Cold & Dry Through Thursday: Christmas Day Looks Mainly Wet with Some Mixed Precip During The Morning.

12/21/09
Monday AM
First Day of Winter Begins today.

I hope everyone enjoyed the 2nd biggest snowfall in PHL history at 23.2". Many areas from Northern/Central DE into SE PA and Interior Southern and Central NJ, received between 14"-25" of snow from this storm.

Once again here's the snowfall reports from the NWS Mt.Holly, NJ
http://forecast.weather.gov/product.php?site=NWS&issuedby=PHI&product=PNS&format=CI&version=1&glossary=0

Continued Cold but mainly dry weather will be the rule Today (Monday) through Thursday. Highs will be between 30-35 and lows in the Mid teens to low 20's through this period. So all this snow is going no where, and very little melting will occur. Only during the afternoon and with some help from the sun, will allow for very limited melting, then temps quickly drop and we quickly re-freeze at night.

The all important question is will we see more snow for Christmas, and the answer is NO. But there's no doubt We'll all have plenty of snow on the ground, so It'll still be a White Christmas.

A strong storm system will develop and move to the center of the country towards mid-week, then begin moving NE towards the Great Lakes Region. This puts the storm track well to our west and NW, which leaves us on the warmer side of the system. This will initially start bringing milder air in aloft from the SW, but at the surface cold air will try to hold it's ground.

Strong High Pressure will be parked over SE Canada, and funnel down cold air at the lower levels and surface. This is a classic CAD signature, and will hold on for Christmas Eve night into Christmas morning. During this time precip. will begin moving into our area from the G/L's storm, this could cause problems with mixed precip and ice for a period of time.

For the PHL area and points North & West, many could see a mix of snow, sleet, and freezing rain, Thursday night into Christmas morning. However. our winds will shift to the south and southeast during the day, which will bring in milder air off the ocean, so all precip will change to rain as temps reach the low to mid 40's from PHL south and east, but will remain in the mid 30's to near 40 for the NW suburbs of PHL. This will cause some melting, but not enough to erode our snow pack. Periods of rain and windy conditions are likely for Christmas night with temps in the Upper 30's and lower 40's.

We then clear our for Saturday and the remainder of the Holiday weekend looks to be dry and turning colder, as a strong cold front sweeps through behind the storm moving into SE Canada. Highs will be near 40 on Saturday and mid to Upper 30's for Sunday. Lows drop back into the 20's for both nights.

So We should have snow left on the ground even after the rain and milder temps for a day or so. This snow pack will then turn into a water logged block of ice next weekend, as we return to a much colder pattern, that continues into next week. I'll do an update and more detailed forecast on Wednesday, for the Christmas Holiday weekend.

Take Care,
Ruggie