Extreme Cold in Alaska, February 1, 2012

NORTHERN ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE FAIRBANKS AK
346 PM AKST TUE JAN 31 2012

.DISCUSSION...

ALOFT...AS THE MONTH OF FEBRUARY BEGINS A LARGE SCALE PATTERN CHANGE
WILL GET UNDERWAY...BUT IT WILL STILL BE SEVERAL DAYS BEFORE THE
PATTERN CHANGE IS COMPLETE.  A DEEP UPPER LOW JUST OFF THE NW COAST
OF ALASKA WILL GRADUALLY ELONGATE OUT DURING THE NEXT 48 HOURS AND
SPLIT INTO TWO LOW CENTERS.  ONE LOW CENTER TRACKS NORTHEAST AND
ENDS UP IN THE ARCTIC OCEAN NORTH OF THE CANADIAN ARCHIPELAGO AS THE
SECOND CENTER ENDS UP ON THE CHUKOTSK PENINSULA.  A DEEP NORTH PAC
LOW THAT MOVES TOWARD KODIAK ISLAND WED HELPS TO BUILD UP A
DOWNSTREAM RIDGE IN THE EASTERN PACIFIC.

SFC...A 984 MB LOW IN THE NORTHERN GULF OF ALASKA CONTINUES TO
WEAKEN TODAY WITH A WEAK SECONDARY LOW TO DEVELOP NORTH OF THE
WRANGELL ISLANDS THAT MOVES EAST AND DISSIPATES BY WED.  A DEEP
945-950 MB LOW DEVELOPS SOUTH OF THE AK PENINSULA WED AND MOVES UP
INTO SOUTH-CENTRAL AK ON THURSDAY.  A RIDGE WELL OFFSHORE OF THE
ARCTIC COAST WILL SETTLE INTO THE CHUKCHI SEA AND FAR EASTERN RUSSIA
OVER THE NEXT COUPLE OF DAYS.

INTERIOR...STILL QUITE COLD ACROSS THE CENTRAL AND NORTHERN
INTERIOR WITH WIDESPREAD TEMPS IN THE 50 TO 60 BELOW RANGE.
CLEARING WILL ALLOW TEMPS TO FALL AGAIN IN THE SOUTHERN
INTERIOR/AK RANGE VALLEYS TONIGHT FOR ONE LAST REAL COLD NIGHT.
THE NEXT LOW WILL BE MUCH DEEPER AND WILL PUSH A MUCH MILDER AIR
MASS ALOFT ACROSS JUST ABOUT ALL OF THE INTERIOR BY LATE WED INTO
THUR ALONG WITH SOME SNOW...MAINLY ACROSS THE WESTERN INTERIOR AT
FIRST. TEMPS AT FAIRBANKS HAVE A GOOD SHOT AT GETTING ABOVE ZERO
ON THURSDAY...AND INTO THE TEENS AND POSSIBLY 20S (ABOVE) ON THE
HILLS.

NORTH SLOPE...THE NORTH SLOPE WILL REMAIN IN THE ICE BOX FOR THE
NEXT FEW DAYS WITH ANY SIGNIFICANT WARMING HOLDING OFF UNTIL AT
LEAST THE UPCOMING WEEKEND.  THE AIR MASS IS COLD ENOUGH TO EASILY
SUPPORT 40 TO 50 BELOW TEMPS AND POTENTIALLY AS COLD AS 65 BELOW FOR
INLAND VALLEYS. THE WIND REGIME REMAINS LIGHT THE NEXT COUPLE OF
DAYS SO AT LEAST NO WIND CHILL ISSUES. POTENTIAL FOR SOME WIND
CHILL ISSUES BY WED NIGHT OR THUR AS THE NORTH PAC LOW MOVES INTO
THE SOUTHERN MAINLAND...BUT WITH NO OFFSHORE ARCTIC HIGH THE WIND
SPEEDS LOOK ONLY MARGINAL FOR WIND CHILL ISSUES.

