Blizzard in Alaska, January 22 to 24, 2011

SOUTHCENTRAL AND SOUTHWEST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ANCHORAGE AK
500 PM AKST SAT JAN 22 2011

.ANALYSIS AND UPPER LEVELS...
A LONGWAVE TROUGH ENCOMPASSES THE BERING SEA AND MUCH OF MAINLAND
ALASKA. IN THE BASE OF THIS TROUGH IS AN UPPER LEVEL LOW SOUTH
OF THE ALEUTIAN ISLANDS THAT IS SUPPORTING A STRONG 958 MB LOW AT THE
SURFACE. FURTHER EAST...A 981 MB SURFACE LOW HAS MOVED ONSHORE NEAR
YAKUTAT AND IS RAPIDLY WEAKENING. AS THIS LOW MOVES AWAY...MODEST
COLD AIR IS MOVING BACK INTO THE COOK INLET REGION FROM THE WEST AND
IS SUPPORTING CONTINUED FLURRIES AND ISOLATED SNOW SHOWERS FROM KENAI
NORTH TO THE MATANUSKA VALLEY. MEANWHILE...VERY COLD AIR REMAINS
ENTRENCHED OVER SOUTHWEST ALASKA AND IS COMBINING WITH GUSTY WINDS TO
PRODUCE DANGEROUS WIND CHILLS TO 40 BELOW ZERO OVER THE KUSKOKWIM
DELTA.

.MODEL DISCUSSION...MODELS HAVE COME INTO BETTER AGREEMENT FROM
PREVIOUS DAYS. ALL MODELS NOW KEEP A WEAK RESIDUAL LOW NEAR THE
EASTERN KENAI PENINSULA TONIGHT...WHICH THEN GETS ABSORBED INTO THE
STRONG FRONT THAT MOVES INTO THE GULF ON SUNDAY. THERE REMAINS SOME
UNCERTAINTY ABOUT WHETHER A TRIPLE POINT LOW WILL DEVELOP IN THE COOK
INLET REGION SUNDAY EVENING. THE AFTERNOON FORECAST WILL ADOPT A
COMPROMISE SOLUTION AND BLEND TOWARD THE GFS MODEL...WITH THE RESULT
OF DEVELOPING A WEAK LOW NEAR KENAI.

.SHORT TERM FORECAST...
.SOUTHCENTRAL...WIDESPREAD SNOW THAT FELL OVERNIGHT HAS LARGELY
DISSIPATED...WITH COLD ADVECTION LIGHT SNOW SHOWERS PERSISTING
GENERALLY NORTH OF KACHEMAK BAY. MORE SUBSTANTIAL SNOWFALL IS NOW
CONFINED TO THE EASTERN COPPER RIVER BASIN...AND WILL BE DIMINISHING
THROUGH THE EVENING. A STRONG FRONT ASSOCIATED WITH THE BERING LOW
MOVES INTO THE AREA TOMORROW...INCREASING EASTERLY WINDS TO NEAR
STORM-FORCE IN THE GULF AND MORE NORTHERLY IN COOK INLET. WINDS WILL
INCREASE THROUGH THE USUAL GAPS SUCH AS TURNAGAIN ARM AND THOMPSON
PASS. THESE WINDS SHOULD REMAIN BELOW WARNING LEVEL DUE TO THE
FORECAST WEAK TRIPLE POINT LOW DEVELOPING IN COOK INLET. HEAVY
PRECIPITATION WILL FALL WITH THIS FRONT ON THE EASTERN SIDE OF THE
KENAI PENINSULA AS WELL AS PRINCE WILLIAM SOUND. MEANWHILE...THE
ANCHORAGE AREA WILL REMAIN LARGELY PROTECTED FROM SNOW ASSOCIATED
WITH THIS FRONT DUE TO DOWNSLOPING ON THE CHUGACH AND KENAI
MOUNTAINS.

.SOUTHWEST AND BERING SEA...DEEP LOW SOUTH OF THE ALEUTIANS WILL MOVE
SLOWLY TO THE NORTHEAST OVER THE NEXT FEW DAYS. BLIZZARD CONDITIONS
EXPECTED TO DEVELOP OVER THE PRIBILOFS LATE TONIGHT AND CONTINUE
THROUGH MUCH OF THE DAY SUNDAY. WARMER CONDITIONS OVER THE EASTERN
ALEUTIANS AND ALASKA PENINSULA SHOULD KEEP THE PRECIPITATION AS
MAINLY RAIN IN THOSE AREAS. WARMING TREND EXPECTED FOR THE SOUTHWEST
MAINLAND OVER THE NEXT COUPLE OF DAYS WITH INCREASING CLOUDS AND
WARMING TEMPERATURES ALOFT.

.AER/ALU...WATCH/WARNING SUMMARY
PUBLIC...BLIZZARD WARNING 195.
MARINE...STORM WARNING 130 165 170 172 179.
       GALE WARNING 120 132 138 140 150 155 160 171 175 176 180 185.
       HEAVY FREEZING SPRAY 160 179 185.
FIRE WEATHER...NONE.

AMD/BL JAN 11