Gale Warning 249, NWS Anchorage, AK

158 
FZAK62 PAFC 161210
OFFALU

OFFSHORE WATERS FORECAST
NATIONAL WEATHER SERVICE ANCHORAGE AK
400 AM AKDT WED MAR 16 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.

PKZ499-170400-
400 AM AKDT WED MAR 16 2011
.SYNOPSIS FOR CENTRAL BERING SEA...

A BROAD AREA OF LOW PRESSURE ALONG THE ALEUTIANS WEAKENS BY WED
AFTERNOON. A NORTH PACIFIC LOW INTENSIFIES TO 938 MB WED EVENING NEAR
48N 163E AND THEN WEAKENS TO 948 MB THU NIGHT NEAR 53N 171E.
ASSOCIATED WEATHER FRONTS MOVE ACROSS THE ALEUTIANS WED AFTERNOON
THROUGH THU NIGHT.

$$

PKZ411-170400-
BERING SEA OFFSHORE WEST OF 180 AND EAST OF THE INTERNATIONAL
DATELINE
400 AM AKDT WED MAR 16 2011

...STORM WARNING TONIGHT AND THURSDAY...

.TODAY...NE WIND 20 KT. SEAS 11 FT. FREEZING SPRAY. 
.TONIGHT...E WIND 25 KT INCREASING TO 50 KT AFTER MIDNIGHT. SEAS 15
FT. SNOW AND RAIN. 
.THU...SE WIND 50 KT DIMINISHING TO 40 KT IN THE AFTERNOON. SE WIND
35 KT SOUTH OF 56 N. SEAS 18 FT. RAIN AND SNOW. 
.THU NIGHT...SE WIND 35 KT. SEAS 26 FT. 
.FRI...SW WIND 40 KT. SEAS 28 FT. 
.SAT...W WIND 30 KT. SEAS 19 FT. 
.SUN...S WIND 20 KT. SEAS 13 FT.  

$$

PKZ412-170400-
BERING SEA OFFSHORE 171W TO 180 AND NORTH OF 56N
400 AM AKDT WED MAR 16 2011

...STORM WARNING THURSDAY...

.TODAY...E WIND 20 KT. SEAS 8 FT. FREEZING SPRAY. 
.TONIGHT...SE WIND 20 KT INCREASING TO 40 KT AFTER MIDNIGHT. SEAS
10 FT. FREEZING SPRAY. 
.THU...SE WIND 50 KT. SEAS 19 FT. RAIN AND SNOW. 
.THU NIGHT...S WIND 35 KT. SEAS 19 FT. 
.FRI...S WIND 35 KT. SEAS 24 FT. 
.SAT...SW WIND 30 KT. SEAS 22 FT. 
.SUN...S WIND 20 KT. SEAS 16 FT.  

$$

PKZ413-170400-
BERING SEA OFFSHORE 171W TO 180 AND SOUTH OF 56N
400 AM AKDT WED MAR 16 2011

...STORM WARNING THURSDAY...

.TODAY...VARIABLE WIND 10 KT. SEAS 10 FT. 
.TONIGHT...SE WIND 30 KT INCREASING TO 45 KT AFTER MIDNIGHT. SEAS
12 FT. SNOW AND RAIN. 
.THU...SE WIND 50 KT. SEAS 16 FT. RAIN.
.THU NIGHT...S WIND 40 KT. SEAS 19 FT. 
.FRI...SW WIND 40 KT. SEAS 25 FT. 
.SAT...SW WIND 30 KT. SEAS 20 FT. 
.SUN...SW WIND 30 KT. SEAS 15 FT.  

$$

PKZ414-170400-
BERING SEA OFFSHORE EAST OF 171W
400 AM AKDT WED MAR 16 2011

...GALE WARNING THURSDAY...

.TODAY...NW WIND 15 KT. SEAS IN ICE FREE WATERS 3 FT. 
.TONIGHT...NW WIND 15 KT BECOMING SE 20 KT AFTER MIDNIGHT. SEAS IN
ICE FREE WATERS 3 FT BUILDING TO 7 FT AFTER MIDNIGHT. 
.THU...SE WIND 25 KT INCREASING TO 45 KT IN THE AFTERNOON. SEAS IN
ICE FREE WATERS 12 FT. RAIN.
.THU NIGHT...SE WIND 45 KT. SEAS IN ICE FREE WATERS 13 FT. 
.FRI AND SAT...S WIND 30 KT. SEAS IN ICE FREE WATERS 14 FT. 
.SUN...SW WIND 20 KT. SEAS IN ICE FREE WATERS 15 FT.  

$$

SOUTHCENTRAL AND SOUTHWEST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ANCHORAGE AK
1230 PM AKDT TUE MAR 15 2011

.ANALYSIS AND UPPER LEVELS...STRONG UPPER HIGH REMAINS CENTERED
OVER THE BERING STRAIT THIS MORNING ALTHOUGH ITS INFLUENCED ON
THE SURROUNDING AREA HAS WANED OVER THE PAST FEW DAYS. A SERIES
OF UPPER LOWS HAVE SET UP SHOP SOUTH OF THE HIGH...ONE NEAR THE
ALASKA PENINSULA AND ONE NEAR THE PRIBILOFS WITH A GENERAL WESTWARD
MOVEMENT...AND THEN ANOTHER JUST WEST OF THE ALEUTIANS MOVING
EASTWARD.

