Snowstorm Still Possible in the Northeast and Mid-Atlantic This Weekend...

Models are continuing to show some disagreement on the development of a storm that will track off the North Carolina coast passing southeast of Long Island. The NWS Hydrometeorological Prediction Center issued the following discussion earlier today:

SHORT RANGE FORECAST DISCUSSION
NWS HYDROMETEOROLOGICAL PREDICTION CENTER CAMP SPRINGS MD
242 PM EST THU DEC 17 2009

VALID 00Z FRI DEC 18 2009 - 12Z SAT DEC 19 2009

A MAMMOTH WINTER STORM IS ON TAP TO HIT THE MID ATLANTIC STATES
AND THE TENNESSEE AND OHIO VALLEYS THIS WEEKEND. THE SYSTEM THAT
WILL EVENTUALLY BRING HEAVY SNOW TO THIS REGION IS CURRENTLY
BRINGING HEAVY RAIN TO THE TEXAS AND LOUISIANA GULF COAST. FLOOD
WATCHES AND WARNINGS ARE OUT FOR AREAS ALONG THE GULF COAST THAT
HAVE RECENTLY BEEN INUNDATED WITH PRECIPITATION. WESTERN PORTIONS
OF NORTH CAROLINA AND VIRGINIA ALREADY HAVE WINTER STORM WATCHES
IN EFFECT IN ANTICIPATION OF THE NORTHWARD MOVEMENT OF THIS STORM.
THE CENTRAL LOW PRESSURE WILL TRACK ALONG THE GULF COAST THROUGH
FRIDAY EVENING BEFORE LIFTING NORTHWARD ALONG THE ATLANTIC COAST
ON SATURDAY. SNOW IS EXPECTED TO START FALLING IN THE APPALACHIANS
FRIDAY EVENING AND WILL CONTINUE INTO THE WEEKEND.

The first map above is a forecast from the 7 PM Thursday evening NAM (North American Mesoscale) model. This run is forecasting a major snowstorm for LI, NYC and NJ. The new 1 AM NAM run out to 30 hours just became available and it indicates a developing storm with a lot of precipitation just off the NC coast (2nd map from above). The GFS model was not available at this time. Look for a good amount of snow in the Tri-State region on Saturday evening into Sunday. A total of 2 to 5 inches can be expected but it is still early and accumulations could be more or less than this range depending upon the actual track of the storm. Also, the models are not in agreement at this time.

George Wright is a Certified Consulting Meteorologist and President of Wright Weather Consulting, Inc. Our web site is WrightWeather.com