HPC Discussion
Posted by JAC on 1/8/2010, 1:14 pm
PRELIMINARY EXTENDED FORECAST DISCUSSION
NWS HYDROMETEOROLOGICAL PREDICTION CENTER CAMP SPRINGS MD
900 AM EST FRI JAN 08 2010

VALID 12Z TUE JAN 12 2010 - 12Z FRI JAN 15 2010

THE BIG DIFFERENCE IN TODAYS MODEL GUIDANCE FROM YESTERDAYS IS
THAT THE NRN STREAM OF WESTERLIES...DOMINANT AND SHOWING
DEAMPLIFICATION OF THE MEAN WRN NOAM RIDGE/E COAST OF NOAM TROF
THE FIRST HALF OF THE MEDIUM RANGE PERIOD...SHOULD DECREASE IN
IMPORTANCE WED AND BEYOND AS A NEW AMPLIFYING SRN STREAM TROF NEAR
THE TX/MEXICO BORDER TAKES OVER.

MODELS SUPPORT FALLING HEIGHTS ACROSS THE SW BORDER STATES WED/THU
FOLLOWING THE ARRIVAL OF A SIGNIFICANT PACIFIC SHORTWAVE INTO
CALIFORNIA EARLY WED/DAY 5. THIS NEW SURGE OF SRN STREAM ENERGY
WILL PUSH ACROSS THE ESE ACROSS SW BORDER STATES AND NRN MEXICO
WED-FRI AS SPLIT FLOW REDEVELOPS. MODELS AND ENSEMBLES ARE IN
DECENT AGREEMENT WITH THIS IMPORTANT NEW SRN STREAM FEATURE THAT
WILL BE AFFECTING THE SERN QUARTER OF THE CONUS THE LATTER HALF OF
NEXT WEEK. ALL GUIDANCE SUPPORTS THE IDEA OF A STRONG SFC SYSTEM
EVOLVING OVER THE WRN GULF OF MEXICO BY FRI...AS AN AMPLIFIED SRN
STREAM 500MB TROUGH SETS UP ACROSS TX AND NORTHEAST MEXICO.  WITH
THE GFS ON THE FAST SIDE OF THE MODELS...AND THE ECMWF
SLOWEST...WE FOLLOWED THE COMPROMISE POSITION ON THE CMC GLOBAL
AND GEFS MEAN. ENSEMBLE SPAGHETTI PLOTS SHOW A WEAKER SRN STREAM
SYS BEING KICKED OUT AHEAD OF THE NEW POTENT SYS ACROSS THE GULF
STATES WED/THU.

00Z/08 MEDIUM RANGE GUIDANCE WAS FAIRLY WELL CLUSTERED IN ITS
HANDLING OF THE PRIMARY SYNOPTIC FEATURES. A 500MB SHORTWAVE WILL
SLIDE FROM THE MIDWEST TO THE EAST COAST ON DAYS 3/4...PROVIDING
RE-ENFORCING COLD POLAR AIR OVER MUCH OF THE EAST BEFORE
MODERATING CONDITIONS SPREAD EASTWARD FROM THE PLAINS. EVEN COLDER
ARCTIC AIR WILL SLIDE INTO NY/NEW ENG WED/THU AS A HUDSON BAY
500MB VORTEX SLIDES SOUTHEAST AND SENDS ANOTHER ARCTIC FRONT ON IT
SWRN FRINGE INTO THE NORTHEAST.



HEDGE/FLOOD

86
In this thread:
Maybe severe weather along GOM Coast late next week. - JAC, 1/8/2010, 11:56 am
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