Blizzard in Alaska, February 3 to 5, 2012

SOUTHCENTRAL AND SOUTHWEST ALASKA FORECAST DISCUSSION...CORRECTED
NATIONAL WEATHER SERVICE ANCHORAGE AK
530 AM AKST FRI FEB 3 2012

.ANALYSIS AND UPPER LEVELS...
THERE ARE TWO STRONG LOWS IMPACTING THE REGION TODAY. OUT WEST A DEEP
LOW IS MOVING NORTHEAST FROM THE NORTH PACIFIC TOWARD THE CENTRAL
ALEUTIANS. AS IT CONTINUES ITS PROGRESSION INTO THE BERING THROUGH
SATURDAY AFTERNOON IT WILL SPREAD HIGH WINDS AND BLIZZARD CONDITIONS
TO PARTS OF THE ALEUTIANS AND COASTAL SECTIONS OF SOUTHWEST.
CURRENTLY OVER SOUTHWEST ALASKA CLEAR SKIES AND CALM WINDS DOMINATE
KEEPING TEMPERATURES BELOW ZERO. FOR SOUTHCENTRAL ALASKA ANOTHER LOW
FROM THE NORTH PACIFIC IS MAKING ITS WAY INTO THE GULF OF ALASKA AND
MOVING TOWARD PRINCE WILLIAM SOUND. THIS SYSTEM IS PUMPING AMPLE
MOISTURE INTO THE REGION AND ALSO BRINGING WARMER TEMPERATURES. MANY
AREAS AROUND SOUTHCENTRAL ARE BEGINNING TO SEE AREAS OF MODERATE TO
HEAVY SNOW. THE TIGHT PRESSURE GRADIENT WITH THIS SYSTEM IS ALSO
BRINGING STRONG WINDS TO WESTERN PRINCE WILLIAM SOUND NEAR WHITTIER
AND THE EASTERN KENAI PENINSULA NEAR SEWARD.

.MODEL DISCUSSION...IN THE SHORT TERM THE MODELS ARE IN GOOD
AGREEMENT. SATURDAY AFTERNOON THINGS BECOME MORE
CHAOTIC...SPECIFICALLY WITH THE LOW TRACKING WEST TO EAST ALONG THE
ALEUTIANS. THE GFS AND NAM BOTH MOVE THE LOW INTO THE BERING WITH THE
GFS BEING FASTER...WHILE THE EC FORMS A TRIPLE POINT LOW AND MOVES
THE ENERGY FROM THE LOW ALONG THE ALEUTIANS INTO THIS NEW LOW.
CONFIDENCE FROM THE MID TERM ON IS LOWER THAN AVERAGE AND WITH
PREFERENCE TO THE GFS FOR ITS CONSISTENCY.

.SHORT TERM FORECAST...
SOUTHCENTRAL...PRECIPITATION TO CONTINUE TO SPREAD ACROSS ALL OF
SOUTHCENTRAL AS LOW IN THE EASTERN GULF MOVES INTO PRINCE WILLIAM
SOUND TODAY. WITH DEEP SOUTHERLY/TROPICAL FETCH OF MOISTURE INTO THIS
SYSTEM EXPECT SIGNIFICANT SNOWFALL ACCUMULATIONS FOR MANY AREAS
BEFORE THIS STORM WINDS DOWN TONIGHT. SNOW ADVISORIES HAVE BEEN
ISSUED FOR BOTH THE COPPER RIVER BASIN AND THE ANCHORAGE AREA WHERE
SNOW HAS ALREADY BEGUN TO FALL AND ACCUMULATE. FURTHER SOUTH...STRONG
WEST WINDS BLOWING OUT OF THE ALASKA RANGE WILL GENERATE PERSISTENT
SNOW SHOWERS AND GUSTY WINDS AROUND KACHEMAK BAY...WHERE A BLOWING
SNOW ADVISORY HAS ALSO BEEN ISSUES. AS LOW PRESSURES MOVE INTO PRINCE
WILLIAM SOUND THIS MORNING EXPECT WEST WINDS IN WHITTIER TO INCREASE
RAPIDLY...COMBINING WITH HEAVY SNOW TO PRODUCE BLIZZARD CONDITIONS.
ALL LOCATIONS SHOULD SEE ALL SNOW THROUGHOUT THE EVENT...WITH THE
EXCEPTION OF CORDOVA WHERE HEAVY RAIN WILL TURN TO HEAVY SNOW BY THIS
AFTERNOON IF NOT EARLIER. SNOW WILL CONTINUE UNTIL THE UPPER LEVEL
TROUGH MOVES THROUGH ANCHORAGE AROUND MIDNIGHT TONIGHT. THE HILLSIDE
WILL SEE THE HIGHEST SNOWFALL TOTALS IN THE ANCHORAGE AREA...WITH A
FOOT OR MORE OF SNOW LIKELY WHEN ALL IS SAID AND DONE.

