Blizzard and Extreme Cold in Alaska, February 1 to 3, 2012

NORTHERN ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE FAIRBANKS AK
348 AM AKST WED FEB 1 2012

.DISCUSSION...
AS A NEW MONTH BEGINS TODAY A MAJOR PATTERN CHANGE WILL GET
UNDERWAY. AFTER ONE OF THE COLDEST...AND IN SOME COMMUNITIES THE
COLDEST JANUARY ON RECORD...A MUCH MILDER WEATHER PATTERN WILL SET
UP IN EARLY FEBRUARY WITH ABOVE NORMAL TEMPS LIKELY ACROSS ALL OF
NORTHERN ALASKA BY THE WEEKEND. SOME AREAS SUCH AS NORTHWEST
ALASKA WILL HAVE TO WAIT A BIT LONGER FOR THE WARMER WEATHER TO
TAKE HOLD.

ALOFT...A DEEP AND VERY COLD LOW ALONG THE WESTERN ARCTIC COAST WILL
CONTINUE TO ELONGATE OUT AND SPLIT INTO TWO LOW CENTERS. THE CENTER
OF INTEREST TO OUR FORECAST AREA WILL SETTLE IN ALONG THE BERING
STRAIT/CHUKOTSK PENINSULA ON THU AS THE OTHER CENTER MOVES TOWARD THE
NORTHERN CANADIAN ARCHIPELAGO.  THIS WILL KEEP THE COLD AIR LOCKED
IN FROM ABOUT BARROW TO THE SEWARD PENINSULA THROUGH FRI.  AN UPPER
LOW SOUTH OF THE AK PENINSULA WEAKENS AS IT MOVES UP INTO THE COOK
INLET TONIGHT.  A STRONG RIDGE BUILDS ALONG THE WEST COAST OF THE
CONUS AND UP INTO WESTERN CANADA THROUGH THU.

SFC...LOW PRESSURE HAS BEEN RAPIDLY DEEPENING OVERNIGHT TO THE SOUTH
OF THE AK PENINSULA AND THE MODELS ARE REASONABLY CONSISTENT THAT
THE LOW BEGINS TO FILL BY THIS EVENING AND ENDS UP AS A 960 MB LOW
OVER KODIAK ISLAND BY 12Z THU.  THE LOW THEN CONTINUES TO FILL
MOVING NORTH OF THE AK RANGE BY THU EVENING. ANOTHER NORTH PAC LOW
IS EXPECTED TO RAPIDLY FOLLOW AND LIFT NORTH INTO THE NORTHERN GULF
OF AK FRI.

INTERIOR...THE INCOMING LOW WILL BRING MODERATE CHINOOK FLOW TO
THE CENTRAL AND EASTERN INTERIOR WITH SIGNIFICANT WARMING OF THE
AIR MASS ALOFT. LIKELY THAT TEMPS IN MANY AREAS RISE DURING THE
NEXT 24 TO 36 HOURS AND FAIRBANKS HAS A GOOD CHANCE EVEN IN THE
VALLEYS OF THE FIRST ABOVE ZERO TEMPS IN THREE WEEKS BY TOMORROW.
TEMPS ON THE HILLS SHOULD EASILY GET INTO THE TEENS AND POSSIBLY
20S ABOVE. A VERY BRIEF PERIOD OF SNOW POSSIBLE IN PARTS OF THE
SOUTHERN AND EASTERN INTERIOR...BUT THEN TONIGHT AS THE CHINOOK
FLOW KICKS IN MOST OF THE OVERRUNNING SNOW WILL BE CONFINED TO THE
FAR WESTERN AND NORTHERN INTERIOR WHERE SOME SPOTS MAY PICK UP A
FEW INCHES OF SNOW. THE CHINOOK FLOW COMES TO AN END THU NIGHT
INTO FRI ALLOWING SOME SNOW AND COLDER AIR TO SLOSH BACK EAST
ACROSS THE INTERIOR. THE COLD AIR WILL BE SHORT LIVED FOR A DAY OR
TWO UNTIL THE MOST PROLONGED WARM-UP GETS UNDER WAY THIS WEEKEND.
A PERIOD OF STRONG WIND POSSIBLE ON THE HIGHWAY SUMMITS THUR NIGHT
INTO FRI AS THE COLD AIR PUSHES BACK ACROSS THE AREA.

