Prognostic Meteorological Discussion
Issued by NWS

Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1
000
FXAK02 KWNH 201857
PMDAK

ALASKA EXTENDED FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
157 PM EST SAT JAN 20 2018

VALID 12Z WED JAN 24 2018 - 12Z SUN JAN 28 2018

GUIDANCE MAINTAINS AN AMPLIFIED AND BLOCKY LARGER SCALE MEDIUM
RANGE FLOW PATTERN OVER THE ALASKAN REGION AND VICINITY FOR THE
UPCOMING WEEK. THIS PATTERN REMAINS HIGHLIGHTED ALOFT BY A NEAR
DATELINE CENTERED HIGH LATITUDE RIDGE SANDWICHED BY UNSETTLED
TROUGHS OFF NERN ASIA AND ANOTHER COLD TROUGH FROM THE ARCTIC AND
NORTH SLOPE DOWN ACROSS THE INTERIOR THROUGH A GULF OF ALASKA MEAN
CLOSED LOW. GULF OF ALASKA MARITIME INTERESTS AND COOLED SRN/SERN
ALASKA COASTAL COMMUNITIES/TERRAIN WILL BE THREATENED BY PERIODS
OF ENHANCED WINDS/MOISTURE AND WINTER PRECIPITATION WRAPPING
AROUND A SERIES OF ORGANIZED OFFSHORE LOWS ALL NEXT WEEK.

TODAYS WPC PRODUCT SUITE WAS PRIMARILTY DERIVED FROM 00 UTC ECMWF
ENSEMBLES THAT NOW CLUSTERS BEST WITH WPC CONTINUITY AFTER
PROVIDING A POOR ROGUE 00 UTC RUN YESTERDAY THAT WAS DISCOUNTED AT
THE TIME. DID TODAY ALSO INCLUDE SIGNIFICANT INPUT FROM THE 12 UTC
GFS AND 00 UTC ECMWF MODELS INTO MIDWEEK TO PROVIDE ADDED DETAIL
CONSISTENT WITH PREDICTABILITY. QUICKLY DECREASED DETERMINISTIC
MODEL INPUT TO LEAN HEAVILY ON THE ECMWF ENSEMBLE MEAN DAYS 5-8
WHEN DETERMINISTIC MODEL GUIDANCE OFFERS LESS MANAGEABLE FORECAST
VARIABILILTY WITH EMBEDDED WEATHER FEATURES DESPITE A REASONABLY
SIMILAR LARGER SCALE FLOW EVOLUTION ALOFT. THIS WPC/ALASKAN WFO
COLLABORATED SOLUTION MAINTAINS EXCELLENT WPC FORECAST CONTINUITY
IN A PATTERN WITH NEAR TO SLIGHTLY ABOVE NORMAL PREDICTABILITY
OVERALL.

SCHICHTEL

$$





USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.