Gale Warning 364, NWS Anchorage, AK

496 
FZAK62 PAFC 082337
OFFALU

OFFSHORE WATERS FORECAST
NATIONAL WEATHER SERVICE ANCHORAGE AK
400 PM AKDT TUE MAY 8 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.

PKZ499-091500-
400 PM AKDT TUE MAY 8 2012
.SYNOPSIS FOR CENTRAL BERING SEA...
A 997 MB LOW NEAR 54N 170W WILL STRENGTHEN TO 984 MB AS IT MOVES 
TO AROUND 56N 158W WED AFTERNOON. THIS LOW WILL THEN DRIFT TO 
58N 158W THU AFTERNOON AT 989 MB. 

$$

PKZ411-091500-
BERING SEA OFFSHORE WEST OF 180 AND EAST OF THE INTERNATIONAL
DATELINE
400 PM AKDT TUE MAY 8 2012

.TONIGHT...N WIND 25 TO 30 KT. SEAS 11 FT.  FREEZING SPRAY.
.WED AND WED NIGHT...NW WIND 25 KT. SEAS 8 FT.  
.THU...NW WIND 30 KT. SEAS 8 FT. 
.THU NIGHT AND FRI...W WIND 20 KT. SEAS 6 FT. 
.SAT...W WIND 25 KT. SEAS 7 FT. 
.SUN...S WIND 25 KT. SEAS 8 FT.  

$$

PKZ412-091500-
BERING SEA OFFSHORE 171W TO 180 AND NORTH OF 56N
400 PM AKDT TUE MAY 8 2012

.TONIGHT...N WIND 25 KT. SEAS IN ICE FREE WATERS 7 FT. FREEZING
SPRAY. 
.WED...N WIND 20 KT. SEAS IN ICE FREE WATERS 6 FT. FREEZING SPRAY. 
.WED NIGHT...NW WIND 25 KT. SEAS IN ICE FREE WATERS 6 FT. AREAS OF
FOG.
.THU THROUGH FRI...N WWIND 25 KT. SEAS IN ICE FREE WATERS 5 FT. 
.SAT AND SUN...SW WIND 20 KT. SEAS IN ICE FREE WATERS 6 FT. 

$$

PKZ413-091500-
BERING SEA OFFSHORE 171W TO 180 AND SOUTH OF 56N
400 PM AKDT TUE MAY 8 2012

.TONIGHT...N WIND 30 KT. SEAS 10 FT. SNOW AND RAIN. 
.WED...N WIND 25 KT. SEAS 9 FT.  
.WED NIGHT...NW WIND 25 KT. SEAS 8 FT. AREAS OF FOG.
.THU THROUGH FRI...NW WIND 25 KT. SEAS 7 FT. 
.SAT...W WIND 20 KT. SEAS 6 FT. 
.SUN...S WIND 25 KT. SEAS 7 FT.  

$$

PKZ414-091500-
BERING SEA OFFSHORE EAST OF 171W
400 PM AKDT TUE MAY 8 2012

.TONIGHT...NE WIND 30 KT. SEAS IN ICE FREE WATERS 8 FT. SNOW.
FREEZING SPRAY. 
.WED...N WIND 25 KT. SEAS IN ICE FREE WATERS 8 FT. AREAS OF FOG.
FREEZING SPRAY. 
.WED NIGHT...NW WIND 20 KT. SEAS IN ICE FREE WATERS 6 FT. AREAS OF
FOG. FREEZING SPRAY. 
.THU THROUGH FRI...NW WIND 20 KT. SEAS IN ICE FREE WATERS 6 FT.
.SAT AND SUN...SW WIND 20 KT. SEAS IN ICE FREE WATERS 5 FT. 

