Blizzard in Alaska, March 5, 2013

NORTHERN ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE FAIRBANKS AK
526 AM AKST TUE MAR 5 2013

.DISCUSSION...
ALOFT...STRONG RIDGE OVER EASTERN ALASKA WITH LONG WAVE TROUGH
OVER EASTERN RUSSIA AND THE WESTERN BERING SEA...RESULTING IN
SOUTHERLY FLOW OVER THE WEST COAST OF ALASKA. THROUGH THE WEEK THE
LONG WAVE TROUGH WILL DRIFT EAST AS SHORT WAVES MOVE THROUGH IT
AND EVENTUALLY THE RIDGE WILL BE OVER CANADA...THUS SETTING UP
SOUTHERLY FLOW OVER ALL OF MAINLAND ALASKA BY EARLY FRI. CURRENTLY
A STRONG SHORT WAVE TROUGH FROM THE PRIBILOFS TO COLD BAY WILL
MOVE TO THE BERING STRAIT TO FAIRBANKS 3PM WED...AND TO THE ARCTIC
COAST 9AM THU WHILE A SMALL LOW MOVES FROM THE NORTH PACIFIC TO
BRISTOL BAY AT THAT TIME.

SURFACE...977 MB LOW OVER THE FAR WEST BERING SEA WILL DRIFT NORTH
AND WEAKEN. ASSOCIATED OCCLUSION FROM SAINT LAWRENCE ISLAND TO
EMMONAK TO WESTERN BRISTOL BAY WILL DRIFT NORTH TUE AND DISSIPATE
WHILE A WEAK LOW ON THE OCCLUSION MOVES TO NOME 3AM WED AND THEN
NORTHWEST TO THE SOUTHERN CHUKCHI SEA AT NOON WED. THE OCCLUSION
WILL MOVE INLAND DURING THIS TIME TO KIVALINA TO GALENA TO BETHEL
WITH COOLER AIR TO THE WEST OF IT. STRONG HIGH PERSISTING IN THE
HIGH ARCTIC WHILE WEAKENING OVER WESTERN CANADA THROUGH THU.
STRONG WARM FRONT MOVING NORTH TO BETHEL TO THE ALASKA RANGE
CREST 3AM THU.

MODELS...THERE IS FAIRLY GOOD AGREEMENT IN THE MODELS THROUGH THU
ON THE BASIC FEATURES ALOFT AND SURFACE AS WELL AS THEIR
MOVEMENTS. IN THE MEDIUM RANGE THE ECMWF AND GFS PART WAYS
BEGINNING SAT AS THE GFS BRINGS A STRONG RIDGE NORTHEAST OVER
ALASKA WHILE THE ECMWF IS SLOWER.

NORTH SLOPE...EXPECT INCREASE IN WINDS TODAY OVER EASTERN COAST
WHILE NEAR BARROW WINDS WILL STAY ABOUT THE SAME. WINDS WILL THEN
PERSIST FOR A FEW DAYS SO WILL CONTINUE THE WINTER WEATHER
ADVISORIES. IF WINDS GET STRONG ENOUGH CONDITIONS MAY REACH
BLIZZARD CRITERIA...PERHAPS WITH THE PROSPECT OF FRESH SNOW
WED NIGHT AND THU WITH THE WEAKENING SHORT WAVE TROUGH.

WESTERN ALASKA...POTENTIAL FOR SNOW AMOUNTS HIGH ENOUGH TO MEET
WARNING CRITERIA WILL LIKELY FAVOR THE HIGHER TERRAIN AND UPSLOPE
AREA OF THE NULATO HILLS. FARTHER NORTH AND WEST THE SNOW AMOUNTS
COULD END UP LOWER...BUT AS EVENT IS JUST IN ITS BEGINNING WILL
MAINTAIN WARNINGS FOR NOW. SNOW SPREADING NORTH TODAY AND
NORTHEAST TONIGHT...LINGERING INTO WED WITH LESSER AMOUNTS AFTER
THIS EVENING. WHILE TEMPERATURES WARM OR WARMING TODAY AHEAD OF
THE OCCLUSION...WINDS WILL DIMINISH TONIGHT AND THEN COOLING WITH
SNOW SHOWERS ON WED BEHIND THE OCCLUSION AS IT MOVES INLAND.

CENTRAL AND EASTERN INTERIOR...SNOW FROM THE OCCLUSION MAINLY
EXPECTD FOR ZONE 221 WED WITH 1 INCH ACCUMULATION...AND A CHANCE
OF SNOW FOR ZONE 219 WED PM. REST OF AREA SHOULD STAY DRY. SOUTH
WINDS INCREASING NEAR ALASKA RANGE THU AS CHINOOK FLOW SETS UP
AS RIDGE SHIFTS EAST INTO CANADA...PROVIDING WARMER TEMPS FOR
MUCH OF THE AREA.

&&

.AFG WATCHES/WARNINGS/ADVISORIES...
WINTER STORM WARNING FOR AKZ210-AKZ211-AKZ212-AKZ215-AKZ216.

WINTER WEATHER ADVISORY FOR AKZ202-AKZ203-AKZ204-AKZ213.

GALE WARNING FOR PKZ210-PKZ220-PKZ225-PKZ235-PKZ240-PKZ245.

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

JL MAR 13