High Wind in Alaska, November 1, 2012

SOUTHCENTRAL AND SOUTHWEST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ANCHORAGE AK
200 PM AKDT THU NOV 1 2012

.MODEL DISCUSSION...MODELS SYNOPTIC SCALE INITIALIZATIONS WERE
REASONABLE. FORECAST TRENDS ALSO LOOK REASONABLE. NAM WILL MOST
LIKELY BE USED TO ADDRESS LOCAL WINDS OVER MAINLAND AREAS..THEN
GENERALLY GFS/ECMWF ELSEWHERE.

.ANALYSIS AND UPPER LEVELS...
UPPER LEVELS...SAT IMAGERY INDICATES A SIGNIFICANT DIGGING OF THE
LONG WAVE TROUGH OVER THE NORTH PACIFIC. THE PRESENCE OF OPEN AND
CLOSED CELL CUMULUS AS FAR SOUTH OF 4ON BETWEEN 160-150W INDICATES
THE STRENGTH AND EXTENT OF THE LOW LEVEL COLD ADVECTION ON THE
BACKSIDE OF TROUGH. THE CENTER DEVELOPING NEAR THE TROUGH BASE WILL
BECOME SOMEWHAT CUT-OFF OVER THE NEXT 24 HRS...THEN DRIFT TO THE
CENTRAL GULF OF ALASKA SAT AFTERNOON WHERE IT THEN BECOMES STATIONARY
AND WEAKENS. A SECONDARY DEVELOPING SHORT WAVE RAPIDLY MOVES SOUTH OF
THIS CENTER AND DEVELOPS AS IT APPROACHES THE SE GULF LATE SUN. A
HIGH AMPLITUDE RIDGE CONTINUES OF THE WESTERN BERING SEA THROUGH THE
SHORT TERM.

.SURFACE...THE 960S LOW CENTER SOUTH OF THE GULF IS CONTINUING TO
INTENSIFY. THE ASSOCIATED OCCLUDED FRONT IS MOVING SLOWLY NORTH
TOWARD KODIAK ISLAND. THIS DEVELOPING CENTER AND THE HIGH OVER THE
WESTERN BERING SEA ARE MAINTAINING AND WILL INTENSIFY THE PRESSURE
GRADIENT ACROSS MUCH OF EASTERN BERING/ALEUTIANS/AK PEN/SW ALASKA
INTO TONIGHT. RESULTANT STORMS TO HURRICANE FORCE WINDS ARE EXPECTED
TO DEVELOP SOUTH OF THE AK PEN AND OVER THE GULF OF ALASKA. MAINLAND
AREAS WERE DRY EXCEPT FOR SNOW SHOWERS ALONG THE GULF AND OVER THE
EASTERN BERING SEA/ALEUTIANS/NORTHERN AK PEN.

.SHORT TERM FORECAST...
.SOUTHCENTRAL ALASKA...
THE HURRICANE FORCE LOW OF THE NORTH PACIFIC WILL SLOWLY DRIFT NORTH
AND EAST. ITS ASSOCIATED FRONT WILL MOVE TO NEAR KODIAK AND THE NORTH
GULF COAST ON FRI. THE FRONT WILL THEN WEAKEN AS IT DRIFTS INLAND FRI
NIGHT/SAT. STORM FORCE WINDS WITH HIGHER GUSTS WILL MOVE AHEAD AND
WITH THE OCCLUSION AND BRING NEAR WARNING LEVEL WINDS NEAR KODIAK
ISLAND TONIGHT/EARLY FRI. WINDS SHOULD DIMINISH MOST AREAS AFTER
FRONTAL PASSAGE...WITH MARINE WINDS TRENDING TOWARD GALES TO SMALL
CRAFT. PRESSURE GRADIENTS WILL INCREASE ACROSS MUCH OF SOUTHCENTRAL
MAINLAND TONIGHT...SO LOCAL GAP AND GRADIENT WINDS CAN BE EXPECTED
THROUGH FRI. PRECIPITATION ASSOCIATED WITH THE FRONT WILL BE
PREDOMINATELY ALONG THE COASTS WITH A LITTLE SPILL OVER INLAND.
PRECIPITATION SHOULD START AS SNOW...THEN SHIFT OVER TO A MIX OR RAIN
WAS WARM ADVECTION SPREADS ACROSS THE GULF.

SOUTHWEST...
SOME MOISTURE FROM GULF SYSTEM WILL BEGIN SPILLING ACROSS THE
ALEUTIAN/ALASKA RANGES FRI NIGHT/SAT WHICH MAY YIELD SOME SNOW
SHOWERS THROUGH BRISTOL BAY. BY AND LARGE HOWEVER..THE SW MAINLAND
REMAINS NESTLED BETWEEN THE SLOW MOVING PACIFIC LOW AND WEAK HIGH
PRESSURE IN THE FAR WESTERN BERING WITH GENERALLY DRY OFF-SHORE FLOW
IN THE INTERIM. THE WINDS LOOK TO REMAIN BRISK UNTIL THE LOW BEGINS
TO WEAKEN AND THE PRESSURE GRADIENT RELAXES WHICH OCCURS LATER IN THE
WEEKEND.

BERING SEA/ALEUTIANS...
FAIRLY BENIGN WEATHER CONTINUES OVER THE BERING SEA. MOST SHOWERS
WILL BE OVER THE EASTERN BERING/CHAIN...WITH A FOCUS ALONG THE AKPEN
AND EASTERN ALEUTIANS WHERE WINDS AND ONSHORE FLOW ARE STRONGEST.
HIGH WIND WARNING CONDITIONS OVER THE EASTERN ALEUTIANS WILL DIMINISH
THROUGH THE EVENING HOURS AFTER AN UPPER WAVE MOVES THROUGH. EXPECT
SUSTAINED HURRICANE FORCE WINDS ALONG THE SOUTHERN AKPEN WATERS
TONIGHT WITH THE PEAK INTENSITY OF THE PACIFIC LOW...TRENDING TO
STORMS AND STRONG GALES THEREAFTER.

.LONG TERM FORECAST...
LONG WAVE TROUGH AXIS BEGINS SHIFTING EAST EARLY TO MID NEXT WEEK
WITH SOME RIDGING EXPANDING THROUGH THE EASTERN BERING AND SW
MAINLAND. INHERENT MODEL DIFFERENCES ON HOW THIS PLAYS OUT...BUT IT
MAY LEAD TO THE WEATHER PATTERN OVER THE WESTERN BERING/ALEUTIANS
BECOMING MORE ACTIVE WITH TIME FROM THE UPSTREAM TROUGH/LOW MOVING IN
BEHIND THE RIDGE...WHILE THE SOUTHERN MAINLAND STAYS GENERALLY DRY.

.AER/ALU...WATCH/WARNING SUMMARY
PUBLIC...HIGH WIND WARNING ZONE 185
MARINE...HURRICANE FORCE WIND...150 155
         STORM...120 130 132 138 351 352
         GALE...127 140 160 165 170 171 172 180 185 413 414
         HEAVY FREEZING SPRAY...140
FIRE WEATHER...NONE.

RMC NOV 12