Blizzard in Alaska, December 23, 2010

NORTHERN ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE FAIRBANKS AK
435 AM AKST THU DEC 23 2010

.DISCUSSION...
MODELS IN DECENT AGREEMENT THROUGH 60 HOURS. SHORT WAVE CENTERED
OVER THE CHUKOTSK PENINSULA WILL MOVE SLIGHTLY WEST AND THEN DRIVE
ITS ENERGY SOUTH TO THE GULF OF ALASKA BY THU MORNING. ASSOCIATED
SURFACE FRONT AND LOW WILL STALL OVER THE WEST COAST AS WELL AND
SLIDE SOUTHWARD RAPIDLY TO WHERE THE SURFACE LOW WILL DISSOLVE NEAR
NORTON SOUND LATE THU NIGHT. WEAK UPPER LEVEL LOW WILL CONTINUE TO
TRACK TO THE GULF OF ALASKA.

HIGH PRESSURE OVER FAR EAST RUSSIA WILL CONTINUE TO BUILD THROUGH
FRIDAY TO ABOUT 1053 MB BEFORE SLOWLY WEAKENING OVER THE NEXT
SEVERAL DAYS. AFTER THE UPPER LEVEL TROUGH DIGS IN OVER THE STATE
THE STRONG COLD ADVECTION WILL POUR IN FROM THE NORTHWEST
BEGINNING FRIDAY.

AN UPPER LEVEL RIDGE WILL TRY TO POKE IN FROM THE EAST THIS
WEEKEND FROM CANADA AND ATTEMPT A SMALL AMOUNT OF WARM ADVECTION
TO THE SOUTHEASTERN PORTION OF NORTHERN ALASKA...HOWEVER IT WILL
BE SHORT LIVED AND MUCH COLDER ADVECTION IS ADVERTISED TO COME
BACK WITH A VENGEANCE NEXT WEEK.

THE FRONT OVER THE WEST COAST CURRENTLY IS DROPPING VISIBILITIES
TO NEAR ZERO IN MANY PLACES WITH WINDS FAR ABOVE WHAT MOS HAS
PREDICTED. WINDS SHOULD BEGIN TO DIMINISH BY THIS AFTERNOON AS
WELL AS SNOWFALL EASING OFF WHILE THE LOW DROPS SOUTHWARD AND
FILLS RAPIDLY.

THE MEDIUM RANGE STARTS OFF SUNDAY WITH AN UPPER LOW SITUATED NEAR
THE AK PENINSULA WITH A BROAD CIRCULATION CENTER THAT COVERS JUST
ABOUT ALL OF NORTHERN AK.  THE CENTER OF THE UPPER LOW MOVES EAST
ACROSS THE GULF OF AK EARLY NEXT WEEK AND WEAKENS AS IT MOVES INTO
BC TUE NIGHT OR WEDNESDAY.  THE MODELS ARE GENERALLY IN GOOD
AGREEMENT ON THIS IDEA.  BEYOND THE MIDDLE OF NEXT WEEK THERE IS
MORE MODEL SPREAD.  THERE IS IN A GENERAL SENSE SOME AGREEMENT THAT
AN UPPER RIDGE WILL BE FOUND ACROSS CENTRAL RUSSIA AND THAT ANOTHER
SURGE OF COLD AIR WILL DROP SOUTH INTO NORTHERN AK MID-LATE WEEK.
THE MODELS AND ENSEMBLES DIFFER ON WHERE THE COLDEST AIR WILL
PENETRATE.  THE 12Z GFS TAKES THE BRUNT OF THE COLD AIR INTO THE
CENTRAL AND EASTERN INTERIOR. THE ECMWF TAKES THE COLDEST AIR INTO THE
NORTHERN INTERIOR AND ALONG THE WEST COAST AND THE LATEST RUN OF THE
GFS LOOKS TO BE COMING MORE IN LINE WITH THE ECMWF. THE ECMWF
HAS 850 MB TEMPS AS LOW AS 40 BELOW ACROSS THE BROOKS RANGE BY
THURSDAY.  IN ANY EVENT THERE IS NO SIGNS OF ANY WARM-UPS ANYTIME
SOON AND THE POTENTIAL FOR THE COLDEST TEMPS SO FAR THIS WINTER
ACROSS MUCH OF THE REALM BY LATE NEXT WEEK.

COASTAL HAZARD POTENTIAL DAYS 3 AND 4...NONE

&&

.AFG WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY FOR AKZ201-AKZ207-AKZ213.

SMALL CRAFT ADVISORY FOR PKZ210.

GALE WARNING FOR PKZ210.

BRISK WIND ADVISORY FOR PKZ200-PKZ215-PKZ220-PKZ225-PKZ230.
&&

CF DEC 10