$$

SOUTHCENTRAL AND SOUTHWEST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ANCHORAGE AK
1250 PM AKDT MON MAY 7 2012

.ANALYSIS AND UPPER LEVELS...A HIGH AMPLITUDE TROUGH IS CENTERED
OVER THE ALASKA REGION WITH AN EMBEDDED CLOSED LOW JUST SOUTH
OF THE GULF. SATELLITE IMAGERY SHOWS THE TROUGH IS JUST BEGINNING
TO LIFT NORTHEASTWARD WHILE SHORT-WAVES ON THE NORTH SIDE OF THE
LOW ROTATE WESTWARD ACROSS THE GULF AND SOUTHERN MAINLAND. ONE
SHORT-WAVE IS EXITING SOUTHCENTRAL THIS MORNING AND TRACKING ACROSS
SOUTHWEST ALASKA. THE COMBINATION OF THIS UPPER LEVEL WAVE WITH THE
REMNANTS OF A SURFACE FRONTAL BOUNDARY ARE PRODUCING SCATTERED
SHOWERS ACROSS SOUTHWEST ALASKA. WEAK LOW LEVEL FLOW AND ABUNDANT
MOISTURE ARE ALSO PRODUCING AREAS OF FOG AND STRATUS...PARTICULARLY
IN THE BRISTOL BAY REGION. SKIES CLEARED OVER THE COOK INLET/SUSITNA
VALLEY CORRIDOR BEHIND THE SHORT-WAVE...BUT CLOUDS ARE ALREADY
FILLING BACK IN OVER LAND THANKS TO AN UNSTABLE AIRMASS AND THE
NEXT SHORT-WAVE APPROACHING FROM THE EAST ACROSS THE NORTHERN GULF
AND PRINCE WILLIAM SOUND.

A SHORT-WAVE NEAR KAMCHATKA IS DIGGING ALONG THE BACK SIDE OF THE
LONG-WAVE TROUGH. A SURFACE LOW IS BEGINNING TO DEEPEN OUT AHEAD
OF IT OVER THE WESTERN ALEUTIANS WHERE RAIN AND FOG IS BEGINNING
TO MOVE IN.

.MODEL DISCUSSION...ECMWF IS AN OUTLIER WITH SPEED OF LOW TRACKING
ALONG THE ALEUTIANS THE NEXT COUPLE DAYS. PREFER THE GFS/NAM WHICH
ARE IN EXCELLENT AGREEMENT...SUPPORTED BY GFS ENSEMBLE MEMBERS...
AND BECAUSE THIS SOLUTION PROVIDES CONTINUITY WITH THE CURRENT
FORECAST.

.SHORT TERM FORECAST...

SOUTHCENTRAL ALASKA...SHORT-WAVE CROSSING THE NORTHERN GULF WILL
ROTATE SOUTHWARD TONIGHT AS THE UPPER LOW CONTINUES TO LIFT
NORTHEASTWARD TOWARD SOUTHEAST ALASKA. THUS SHOWER ACTIVITY SHOULD
DIE OFF THIS EVENING ACROSS MOST OF SOUTHCENTRAL. HOWEVER...A SERIES
OF SHORT-WAVES CURRENTLY OVER THE EASTERN GULF WILL TRACK INTO THE
COPPER BASIN AND EASTERN PRINCE WILLIAM SOUND REGION TONIGHT INTO
TUESDAY MORNING. BASED ON OBSERVATIONS FROM SOUTHEAST ALASKA RIGHT
NOW LOOKS LIKE STEADY STRATIFORM PRECIP WILL ACCOMPANY THE STRONGEST
OF THESE SHORT-WAVES. MODELS DIFFER ON THE WESTWARD EXTENT OF PRECIP
WITH NAM BRINGING RAIN TO THE DOORSTEP OF ANCHORAGE. BASED ON UPPER
LEVEL FLOW WHICH WILL BE BACKING WITH TIME DON'T THINK STEADY RAIN
WON'T MAKE IT ANY FURTHER THAN PRINCE WILLIAM SOUND...ALTHOUGH SOME
LOWER CLOUDS COULD MAKE IT OVER THE KENAI AND CHUGACH MOUNTAINS. DO
ONCE AGAIN EXPECT DIURNAL CONVECTION IN THESE WESTERN AREAS WITH
DAYTIME HEATING AND THE CONTINUED COLD TEMPERATURES ALOFT. UPPER
LEVEL FLOW WILL SHIFT AROUND TO SOUTHERLY BY WEDNESDAY AS ALEUTIAN
SYSTEM MOVES INTO THE GULF. THE RESULTS WILL BE SIMILAR WITH WEAK
UPPER WAVES AND COLD AIR ALOFT LEADING TO MOSTLY DIURNAL CONVECTION
INLAND WHILE STEADY RAIN OR SHOWERS SETTLE IN ALONG THE GULF COAST.

