Gale Warning 638, NWS Anchorage, AK

105 
FZAK62 PAFC 241123
OFFALU

OFFSHORE WATERS FORECAST
NATIONAL WEATHER SERVICE ANCHORAGE AK
400 AM AKDT WED OCT 24 2012

OFFSHORE WATERS FORECAST FOR THE BERING SEA

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.

PKZ499-250300-
400 AM AKDT WED OCT 24 2012
.SYNOPSIS FOR CENTRAL BERING SEA...

A 990 MB LOW NEAR 47N 164W WILL REMAIN NEARLY STATIONARY AND
INTENSIFY TO 981 MB BY LATE THU NIGHT WITH HIGH PRESSURE BUILDING
ACROSS THE BERING SEA.

$$

PKZ411-250300-
BERING SEA OFFSHORE WEST OF 180 AND EAST OF THE INTERNATIONAL
DATELINE
400 AM AKDT WED OCT 24 2012

.TODAY...SE WIND 25 KT. SEAS 15 FT. PATCHY FOG. 
.TONIGHT...SE WIND 25 KT. SEAS 12 FT. PATCHY FOG. 
.THU...SE WIND 15 TO 25 KT. SEAS 10 FT. 
.THU NIGHT...SE WIND 15 KT. SEAS 9 FT. 
.FRI...E WIND 15 KT. SEAS 8 FT. 
.SAT AND SUN...NE WIND 20 KT. SEAS 6 FT.  

$$

PKZ412-250300-
BERING SEA OFFSHORE 171W TO 180 AND NORTH OF 56N
400 AM AKDT WED OCT 24 2012

.TODAY...E WIND 30 KT DIMINISHING TO 20 KT IN THE AFTERNOON. SEAS 15
FT SUBSIDING TO 10 FT. PATCHY FOG.
.TONIGHT...E WIND 20 KT. SEAS 10 FT. 
.THU AND THU NIGHT...E WIND 15 KT. SEAS 6 FT. 
.FRI AND SAT...E WIND 20 KT. SEAS 7 FT. 
.SUN...NE WIND 15 KT. SEAS 6 FT.  

$$

PKZ413-250300-
BERING SEA OFFSHORE 171W TO 180 AND SOUTH OF 56N
400 AM AKDT WED OCT 24 2012

.TODAY...E WIND 30 KT DIMINISHING TO 20 KT IN THE AFTERNOON. SEAS 15
FT SUBSIDING TO 11 FT. PATCHY FOG. 
.TONIGHT...E WIND 20 KT. SEAS 10 FT. 
.THU...E WIND 15 KT. SEAS 8 FT. 
.THU NIGHT THROUGH SAT...NE WIND 20 KT. SEAS 8 FT.
.SUN...NE WIND 15 KT. SEAS 6 FT.  

$$

PKZ414-250300-
BERING SEA OFFSHORE EAST OF 171W
400 AM AKDT WED OCT 24 2012

.TODAY...E WIND 25 KT. SEAS 9 FT. 
.TONIGHT THROUGH THU NIGHT...E WIND 20 KT. SEAS 6 FT. 
.FRI THROUGH SAT...NE WIND 25 KT. SEAS 8 FT. 
.SUN...NE WIND 20 KT. SEAS 6 FT.  

$$

SOUTHCENTRAL AND SOUTHWEST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ANCHORAGE AK
536 AM AKDT TUE OCT 23 2012

.ANALYSIS AND UPPER LEVELS...
BLOCKING HIGH OVER THE EASTERN AND CENTRAL BERING SEA WILL CONTINUE
TO BUILD AS A STRONG STORM SYSTEM ALONG AND SOUTH OF THE WESTERN
ALEUTIANS DIVES SOUTH AND CUTS OFF FROM THE POLAR JET STREAM. THE
BLOCKING HIGH WILL BUILD ACROSS WESTERN ALASKA INTO THE WEEKEND WITH
A SERIES OF WEAK UPPER DISTURBANCES IN NORTHEAST FLOW PROPAGATING
ACROSS SOUTHERN ALASKA AND THE GULF AROUND THE SOUTHERN PERIPHERY OF
THE HIGH. THESE DISTURBANCES WILL GENERALLY PROMOTE INCREASED
OFFSHORE FLOW THROUGH WEDNESDAY...ESPECIALLY THROUGH CHANNELED
TERRAIN AS HIGH PRESSURE BUILDS ACROSS THE INTERIOR. BY FRIDAY...THE
ENTIRE STATE OF ALASKA AND THE BERING SEA WILL BE UNDER THE INFLUENCE
OF THE DRY AND STABLE BLOCKING HIGH.

