Blizzard in Alaska, February 14 to 15, 2008

AREA FORECAST DISCUSSION
SOUTHCENTRAL AND SOUTHWEST ALASKA
115 PM AST THU FEB 14 2008

.ANALYSIS AND UPPER LEVELS...MAJOR LOW THAT HAS IMPACTED MUCH OF
THE ALASKA THE LAST 24 HOURS IS CURRENTLY CENTERED NORTHEAST OF
KODIAK TRACKING NORTHWARD TOWARD THE KENAI PENINSULA. EXTREMELY
STRONG COLD ADVECTION CONTINUES BEHIND THE SYSTEM OVER THE EASTERN
BERING/SOUTHWEST ALASKA/ALASKA PENINSULA AND IS CURRENTLY MOVING
INTO THE KODIAK ISLAND REGION. BLIZZARD CONDITIONS HAVE SUBSIDED
ALONG THE ALASKA PENINSULA...BUT CONTINUE ALONG KUSKOKWIM DELTA AND
MUCH OF BRISTOL BAY IS OBSERVING CONDITIONS APPROACHING BLIZZARD
CRITERIA. TEMPERATURES OVER PORTIONS OF SOUTHWEST ALASKA HAVE
PLUMMETED THIS MORNING...DROPPING FROM THE 30S TO TEENS WITHIN A
COUPLE HOURS. EASTERLY CHINOOK WINDS CONTINUE AHEAD OF THE LOW
ACROSS SOUTHCENTRAL ALASKA...KEEPING THE LEE SIDE OF THE MOUNTAINS
DRY. COASTAL LOCATIONS HAVE CHANGED TO MAINLY RAIN WHILE SNOW
CONTINUES IN THE UPSLOPE AREA OF THE WESTERN SUSITNA VALLEY. A NEW
LOW HAS DEVELOPED ABOUT 500 MILES SOUTH OF THE CENTRAL ALEUTIANS. A
VERY LOW AMPLITUDE RIDGE EXTENDING FROM RUSSIA EASTWARD ACROSS THE
SOUTHERN BERING TO THE CENTRAL ALEUTIANS IS KEEPING THIS LOW FROM
MOVING MUCH...SO THERE IS A VERY SLOW NORTHWARD PROGRESSION. FRONT
RUNS EAST-WEST JUST NORTH OF THE LOW...EASTERLY WINDS ARE ON THE
INCREASE ACROSS THE ALEUTIANS AS THIS FRONT MOVES CLOSER.

.MODEL DISCUSSION...MODELS CONTINUE TO HAVE A GOOD HANDLE ON LOW
NORTH OF KODIAK. AS WOULD BE EXPECTED MODEL WINDS ARE TOO LIGHT
ACROSS THE REGION OF STRONG COLD ADVECTION AND CURRENT FORECASTS
ACCOUNT FOR THIS. MODELS CONTINUE TO HAVE PROBLESM WITH EVOLUTION
OF SYSTEMS OVER THE NORTH PACIFIC FRIDAY AND SATURDAY SO CONTINUE
TO HAVE LOW CONFIDENCE IN THIS TIME PERIOD.

.SHORT TERM FORECAST...

