Prognostic Meteorological Discussion
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000
FXAK02 KWNH 061857
PMDAK

ALASKA EXTENDED FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
156 PM EST SAT FEB 06 2016

VALID 12Z WED FEB 10 2016 - 12Z SUN FEB 14 2016

...GUIDANCE AND UNCERTAINTY ASSESSMENT...

THE WPC ALASKAN MEDIUM RANGE PRODUCT SUITE WAS PRIMARILY DERIVED
FROM THE 00 UTC ECMWF DAYS 4/5 WED/THU...THEN GRADUALLY BLENDED
THE ECMWF INCREASINGLY WITH A COMPATABLE MIX OF THE 06 UTC GEFS
MEAN AND 00 UTC NAEFS/ECMWF ENSEMBLE MEANS DAYS 6-8 CONSISTENT
WITH SLOWLY DECREASING FLOW PREDICTABILITY OVER TIME.
OVERALL...THE MODELS AND ENSEMBLES OFFER BELOW NORMAL FORECAST
SPREAD AND BETTER THAN NORMAL CONTINUITY DAYS 4-8 WITH THE
EVOLUTION OF THE WEATHER PATTERN.

...PATTERN AND WEATHER HIGHLIGHTS/THREATS...

THE GFS/ECMWF/CANADIAN DO OFFER SOME VARIANCE WITH TIMING...BUT
OVERALL HAVE TRENDED TOWARD THE IDEA OF CUTTING ENHANCED MID-UPPER
LEVEL TROUGH ENERGY AND COOLING FROM THE SRN ARCTIC ACROSS NRN AK
BY MIDWEEK THAT SHIFTS TO THE VICINITY OF THE BERING STRAIT INTO
NEXT WEEKEND. WPC PROGS NOW SHOW MORE TROUGHING ALOFT HERE
COMPARED TO YESTERDAYS WPC PROGS GIVEN POTENTIAL/TRENDS...BUT
TEMPERED AMPLITUDE SOME WITH INCLUSION OF ENSEMBLE MEAN GUIDANCE
GIVEN FORECAST SPREAD.

UNDERNATH...THIS PATTERN REMAINS HIGHLIGHTED BY AN AMPLIFIED MEAN
RIDGE EXTENDING NWWD FROM SERN AK TO THE INTERIOR. THIS TENDS TO
SHIELD AN ACTIVE FLOW OF DEEPENING LOWS FROM THE NERN PACIFIC UP
THROUGH THE ALEUTIANS/SW AK TO THE SRN BERING SEA AND ALSO WORKING
OUT ACROSS THE GULF OF AK WITH TIME AS EMBEDDED DEEP LOWS WRAP
AROUND THE A MEAN LOW/TROUGH POSITION CENTERED JUST SOUTH OF THE
ALEUTIANS/SW AK. WRAPPING PCPN SHOULD FOCUS ACROSS THESE AREAS AND
ALSO INTO COASTAL AREAS/TERRAIN OF SRN/SERN AK WITH PERIODICALLY
ENHANCED LEAD LOW LEVEL INFLOW.

SCHICHTEL

$$




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