Sunday Night Shower? Some Ice, Snow Up North

We still need to monitor the upcoming double trouble event for Sunday night through Tuesday but there are a couple of trends that are starting to show up in the computer modeling, besides the first wave being warmer than the second.

One, most guidance is now keeping a majority of the precipitation with wave one to the north of the Philadelphia region. While some showers, drizzle, and perhaps a brief period of flurries or sleet pellets can't be ruled out during the front end of the event, round one does not look like it will do much around the Delaware Valley. The farther north one goes, however, the more likely the odds are for some freezing and/or frozen precipitation to fall during the first round of the storm.   The NAM computer model, shown below, is suggesting the freezing mark line (32 degrees) line up generally around the Lehigh Valley, with colder air over the Poconos and temperatures safely above freezing to the south.    Round one could bring a period of freezing rain, sleet, and snow to the Poconos and some freezing rain and sleet on the front end to the Lehigh Valley before transitioning to rain in the Lehigh Valley.   A couple of inches of snow can't be ruled out in the Poconos, with heavier totals across the New York/Pennsylvania border region.

Temperatures aloft and at the surface here will moderate rather quickly so the freezing/frozen threat looks muted with round one.   In fact, there will be a rather marked temperature contrast on Monday from north to south, with 30's in the Poconos during the day while it will be 65 or so across Southern Delaware.   There are some hints from time to time with the computer guidance that Philly could crack 50 on Monday before the cold front that trails behind the first low slides through...it remains to be seen how warm the city itself gets but Monday will feature some will variations in temperatures across the region.   As the front slides south, a second low works east from the Ohio Valley and brings more precipitation.   As if 65 on Monday wasn't "wild" enough for Delaware, the fact it could snow early Tuesday morning across Delaware and South Jersey after temperatures that warm is pretty crazy in itself.

Round two (and this is the other trend) looks to be a snow event that will bring a bit more snow to areas south of the city on Monday night and Tuesday morning.   Not much is anticipated as this wave slides southeast off the coast -- a couple of inches, perhaps three in a few rogue spots -- generally in South Jersey and Delaware.  Some of this could sneak into the city but most computer guidance is suppressing this system to our south as colder air works in from the north and shoves the second low pressure system farther south.

Neither event looks epic at this point but it's possible that some areas south of town could see some snow as they wake up on Tuesday morning, just like areas farther to our north could see some snow on Monday morning.