Prognostic Meteorological Discussion
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083
FXAK02 KWNH 051956
PMDAK

ALASKA EXTENDED FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
256 PM EST MON DEC 05 2016

VALID 12Z FRI DEC 09 2016 - 12Z TUE DEC 13 2016

...BELOW NORMAL TEMPERATURES WILL PERSIST ACROSS THE INTERIOR OF
AK AND DOWN INTO THE PANHANDLE REGION...

THE SYNOPTIC PATTERN SETTING UP WILL FEATURE HIGH-LATITUDE RIDGING
AROUND THE ARCTIC OCEAN WHILE A BROAD CYCLONIC CIRCULATION
SITUATES ITSELF OVER NORTH-CENTRAL CANADA. SOME OF THESE
SHORTWAVES MAY DRIFT WESTWARD TOWARD THE AK PANHANDLE AND MEANDER
WITHIN THE PRESENCE OF THE BLOCK. FEATURES FARTHER UPSTREAM SHOULD
BE MUCH MORE PROGRESSIVE IN NATURE AS A SERIES OF SYSTEMS MIGRATE
FROM THE VICINITY OF THE SEA OF OKHOTSK TO SOUTH OF THE ALEUTIANS.
THE OVERALL PATTERN IN PLACE WILL FAVOR THE ABUNDANCE OF HIGH
PRESSURE OVER MUCH OF THE INTERIOR WITH A STATIONARY ARCTIC
BOUNDARY ALONG THE VICINITY OF THE SOUTHEASTERN TO SOUTHERN AK
COASTLINE. THIS WILL MAINTAIN A COLD AND RELATIVELY DRY PATTERN
WITH FORECAST MINIMA PLUNGING INTO THE -30S OVER SECTIONS OF
EAST-CENTRAL AK EARLY IN THE PERIOD. CONSIDERING
PRECIPITATION...IT SHOULD BE ON THE DRIER SIDE GIVEN THE DOMINANCE
OF HIGH PRESSURE. THE ONLY AREA WHICH SHOULD SEE PERIODS OF
PRECIPITATION ARE FROM THE ALEUTIANS EASTWARD TO SOUTH-CENTRAL AK.

THROUGH THE WEEKEND...THE MOST STABLE ASPECT OF THE FORECAST IS
WITH THE HIGH-LATITUDE BLOCKING REGIME FEATURING ABOVE NORMAL
HEIGHTS NEAR THE POLAR REGION WHILE NEGATIVE ANOMALIES DOMINATE
OVER WESTERN/CENTRAL CANADA. THE AREA OF GREATER UNCERTAINTY IS
WITH THE POTENTIAL FOR AMPLIFIED FLOW EAST OF THE INTERNATIONAL
DATELINE AND SOUTH OF THE ALEUTIANS. EXCEPT FOR THE PAST FEW RUNS
OF THE GFS/GEFS...ALL RECENT MODEL GUIDANCE FAVOR AN IMPRESSIVE
CLOSED LOW TRACKING ACROSS THE NORTH-CENTRAL PACIFIC WHICH WOULD
BUILD HEIGHTS OVER THE WESTERN ALEUTIANS. GIVEN THE MAJORITY OF
SOLUTIONS FAVORED THIS SCENARIO...WENT IN THE DIRECTION OF THE 00Z
ECMWF/ECMWF ENSEMBLE MEAN WHILE INCORPORATING SOME OF THE 00Z
NAEFS MEAN FOR THE PERIOD. THE LATTER WAS ADDED TO GIVE SOME
VARIABILITY TO THE PREFERENCE TO ACCOUNT FOR GENERAL UNCERTAINTIES.


RUBIN-OSTER

$$





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