Blizzard in Alaska, February 25 to 26, 2015

NORTHERN ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE FAIRBANKS AK
408 AM AKST WED FEB 25 2015

.DISCUSSION...

MODELS...EXCELLENT RUN TO RUN CONTINUITY THE LAST COUPLE RUNS.
THIS RUN INITIALIZED WELL AGAINST THE 06Z SURFACE ANALYSIS AND
GOOD AGREEMENT CONTINUES INTO EARLY NEXT WEEK. WILL USE A BLEND
OF THE MODELS TO TWEAK THE CURRENT FORECAST DATABASE.

ALOFT...AT 500 HPA...RIDGE HAS MOVED EAST OVER THE YUKON AND
NORTHWEST TERRITORIES THIS MORNING. SHORTWAVE EXTENDING FROM LOW
OVER WRANGEL ISLAND IS MOVING THROUGH THE EASTERN THIRD OF THE
STATE THIS MORNING AND WILL BE INTO THE YUKON TERRITORY BY NOON.
THE 494 DAM LOW OVER WRANGEL ISLAND WILL MOVE NORTHEAST INTO THE
HIGH CANADIAN ARCTIC BY THURSDAY MORNING. A 546 DAM LOW OVER THE
NORTHWEST PACIFIC SOUTH OF KODIAK WILL MOVE EAST AND DISSIPATE
OVER THE SOUTHEAST PANHANDLE. ZONAL FLOW WILL DEVELOP ACROSS THE
AREA TODAY AND SEVERAL WEAK SHORTWAVES WILL MOVE ACROSS THE AREA
OVER THE NEXT FEW DAYS. A LONG FETCH OF MOISTURE WILL DEVELOP FROM
THE WESTERN PACIFIC ACROSS THE BERING STRAIT AND NORTHWEST ALASKA
TO THE EASTERN BEAUFORT SEA TODAY AND PERSIST INTO FRIDAY BEFORE
BEING SHUT OFF. A MAJOR SHORTWAVE WILL DEVELOP OVER THE WESTERN
BERING SEA THURSDAY MORNING MOVING TO THE CENTRAL BERING SEA
FRIDAY EVENING AND CUTTING OFF THE MOISTURE. THE SHORTWAVE THEN
MOVES TO THE WEST COAST BY EARLY SATURDAY MORNING...INTO THE
WESTERN INTERIOR BY SATURDAY AFTERNOON...THE EASTERN INTERIOR BY
LATE SATURDAY EVENING AND INTO THE YUKON SUNDAY MORNING. A 564 DAM
HIGH WILL MOVE FROM THE CENTRAL NORTH PACIFIC OVER KODIAK ISLAND
BY THURSDAY MORNING AND RIDGING WILL BUILD NORTH OVER THE CENTRAL
PART OF THE STATE AND SLOWLY MOVE EAST INTO THE YUKON TERRITORY
SATURDAY MORNING. AT 850 HPA...MODELS ARE NOW SHOWING WEAK WARM
AIR ADVECTION AS THE RIVER OF MOISTURE MAKES ITS WAY OVER THE
AREA...BUT TEMPERATURES STAY BELOW ZERO THROUGH THE EVENT. THERE
MAY STILL BE SOME POCKETS OF WARMER AIR THAT THE MODELS CANNOT
DEFINE DUE TO THE SIZE OF THE GRID.

