Prognostic Meteorological Discussion
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FXAK02 KWNH 291830
PMDAK

ALASKA EXTENDED FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
230 PM EDT WED JUL 29 2015

VALID 12Z SUN AUG 02 2015 - 12Z THU AUG 06 2015

AN UPPER RIDGE WILL MOVE ACROSS THE WESTERN TO SOUTHERN INTERIOR
REGION OF ALASKA AS A SLOW MOVING UPPER TROUGH MIGRATES SLOWLY
EASTWARD ACROSS THE CENTRAL TO EASTERN ALEUTIANS BEFORE DRIFTING
TOWARD THE WESTERN GULF OF ALASKA LATE IN THE PERIOD.  A COLD
UPPER LEVEL LOW WILL PERSIST NORTH OF THE STATE AND HELP KEEP
CHILLY TEMPERATURES ACROSS THE NORTH SLOPE.

THERE WAS GENERALLY RELATIVELY GOOD AGREEMENT WITH THE ENSEMBLE
MEANS THROUGH THE ENTIRE FORECAST PERIOD ALTHOUGH THE 00Z EUROPEAN
ENSEMBLE MEANS TENDED TO BE SLIGHTLY FARTHER NORTH WITH AN UPPER
TROUGH EAST OF THE KAMCHATKA PENINSULA.  THE 12Z GFS APPEARED TO
BE QUITE IN SYNC WITH THE OVERALL COMBINATION OF THE 06Z
GEFS/NAEFS AND 00Z EUROPEAN ENSEMBLE MEANS WHILE THE 00Z ECMWF WAS
NOT INCLUDED IN THE BLEND THROUGH DAYS 4 TO 6 BECAUSE IT APPEARED
TO BE ON THE FAST SIDE WITH THE TROUGH/SURFACE LOW CROSSING NEAR
THE ALEUTIANS INTO THE WESTERN GULF OF ALASKA.  AS A
RESULT...GENERALLY BLENDED A COMBINATION OF THE 12Z GFS/06Z NAEFS
AND 00Z EUROPEAN ENSEMBLE MEANS THROUGH DAY 6 AND THEN
INCORPORATED SOME 12Z GFS/00Z ECMWF ON DAYS 7 AND 8 SINCE THEY
APPEARED MORE IN LINE WITH THE MEANS...EVEN THOUGH THE MAJORITY OF
THE BLENDS WERE COMPOSED OF THE MEANS.

KOCIN

$$





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