High Wind Watch 20, NWS Anchorage, AK

942 
WWAK71 PAFC 281352
NPWAER

URGENT - WEATHER MESSAGE
NATIONAL WEATHER SERVICE ANCHORAGE AK
452 AM AKST FRI DEC 28 2012

...DANGEROUS WIND TONIGHT INTO SATURDAY FOR TURNAGAIN ARM AND HIGHER
ELEVATIONS...

A STRONG LOW PRESSURE CENTER MOVING ALONG THE WEST COAST OF ALASKA
WILL BRING DANGEROUS WINDS TO TURNAGAIN ARM AND HIGHER ELEVATIONS
BY MIDNIGHT TONIGHT. AS THE LOW MOVES AWAY FROM MAINLAND ALASKA
BY MIDDAY SATURDAY...WINDS WILL BEGIN TO DIMINISH.

AKZ101-290300-
/X.UPG.PAFC.HW.A.0020.121229T1000Z-121230T0300Z/
/X.NEW.PAFC.HW.W.0030.121229T0900Z-121230T0000Z/
ANCHORAGE-
INCLUDING THE CITIES OF...ANCHORAGE...EAGLE RIVER...INDIAN...
EKLUTNA
452 AM AKST FRI DEC 28 2012

...HIGH WIND WARNING IN EFFECT FROM MIDNIGHT TONIGHT TO 3 PM AKST
SATURDAY FOR TURNAGAIN ARM AND HIGHER ELEVATIONS...

THE NATIONAL WEATHER SERVICE IN ANCHORAGE HAS ISSUED A HIGH WIND
WARNING...WHICH IS IN EFFECT FROM MIDNIGHT TONIGHT TO 3 PM AKST
SATURDAY. THE HIGH WIND WATCH IS NO LONGER IN EFFECT. 

* LOCATION...TURNAGAIN ARM AND HIGHER ELEVATIONS.

* WIND...SOUTHEAST WIND 50 TO 65 WITH GUSTS TO 80 MPH.

* TIMING...WINDS WILL RAPIDLY INCREASE THIS EVENING AND CONTINUE
  INTO SATURDAY AFTERNOON BEFORE DIMINISHING.

* IMPACTS...TRAVEL MAY BE DIFFICULT. TREES MAY BE BLOWN OVER. 
  LOOSE DEBRIS CAN BE MOVED AND DAMAGE PROPERTY.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A HIGH WIND WARNING MEANS A HAZARDOUS HIGH WIND EVENT IS EXPECTED
OR OCCURRING. PEOPLE ARE URGED TO SECURE LOOSE OBJECTS THAT COULD
BE BLOWN AROUND OR DAMAGED BY THE WIND.

&&

$$

SOUTHCENTRAL AND SOUTHWEST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ANCHORAGE AK
400 PM AKST THU DEC 27 2012

.ANALYSIS AND UPPER LEVELS...
A BROAD LONGWAVE TROUGH REMAINS IN PLACE OVER THE BERING SEA THIS
AFTERNOON WITH AN UPPER LEVEL RIDGE CENTERED OVER THE CANADIAN WEST
COAST AND EXTENDING NORTHWESTWARD INTO THE INTERIOR...LEAVING MUCH OF
THE SOUTHERN MAINLAND UNDER THE INFLUENCE OF DEEP LAYER SOUTHEASTERLY
FLOW BETWEEN THESE TWO FEATURES. THE UPPER LOW SOUTH OF THE AKPEN
CONTINUES TO STEADILY WEAKEN AS ITS ATTENDANT SURFACE FEATURE BREAKS
INTO A COMPLEX LOW WITH MULTIPLE CENTERS...WITH ONE LOCATED JUST
SOUTHEAST OF KODIAK ISLAND AND ANOTHER OVER BRISTOL BAY. AN
ASSOCIATED SURFACE FRONT REMAINS STALLED ALONG THE NORTHERN GULF
COAST...CONTINUING TO BRING A MIX OF RAIN AND SNOW TO COASTAL
PORTIONS OF SOUTHCENTRAL AK. SCATTERED RAIN AND SNOW SHOWERS ARE ALSO
PRESENT ALONG COASTAL PORTIONS OF SOUTHWEST ALASKA AS THE LOW MOVES
INTO BRISTOL BAY. FURTHER WEST...A STRONG VERTICALLY STACKED LOW
PRESSURE SYSTEM IS DRIFTING SLOWLY EASTWARD ALONG 50N SOUTH OF THE
WESTERN ALEUTIANS...WITH AN ASSOCIATED FRONT BRINGING STORM FORCE
WINDS ALONG WITH RAIN AND SNOW TO THAT PART OF THE CHAIN.

.MODEL DISCUSSION...
MODELS CONTINUE TO BE IN GOOD AGREEMENT IN HANDLING THE WEAKENING LOW
NEAR THE AKPEN AS IT CONTINUES TO DISSIPATE THROUGH FRIDAY MORNING.
HOWEVER...SOME UNCERTAINTY REMAINS REGARDING THE EVOLUTION OF THE
NEXT SYSTEM WHICH WILL AFFECT THE REGION IN THE FRIDAY NIGHT/SATURDAY
MORNING TIMEFRAME AS THE LOW CURRENTLY SOUTH OF THE ALEUTIAN CHAIN
MOVES EASTWARD. THE 12Z EC SOLUTION TRENDED MUCH WEAKER AND SHIFTED
THE POSITION OF THE LOW FURTHER EAST. THE 18Z RUNS OF THE GFS AND NAM
THEN DEEPENED THE LOW AND MOVED IT BACK TO THE WEST...MORE IN LINE
WITH THE PREVIOUS EC SOLUTION. DESPITE THE DISCREPANCIES IN STRENGTH
AND POSITION AS WELL AS THE RUN TO RUN INCONSISTENCIES...THERE IS A
GENERAL CONSENSUS DEPICTING AN AMPLIFYING UPPER LEVEL WAVE ROUNDING
THE EASTERN PERIPHERY OF THE MAIN LOW AND THE SUBSEQUENT DEVELOPMENT
OF A STRONG SURFACE LOW MOVING OVER THE AKPEN AND INTO BRISTOL BAY BY
SATURDAY MORNING.

