710
FXUS02 KWBC 151904
PMDEPD
EXTENDED FORECAST DISCUSSION
NWS HYDROMETEOROLOGICAL PREDICTION CENTER CAMP SPRINGS MD
304 PM EDT THU OCT 15 2009
VALID 12Z SUN OCT 18 2009 - 12Z THU OCT 22 2009
PRELIMINARY UPDATE...
BEGAN WITH THE 00Z/15 ECMWF FOR THE UPDATED PRELIMINARY FRONTS AND
PRESSURES FOR DAYS 3 THROUGH 7...WITH A SLOW SHIFT TOWARD THE
00Z/15 EC ENSEMBLE MEAN...SO THAT BY THE END OF THE PERIOD...THE
MANUAL PROGS ROUGHLY REFLECT ONE THIRD DETERMINISTIC ECMWF AND TWO
THIRDS EC MEAN. THE 06Z/15 DETERMINISTIC GFS IS MORE SERVICEABLE
THAN THE 00Z/15 VERSION...PARTICULARLY ALONG THE NORTHEAST
COAST...WHERE THE LATTER MODEL HERDS THE OCEAN WAVE FARTHER
OFFSHORE...IN LINE WITH THE OTHER GLOBAL GUIDANCE. THE POSITIVE
TILT TO THE LONGWAVE TROUGH IS THE MAIN THING PRECLUDING TOO MUCH
CLOSING OFF OF A MID LEVEL CENTER OVER THIS REGION...BUT EVEN THE
MODEST ECMWF DEPICTION USED FOR THE MANUAL PRODUCT STILL SWIPES
THE COASTAL REGIONS WITH RAIN AND SNOW FOR DAY 3 INTO DAY 4.
OVER THE WEST...THE ECMWF...EC MEAN...GEM GLOBAL...AND GEM MEAN
ALL SHOW A BIG CYCLONE WRAPPING UP OVER THE NORTHEAST
PACIFIC...WELL NORTHWEST OF THE GFS AND UKMET SOLUTIONS WHICH
SPLIT THIS ENERGY AND SEND A SMALLER STORM TOWARD THE OREGON
COAST. THE NEW TWIST IN THIS FORECAST IS WHAT BECOMES OF SOME OF
THIS PACIFIC ENERGY ONCE IT REACHES THE LOWER MISSISSIPPI VALLEY
DAY 7. THE ECMWF...00Z/15 GEFS MEAN...AND GEM MEAN ALL INDICATE A
MID LEVEL CENTER TRYING TO CLOSE OFF THERE...SO DREW THE SURFACE
MAP TO INDICATE THE BEGINNINGS OF A SEPARATION IN STREAMS.
FINAL...
THE 12Z/15 GFS CONTINUES TO BE PROBLEMATIC WITH THE HANDLING OF
THE SYSTEM ALONG THE EAST COAST EARLY IN THE PERIOD. THE UKMET
DISTINGUISHES ITSELF WITH EAST COAST CYCLOGENESIS CLOSE TO CAPE
HATTERAS DAY 3...ON THE FAR SOUTHWEST SIDE OF ALL THE OTHER GLOBAL
GUIDANCE. THE 12Z/15 GEFS MEAN...GEM GLOBAL...AND ECMWF CLUSTER
WELL WITH THE MANUAL UPDATE PACKAGE...SO MADE NO CHANGES FOR THE
FINAL ISSUANCE.
CISCO
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page