Gale Warning 10, NWS Fairbanks, AK

NORTHERN ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE FAIRBANKS AK
346 AM AKST TUE JAN 20 2009

.DISCUSSION...
HE WEATHER PATTERN WILL MUCH QUIETER THIS WEEK...BUT NOT WITHOUT
SOME CONCERNS.  THE MODELS ARE IN GOOD AGREEMENT IN THE SHORT TERM
(48-60 HOURS)...WITH INCREASING SPREAD BY THURSDAY AS THE MODELS
STRUGGLE WITH THE DETAILS OF HIGH LATITUDE CUTOFF HIGHS AND LOWS.
TOWARD THE END OF THEIR RESPECTIVE RUNS THE MODELS COME BACK INTO
BETTER AGREEMENT BY DAYS 8-10.

AN UPPER TROUGH PUSHING ACROSS THE CENTRAL INTERIOR WILL SLIDE OFF
INTO THE EASTERN INTERIOR TODAY...AND OFF INTO CANADA BY LATE
TONIGHT.  THE UPPER TROUGH WILL BE ACCOMPANIED BY AREAS OF LIGHT
SNOW WITH THE UPPER FLOW GRADUALLY VEERING INTO THE NORTH IN THE
WAKE OF THE UPPER TROUGH.  AN UPPER RIDGE BUILDING ACROSS SOUTHWEST
AK WILL GRADUALLY EXPAND NORTH INTO THE CHUKCHI SEA BY WED NIGHT AND
THEN MOVE THE CLOSED CENTER TO THE EASTERN BEAUFORT SEA COAST BY THE
END OF THE WEEK. MODELS AND ENSEMBLES ARE IN REASONABLY GOOD
AGREEMENT ON THIS IDEA.  A BUILDING SURFACE RIDGE ACROSS NORTHERN AK
MID-WEEK SLIDES OFF INTO NW CANADA ON THURSDAY.  THIS WILL BRING
SOME STRONGER WIND AND POSSIBLE WIND CHILL AND BLOWING SNOW CONCERNS
TO THE SUMMITS OF THE INTERIOR WED-THUR.

MODELS AND ENSEMBLES REALLY START TO DIVERGE LATE IN THE WEEK AND
THUS FORECAST CONFIDENCE DIMINISHES. THE POINT OF CONTENTION IS
WHETHER OR NOT A LOW DEVELOPS ACROSS THE SOUTHERN INTERIOR LATE IN
THE WEEK UNDERNEATH THE UPPER RIDGE THAT PINCHES OFF ACROSS THE
ARCTIC.  THE ECMWF AND CANADIAN ARE ON BOARD WITH THIS SOLUTION BUT
THE GFS AND MOST OF THE ENSEMBLES KEEP THE UPPER LOW WELL TO THE
EAST OF THE AREA.

HOWEVER...BY EARLY NEXT WEEK THE MODELS AND ENSEMBLES COME INTO
BETTER AGREEMENT AGAIN IN BUILDING A RIDGE IN THE BERING SEA AND
BRINGING A MUCH COLDER AIRMASS BACK INTO NORTHERN AK.

&&

.AFG WATCHES/WARNINGS/ADVISORIES...
GALE WARNING FOR PKZ210.

BRISK WIND ADVISORY FOR PKZ200-PKZ220-PKZ225.
&&

CF JAN 09