.SHORT TERM FORECAST...

SOUTHCENTRAL ALASKA...

WEAK DISTURBANCES WILL CONTINUE TO MOVE ONSHORE OVER THE NORTH GULF
COAST...KEEPING KODIAK ISLAND AND PRINCE WILLIAM SOUND IN PERIODS OF
RAIN AND SNOW THROUGH LATE FRIDAY.

ATTENTION THEN TURNS TO AN INTENSIFYING LOW APPROACHING BRISTOL BAY
FROM THE SOUTH LATE FRIDAY NIGHT INTO SATURDAY. THIS LOW WILL BE
ACCOMPANIED BY A STRONG MID-LEVEL JET STREAK MOVING NORTH OF THE COOK
INLET REGION. HIGH WINDS APPEAR POSSIBLE AT THIS POINT THROUGH
PORTAGE AND TURNAGAIN ARM AS WELL AS THE HIGHER ELEVATIONS. THERE IS
A LOT OF UNCERTAINTY AT THIS POINT BUT THERE IS ALSO A CHANCE THAT
STRONG WINDS COULD IMPACT PARTS OF THE HILLSIDE OR THE ANCHORAGE BOWL
AS WELL BY LATE SATURDAY MORNING. A HIGH WIND WATCH WILL BE ISSUED
WITH THE AFTERNOON FORECAST PACKAGE AND WILL HIGHLIGHT THE AREAS
WHERE WE CURRENTLY HAVE THE MOST CERTAINTY THAT HIGH WINDS WILL
OCCUR...WHICH IS OVER WESTERN TURNAGAIN ARM AND HIGHER ELEVATIONS.
UNSEASONABLY WARM TEMPERATURES ARE POSSIBLE AS WELL WITH THIS
POTENTIAL CHINOOK EVENT SATURDAY MORNING INTO SATURDAY EVENING.

SOUTHWEST ALASKA...

SNOW AND RAIN SHOWERS WILL PERSIST AS DISTURBANCES MOVE NORTH ACROSS
THE AREA. BY FRIDAY NIGHT A POWERFUL DISTURBANCE ASSOCIATED WITH THE
APPROACHING LOW FROM THE SOUTH WILL MOVE SOUTH TO NORTH ACROSS THE
REGION. STRONG CHINOOK WINDS ARE EXPECTED ALONG THE ALEUTIAN RANGE
FROM BRISTOL BAY NORTH INTO THE SOUTHERN FOOTHILLS OF THE ALASKA
RANGE. A HIGH WIND WATCH WILL BE ISSUED TO REFLECT THE POSSIBILITY OF
HIGH WINDS IN LOCATIONS SUCH AS ILIAMNA AND THE FOOTHILLS OF THE
ALASKA RANGE IN ASSOCIATION WITH THIS SYSTEM. OTHERWISE...GIVEN THE
WARMTH ASSOCIATED WITH THIS SYSTEM...ANY SNOW THAT FALLS WILL
GENERALLY BE ON THE WET SIDE. THERE IS ALSO A LOT OF UNCERTAINTY IN
THE TRACK OF THE LOW AND TIMING OF ONSET OF PRECIPITATION. ALL OF
THIS PRECLUDES ANY ISSUANCE OF ANY WINTER WEATHER WATCHES OR WARNINGS
AT THIS TIME.

ALEUTIANS/BERING SEA...

LARGE LOW PRESSURE SYSTEM WILL MOVE SLOWLY EAST JUST SOUTH OF THE
WESTERN AND CENTRAL ALEUTIANS THROUGH SATURDAY WHILE GRADUALLY
WEAKENING. STORM FORCE WINDS WILL BE OVER THE FAR WESTERN ALEUTIAN
ZONES WITHIN A BROADER ENVELOPE OF GALE FORCE WINDS. STRONG LOW
PRESSURE WILL MOVE ACROSS THE ALASKA PENINSULA AND OVER THE FAR
EASTERN BERING SEA FRIDAY INTO FRIDAY NIGHT. STORM FORCE WINDS WILL
BE POSSIBLE ON THE BACK SIDE OF THIS LOW AS IT MOVES NORTH DURING
THIS TIME.

.LONG TERM FORECAST...
WHILE THERE REMAINS SIGNIFICANT UNCERTAINTY AMONGST THE MODELS IN THE
EXTENDED TERM...THE GENERAL INDICATION IS THAT TROUGHING WILL REMAIN
OVER THE BERING INTO NEXT WEEK...SUPPORTING A CONTINUATION OF
SOUTHERLY FLOW AND ASSOCIATED WARMER TEMPERATURES FOR SOUTHCENTRAL
AK.

.AER/ALU...WATCH/WARNING SUMMARY
PUBLIC...HIGH WIND WATCH...101 152 161
MARINE...GALES...120 125 130 132 138 150 155 172 175 185
         STORMS...176
         HVY FRZG SPRY...179 185
FIRE WEATHER...NONE

CB/CC DEC 12