as precipitation moves in during the morning hours.  It's possible 1-3" of snow, perhaps a coating of sleet, could accumulate in the Poconos as the system moves through, with coating amounts possible down to around Allentown and Reading.  For the city, this looks like a mainly rain event as there's just enough surface and low level warmth to nudge temperatures out of the snowy zone but rainfall could include a few sleet pellets on the front end of the storm system.   Temperatures aloft have generally trended towards remaining below freezing during the precipitation part of this event to the city's north -- the odds for this system transitioning folks from snow to rain in the Poconos seem pretty low at this point and the closer we get to this event, the better the odds for a mostly frozen event up to the north.

Locally (south of I-78), we're thinking a quarter inch rainfall seems the most realistic scenario.

Temperatures on Tuesday will again be pretty tricky to forecast around the region -- 30's are looking more likely to the city's north but the warmth to the south could be tough to nudge up this far into the region.  Modeling is trying to push the city and points south to or above 50 degree but it may be one of those situations where that warmth occurs at the tail end of the precipitation, with much of the balance of the event spent around 40 or in the low 40's locally in the city.