Gale Warning 720, NWS Anchorage, AK

799 
FZAK61 PAFC 170023
OFFAER

OFFSHORE WATERS FORECAST
NATIONAL WEATHER SERVICE ANCHORAGE AK
400 PM AKST FRI NOV 16 2012

OFFSHORE WATERS FORECAST FOR THE GULF OF ALASKA WEST OF 144W

WIND FORECASTS REFLECT THE PREDOMINANT SPEED AND DIRECTION
EXPECTED. SEA FORECASTS REPRESENT AN AVERAGE OF THE HIGHEST
ONE-THIRD OF THE COMBINED WIND WAVE AND SWELL HEIGHT.

PKZ399-171500-
400 PM AKST FRI NOV 16 2012
.SYNOPSIS FOR THE WESTERN GULF OF ALASKA...

A 991 MB LOW WILL FORM NEAR 58N 143W TONIGHT AND THEN MOVE 
TO 58N 147W SAT NIGHT AT 980 MB.

$$

PKZ351-171500-
GULF OF ALASKA OFFSHORE NORTH OF 57N AND WEST OF 144W
400 PM AKST FRI NOV 16 2012

.TONIGHT...N WIND 20 KT. SEAS 8 TO 12 FT. 
.SAT...NORTH TO EAST WIND 15 TO 25 KT. SEAS 8 FT. RAIN AND SNOW. 
.SAT NIGHT...VARIABLE WIND 15 KT. SEAS 8 FT. RAIN AND SNOW. 
.SUN...VARIABLE WIND 15 KT. SEAS 7 FT. 
.SUN NIGHT...E WIND 15 TO 25 KT. SEAS 9 FT. 
.MON...E WIND 35 KT. SEAS 13 FT. 
.TUE...E WIND 20 KT. SEAS 9 FT. 
.WED...VARIABLE WIND 10 KT. SEAS 5 FT.  

$$

PKZ352-171500-
GULF OF ALASKA OFFSHORE SOUTH OF 57N NORTH OF 55N AND WEST OF
144W
400 PM AKST FRI NOV 16 2012

.TONIGHT...NW WIND 15 TO 25 KT. SEAS 10 TO 14 FT. 
.SAT...NW WIND 15 KT. SEAS 8 FT. 
.SAT NIGHT...NW WIND 20 KT. SEAS 7 FT. RAIN AND SNOW. 
.SUN AND SUN NIGHT...N WIND 20 KT. SEAS 7 FT. 
.MON...NE WIND 30 KT. SEAS 12 FT. 
.TUE...N WIND 25 KT. SEAS 11 FT. 
.WED...VARIABLE WIND 10 KT. SEAS 6 FT.  

$$

SOUTHCENTRAL AND SOUTHWEST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ANCHORAGE AK
500 PM AKST THU NOV 15 2012

.ANALYSIS AND UPPER LEVELS...
BROAD CYCLONIC FLOW CONTINUES TO PERSIST OVER MAINLAND ALASKA THIS
EVENING...WITH A BUILDING UPPER LEVEL RIDGE AXIS OVER THE CENTRAL
BERING SEA. EMBEDDED WITHIN THE MEAN CYCLONIC FLOW...SATELLITE
IMAGERY DEPICTS TWO WELL DEFINED UPPER LEVEL CIRCULATIONS...ONE
DEEPENING ACROSS THE GULF OF ALASKA WITH ANOTHER DIVING SOUTHWARD
OVER THE ALASKA PENINSULA. LINGERING MOISTURE ACROSS SOUTHCENTRAL
CONTINUES TO SUPPORT PERIODIC SNOW SHOWERS...ESPECIALLY LOCATIONS
NEAR THE UPPER LEVEL LOW PUSHING ACROSS THE ALASKA PENINSULA. A
GENERAL OFFSHORE FLOW REGIME WILL SETUP THROUGH THE WEEKEND AS THE
TWO UPPER LOWS MERGE AND DEEPEN AN ASSOCIATED SURFACE LOW ACROSS THE
GULF OF ALASKA. A LOBE OF THE POLAR VORTEX ORIGINATING OVER THE
BEAUFORT SEA WILL PUSH SOUTHWARD OVER ALASKA FRIDAY...BRINGING WITH
IT A DEEP AND COLD ARCTIC AIR MASS. HIGH PRESSURE WILL BUILD OVER THE
INTERIOR...WITH INTENSE OFFSHORE GAP WINDS DEVELOPING FRIDAY INTO
SATURDAY.

.MODEL DISCUSSION...
MODELS IN FAIR AGREEMENT WITH THE LARGE SCALE CIRCULATION PATTERN
INTO EARLY NEXT WEEK. HOWEVER...THEY BEGIN TO DIVERGE WITH RESPECT TO
THE SMALLER DETAILS LATE SATURDAY AND BEYOND...ESPECIALLY WITH
RESPECT TO PLACEMENT AND STRENGTH OF A DEVELOPING GULF OF ALASKA LOW.
ACROSS MAINLAND ALASKA...THE NAM WAS FAVORED DUE TO ITS SUPERIOR
HANDLING OF STRONG OFFSHORE GAP FLOWS. FARTHER WEST ACROSS THE BERING
SEA...THE ECMWF WAS FAVORED DUE TO ITS BETTER HANDLING OF A COMPLEX
BLOCKING PATTERN AND A STRONG FRONT MOVING ACROSS THE WESTERN BERING.

