Prognostic Meteorological Discussion
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FXAK02 KWNH 181958
PMDAK

ALASKA EXTENDED FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
258 PM EST WED JAN 18 2017

VALID 12Z SUN JAN 22 2017 - 12Z THU JAN 26 2017

THE WESTERN EXTENT OF THE BROAD AND EXTENDED COLD UPPER LOW OVER
THE STATE AT THE MOMENT WILL BE LOCATED OVER THE WESTERN PORTION
OF THE STATE ON SUN AND BE A RATHER CONSTANT WEAKNESS/NEG DURING
THE MEDIUM RANGE PERIOD. A STORM SYSTEM EXTENDING FROM THIS
WEAKNESS THROUGH THE GULF OF AK/NERN PAC WILL GIVE WAY TO A RATHER
DEEP CYCLONE UPSTREAM. ALL OF THE GLOBAL MODELS AND ENSEMBLES
DEPICT SUCH A STORM... AS IT TRACKS SOUTH OF THE ALEUTIAN CHAIN TO
GULF OF AK/NERN PAC FROM SUN TO NEXT THURS. THE SPREAD FROM
YESTERDAY CONCERNING THIS FEATURE HAS NARROWED SIGNIFICANTLY AND
WPC FELT CONFIDENT WITH A 12Z GFS AND 00Z/18 ECMWF BLEND AS A BASE
EARLY ON IN THE FORECAST PERIOD. TEMPS SHOULD REMAIN BELOW AVG
THROUGHOUT THE FORECAST FOR THE WESTERN PORTION OF THE STATE... AS
MUCH AS 2 STANDARD DEVIATIONS BELOW AVG PER 850 MB TEMPS.
MEANWHILE TEMPS OVER THE ERN PORTION OF THE STATE WILL BEGIN TO
MODIFY TO SLIGHTLY ABOVE AVG BY NEXT THURS WITH THE LARGE SCALE
WARM ADVECTION REGIME. ONSHORE FLOW SHOULD ALSO KEEP THE ALEUTIANS
AND ENTIRE SOUTHERN COAST TO THE PANHANDLE WET WITH MOISTURE
SPREADING INTO THE INTERIOR OF THE STATE.

MUSHER


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