High Wind in Alaska, January 10, 2010

AREA FORECAST DISCUSSION  CCA
SOUTHCENTRAL AND SOUTHWEST ALASKA...CORRECTED
530 AM AKST SUN JAN 10 2010

.ANALYSIS AND UPPER LEVELS...
A NORTH PACIFIC LOW 800 MILES SOUTH OF KODIAK ISLAND COVERS MUCH OF
THE GULF OF ALASKA AND CONTAINS NUMEROUS SHORTWAVES. A SEPARATE UPPER
LEVEL LOW IS CENTERED NORTH OF HUDSON BAY AND STRETCHES WESTWARD INTO
NORTHEASTERN ALASKA.  HIGH PRESSURE CENTERED OVER THE NORTH BERING
CONTINUES TO DOMINATE MUCH OF THE BERING SEA AND WESTERN MAINLAND
ALASKA. ALTHOUGH RIDGING EXTENDS FROM THIS HIGH TOWARDS THE CANADIAN
WEST COAST...IT IS BEGINNING TO WEAKEN UNDER THE DIGGING OF THE NORTH
ARCTIC LOW AND THE NORTHWARD PROGRESSION OF THE NORTH PACIFIC LOW. AT
THE SURFACE...A STACKED LOW IS UNDERNEATH THE UPPER LEVEL GULF LOW
WITH SEVERAL ROTATING SHORTWAVES. A STRONG WRAPPED OCCLUDED FRONT
STRETCHES TOWARDS THE ALASKA PANHANDLE FROM THIS LOW. SURFACE HIGH
PRESSURE IS OFFSET NORTHEASTWARD FROM UPPER LEVEL HIGH PRESSURE WITH
A CENTER NEAR BARROW.

.MODEL DISCUSSION...MODELS ARE CURRENTLY IN AGREEMENT ON
THE NORTHEASTWARD PROGRESSION OF THE NORTH PACIFIC LOW IN THE SHORT
TERM. HOWEVER...SOME MODELS FAVOR THE DEVELOPMENT OF A DOUBLE
BARRELED LOW SUNDAY INSTEAD OF AN ELONGATED LOW. IN THE MID TERM
MODELS CONTINUE TO AGREE ON THE NORTHEASTWARD MOVEMENT OF THIS LOW
SYSTEM THROUGH THE GULF OF ALASKA. HOWEVER...THERE IS LOW RUN TO RUN
CONSISTENCY WITH MORE RECENT MODELS FAVORING A MORE EASTWARD
PROGRESSION. THE GFS APPEARS TO BE THE MORE CONSISTENT OF THESE
SOLUTIONS HOWEVER CONFIDENCE IS LOW. HPC GUIDANCE WAS USED FOR THE
LONG TERM FORECAST HOWEVER MODEL SOLUTIONS DIVERGE IN THE LONG TERM
AND CONFIDENCE REMAINS LOW.

.SHORT TERM FORECAST...
SOUTHCENTRAL...THE WESTWARD PROGRESSION OF A SHORTWAVE EARLY SUNDAY
AND APPROACH OF A WRAPPED OCCLUDED FRONT SUNDAY AFTERNOON WILL RESULT
IN STRONG WINDS ALONG THE SOUTHCENTRAL GULF TODAY. THE PRESSURE
GRADIENT WILL BE SUFFICIENT FOR STRONG CHANNELED FLOWS THROUGH
SHELIKOF STRAIT AND COOK INLET WITH STORM FORCE WINDS ALONG SHELIKOF
STRAIT. STORM FORCE COASTAL JETS WILL FORM ALONG THE SOUTHCENTRAL
GULF COAST...SOUTHERN SHORES OF THE ALASKA PENINSULA...AND THE
EASTERN SHORE OF KODIAK ISLAND. WINDS WILL SLOWLY WEAKEN MONDAY AS
THE FRONT PROGRESSES THROUGH THE REGION AND THE ASSOCIATED LOW
PRESSURE WEAKENS. COLD AIR WILL CONTINUE TO POOL SOUTHWARD ACROSS
THE COPPER RIVER BASIN DUE TO THE STRONG NORTHEASTERLY FLOW AHEAD OF
THE FRONT. THIS NORTHEASTERLY FLOW ALONG WITH THE BUILDING OF THE
TEMPERATURE AND PRESSURE GRADIENTS ACROSS THE SOUTHCENTRAL COAST
WILL RESULT IN STRONG WINDS THROUGH EASTERN PRINCE WILLIAM
SOUND...COPPER RIVER DELTA...AND THE VALDEZ ARM AND NARROWS REGION
SUNDAY INTO MONDAY. WINDS WILL ALSO BE PARTICULARLY STRONG THROUGH
THE MATANUSKA VALLEY THROUGH MONDAY. SNOWSHOWERS ASSOCIATED WITH THE
FRONT WILL REACH THE EASTERN COPPER RIVER BASIN SUNDAY EVENING AND
CONTINUE INTO MONDAY. HOWEVER...THIS FRONT WILL QUICKLY WEAKEN AND
PRECIPITATION WILL NOT REACH THE SOUTHCENTRAL COAST UNTIL A
SHORTWAVE APPROACHES EARLY TUESDAY MORNING.

