High Wind Watch 15, NWS Anchorage, AK

741 
WWAK71 PAFC 220326
NPWAER

URGENT - WEATHER MESSAGE
NATIONAL WEATHER SERVICE ANCHORAGE AK
626 PM AKST WED NOV 21 2012

A RAPIDLY INTENSIFYING NORTH PACIFIC LOW WILL MOVE INTO THE
SOUTHEASTERN GULF OF ALASKA DURING THE DAY
THURSDAY. DEEP AND COLD ARCTIC AIR OVER THE EASTERN INTERIOR WILL
CONTINUE TO FLOW THROUGH THE PASSES OF THE CHUGACH MOUNTAINS IN
RESPONSE TO THE LOW IN THE GULF OF ALASKA AND HIGH PRESSURE OVER
THE INTERIOR. THIS WILL HAVE THE EFFECT OF INCREASING THE ALREADY-
STRONG PRESSURE GRADIENTS ACROSS THE NORTH GULF COAST.

AKZ131-221530-
/X.UPG.PAFC.HW.A.0015.121122T2100Z-121123T0600Z/
/X.NEW.PAFC.HW.W.0025.121122T2100Z-121123T0900Z/
NORTHEAST PRINCE WILLIAM SOUND-
INCLUDING THE CITIES OF...VALDEZ...THOMPSON PASS
626 PM AKST WED NOV 21 2012

...HIGH WIND WARNING IN EFFECT FROM NOON THURSDAY TO MIDNIGHT
AKST THURSDAY NIGHT THROUGH THOMPSON PASS...

THE NATIONAL WEATHER SERVICE IN ANCHORAGE HAS ISSUED A HIGH WIND
WARNING...WHICH IS IN EFFECT FROM NOON THURSDAY TO MIDNIGHT AKST
THURSDAY NIGHT THROUGH THOMPSON PASS. THE HIGH WIND WATCH IS NO
LONGER IN EFFECT.

* LOCATION...THOMPSON PASS.

* WIND...NORTHEAST WIND 45 TO 55 MPH WITH GUSTS TO 80 MPH.

* TIMING...NOON THURSDAY THROUGH LATE THURSDAY EVENING.

* IMPACTS...DIFFICULT DRIVING THROUGH THE PASS FOR HIGH PROFILE
  VEHICLES.

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
500 AM AKST WED NOV 21 2012

.ANALYSIS AND UPPER LEVELS...

BROAD UPPER LOW OVER MAINLAND ALASKA CONTINUES TO INFLUENCE THE
REGION AS A BLOCKING HIGH OVER THE BERING AND EASTERN SIBERIA
CONTINUES TO AMPLIFY. SATELLITE IMAGERY DEPICTS NUMEROUS SMALL SCALE
WAVE DISTURBANCES EMBEDDED WITHIN THE LARGER SCALE TROUGH AS WELL AS
A NUMBER OF DISTINCT LOWS ACROSS THE GULF. THE LATTER FEATURES WILL
CONTINUE TO WRAP ACROSS THE SOUTHERN GULF COAST...AFFECTING KODIAK
ISLAND WITH PERIODIC SNOW SHOWERS INTO THURSDAY AND FRIDAY. FARTHER
SOUTH...A MIGRATORY WAVE DISTURBANCE IS CURRENTLY PHASING WITH A DEEP
UPPER LOW SOUTH OF THE ALASKA PENINSULA...AND THIS FEATURE WILL
UNDERGO RAPID INTENSIFICATION AS IT ENTERS THE GULF OF ALASKA
WEDNESDAY NIGHT INTO THURSDAY IN THE FORM OF A POWERFUL 960 HPA LOW.
COLD HIGH PRESSURE CONTINUING TO BUILD UP ACROSS INTERIOR ALASKA WILL
BEGIN TO ACCELERATE RAPIDLY THROUGH CHANNELED TERRAIN THURSDAY AND
FRIDAY AS THE LOW MOVES TOWARDS THE GULF COAST...WITH STRONG WINDS
LIKELY THROUGH FAVORED GAPS.

.MODEL DISCUSSION...

ALL MODELS ARE IN GOOD AGREEMENT WITH THE LARGE SCALE FLOW THROUGH
THE WEEK...BUT AS USUAL...THEY DIFFER WITH RESPECT TO SEVERAL SMALLER
SCALE DISTURBANCES. AND WHILE THEY CONTINUE TO CONVERGE ON A SIMILAR
SOLUTION WITH RESPECT TO THE INTENSE LOW ENTERING THE GULF
THURSDAY...THERE ARE STILL SLIGHT POSITION AND STRENGTH DIFFERENCES.
A BLEND OF THE ECMWF...NAM...AND GFS WAS FAVORED FOR THIS FORECAST.
THE NAM...IN PARTICULAR...DUE TO ITS INCREASED RESOLUTION AND BETTER
HANDLING OF CHANNELED OFFSHORE GAP WINDS HEADING INTO THANKSGIVING
DAY.

.SHORT TERM FORECAST...

