EXTENDED FORECAST DISCUSSION
NWS HYDROMETEOROLOGICAL PREDICTION CENTER CAMP SPRINGS MD
204 PM EST TUE FEB 09 2010
 
VALID 12Z FRI FEB 12 2010 - 12Z TUE FEB 16 2010
 

...WINTER STORM FOR THE CENTRAL GULF COAST STATES AND SOUTHEAST...


PRELIMINARY UPDATE...

USED THE 00Z/09 ECMWF FOR DAYS 3 AND 4 ACROSS THE NATION...WITH A
GRADUAL INCORPORATION OF THE 00Z/09 ECENS MEAN THEREAFTER TO
ADDRESS THE UNCERTAINTIES IN SYNOPTIC DETAIL INHERENT TO THAT TIME
RANGE.  PREFER THE NORTHERN MOST GUIDANCE WITH THE WAVE CROSSING
THE GULF OF MEXICO EARLY IN THE PERIOD...WITH MANY WAVES IN THE
SOUTHERN STREAM THIS WINTER ULTIMATELY TRACKING LESS SUPPRESSED
THAN THE MODELS INITIALLY PROG.  THE MANUAL PROGS INDICATE SNOW
AND ICE ACROSS PORTIONS OF THE INTERIOR SOUTH...EXCEPT FOR SOUTH
CAROLINA WHERE WINTRY PRECIPITATION IS LIKELY TO SPREAD ALL THE
WAY TO THE COAST.  CLIPPER SYSTEMS WILL BE THE ORDER OF THE WEEK
FOR THE PLAINS AND MIDWEST...WITH THE MEAN LONGWAVE RIDGE HOLDING
OVER THE ROCKIES.  FRONTS ARE EXPECT TO COME INTO THE NORTHWEST
OFF THE PACIFIC...WITH LESS ENERGY DIVING INTO CALIFORNIA.


FINAL...

THE 12Z/09 GEFS MEAN...ECMWF...AND GEM GLOBAL ALL TRENDED
NORTHWARD WITH THE GULF WAVE DURING THE FIRST HALF OF THE
PERIOD...SO BUMPED UP PRECIPITATION ALONG THE SOUTHEAST COAST FOR
THE FINAL ISSUANCE.  THE GEM GLOBAL IS THE MOST AGGRESSIVE WITH
THE LOW ONCE IT REACHES THE ATLANTIC...LIFTING A DEEP CENTER A
GOOD BIT OF THE WAY TOWARD CAPE HATTERAS.  THIS IS CERTAINLY A
TREND TO WATCH...WITH LARGE IMPACTS FOR THE SOUTHEAST COAST IN
TERMS OF WINTER WEATHER.  ELSEWHERE...STUCK WITH THE EARLIER BLEND
FOR THE WESTERN AND CENTRAL STATES...RULING THE GEM GLOBAL AS AN
AMPLIFIED OUTLIER AT THIS POINT WITH THE CLIPPER DIVING INTO THE
MIDWEST DAY 6.


CISCO