Gale Warning 520, NWS Anchorage, AK

309 
FZAK62 PAFC 071145
OFFALU

OFFSHORE WATERS FORECAST
NATIONAL WEATHER SERVICE ANCHORAGE AK
400 AM AKDT SUN AUG 7 2011

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.

PKZ499-080300-
400 AM AKDT SUN AUG 7 2011
.SYNOPSIS FOR CENTRAL BERING SEA...

A LOW OVER SIBERIA WILL MOVE TO 62N 170W MON AFTERNOON AT 1005 MB
AND MOVE ONSHORE NEAR 66N 166W AT 1008 MB MON NIGHT. WEAK HIGH
PRESSURE WILL PERSIST OVER THE BERING SEA THROUGH MON NIGHT.

$$

PKZ411-080300-
BERING SEA OFFSHORE WEST OF 180 AND EAST OF THE INTERNATIONAL
DATELINE
400 AM AKDT SUN AUG 7 2011

.TODAY...SW WIND 15 TO 25 KT. SEAS 7 FT. PATCHY FOG. 
.TONIGHT...SW WIND 25 KT. SEAS 8 FT. PATCHY FOG. 
.MON...W WIND 25 KT. SEAS 8 FT. 
.MON NIGHT THROUGH TUE...S WIND 20 KT. SEAS 7 FT. 
.WED...S WIND 25 KT. SEAS BUILDING TO 13 FT. 
.THU...SW WIND 25 KT. SEAS 17 FT.  

$$

PKZ412-080300-
BERING SEA OFFSHORE 171W TO 180 AND NORTH OF 56N
400 AM AKDT SUN AUG 7 2011

.TODAY...SW WIND 15 TO 25 KT. SEAS 7 FT. PATCHY FOG. 
.TONIGHT...SW WIND 25 KT. SEAS 9 FT. PATCHY FOG. RAIN.
.MON...SW WIND 25 KT. SEAS 10 FT. RAIN.
.MON NIGHT...W WIND 20 KT. SEAS 8 FT. 
.TUE...SW WIND 20 KT. SEAS 6 FT. 
.WED...S WIND 20 KT. SEAS 10 FT. 
.THU...S WIND 20 KT. SEAS BUILDING TO 16 FT.  

$$

PKZ413-080300-
BERING SEA OFFSHORE 171W TO 180 AND SOUTH OF 56N
400 AM AKDT SUN AUG 7 2011

.TODAY...SW WIND 15 KT. SEAS 5 FT. PATCHY FOG. 
.TONIGHT...SW WIND 20 KT. SEAS 5 FT. PATCHY FOG. 
.MON THROUGH TUE...SW WIND 20 KT. SEAS 6 FT. 
.WED...S WIND 25 KT. SEAS 10 FT. 
.THU...SW WIND 25 KT. SEAS 13 FT.  

$$

PKZ414-080300-
BERING SEA OFFSHORE EAST OF 171W
400 AM AKDT SUN AUG 7 2011

.TODAY...W WIND INCREASING TO 20 KT BY MIDDAY. SEAS 6 FT.
PATCHY FOG. 
.TONIGHT...SW WIND 20 KT. SEAS 6 FT. 
.MON...SW WIND 25 KT. SEAS 8 FT. RAIN.
.MON NIGHT...SW WIND 20 KT. SEAS 8 FT. 
.TUE...SW WIND 15 KT. SEAS 7 FT. 
.WED THROUGH THU...S WIND 20 KT. SEAS 7 FT.  

$$

SOUTHCENTRAL AND SOUTHWEST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ANCHORAGE AK
520 AM AKDT SAT AUG 7 2011

.ANALYSIS AND UPPER LEVELS...A STRONG UPPER LEVEL LOW CURRENTLY JUST
WEST OF MEKORYUK WILL BE IMPACTING MUCH OF THE FORECAST AREA OVER THE
NEXT 48 HOURS. THIS SYSTEM HAS AN ANOMALOUSLY STRONG POTENTIAL
VORTICITY ANOMALY WITH A 100 KT ADJACENT JET. THIS JET WILL CONTINUE
TO HELP TO PROVIDE A STEADY STREAM OF MOISTURE TO THIS SYSTEM AS IT
MOVES WESTWARD OVER THE NEXT 48 HOURS.

.AT THE SURFACE...A RELATIVELY WEAK LOW PRESSURE SYSTEM IS LOCATED
BENEATH THE UPPER LEVEL LOW NEAR MEKORYUK AND MOST OF THE FORCING FOR
PRECIPITATION WITH THIS SYSTEM IS AT UPPER LEVELS. RAIN SHOWERS ARE
FALLING ACROSS THE KUSKOKWIM DELTA AS THIS SURFACE LOW APPROACHES THE
REGION. A FRONT ASSOCIATED WITH THIS LOW IS MOVING THROUGH BRISTOL
BAY AND TOWARDS KING SALMON. A WEAK SURFACE RIDGE COVERS THE
SOUTHCENTRAL REGION BUT WILL BE QUICKLY OVERTAKEN BY THIS SURFACE LOW
AND FRONT TODAY. A STRONG RIDGE IS ALSO CURRENTLY BUILDING INTO THE
WESTERN BERING BEHIND THE LOW PRESSURE SYSTEM AND FRONT IN THE
EASTERN BERING.