.SHORT TERM FORECAST...
SOUTHCENTRAL ALASKA...
LINGERING MOISTURE ASSOCIATED WITH A WEAKENING PRINCE WILLIAM SOUND
LOW CONTINUES TO SUPPORT AREAS OF SHOWERS ACROSS SOUTHCENTRAL. AN
ENHANCED BAND OF SNOW SHOWERS HAS FORMED OVER COOK INLET AND THE
KENAI PENINSULA...AND THESE SHOWERS WILL CONTINUE INTO THE EARLY
EVENING BEFORE WEAKENING. ANOTHER AREA OF SHOWERS ALONG THE COAST AND
INTO PRINCE WILLIAM SOUND WILL CONTINUE THROUGH THE EVENING.
LOCATIONS NEAR THE COAST WILL SEE A RAIN AND SNOW MIX...WITH SNOW
SHOWERS INLAND. AS THE UPPER LOW DEPARTS...INCREASING OFFSHORE WINDS
WILL DEVELOP...PEAKING MIDDAY FRIDAY INTO SATURDAY THROUGH FAVORED
LOCATIONS INCLUDING COPPER RIVER DELTA...THOMPSON PASS...MATANUSKA
VALLEY...WHITTIER...SEWARD...AND VALDEZ. WITH WIND GUSTS APPROACHING
40 TO 60 MPH THROUGH THOMPSON PASS...BLIZZARD CONDITIONS WILL BE
POSSIBLE GIVEN THE RECENT SNOWFALL. MORE RAIN AND SNOW SHOWERS WILL
DEVELOP SATURDAY AND SUNDAY ACROSS PRINCE WILLIAM SOUND AND THE COAST
AS ANOTHER LOW FORMS IN THE GULF OF ALASKA.

SOUTHWEST ALASKA...
A VERY DEEP UPPER LEVEL POTENTIAL VORTICITY ANOMALY WILL CONTINUE TO
TRANSLATE SOUTHEASTWARD INTO THE GULF OF ALASKA THIS EVENING. SNOW
SHOWERS ASSOCIATED WITH THIS FEATURE WILL RAPIDLY DIMINISH DURING THE
EVENING...WITH LITTLE TO NO ADDITIONAL ACCUMULATING SNOW. STRONG
SUBSIDENCE AND IMPRESSIVE COLD AIR ADVECTION BEHIND THE UPPER LOW
WILL KEEP THE REGION BLUSTERY INTO FRIDAY...WITH WIND GUSTS IN EXCESS
OF 45 MPH THIS EVENING NEAR BRISTOL BAY. WIND CHILLS MAY FALL INTO
THE -20 F RANGE BY TONIGHT AS TEMPERATURES PLUMMET INTO THE SINGLE
DIGITS AND TEENS ACROSS MUCH OF THE REGION.

ALEUTIANS AND BERING SEA...
A SURFACE RIDGE AXIS OVER THE CENTRAL BERING SEA WILL SLIDE EASTWARD
THIS EVENING...WITH A STORM FORCE FRONT PUSHING NORTHEASTWARD THEN
STALLING AND WEAKENING JUST WEST OF THE PRIBILOF ISLANDS FRIDAY
EVENING. THE STRONGEST STORM FORCE WINDS WILL REMAIN OFFSHORE...WITH
MODERATE TO HEAVY RAIN AND SNOW SHOWERS PUSHING ACROSS THE CENTRAL
AND EASTERN ALEUTIANS THROUGH FRIDAY BEFORE WEAKENING.

.LONG TERM FORECAST...
A LARGE BLOCKING HIGH IS EXPECTED TO FORM OVER EASTERN SIBERIA AND
THE CHUCKCHI SEA THIS WEEKEND AND PERSIST WELL INTO NEXT WEEK. THE
PREDOMINANT FLOW PATTERN WILL BE NORTHERLY AND EASTERLY...WITH A
SERIES OF UPPER LEVEL WAVES PASSING THROUGH THE FLOW. THIS PATTERN
WILL FAVOR MOSTLY DRY AND COLDER CONDITIONS...WITH OFFSHORE FLOW
DOMINATING THE LOCAL WEATHER PATTERNS.

.AER/ALU...WATCH/WARNING SUMMARY
PUBLIC...BLIZZARD 131
MARINE...STORMS 155 185 411 412
         GALES 127 128 130 132 150 160 165 176 180 352 413 414
         FREEZING SPRAY 121 126 127 128 129 140 141 160 180
FIRE WEATHER...NONE

AHSENMACHER NOV 12