.SOUTHWEST/BERING...STRONG AND GUSTY WINDS ARE EXPECTED TO AFFECT
MUCH OF THE SOUTHWEST MAINLAND TODAY AND STRENGTHEN INTO TONIGHT AS A
SHORTWAVE MOVES NORTHWARD AND TIGHTENS THE ISOBARS THROUGHOUT THE
REGION. IN ADDITION...MUCH COOLER AIR WILL SPILL IN FROM THE
NORTHWEST WHICH WILL INCREASE THE COAST PERPENDICULAR PRESSURE
GRADIENT AND INCREASE SURFACE MIXING WHICH RESULTS IN HIGHER WINDS.
PARTICULARLY STRONG WINDS MAY OCCUR IN CHANNELED VALLEYS ORIENTED
FROM THE NORTHEAST TO SOUTHWEST SUCH AS TOKSOOK BAY.  ALONG THE
ALASKA PENINSULA...WINDS WILL APPROACH STORM FORCE INTENSITY ALONG
THE SOUTHERN SHORE OF THE PENINSULA AS A SHORTWAVE AND THEN AN
OCCLUDED FRONT APPROACH THE REGION TODAY AND TOMORROW. PRECIPITATION
TODAY WILL BE LIMITED TO LIGHT SHOWERS OVER THE NEXT FEW DAYS.

.ALEUTIANS...A WEAK SHORTWAVE ASSOCIATED WITH A NORTH PACIFIC LOW
WILL MOVE ACROSS THE EASTERN AND CENTRAL ALEUTIAN ISLANDS
TODAY...BRINGING THE CHANCE OF SHOWERS. A SEPARATE SHORTWAVE WILL
BRING LIGHT SHOWERS TO THE WESTERN ALEUTIANS AS WELL. NO INTENSE LOWS
ARE EXPECTED TO REACH THE REGION IN THE SHORT TERM SO RELATIVELY WEAK
WINDS ARE FORECAST.

.LONG TERM FORECAST...A PATTERN CHANGE APPEARS TO BE BREWING FOR THE
LONG TERM. MODELS ARE BEGINNING TO SHOW MORE AGREEMENT IN THE
PROPAGATION OF AN UPPER LEVEL ARCTIC LOW ACROSS MUCH OF MAINLAND
ALASKA BY THE END OF THE WEEK.  HOWEVER...MODELS DIFFER IN THE
TIMING...INTENSITY...AND SOUTHWARD REACH OF THIS LOW SO A LARGE
AMOUNT OF UNCERTAINTY EXISTS.

.AER/ALU...WATCH/WARNING SUMMARY
PUBLIC...HIGH WIND WATCH...155
MARINE...STORM 120 127 130 132 136 137 138 150
            GALE 121 126 128 140 155
   HEAVY FREEZING SPRAY...140 160 180 185
FIRE WEATHER...NONE

ELN/JAM JAN 10