NORTH SLOPE...THE ARCTIC TO REMAIN LOCKED IN THE ICE BOX FOR THE
NEXT FEW DAYS.  AREAS EAST OF BARROW WILL SEE SOME MODERATION OF THE
AIR MASS LATE THU INTO FRI ASSOCIATED WITH THE SLY FLOW
ALOFT/CHINOOK FLOW OFF THE EASTERN BROOKS RANGE.  THE WESTERN ARCTIC
COAST WILL REMAIN DEEPLY IN THE ARCTIC AIR THROUGH FRI WITH
TEMPERATURES AS LOW AS 65 BELOW IN THE INTERIOR RIVER VALLEYS THAT
REMAIN CLEAR AND CALM.  THERE WILL BE SOME SCRAPS OF CLOUDS FLOATING
AROUND WITH THE UPPER LOW THAT WILL MODERATE TEMPS IN SOME AREAS.
MUCH MORE SIGNIFICANT MODERATION FOR ALL AREAS TO COMMENCE THIS
WEEKEND AS THE LOW ALOFT LIFTS OUT.

WEST COAST...THE MAIN CONCERN IN THE SHORT TERM WILL BE FOR SOME LOW
WIND CHILLS AS THE GRADIENT CONTINUES TO TIGHTEN UP A BIT AROUND THE
INCOMING NORTH PAC LOW.  THE ONGOING WIND CHILL ADVISORIES LOOK GOOD
BUT WILL NEED TO EXPAND THEM TO THE NORTH.  TEMPS LIKELY COLD ENOUGH
IN ZONES 210 AND 207 FOR WIND CHILL WARNINGS TONIGHT INTO THURSDAY
AND WILL ISSUE WARNINGS FOR THESE AREAS.  AS THE COLD AIR FINALLY
RETREATS THIS WEEKEND A WEATHER FRONT WILL LIKELY BRING THE FIRST
SIGNIFICANT SNOW TO PARTS OF THE WEST COAST IN QUITE SOME TIME.

MEDIUM RANGE...A MAJOR PATTERN CHANGE WILL BE LARGELY COMPLETE
OVR NORTHERN ALASKA BY THE START OF THE MID-RANGE PERIOD...WITH
RIDGE BUILDING FROM BRITISH COLUMBIA NORTHWESTWARD INTO
ALASKA...WITH LOW ALOFT OVR THE SRN BERING SEA THAT EXTENDS AT
TIMES INTO THE SWRN GULF OF ALASKA. THERE IS A LOT OF VARIABILITY
IN MODEL HANDLING OF SHORTWAVES AND IMPACTS ON ORIENTATION OF THE
RIDGE...BUT ALL GUIDANCE AGREES ON THE BASIC PATTERN. PRECIP
SHOULD BE LITTLE OR NONE OVER THE CENTRAL AND ERN INTERIOR AND
MOST OF THE NORTH SLOPE. ALONG THE WEST COAST...SPCLY SEWARD PEN
SWD...THERE WILL BE A BETTER CHANCE FOR PCPN FROM NWWD MOVING
OCCLUSIONS...BUT TIMING AND EVEN THE OCCURRENCE WILL DEPEND ON
SHORTWAVE EVOLUTION.

&&

.CLIMATE...PUBLIC INFORMATION STATEMENTS WILL BE ISSUED LATER
TODAY SUMMARIZING THE COLD WEATHER ACROSS ALL OF NORTHERN AK AS
WELL AS ONE FOR THE MORE IMMEDIATE FAIRBANKS AREA.

&&

.AFG WATCHES/WARNINGS/ADVISORIES...
WIND CHILL ADVISORY FOR AKZ211-AKZ212-AKZ213-AKZ214-AKZ215.

WIND CHILL WARNING FOR AKZ207-AKZ210.

BRISK WIND ADVISORY FOR PKZ200-PKZ210-PKZ220-PKZ225.

&&

CB FEB 12