SOUTHWEST ALASKA...SOUTHWEST ALASKA WILL BE ON THE PERIPHERY OF
MAJOR FEATURES THE NEXT FEW DAYS...OFTENTIMES WITH WEAK AND
VARIABLE FLOW. THIS MEANS THAT LOW LEVEL MOISTURE WILL REMAIN ON
THE HIGH SIDE...LEADING TO PERSISTENT AREAS OF FOG AND STRATUS.
WITH WEAK FORCING CONVECTION WILL PRIMARILY BE DIURNAL IN NATURE.

BERING SEA/ALEUTIANS...AS UPPER LOW IS LIFTING UP THE FRONT SIDE
OF TROUGH AND SHORT-WAVE IS DIGGING DOWN BACK SIDE OF TROUGH THE
BASE OF THE TROUGH WILL FLATTEN OUT AND WESTERLY FLOW WILL
STRENGTHEN ALONG THE ALEUTIANS. THIS MEANS LOW CURRENTLY OVER THE
WESTERN ALEUTIANS WILL TRACK QUICKLY...REACHING KODIAK ISLAND BY
WEDNESDAY AFTERNOON. A SHORT-WAVE MOVING OVER TOP OF A STRONG RIDGE
OVER SIBERIA WILL DROP DOWN OUT OF THE ARCTIC WEDNESDAY AMPLIFYING
THE LONG-WAVE TROUGH ONCE AGAIN AND REINFORCING THE ARCTIC AIR IN
PLACE OVER THE BERING SEA REGION.

.LONG TERM FORECAST...UPPER LEVEL FLOW LOOKS LIKE IT WILL REMAIN
HIGHLY AMPLIFIED AND DYNAMIC THROUGH THE DAY 4 THROUGH 7 PERIOD.
NORMALLY THIS WOULD LEAD TO BELOW AVERAGE CONFIDENCE.
HOWEVER...GFS/ECMWF SHOW SIMILAR SOLUTIONS SO CONFIDENCE IS ABOUT
AVERAGE. THE TROUGH DROPPING SOUTHWARD ACROSS THE BERING MID WEEK
WILL PICK UP A PACIFIC LOW AND TRACK IT INTO THE GULF LATE THIS
WEEK. AS IS TYPICAL FOR THIS TIME OF YEAR EXPECT THE BULK OF
STRATIFORM PRECIP TO REMAIN ALONG THE COAST WITH A MORE SHOWERY
REGIME INLAND. AS WE HEAD THROUGH THE WEEKEND AND INTO NEXT WEEK
THIS TROUGH WILL LIFT WHILE ANOTHER DIGS OUT OF ASIA INTO THE
BERING SEA. SO EXPECT IMPROVING CONDITIONS OVER THE MAINLAND AS
THE FOCUS SHIFTS TO A PACIFIC STORM TRACKING INTO THE BERING SEA.

.AER/ALU...WATCH/WARNING SUMMARY
PUBLIC...NONE.
MARINE...GALE WARNING...172.
FIRE WEATHER...NONE.

SEB MAY 12