Blizzard Watch 12, NWS Anchorage, AK

516 
WWAK42 PAFC 050021
WSWALU

URGENT - WINTER WEATHER MESSAGE
NATIONAL WEATHER SERVICE ANCHORAGE AK
421 PM AKDT FRI NOV 4 2011

...STRONG LOW PRESSURE SYSTEM TO AFFECT SOUTHWEST ALASKA ON
SATURDAY...

.A STRONG LOW PRESSURE SYSTEM WILL DEVELOP IN THE NORTHEASTERN
BERING SEA ON SATURDAY...BRINGING STRONG WINDS AND WIDESPREAD
SNOW TO SOUTHWEST ALASKA.

AKZ155-051400-
/X.UPG.PAFC.BZ.A.0012.111105T1500Z-111106T0000Z/
/X.NEW.PAFC.BZ.W.0030.111105T1500Z-111106T0000Z/
KUSKOKWIM DELTA-
INCLUDING THE CITIES OF...BETHEL...HOOPER BAY...NUNIVAK ISLAND
421 PM AKDT FRI NOV 4 2011

...BLIZZARD WARNING IN EFFECT FROM 7 AM TO 4 PM AKDT SATURDAY...

THE NATIONAL WEATHER SERVICE IN ANCHORAGE HAS ISSUED A BLIZZARD
WARNING...WHICH IS IN EFFECT FROM 7 AM TO 4 PM AKDT SATURDAY. THE
BLIZZARD WATCH IS NO LONGER IN EFFECT. 


* SNOW...SNOW ACCUMULATION OF 2 TO 4 INCHES.

* VISIBILITY...WILL BE REDUCED TO ONE QUARTER MILE OR LESS IN SNOW
  AND BLOWING SNOW.

* WIND...EAST WINDS WILL INCREASE ON SATURDAY MORNING TO 20 TO 35
  MPH. ALONG THE COAST...WINDS WILL BE STRONGER AT 30 MPH TO 40
  MPH WITH GUSTS TO 50 MPH.

* LOCATION...BLIZZARD CONDITIONS ARE EXPECTED ACROSS THE KUSKOKWIM
  DELTA. HOWEVER...BLIZZARD CONDITIONS WILL BE THE STRONGEST AND
  LAST THE LONGEST ALONG THE NORTHERN KUSKOKWIM DELTA COAST
  INCLUDING NUNIVAK ISLAND.

* TIMING...BLIZZARD CONDITIONS ARE EXPECTED FROM SATURDAY MORNING
  THROUGH LATE SATURDAY AFTERNOON. CONDITIONS WILL IMPROVE SATURDAY
  EVENING AS THE LOW MOVES EASTWARD AND TEMPERATURES WARM.

* IMPACTS...BLOWING SNOW WILL REDUCE VISIBILITIES AND MAKE FOR
  DANGEROUS OR DIFFICULT TRAVEL CONDITIONS.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A BLIZZARD WARNING MEANS SEVERE WINTER WEATHER CONDITIONS ARE
EXPECTED OR OCCURRING. FALLING AND BLOWING SNOW WITH STRONG WINDS
AND POOR VISIBILITIES ARE LIKELY. THIS WILL LEAD TO WHITE-OUT
CONDITIONS...MAKING TRAVEL EXTREMELY DANGEROUS. ALL TRAVEL AND
OUTDOOR ACTIVITY IS STRONGLY DISCOURAGED.

&&

$$

SOUTHCENTRAL AND SOUTHWEST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ANCHORAGE AK
452 AM AKDT FRI NOV 4 2011

.ANALYSIS AND UPPER LEVELS...

MAIN WEATHER FEATURE IS LOW PRESSURE SYSTEM OVER SOUTHWEST
ALASKA...WITH SECONDARY LOW DEVELOPMENT OCCURRING IN THE BARREN
ISLANDS REGION CURRENTLY ALONG A WEATHER FRONT SITUATED ALONG THE
NORTH THROUGH EASTERN GULF. THIS SECONDARY GULF LOW WILL STRENGTHEN
THROUGH THIS AFTERNOON AND THEN BEGIN TO WEAKEN AS IT DRIFTS EAST
TOWARDS THE PANHANDLE AND DISSIPATES SATURDAY AFTERNOON. TRANSITORY
RIDGING MOVES EAST ACROSS THE AREA RAPIDLY ON THE BACK SIDE OF THE
LOW AHEAD OF THE NEXT SYSTEM MOVING ACROSS THE BERING TODAY THROUGH
SUNDAY MORNING. WHILE THE TRACK IS QUITE SIMILAR TO THE PREVIOUS
SYSTEM...THERE APPEARS THERE WILL BE ENOUGH COLD AIR IN PLACE FOR ALL
SNOW OVER SOUTHWEST ALASKA SATURDAY INTO SATURDAY NIGHT.

.MODEL DISCUSSION...

MODELS ARE HANDLING KEY SYNOPTIC WEATHER FEATURES SATISFACTORILY.
DIFFERENCES BETWEEN GLOBAL MODELS IN THE EXTENDED TIME FRAME WERE
ADDRESSED BY USING A BLEND OF THE EUROPEAN AND GFS MODELS BLENDED
WITH HPC GUIDANCE.

