Heavy Snow in Alaska, February 1 to 2, 2012

NORTHERN ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE FAIRBANKS AK
211 PM 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 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...A STRONG 944 MB LOW IN THE GULF OF ALASKA WILL WEAKEN TO
961 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. TEMPS IN MANY AREAS WILL 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.

STRONG SOUTHERLY WINDS IN THE PASSES OF THE ALASKA RANGE WILL PRODUCE
BLOWING SNOW AND LOCALLY POOR VISIBILITY OF ZONES 225 AND 226. WINTER
WX ADVISORIES WILL BE ISSUED THIS AFTERNOON.

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.

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 THRU THURSDAY AFTERNOON.
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-AKZ213-AKZ214-AKZ215.

WIND CHILL WARNING FOR AKZ207-AKZ210-AKZ212.

WINTER WEATHER ADVISORY FOR AKZ225-AKZ226.

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

FEB 12