.MODEL DISCUSSION...MODELS ARE IN DECENT AGREEMENT IN THE SHORT TERM
BUT ARE CHANGING RAPIDLY...EVEN WITHIN THE FIRST 48 HOURS OF THE
FORECAST. THE GREATEST DISCREPENCY IS IN THE LOCATION AND INTENSITY
OF AN UPPER LEVEL SHORTWAVE THAT WILL MOVE THROUGH THE ANCHORAGE AREA
BY SATURDAY EVENING. THE ECMWF HAS THE MOST REALISTIC SOLUTION AND IS
ALSO PICKING UP ON A SECOND SHORTWAVE OVER ANCHORAGE LATE SUNDAY
NIGHT AND WAS THE MODEL OF CHOICE.

.SHORT TERM FORECAST...

.SOUTHCENTRAL ALASKA...
WET WEATHER WILL RETURN TO THE SOUTHCENTRAL REGION TODAY AS A FRONT
APPROACHES FROM THE WEST. ALTHOUGH THIS SYSTEM WILL BE WEAKENING AS
IT MOVES ACROSS THE ALASKAN RANGE...UPPER LEVEL MOISTURE SUPPORT WILL
HELP TO GENERATE RAIN ACROSS MUCH OF THE REGION. WINDS WILL BE
SOUTHWESTERLY THROUGH MOST OF THE DEPTH OF THE ATMOSPHERE SO
DOWNSLOPING WINDS NEAR THE SURFACE WILL ONLY REDUCE PRECIPITATION
SLIGHTLY ACROSS THE ANCHORAGE BOWL AND KENAI PENINSULA. OVERALL IT
WIL BE WET IN KODIAK BY MID MORNING AND IN ANCHORAGE BY THE EVENING.
STEADY RAIN WILL REACH PRINCE WILLIAM SOUND BY EARLY SUNDAY MORNING
AND CONTINUE THROUGH THE AFTERNOON. STRONG WINDS WILL ALSO BE
POSSIBLE THROUGH TURNAGAIN ARM AND ALONG HIGHER ELEVATIONS AS THE
FRONT APPROACHES AND PRESSURE GRADIENTS ACROSS THE AREA INCREASE.
MODELS ARE CURRENTLY INDICATING THE POSSIBILITY OF GUSTS UP TO 55 MPH
IN THESE REGIONS BY LATE AFTERNOON SATURDAY THROUGH EARLY SUNDAY
MORNING.

.SOUTHWEST ALASKA...THE LOW PRESSURE SYSTEM JUST WEST OF MEKORYUK IS
ALREADY SUPPORTING RAIN ACROSS THE KUSKOKWIM DELTA AND BRISTOL BAY.
RAIN SHOULD CONTINUE ACROSS THESE REGIONS THROUGH THE EVENING HOURS
AS THIS LOW TRACKS WESTWARD. DUE TO THE STRONG UPPER LEVEL FORCING
AND MOISTURE TRANSPORT...RAIN SHOULD REMAIN STEADY EVEN AS THE SYSTEM
MOVES INLAND. STRONG SUBSIDENCE AND COLD AIR ADVECTION BEHIND THIS
FRONT SHOULD HELP TO SUPPORT PARTIAL CLEARNING IN THE BRISTOL BAY
REGION BY SUNDAY MORNING.

BERING SEA...ALEUTIANS...A FRONT IS BRINGING MOSTLY STRATUS AND
DRIZZLE TO THE CENTRAL AND EASTERN ALEUTIAN ISLANDS THIS
MORNING...ALTHOUGH SHOWERS ARE STILL POSSIBLE UNTIL THIS FRONT MOVES
SOUTHEAST OF THE ALEUTIANS BY THIS EVENING. PARTIAL CLEARING WILL
OCCUR BEHIND THIS FRONT DUE TO THE STRONG COLD AIR ADVECTION AND
SUBSIDENCE TONIGHT. A WEAKER LOW PRESSURE SYSTEM WILL MOVE INTO THE
NORTH BERING BY LATE SUNDAY EVENING.

.LONG TERM FORECAST...A SERIES OF UPPER LEVEL LOWS WILL DOMINATE
ALASKA AND THE BERING SEA THROUGH THE MIDDLE OF NEXT WEEK.
HOWEVER...MODELS ARE BEGINNING TO MORE STRONGLY INDICATE THAT A RIDGE
WILL BUILD ACROSS THE ALASKA MAINLAND BY NEXT THURSDAY...WHICH WOULD
BRING IN DRIER WEATHER.

.AER/ALU...WATCH/WARNING SUMMARY
PUBLIC...FLOOD ADVISORY 145
MARINE...GALE...NONE
FIRE WEATHER...NONE

ELN AUG 11