SURFACE...WEAK FRONT MOVING ACROSS THE INTERIOR THIS MORNING
SPREADING SOME SCATTERED SNOW SHOWERS AND FLURRIES AROUND THE AREA
MAINLY EAST OF FAIRBANKS. FRONT MOVES INTO YUKON BY AFTERNOON AS
1034 MB RIDGE OF HIGH PRESSURE MOVES INTO THE SOUTHWEST AND
WESTERN INTERIOR THIS MORNING AND WORKS INTO THE CENTRAL INTERIOR
BY EARLY AFTERNOON. 998 MB LOW NEAR WRANGEL ISLAND WILL MOVE NORTH
TO THE HIGH ARCTIC TONIGHT THEN MOVES EAST. A 1005 MB LOW WILL
DEVELOP IN THE SOUTHWEST CHUKCHI SEA AND MOVE JUST NORTH OF BARROW
BY THURSDAY MORNING AND DISSIPATE. A LONG FETCH OF MOISTURE AND
SOUTHWEST FLOW FROM THE WESTERN PACIFIC WILL EXTEND ACROSS THE
BERING STRAIT AND NORTHWEST ALASKA TO THE EASTERN BEAUFORT SEA. A
991 MB LOW IN THE NORTHWEST BERING SEA WILL MOVE TO THE NORTHERN
GULF OF ANADYR BY THURSDAY MORNING AT 1001 MB THEN MOVE NORTH OVER
EASTERN SIBERIA. A 1005 MB LOW WILL DEVELOP SOUTH OF THE GULF OF
ANADYR THURSDAY MORNING AND MOVE TO THE CHUKCHI SEA BY THURSDAY
AFTERNOON AT 1006 MB...THEN MOVE TO OVER BARROW BY EARLY FRIDAY
MORNING...THEN INTO MACKENZIE BAY BY FRIDAY AFTERNOON. A 1008 MB
LOW WILL SPIN UP INTO THE CENTRAL BERING SEA EARLY FRIDAY MORNING
AND MOVE TO THE BERING STRAIT FRIDAY AFTERNOON...MOVING TO THE
NORTHWEST COAST EARLY SATURDAY MORNING AS FRONTAL SYSTEM DEVELOPS
OVER THE WEST COAST. THE FRONT WILL MOVE EAST ACROSS THE STATE
EXITING INTO THE YUKON SUNDAY MORNING AS A 1045 MB HIGH BUILDS
OVER THE WESTERN INTERIOR.

ARCTIC COAST AND BROOKS RANGE...SOUTHWEST FLOW OVER MOST OF THE
AREA WITH SIGNIFICANTLY VARYING CONDITIONS AS EACH FRONT GETS
CAUGHT IN THE FLOW AND MOVES RAPIDLY ACROSS THE AREA. THERE WILL
BE PERIODS OF FLURRIES WITH SOUTHWEST WINDS 10 TO 20 MPH...THEN
PERIODS WHEN NEAR BLIZZARD CONDITIONS WILL OCCUR AS HEAVIER SNOW
AND STRONGER WINDS MOVE THROUGH WITH THE FRONTS. WILL ISSUE
BLIZZARD WARNING FOR ZONE 201 AND 205...BUT AS NOTED CONDITIONS
WILL BE HIGHLY VARIABLE. WINDS INCREASING TODAY TO 30 TO 50 MPH AS
ONE OF THE STRONGER FRONTS MOVES ACROSS THE AREA AND THE RIDGE
BUILDS OVER INTERIOR ALASKA. THE LONG FETCH OF MOISTURE IS NOT
EXPECTED TO PRODUCE HEAVY SNOW IN THE ARCTIC...BUT AREAS IN THE
WESTERN BROOKS RANGE WILL SEE SOME HEAVY SNOW. TEMPERATURES WILL
BE FAIRLY FLAT NEXT COUPLE OF DAYS THEN WARM A LITTLE ON FRIDAY.