SOUTHCENTRAL...
ONCE AGAIN...LITTLE CHANGE FROM PREVIOUS DAYS WITH COLD HIGH PRESSURE
DOMINATING INTERIOR ALASKA AND WEAK WAVE DISTURBANCES IN THE GULF
ROTATING OVER KODIAK ISLAND. WINDS WILL BE LIGHT ACROSS MOST INTERIOR
LOCATIONS....BUT THEY WILL CONTINUE TO FUNNEL THROUGH FAVORED AREAS
NEAR THE COAST SUCH AS SEWARD...VALDEZ COASTAL
LOCATIONS...WHITTIER...AND THE COPPER RIVER DELTA. WINDS WILL REMAIN
BLUSTERY ENOUGH NORTH OF TALKEETNA TO CONTINUE TO SUPPORT DANGEROUS
WIND CHILLS AS LOW AS NEGATIVE 30 DEGREES BELOW ZERO THROUGH
THANKSGIVING DAY. WEDNESDAY EVENING INTO THURSDAY...LOCALIZED
CHANNELED WINDS WILL BEGIN TO INCREASE AGAIN AS A POWERFUL LOW ENTERS
THE GULF OF ALASKA. LOCATIONS SUCH AS THE MATANUSKA
VALLEY...VALDEZ...COPPER RIVER...SEWARD...AND WHITTIER WILL SEE WINDS
PEAKING INTO THE 35 TO 60 MPH RANGE.

NEAR KODIAK...SNOW SHOWERS WILL BEGIN TO DIMINISH BY THIS
AFTERNOON...ALTHOUGH GUSTY NORTHERLY WINDS INTO THE 40 MPH RANGE WILL
CONTINUE TO SUPPORT AREAS OF BLOWING SNOW. ANOTHER WEAK DISTURBANCE
WILL BEGIN TO AFFECT THE REGION LATE WEDNESDAY NIGHT INTO
THURSDAY...WITH MORE PERIODIC SNOW SHOWERS.

SOUTHWEST ALASKA...
NO CHANGE FROM THE PAST COUPLE DAYS AS COLD AIR CONTINUES TO POUR
INTO BRISTOL BAY AND OVER THE ALASKA PENINSULA. PERIODIC SNOW SHOWERS
WILL CONTINUE ALONG THE PENINSULA THROUGH THANKSGIVING DAY...ALTHOUGH
ACCUMULATIONS WILL GENERALLY BE MINIMAL. STRONG NORTHERLY WINDS WILL
CONTINUE TO BLOW THROUGH FAVORED CHANNELED TERRAIN ALONG THE
PENINSULA TODAY BEFORE SLOWLY DIMINISHING THANKSGIVING DAY. ACROSS
MAINLAND ALASKA...COLD AND DRY CONDITIONS WILL LINGER INTO THE
WEEKEND...WITH BREEZY NORTHERLY WINDS CONTINUING TO SUPPORT WIND
CHILL VALUES INTO THE NEGATIVE 30 BELOW ZERO RANGE.

ALEUTIANS AND BERING SEA...
HIGH PRESSURE WILL DOMINATE MOST OF THE BERING SEA AND ALEUTIANS
THROUGH THANKSGIVING. STRONG WINDS FROM SEGUAM ISLAND TO DUTCH HARBOR
WILL BEGIN TO TAPER OFF TONIGHT. FARTHER WEST...A WEATHER FRONT WILL
BEGIN TO AFFECT THE WESTERN ALEUTIANS TONIGHT INTO
THURSDAY...BRINGING GALE FORCE WINDS AND RAIN TO THE AREA. THE FRONT
WILL SLOWLY TRACK TOWARDS THE CENTRAL ALEUTIANS BY FRIDAY.

.LONG TERM FORECAST...

SATURDAY AND BEYOND...CLOSED UPPER LEVEL BLOCKING HIGH WILL MEANDER
EASTWARD OVER MAINLAND ALASKA...ALLOWING FOR TEMPERATURES TO MODERATE
CLOSER TO SEASONAL VALUES WHILE BRINGING AN END TO THE STRONG
OFFSHORE WIND REGIME...AT LEAST THROUGH THE WEEKEND. LATE WEEKEND
INTO EARLY NEXT WEEK...AN UPPER LOW TRANSLATING SOUTH OF THE BLOCKING
HIGH WILL BEGIN TO SLIDE NORTHEASTWARD OVER KODIAK ISLAND AND INTO
THE WESTERN GULF. RAIN AND SNOW SHOWERS WILL DEVELOP ALONG THE COAST
AND POSSIBLY INTO PRINCE WILLIAM SOUND...BUT IT IS LIKELY MUCH OF THE
INTERIOR REMAINS DRY. THERE ARE HINTS THE STOUT BLOCKING PATTERN
BEGINS TO BREAK DOWN SOMETIME MID TO LATE NEXT WEEK...WITH THE ECMWF
AND ECMWF ENSEMBLE MEAN DEVELOPING A MORE PROGRESSIVE FLOW PATTERN
ACROSS THE BERING AND MAINLAND ALASKA. THE GFS AND GFS ENSEMBLE
CONTINUE TO DEPICT A BLOCKING PATTERN OVER THE BERING...WHICH WOULD
MEAN COLD AND DRY WITH STRONG OFFSHORE FLOW. WHILE IT IS PLAUSIBLE
THE ECMWF VERIFIES...FOR NOW...WILL CONTINUE WITH PERSISTENCE UNTIL
THE GFS AND GFS ENSEMBLE BEGIN TO DEPICT SUCH A PATTERN EVOLUTION AS
WELL.

.AER/ALU...WATCH/WARNING SUMMARY
PUBLIC...NONE
MARINE...STORM WARNING 352.
         GALE WARNING 127 128 130 132 150 160 165 170 171 175 176 180
         351 411 414.
         HEAVY FREEZING SPRAY WARNING 140 160 180 414.
FIRE WEATHER...NONE

AHSENMACHER NOV 12