Prognostic Meteorological Discussion
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FXAK02 KWNH 211802
PMDAK

ALASKA EXTENDED FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
201 PM EDT MON JUL 21 2014

VALID 12Z FRI JUL 25 2014 - 12Z TUE JUL 29 2014

STRONG RIDGING NEAR THE WESTERN/CENTRAL ALEUTIANS IS FORECAST TO
REMAIN NEARLY IN PLACE THROUGH THE MEDIUM RANGE... WHICH SUPPORTS
MAINTAINING A TROUGH/CLOSED LOW IN THE GULF. THE FORECAST
MID-LEVEL FLOW THROUGH THE ARCTIC REGION HAS SHOWN A TREND TOWARD
A SHARPER TROUGH THAT WILL ACT TO REINFORCE THE IN SITU UPPER LOW
IN THE GULF EARLY IN THE FORECAST PERIOD. ANOTHER AREA OF
CONTENTION FALLS OUT OF NORTHEASTER RUSSIA... WHERE THE TREND HAS
BEEN TOWARD A STRONGER SYSTEM PUSHING INTO NW AK SUNDAY. THE 00Z
ECMWF APPEARS MOST OVERDONE WITH THIS ENERGY /WITH NO SUPPORT FROM
THE UKMET OR CANADIAN/... AND THUS SQUASHES THE RIDGING MUCH
FARTHER TO THE SOUTH THAN THE GFS/GEFS. GIVEN THE STRENGTH OF THE
RIDGING... GAVE A BIT MORE WEIGHT TO THE 06Z GEFS OVER THE 00Z
ECENS MEAN BY THE END OF THE PERIOD SINCE THE CANADIAN
ENSEMBLES... AND THUS THE NAEFS MEAN... LIE CLOSER TO THE GEFS.
FOR THE FIRST HALF OF THE FORECAST... THE 12Z GFS/06Z GEFS/00Z
ECENS MEAN... AND A BIT OF THE 00Z ECMWF... AGAIN OFFERED A
REASONABLE STARTING POINT.


FRACASSO

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