WEST COAST...COLD AIR REMAINS LOCKED IN PLACE ACROSS THE INTERIOR
VALLEYS AND WILL REMAIN IN PLACE ACROSS NORTHWEST AK THE REMAINDER
OF THE WEEK.  SOME MODERATION INLAND AREAS SUCH AS THE MIDDLE YUKON
VALLEY THU ASSOCIATED WITH THE CLOUDS AND SNOW WITH THE INCOMING
LOW.  THE COLD AIR LIKELY SLOSHES BACK IN FOR A DAY OR TWO IN THE
WAKE OF THE SHORTWAVE PASSAGE ALOFT...BEFORE A MORE SIGNIFICANT
MODERATION TAKES PLACE OVER THE WEEKEND. THE GRADIENT BEGINS TO
TIGHTEN UP A BIT LATE TONIGHT AND WEDNESDAY AND COLD ENOUGH FOR
SOME LOW WIND CHILLS IN ZONES 212 AND 213 214 AND 215 AFTER
MIDNIGHT TONIGHT. THE POTENTIAL FOR LOW WIND CHILL FOR ZONES 207 AND
210...211 FOR LATE WEDNESDAY NIGHT INTO THU.

IN THE MID-RANGE...MAJOR PATTERN CHANGE WILL BE WELL UNDERWAY AS
TROF ALOFT AMPLIFIES THU-FRI ALONG ABOUT 175W AND RIDGE BUILDS OVR
WRN NORTH AMERICA. HOWEVER...THERE IS A LOT OF SPREAD IN THE DETAILS
OF HOW THE ATMOSPHERE GETS THERE..WITH ENSEMBLE SPREAD FOR 500 MB
HEIGHTS HIGHER OVR THE WEEKEND THAN EARLY NEXT WEEK. CLOSED LOW
ALOFT VCNTY BERING STRAIT FRI PM WILL BE KICKED OUT WITH RIDGE
BUILDING OVER SRN MAINLAND ALASKA OVR THE WEEKEND. BY NEXT WEEKEND A
MILD PATTERN IS EXPECTED TO BE IN PLACE...THOUGH ESPECIALLY OVR THE
INTERIOR THIS WILL LIKELY EVOLVE INTO A STRONG INVERSION SITUATION.
POTENTIAL FOR A LOW TO LIFT UP ALONG THE WEST COAST WITH SOME SNOW
OVER THE WEEKEND.

THE CFS CONTINUES TO PUSH THE WARM ANOMALIES FURTHER WEST WITH EACH
RUN ON DAYS 6-10 AND 8-14...WITH WARM ANOMALIES NOW ACROSS ALL OF
THE FORECAST AREAS ON WEEKS 2 AND 3. ONCE THE PATTERN CHANGES OVER
THE NEXT SEVERAL DAYS PERHAPS A MORE PROLONGED PERIOD WITH A
RELATIVELY MILD AIR MASS ALOFT ACROSS THE AREA.  OF COURSE...THE
DEVIL IS IN THE DETAILS. SHOULD A STRONG RIDGE ALOFT SETTLE OVER
THE MAINLAND STRONG VALLEY INVERSIONS WOULD MAKE FOR COLD NIGHTS
AND MORNINGS.

CLIMATE...WITH ONLY ONE DAY LEFT IN THE MONTH OF JANUARY THE
AVERAGE TEMPERATURE OF -26.7 DEGREES AT THE FAIRBANKS INTERNATIONAL
AIRPORT IS THE COLDEST SINCE 1971. BASED ON THE FORECASTED
TEMPERATURES TODAY THE MONTH WILL LIKELY END UP AS THE 5TH COLDEST
JANUARY ON RECORD BEHIND ONLY 1906...1934...1966 & 1971.

GALENA AND NOME ARE BOTH ON PACE FOR THE COLDEST JANUARY ON
RECORD. KOTZEBUE IS EXPECTED TO END UP WITH THE COLDEST JANUARY
SINCE 1934.

&&

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

JK JAN 12