.MODEL DISCUSSION...
IN GENERAL...THE NUMERICAL GUIDANCE CONTINUES TO REMAIN IN RELATIVELY
STRONG AGREEMENT THROUGH THURSDAY WITH RESPECT TO THE LARGE SCALE
SYNOPTIC FLOW PATTERN. THE NAM WAS FAVORED IN THE SHORT TERM WITH
SOME ADDITION OF THE LOCAL WRF MODEL FOR CHANNELED FLOW ACROSS THE
MAINLAND. FOR THE EXTENDED RANGE FORECAST THIS WEEKEND AND
BEYOND...HPC GUIDANCE BLENDED WITH THE ECMWF WAS FAVORED...ALTHOUGH
DIFFERENCES AMONG THE GLOBAL NUMERICAL GUIDANCE SUITE ARE MINIMAL
THROUGH THE WEEKEND.

.SHORT TERM FORECAST...

SOUTHCENTRAL...
THE RELATIVELY PERSISTENT PATTERN OF COLD HIGH PRESSURE BUILDING
ACROSS THE INTERIOR AND WEAK UPPER LEVEL DISTURBANCES MOVING OVER THE
REGION WILL CONTINUE TO SUPPORT AN OFFSHORE FLOW PATTERN INTO THE
WEEKEND. GUSTY WINDS THROUGH FAVORED VALLEYS AND CHANNELED TERRAIN
WILL PEAK LATE TODAY THROUGH WEDNESDAY MORNING BEFORE SUBSIDING
THURSDAY. OTHERWISE...DRY...COLD...AND MOSTLY CLEAR SKIES WILL
DOMINATE THE REGION HEADING INTO THE WEEKEND.

SOUTHWEST ALASKA/PENINSULA...
STABLE HIGH PRESSURE WILL PERSIST OVER THE REGION HEADING INTO THE
WEEKEND WITH A GENERAL OFFSHORE FLOW PATTERN ALONG THE COASTS. A FEW
AREAS OF LOW CLOUDS AND PATCHY FOG ACROSS THE KUSKOKWIM DELTA AND
PENINSULA THIS MORNING WILL GIVE WAY TO MAINLY CLEAR SKIES AS STABLE
AND DRY AIR FILTERS IN FROM THE NORTH AND EAST.

BERING SEA AND ALEUTIAN ISLANDS...
A STRONG STORM SYSTEM WITH GALE AND STORM FORCE WINDS CURRENTLY OVER
THE WESTERN ALEUTIANS WILL MOVE SOUTH OF THE ALEUTIAN CHAIN AND
WEAKEN BY LATE TONIGHT. THE STRONGEST CORE OF WINDS AND HEAVIEST
PRECIPITATION WILL GENERALLY REMAIN ALONG THE FRONT...WHICH STRETCHES
FROM THE PRIBILOF ISLANDS SOUTH TO DUTCH HARBOR AND WEST TO ATKA.
STRONG NORTHWEST WINDS ON THE BACKSIDE OF THE LOW WILL ALSO CLIP ATTU
ISLAND. HIGH PRESSURE WILL RAPIDLY BUILD IN AFTER WEDNESDAY MORNING
ALTHOUGH THE SAME STORM SYSTEM WILL LIFT BACK NORTH LATE THURSDAY
INTO FRIDAY SOUTH OF THE EASTERN ALEUTIANS...WITH GALE FORCE WINDS
FROM DUTCH HARBOR TO SAND POINT.

.LONG TERM FORECAST...
STABLE AND STRONG UPPER LEVEL BLOCKING PATTERN WILL PERSIST THROUGH
MONDAY. THE NET RESULT IN TERMS OF SENSIBLE WEATHER MEANS DRY AND
MOSTLY CLEAR SKIES WILL BE THE DOMINANT WEATHER MODE...WITH A SLOW
WARM-UP BACK TO NEAR CLIMATOLOGICAL NORMS BY THE END OF THE WEEKEND.
WHILE TIMING DIFFERENCES DO EXIST...THE GENERAL PATTERN WILL SEE THE
UPPER LEVEL BLOCKING HIGH RETROGRADE INTO EASTERN RUSSIA...WITH A
POLAR FRONT PUSHING THROUGH MAINLAND ALASKA AND THE BERING SEA
SOMETIME EARLY NEXT WEEK. THERE IS A HIGHER THAN AVERAGE CONFIDENCE
IN THIS PATTERN CHANGE...WITH THE POSSIBILITY THIS POLAR AIR MASS
WILL SUPPORT THE COLDEST AIR OF THE SEASON.

.AER/ALU...WATCH/WARNING SUMMARY
PUBLIC...NONE
MARINE...STORM 170 172 412 413
         GALE 176 179 185 411 414
FIRE WEATHER...NONE

AHSENMACHER OCT 12