Prognostic Meteorological Discussion
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FXAK02 KWNH 221809
PMDAK

ALASKA EXTENDED FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
109 PM EST MON JAN 22 2018

VALID 12Z FRI JAN 26 2018 - 12Z TUE JAN 30 2018

IT REMAINS THE CASE THAT MODELS AND ENSEMBLES MAINTAIN AN
AMPLIFIED AND BLOCKY LARGER SCALE MEDIUM RANGE FLOW PATTERN OVER
THE ALASKAN REGION AND VICINITY THIS WEEK. THIS PATTERN IS
HIGHLIGHTED ALOFT BY A SHARP NEAR DATELINE CENTERED HIGH LATITUDE
RIDGE SANDWICHED BY UNSETTLED TROUGHS OVER/OFF NERN ASIA AND A
COLD TROUGH DUG FROM THE INTERIOR INTO A GULF OF ALASKA MEAN
CLOSED LOW POSITION. GULF OF ALASKA MARITIME INTERESTS AND COOLED
SRN/SERN ALASKA COASTAL COMMUNITIES/TERRAIN ARE THREATENED IN THIS
PATTERN BY PERIODS OF ENHANCED WINDS/MOISTURE AND SNOW WRAPPING
AROUND A SERIES OF OFFSHORE LOWS THIS WEEK...WITH THE BRUNT OF
ACTIVITY DIGGING INCREASINGLY OFFSHORE THIS WEEKEND INTO EARLY
NEXT WEEK.

TODAYS WPC PRODUCT SUITE WAS PRIMARILTY DERIVED FROM A COMPOSITE
BLEND OF THE LATEST GFS/ECMWF AND GEFS/ECMWF ENSEMBLES WHOSE
INCREASINGLY COMPATABLE SOLUTIONS OVER THE PAST FEW DAYS CLUSTER
WELL WITH WPC CONTINUITY. THE GFS AND ECMWF PROVIDE ADDED EMBEDDED
SYSTEM/OFFSHORE LOW DEPTH CONSISTENT WITH PREDICTABILITY AND
DYNAMIC SUPPORT ALOFT IN AMPLIFIED FLOW THAT WAS FURTHER AUGMENTED
BY MANUAL MODIFCIATIONS. ENSEMBLE MEANS INPUT IN THE BLEND PROCESS
FURTHER DECREASED RUN TO RUN VARIANCE. THIS RESULTANT WPC/ALASKAN
WFO COLLABORATED SOLUTION MAINTAINS EXCELLENT WPC FORECAST
CONTINUITY IN A PATTERN WITH NEAR TO SLIGHTLY ABOVE NORMAL
PREDICTABILITY.

SCHICHTEL

$$





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