WEST COAST AND WESTERN INTERIOR...THE RIVER OF MOISTURE WILL BRING
HEAVY SNOW TO ZONES 207...208...210...211...213 AND 217. THE WINDS
ARE LOOKING TO BE SIGNIFICANTLY STRONGER THAN PREVIOUSLY SUGGESTED
BY THE MODELS SO INSTEAD OF WINTER STORM WARNING FOR ALL THE AREAS
WILL ISSUE BLIZZARD WARNING FOR ZONE 213 AND UPGRADE THE REST TO
WARNINGS IF THEY HAVE NOT BEEN ALREADY. QPF IS STILL PRETTY HIGH
OVER THOSE AREAS...BUT GFS SEEMS A LITTLE HIGH SO WILL LEAN TOWARD
THE ECMWF FOR PRECIPITATION AMOUNTS AND SNOWFALL. WINDS ARE A
LITTLE MORE FRISKY THAN PREVIOUSLY SUGGESTED SO LOOK FOR WINDS
FROM NOME NORTH OF 20 TO 30 MPH GUSTING TO 40 MPH...EXCEPT ON THE
BERING STRAIT COAST...ST LAWRENCE ISLAND...AND FROM KIVALINA
NORTH WINDS WILL BE IN THE 35 TO 50 MPH RANGE WINDS GUSTS NEAR 65
MPH. TEMPERATURES WILL BE PRETTY FLAT THOUGH SOME WARM AIR WILL
BE PULLED NORTH AND MAY RESULT IN SOME RAIN MIXING WITH THE SNOW
ON THE SOUTHERN SEWARD PENINSULA.

CENTRAL AND EASTERN INTERIOR...A FEW FLURRIES FROM FAIRBANKS WEST
THIS MORNING AS THE WEAK FRONTAL SYSTEM MOVES THROUGH THE AREA.
FLURRIES ENDING TO THE EAST BY AFTERNOON. SOME CLEARING AS THE
SURFACE HIGH BUILDS OVER THE AREA TODAY. A WEAK FRONT WILL RIDE
OVER THE TOP OF THE RIDGE THIS AFTERNOON AND EVENING AND THIS WILL
BRING SOME SNOW SHOWERS OR LIGHT SNOW TO AREAS MAINLY NORTH OF
THE YUKON RIVER. THURSDAY THROUGH SATURDAY THE RIDGE WILL
STRENGTHEN OVER THE AREA WITH NOT SIGNIFICANT PRECIPITATION OVER
THE AREA. A STRONG FRONT WILL MOVE WEST TO EAST ACROSS THE STATE
BEGINNING SATURDAY...SPREADING SNOW FROM THE WEST OVER THE
INTERIOR BEGINNING SATURDAY AFTERNOON THROUGH SUNDAY MORNING.
SNOWFALL AMOUNTS OF 2 TO 4 INCHES ARE LIKELY AT THIS TIME. WINDS
WILL GENERALLY BE LIGHT THROUGH SATURDAY...BUT SOME STRONGER WINDS
OF 20 TO 35 MPH MAY ACCOMPANY THE FRONT SIGNIFICANTLY REDUCING THE
VISIBILITY IN BLOWING SNOW. TEMPERATURES WILL CONTINUE TO BE
SLIGHTLY ABOVE NORMAL FOR THIS TIME OF YEAR.

SATELLITE...SPORT MODIS 24 HOUR AND NIGHTTIME MICROPHYSICS RGBS
AT 25/0845Z SHOW LARGE AREAS OF STRATUS ASSOCIATED WITH THE
SHORTWAVE MOVING THROUGH THE AREA THIS MORNING AND THE LOW IN THE
GULF OF ALASKA. NO VIIRS FOG PRODUCTS SO FAR THIS MORNING TO
COMPARE...BUT THE MVFR/IFR/LIFR PROBABILITY PRODUCTS WITH THE
SAME TIME STAMP INDICATE IT IS MOSTLY STRATUS AND NOT FOG.

&&

.AFG WATCHES/WARNINGS/ADVISORIES...

WINTER STORM WARNING FOR AKZ207-AKZ208-AKZ210-AKZ211-AKZ213-
AKZ217.

BLIZZARD WARNING FOR AKZ201-AKZ205.

WINTER WEATHER ADVISORY FOR AKZ202.

GALE WARNING FOR PKZ210-PKZ220-PKZ225-PKZ230.

BRISK WIND ADVISORY FOR PKZ200-PKZ215-PKZ225-PKZ230-PKZ235-
PKZ240-PKZ245.

&&

SDB FEB 15