Prognostic Meteorological Discussion
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FXAK02 KWNH 231920
PMDAK

ALASKA EXTENDED FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
319 PM EDT MON MAY 23 2016

VALID 12Z FRI MAY 27 2016 - 12Z TUE MAY 31 2016

...GUIDANCE/UNCERTAINTY ASSESSMENT...

THE WPC ALASKAN MEDIUM RANGE PRODUCT SUITE HAS BEEN PRIMARILY
DERIVED FROM A COMPOSITE BLEND OF THE 00 UTC NAEFS/ECMWF ENSEMBLE
MEANS AND NOW QUITE COMPATABLE 12 UTC GEFS MEAN. THIS SOLUTION
MAINTAINS BETTER WPC CONTINUITY THAN USAGE OF THE MORE VARIED AND
RUN TO RUN UNCERTAIN DETERMINISTIC MODEL GUIDANCE DAYS 4-8/FRI
THROUGH NEXT TUE. THIS WPC ENSEMBLE BASED SOLUTION WAS COORDINATED
WITH WFO ANCHORAGE AND WFO JUNEAU AND SEEMS A GOOD FIT WITH
UPSTREAM FLOW POSITION AND AMPLITUDE. FORECAST SPREAD AND
UNCERTAINTY IS SLIGHTLY ABOVE AVERAGE OVERALL.


...WEATHER PATTERN HIGHLIGHTS/THREATS...

COOLING AND UNSETTLING MID-UPPER LEVEL TROUGH ENERGIES AND LEAD
PCPN SWATH DIG ROBUSTLY SEWD FROM THE ALASKAN INTERIOR INTO WRN
CANADA FRI. SUBSEQUENT DIGGING IMPULSES DOWN THROUGH THE INTERIOR
THEN SRN AK/GULF OF AK IN THIS FLOW SEEM LESS PREDICTABLE THIS
WEEKEND...BUT ARE SLATED TO CARVE OUT SOME FORM OF AN AMPLIFIED
TROUGH ALOFT AND INDUCE A NRN GULF OF AK LOW. UNDERNEATH...A MAIN
STORM TRACK OVER THE ERN PACIFIC MID-UPPER LATITUDES IS EXPECTED
TO HOLD SOUTH OF THE STATE THIS WEEK.

MEANWHILE UPSTREAM...A DEEPENED WRN ALEUTIAN LOW FRI PULLS AWAY
THIS WEEKEND...BUT A MORE BENIGN WEATHER PERIOD ACROSS THE
ALEUTIANS AND BERING SEA MAY GET QUITE ACTIVE SUN-NEXT TUE. LATEST
GUIDANCE TRENDS SUPPORT A WELL DEVELOPED LOW APPROACH FROM THE
N-CENTRAL PACIFIC IN AMPLIFIED AND SLOWLY PROGRESSIVE FLOW WITH
ENHANCED WINDS/WAVES/PCPN.

SCHICHTEL

$$




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