.SHORT TERM FORECAST...

SOUTH AND EAST OF THE ALASKA RANGE...

BLIZZARD WARNING FOR EASTERN TURNAGAIN ARM AND PORTAGE VALLEY AND
WINTER WEATHER ADVISORY FOR THE SUSITNA VALLEY WILL BE EXTENDED A FEW
MORE HOURS AS THESE EVENTS BEGIN TO WIND DOWN. COLD ADVECTION
COMMENCES ON THE BACK SIDE OF THIS LOW AS IT TRACKS ACROSS THE
GULF...AND THE FOCUS WILL TURN TO THE DEVELOPMENT OF SNOW ACROSS THE
ANCHORAGE BOWL AND MATANUSKA VALLEY FOR SEVERAL HOURS BEGINNING EARLY
TO MID AFTERNOON AND LASTING INTO THE EVENING HOURS. THE QUICK
MOVEMENT OF THE LOW PRESSURE ACROSS THE NORTHERN GULF WILL PRECLUDE A
LENGTHY EVENT. HIGH PRESSURE WILL BRING MOSTLY SUNNY SKIES ACROSS THE
REGION FOR SATURDAY...BUT WILL QUICKLY BE FOLLOWED BY THE NEXT SYSTEM
APPROACHING FROM THE WEST. THIS SYSTEM WILL BE SIMILAR IN THAT
SECONDARY LOW DEVELOPMENT WILL OCCUR IN THE GULF...BUT THE UPPER
LEVEL LONGWAVE TROUGH WILL REMAIN ALONG AND JUST WEST OF THE ALEUTIAN
AND ALASKA RANGE. THIS WILL QUITE LIKELY RESULT IN A MORE PROLONGED
SNOW EVENT OVER MOST OF THE SOUTHCENTRAL REGION.

SOUTHWEST ALASKA...

LOW PRESSURE OVER THE INTERIOR SOUTHWEST WILL ALLOW FOR COLD
ADVECTION SNOW SHOWERS AGAINST WEST AND NORTHWEST FACING SLOPES OF
THE ALASKA AND ALEUTIAN RANGES THROUGH EARLY THIS EVENING. HIGH
PRESSURE OVER THE REGION TONIGHT AND A FRESH SNOWPACK WILL LIKELY
ALLOW FOR THE DEVELOPMENT OF FOG OVER MOST OF THE REGION TONIGHT.
CLOUDS MOVE IN QUICKLY LATE TONIGHT WITH SNOW MOVING IN WITH THE NEXT
SYSTEM FROM THE SOUTH AND WEST. A STRONG WARM FRONT WILL BE MOVING
ONSHORE SATURDAY MORNING AND THIS WILL ALLOW FOR WINDS TO
INCREASE...PARTICULARLY ALONG THE COAST. WILL BE ISSUING A BLIZZARD
WATCH FOR THE KUSKOKWIM DELTA IN ANTICIPATION OF POSSIBLE BLIZZARD
CONDITIONS ACROSS THE AREA...PARTICULARLY ALONG THE COAST...FOR
SATURDAY.

BERING SEA/ALEUTIANS...

STRONG GALE TO STORM FORCE WINDS WILL GRADUALLY DIMINISH ACROSS THE
SOUTHEASTERN BERING AND NORTHERN PACIFIC ON THE BACK SIDE OF THE LOW
PRESSURE SYSTEM OVER THE MAINLAND THROUGH THE DAY TODAY. NEXT SYSTEM
WILL SEE GALE FORCE WINDS DEVELOP OVER MOST OF THE REGION. AS A
TRIPLE POINT LOW DEVELOPS OVER THE CENTRAL BERING TONIGHT...A SMALL
AREA OF STORM FORCE WINDS IS LIKE TO DEVELOP ON THE BACK SIDE OF THE
LOW AS IT WINDS UP. WILL MONITOR MODEL TRENDS FOR THE POSSIBLE
ISSUANCE OF STORM WARNINGS AND THE POSSIBILITY OF HIGH WINDS OVER THE
ALASKA PENINSULA ONCE AGAIN SATURDAY NIGHT AND/OR SUNDAY MORNING.

.LONG TERM FORECAST...

MODELS CONTINUE TO SUGGEST LOW PRESSURE WILL RAPIDLY STRENGTHEN AS IT
MOVES NORTH AND EAST ACROSS THE WESTERN AND NORTHERN BERING SEA
SOMETIME IN THE LATE MONDAY THROUGH WEDNESDAY TIME FRAME.
MEANWHILE...RIDGING ALOFT OVER THE SOUTHWEST MAINLAND AND LOW
PRESSURE MEANDERING IN THE NORTHEASTERN GULF WOULD SUGGEST THE
POSSIBILITY OF DRY CONDITIONS AND STRONG NORTHERLY OUTFLOW WINDS OVER
SOUTHCENTRAL ALASKA FOR MIDWEEK.

.AER/ALU...WATCH/WARNING SUMMARY
PUBLIC...BLIZZARD WARNING...125
         BLIZZARD WATCH...155
         HIGH WIND WARNING...181
MARINE...GALES...120 125 129 130 132 138 155 160 165 170 172 175 176
         179 180 185
         STORMS...150
FIRE WEATHER...NONE.

29 NOV 11