President's Day 2011 Forecast

Some wintry precipitation is in the cards for northern parts of the region overnight as a family of weak low pressure systems begin their march east through the Mid Atlantic over the next 36 hours.  The first wave of low pressure will bring snow to northern sections, a mix just north of Philly, and light showers from the city on south.   Round two will impact the region on Monday night with rain transitioning to snow as colder air drains south as a frontal boundary pushes south on Monday evening.

Tonight:   A period of precipitation will move through the region after 9 PM, with generally rain south of the city, rain that could mix with sleet or snow around town, a snow/sleet/rain mix in the burbs, and snow farther north.   Accumulating snow is likely north of I-78 and 2-4" of snow across the southern parts of the Poconos and Lehigh Valley can't be ruled out.   The mix should transition to rain around the Philadelphia suburbs by morning.   Lows overnight will range from the upper 20's in the Lehigh Valley to the mid 30's in Philadelphia and points south.

Monday:  Early morning precipitation will end, with variably cloudy skies for the remainder of the daylight hours.   A milder period of weather will take over in the midday and early afternoon before a cold front pushes in from the north and brings colder air later in the day.   Temperatures will range quite a bit, however, as 30's in the Poconos and the Lehigh Valley give way to upper 40's in Philly.  South of the city, temperatures in the 50's are likely and from Philly on south the temperatures could end up warmer than advertised if we see more sunshine than currently anticipated.  Breezy conditions take over in the afternoon, with northwest winds at 10-18 mph.

The Week Ahead:   Monday night brings snow to the region with the second wave, perhaps starting as rain. A couple of inches of snow are possible for Philly, South Jersey, and Delaware overnight...possibly more.   Stay tuned.   It will be cold on Tuesday and chilly on Wednesday as temperatures only top out in the mid 30's and 40 those two days, respectively.   However, moderating temperatures are likely before Friday as a storm system will work in late Thursday night and into Friday with rain.   We cool off again for the weekend but only into the 40's.