SOUTHCENTRAL...BASED ON SATELLITE IMAGERY IT LOOKS LIKE THE LOW
WILL MOVE INLAND ALONG 150W OVER THE KENAI PENINSULA AND ANCHORAGE.
COLD AIR WILL MOVE ACROSS SOUTHCENTRAL ALASKA VERY QUICKLY CHANGING
RAIN TO SNOW AND CAUSING TEMPERATURES TO QUICKLY FALL. A SHARP UPPER
LEVEL TROUGH WILL MOVE ACROSS TONIGHT THROUGH TOMORROW SO SNOW SHOULD
HANG IN THERE. SHIFT TO SOUTH TO SOUTHWEST FLOW WILL BRING SNOW INTO
AREAS THAT HAVE REMAINED DRY THIS FAR. COMBINATION OF STRONG COLD
ADVECTION AND LIFT ALOFT WILL SOME SNOW ACCUMULATION FOR MOST OF
SOUTHCENTRAL. GENERALLY LOOKING FOR 3 TO 6 INCHES WITH HIGHER AMOUNTS
IN UPSLOPE AREAS. THE OTHER FACTOR IN TONIGHTS WEATHER WILL BE THE
WINDS. STRONG COLD ADVECTION WILL PRODUCE VERY STORM FORCE GUSTS
(PERHAPS CLOSE TO HURRICANE FORCE) THROUGH THE KODIAK ISLAND/COOK
INLET WATERS. MOST PLACES WILL SEE AT LEAST A LITTLE WIND.
COMBINATION OF SNOW AND WINDS WILL RESULT IN BLIZZARD CONDITIONS
FOR THE KACHEMAK BAY TO CARIBOU HILLS REGION AS WELL AS FOR THOMPSON
PASS. WILL LIKELY EXTEND SUSITNA VALLEY SNOW ADVISORY FROM WEST OF
THE PARKS HIGHWAY TO THE WHOLE ZONE AS UPSLOPE AREAS NORTH OF
TALKEETNA SHOULD SEE AT LEAST 6 INCHES OF SNOW. THE SNOW WILL
DIMINISH FRIDAY MORNING ACROSS SOUTHCENTRAL...BUT WONT END
COMPLETELY IN NORTHERN TO EASTERN AREAS UNTIL AFTERNOON AND EVENING
AS THE UPPER TROUGH FINALLY MOVES INTO THE INTERIOR. THE NEXT SYSTEM
WILL NOT BE TOO FAR AWAY WITH SNOW AND WIND LIKELY MOVING INTO KODIAK
FRIDAY NIGHT AND THE REST OF SOUTHCENTRAL SATURDAY. WITH GREAT
UNCERTAINTY IN STRENGTH AND TRACK OF NEXT SYSTEM IT IS TOO SOON TO
ELABORATE ON ANY OF THE EXPECTED IMPACTS.

SOUTHWEST ALASKA...COLD ADVECTION AND SNOW WILL SPREAD INLAND TONIGHT
WHILE WINDS ALONG THE COAST WILL FINALLY BEGIN TO DIMINISH. GUSTY
WINDS WILL EXTEND ALL THE WAY INTO THE KUSKOKWIM VALLEY PRODUCING
AREAS OF BLOWING SNOW. SNOW WILL TAPER OFF FROM SOUTH TO NORTH LATE
TONIGHT THROUGH FRIDAY MORNING AS THE UPPER TROUGH MOVES BY.
TEMPERATURES WILL CONTINUE TO FALL TO BELOW ZERO MOST AREAS. NEXT
ROUND OF WIND AND SNOW WILL LIKELY MOVE BACK IN FRIDAY NIGHT INTO
SATURDAY. BLIZZARD CONDITIONS WILL BE POSSIBLE ONCE AGAIN...BUT TOO
MUCH UNCERTAINTY IN TRACK OF SYSTEMS TO DETERMINE THAT YET.

BERING SEA/ALEUTIANS/ALASKA PENINSULA...PACIFIC LOW WILL REMAIN SOUTH
OF ALEUTIANS BUT FRONT WILL PUSH NORTHWARD ACROSS CENTRAL TO EASTERN
ALEUTIANS AND SOUTHERN ALASKA PENINSULA...RESULTING IN MORE SNOW AND
WINDS. THIS IS A LESS FAVORABLE WIND DIRECTION FOR BLIZZARD
CONDITIONS SO AT THIS POINT DO NOT THINK ANY WARNINGS WILL BE ISSUED.
AS SYSTEMS DEVELOP EAST OF THE PARENT LOW COLD ADVECTION WILL MOVE
DOWN ACROSS BERING SEA ONCE AGAIN...BUT A LITTLE FURTHER WEST THIS
TIME.

.LONG TERM FORECAST...EXTENDED MODELS CONTINUE TO SHOW SIGNS OF A
PATTERN CHANGE LATE NEXT WEEK. UNTIL THEN EXPECT ACTIVE STORM TRACK
TO PERSIST.

.AER/ALU...WATCH/WARNING SUMMARY
PUBLIC...BLIZZARD WARNING 121 131.
MARINE...GALES...120 125 130 132 138 140 141 150 155 160 165 170 171
                 172 175 176.
         HEAVY FREEZING SPRAY...130 132 138 140 141 150 179 185.
FIRE WEATHER...NONE.

SEB FEB 08