Prognostic Meteorological Discussion
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FXAK02 KWNH 262016
PMDAK

ALASKA EXTENDED FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
416 PM EDT WED APR 26 2017

VALID 12Z SUN APR 30 2017 - 12Z THU MAY 04 2017

THE MEDIUM RANGE PERIOD APPEARS VERY STABLE PER OPERATIONAL AND
ENSEMBLE GUIDANCE. THE FORECAST STARTS OFF ON SUN WITH UPPER RIDGE
EXTENDING FROM THE YUKON TERRITORY INTO CENTRAL AK AND A VERY DEEP
CYCLONE LOCATED NEAR THE CENTRAL/SRN ALEUTIANS. OVER THE COURSE OF
THE NEXT SEVERAL DAYS, THE UPPER RIDGE GRADUALLY BEGINS TO
BREAKDOWN AS THE UPPER VORTEX PROGRESSES SLOWLY TO THE WRN GULF OF
AK AND POTENTIALLY PHASES WITH ADDITIONAL PAC SHORT WAVE DYNAMICS.
THIS SCENARIO SHOULD ALLOW AN INCREASE IN MOISTURE RETURN INTO THE
STATE, ESPECIALLY THE SRN PORTION AND PANHANDLE. THE 12Z GFS AND
00Z ECMWF ARE EXTREMELY SIMILAR WITH THIS EVOLUTION THROUGH NEXT
MON AND TUES. SOME SPREAD, MOSTLY SMALL SCALE, SHOWS UP NEXT
WED/THURS BUT ITS WITHIN THE NOISE. WPC USED LARGE PERCENTAGES OF
THE 12Z GFS AND 00Z ECMWF THROUGH MON/TUES AND THEN THESE TWO WITH
GEFS/ECMWF MEANS FOR WED/THURS. 12Z GFS 850MB TEMP STANDARDIZED
ANOMALIES ARE MOSTLY NIL WITH NOT MUCH WARM OR COLD AIR AND TEMPS
NEAR AVG. MOST OF THE PRECIPITATION CHANCES WILL FOCUS RIGHT ALONG
THE IMMEDIATE SOUTHERN COASTAL AREAS FROM THE ALEUTIANS TO THE
SOUTHERN COAST TO THE AK PANHANDLE, INCLUDING FAVORABLE
OROGRAPHICS FOR SOUTHERN TIER TERRAIN TO THE ALASKA RANGE.


MUSHER

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