SOUTHWEST...ONE MORE BITTERLY COLD DAY ON TRACK BEFORE A BIG WARMUP
BEGINS TONIGHT. A STRONG FRONT ASSOCIATED WITH THE LOW IN THE BERING
WILL APPROACH TONIGHT. WITH PLENTY OF COLD AIR REMAINING IN
PLACE...BLIZZARD CONDITIONS ARE EXPECTED TO DEVELOP OVER THE
KUSKOKWIM DELTA OVERNIGHT TONIGHT WITH STRONG EASTERLY WINDS. ALL
MODELS SHOW THE FRONT STALLING OVER SOUTHWEST ALASKA THROUGH SATURDAY
NIGHT...BEFORE SLOWLY WEAKENING IN PLACE. THIS WILL USHER IN THE
WARMEST TEMPERATURES THAT HAVE BEEN SEEN IN QUITE A WHILE...WITH MANY
LOCATIONS IN THE DELTA AND BRISTOL BAY AREAS APPROACHING THE FREEZING
MARK THIS WEEKEND.

BERING SEA AND ALEUTIANS...STRONG 955 MB LOW SOUTH OF SHEMYA WILL
MOVE SLOWLY EASTWARD AND WEAKEN...REACHING THE EASTERN ALEUTIANS BY
SATURDAY AFTERNOON. BEHIND THE LOW CENTER...BLIZZARD CONDITIONS OVER
THE WESTERN ALEUTIANS WILL CONTINUE WITH STRONG NORTHERLY WINDS AND
HEAVY SNOW. TO THE EAST OF THE LOW CENTER...DUTCH HARBOR AND THE
ALASKA PENINSULA WILL SEE VERY STRONG SOUTHERLY WINDS AS THE STORM
PASSES. A HIGH WIND WARNING HAS BEEN ISSUED FOR THE ALASKA PENINSULA
WHERE THE MORE COMPLEX TERRAIN SHOULD LEND ITSELF TO FUNNELING AND
ENHANCEMENT OF THE ALREADY-STRONG WINDS THIS STORM WILL BRING. BY THE
END OF THE WEEKEND...THE EASTWARD PROGRESS OF THE LOW WILL BE
HINDERED BY BUILDING HIGH PRESSURE OVER MAINLAND ALASKA...WEAKENING
AND MOVING THE LOW TO THE NORTH.

.LONG TERM FORECAST...
GLOBAL MODELS IN GOOD AGREEMENT THAT A RIDGE WILL BUILD OVER WESTERN
BRITISH COLUMBIA THIS WEEKEND...USHERING IN A CHANGE TO THE LONGWAVE
WEATHER PATTERN OVER THE ALASKAN DOMAIN. THIS NEW PATTERN WILL
FEATURE BROAD SOUTHERLY FLOW AND BRING MUCH WARMER TEMPERATURES TO
MAINLAND ALASKA. OVERALL...EXPECT WARMER AND DRIER CONDITIONS TO
PREVAIL FOR INTERIOR SECTIONS OF THE STATE FOR THE NEXT WEEK (AFTER
TODAY)...WITH PERIODS OF RAIN OR A RAIN/SNOW MIX OVER COASTAL
LOCATIONS. THIS NEW PATTERN WILL FEATURE THE MOST ACTIVE WEATHER
REMAINING OVER THE BERING SEA REGION FOR THE FORESEEABLE FUTURE.

.AER/ALU...WATCH/WARNING SUMMARY
PUBLIC...BLIZZARD WARNING 125 155 191 195
         HIGH WIND WARNING 181
MARINE...GALE WARNING...120 121 129 132 138 150 171 185 179
         STORM WARNING...130 155 160 165 180 170 172 175 176
         HEAVY FREEZING SPRAY WARNING 121 129 130 132 138 141 150
FIRE WEATHER...NONE

KRAMER/DIXON FEB 12