862
FXUS02 KWBC 141921
PMDEPD
EXTENDED FORECAST DISCUSSION
NWS HYDROMETEOROLOGICAL PREDICTION CENTER CAMP SPRINGS MD
320 PM EDT WED OCT 14 2009
VALID 12Z SAT OCT 17 2009 - 12Z WED OCT 21 2009
PRELIMINARY UPDATE...
THE PRELIMINARY FRONTS AND PRESSURES FOR DAYS 3 THROUGH 7 WERE
UPDATED WITH A HEAVY EMPHASIS ON THE 00Z/14 EUROPEAN CENTRE
ENSEMBLE MEAN PAST DAY 4. THE RELIANCE ON THIS MEAN MITIGATES THE
CONTENTIOUS WAVE DEVELOPMENT OVER THE WESTERN ATLANTIC DEPICTED BY
THE LAST SEVERAL RUNS OF THE DETERMINISTIC GFS...AS WELL AS
BROADBRUSHING THE FLOW COMING INTO THE WEST OFF THE PACIFIC. THE
TIMING OF INDIVIDUAL SHORTWAVES CROSSING THE WEST COAST IS AKIN TO
PIN THE TAIL ON THE DONKEY. UNSETTLED IS THE SAFEST DESCRIPTIVE
FOR THAT REGION. THE NATION EAST OF THE ROCKIES LOOKS DRY FOR THE
MOST PART...WITH THE AREAS EAST OF THE APPALACHIANS UNSEASONABLY
COLD EARLY IN THE PERIOD BEFORE THE COLD TROUGH SHEARS OUT.
FINAL...
THE 12Z/14 GFS CONTINUES ITS OUTLIER STATUS WITH THE CLOSING OFF
OF THE MID LEVEL TROUGH ALONG THE ATLANTIC COAST EARLY IN THE
PERIOD...WITH THE NEW GEFS MEAN...GEM GLOBAL...UKMET...AND
DETERMINISTIC ECMWF MORE PROGRESSIVE WITH THIS TROUGH.
STILL...ENOUGH FORCING MAY OCCUR DAYS 3 AND 4 TO THROUGH A GOOD
BIT OF PRECIPITATION BACK INTO THE MID ATLANTIC AND COASTAL
NORTHEAST...WITH SNOW NEAR THE COMMA HEAD AND OVER THE MOUNTAINS.
THE PATTERN DEPICTED IN THE PRELIMINARY UPDATE OVER THE WESTERN
HALF OF THE NATION IS LARGELY SUPPORTED BY BOTH THE NEW GEFS MEAN
AND DETERMINISTIC ECMWF.
CISCO
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