Prognostic Meteorological Discussion
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FXAK02 KWNH 241922
PMDAK

ALASKA EXTENDED FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
222 PM EST FRI NOV 24 2017

VALID 12Z TUE NOV 28 2017 - 12Z SAT DEC 02 2017

LATEST 12Z GFS/06Z GEFS AND THE 00Z ECMWF/ECENS MEAN OFFERED A
REASONABLY CLUSTERED STARTING POINT FOR THE MEDIUM RANGE FORECAST
AGAIN TODAY, THOUGH CONTINUITY SINCE YESTERDAY WAS A BIT LACKING
TO START THE FORECAST NEXT TUESDAY. AN UPPER LOW WILL REMAIN
PARKED OVER NORTHEASTERN RUSSIA NEAR THE SEA OF OKHOTSK AS THE
ONCE DOMINANT UPPER RIDGING OVER THE BERING SPLITS INTO TWO PIECES
- ONE NEAR THE NORTH POLE AND THE OTHER ALONG 50N (MORE AS A
FUNCTION OF PRE-FRONTAL RIDGING). THAT LEAVES ALASKA OPEN TO A BIT
OF A SHIFT IN THE STORM TRACK WITH SUCCESSIVE SYSTEMS. THE FIRST
(TUE-THU) WILL FOCUS ON THE SW MAINLAND/SOUTHCENTRAL/PANHANDLE
WHILE THE SECOND (NEXT FRI/SAT) WILL LIKELY LIFT THROUGH THE
BERING SEA. GFS/GEFS BECAME A BIT QUICKER THAN THE ECMWF ENSEMBLE
MEAN AND THE GEFS WAS LESS DEFINED BY LATER NEXT WEEK THOUGH THE
PATTERN DOES NOT SUPPORT THAT. OPTED TO PUT MORE WEIGHT ON THE 00Z
ECMWF ENSEMBLE MEAN BY ESPECIALLY NEXT FRI/SAT.

TEMPERATURES WILL MODERATE WITH TIME FROM BELOW AVERAGE TO NEAR TO
ABOVE AVERAGE AS HEIGHT SLOWLY BUT STEADILY RISE. A STORM TRACK
WEST OF THE MAINLAND COULD BRING MILDER AIR TO THE WESTERN COAST
-- UPPER 20S AT LEAST BUT PERHAPS ABOVE FREEZING EVEN NORTH OF
KING SALMON/60N. PRECIPITATION WILL FOCUS OVER SOUTHCENTRAL AND
THE PANHANDLE THROUGH MUCH OF THE WEEK AND THEN SHIFT TOWARD
WESTERN AREAS NEXT FRI/SAT.


FRACASSO


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