AT THE SURFACE A MODERATE STRENGTH LOW IS MOVING WESTWARD ACROSS
THE GULF TOWARD KODIAK ISLAND. MIDDLETON ISLAND RADAR SHOWS A SOLID
AREA OF PRECIPITATION PRIMARILY OFFSHORE. PRESSURE GRADIENT DRIVEN
GAP WINDS CONTINUE IN THE USUAL PLACES. THE LOW LEVEL OFFSHORE FLOW
WILL MAINTAIN A VERY DRY AIR MASS NEAR THE SURFACE AND LIMIT
PRECIPITATION ALONG THE NORTH GULF COAST TO FLURRIES OR VERY LIGHT
SNOW. KODIAK ISLAND ON THE OTHER HAND IS RIGHT IN THE PATH OF THE
LOW SO EXPECT STEADY SNOW TO DEVELOP AS WE HEAD INTO THE AFTERNOON.
OUT WEST A SURFACE LOW IS WEAKENING AS IT TRACKS TOWARD THE
ALEUTIANS.

.MODEL DISCUSSION...MODELS ARE IN GOOD AGREEMENT THROUGH THE NEXT
FEW DAYS WITH JUST A FEW MINOR DIFFERENCES IN POSITIONS OF SYNOPTIC
FEATURES. RUN-TO-RUN CONSISTENCY IS ALSO VERY GOOD.

.SHORT TERM FORECAST...

SOUTHCENTRAL ALASKA...AS THE GULF LOW APPROACHES KODIAK ISLAND
TONIGHT WEST TO NORTHWEST WINDS WILL INCREASE AND SNOW WILL
INTENSIFY. DO NOT EXPECT WINDS TO BECOME STRONG ENOUGH TO PRODUCE
A BLIZZARD BUT THERE WILL BE BLOWING SNOW WHICH WILL CONTRIBUTE TO
LOW VISIBILITIES AT TIMES. WITH STEADY SNOW ALL NIGHT WILL INCREASE
SNOW AMOUNTS. SURFACE TEMPERATURES WILL REMAIN NEAR THE FREEZING
MARK WHICH SHOULD KEEP AMOUNTS BELOW ADVISORY LEVELS...ALTHOUGH
HIGHER ELEVATION AREAS MAY COME VERY CLOSE TO THE 6 INCH ADVISORY
THRESHOLD TONIGHT. THE NORTH GULF COAST WILL INITIALLY REMAIN
RIGHT ON THE PERIPHERY OF THIS SYSTEM...SO PRIMARY IMPACT WILL
BE CLOUDS. HOWEVER...AN UPPER LOW WILL FORM OVER THE SOUTHERN
GULF TUESDAY NIGHT AND WEDNESDAY AND HELP PUSH THE REMNANTS OF THE
OCCLUDED FRONT ONSHORE. THUS...EXPECT AN INCREASING CHANCE OF SNOW
ALONG COASTAL SOUTHCENTRAL WEDNESDAY. ON WEDNESDAY NIGHT INTO
THURSDAY A TROUGH WILL DIG DOWN FROM THE NORTH BRINGING A CHANCE
OF SNOW TO THE REST OF SOUTHCENTRAL. IF IT DOES SNOW EXPECT IT WILL
BE LIGHT AND SHORT-LIVED AS THE UPPER TROUGH MOVES QUICKLY THROUGH.

SOUTHWEST ALASKA...THE ALASKA PENINSULA WILL SEE COME CLOUDS
ASSOCIATED WITH THE GULF LOW THE NEXT COUPLE DAYS. THERE COULD
EVEN BE A FEW FLURRIES OR SNOW SHOWERS. OTHERWISE...SOUTHWEST
ALASKA WILL REMAIN DRY UNDER THE INFLUENCE OF THE RIDGE TO THE
NORTH.

BERING SEA/ALEUTIANS...UPPER LOW NEAR THE PRIBILOFS WILL TRACK
WESTWARD ACROSS THE BERING SEA WHILE THE LOW CURRENTLY WEST OF
THE ALEUTIANS TRACKS EASTWARD AND WEAKENS ALONG THE ALEUTIANS.
THE BIG STORY THOUGH IS THE MAJOR LOW WHICH WILL DEVELOP OVER
THE PACIFIC TONIGHT AND WEDNESDAY AND INTO THE BERING BY FRIDAY.
THE SIZE OF THIS SYSTEM WILL BE HUGE WITH A ROUGH APPROXIMATED
AREA OF INFLUENCE OF 2500 MILES NORTH TO SOUTH AND 2500 MILES
EAST TO WEST. THE STRONGEST WINDS ON THE SOUTH TO WEST SIDE OF
THE LOW WILL OCCUR WHEN THE LOW IS STILL OVER THE NORTHWEST
PACIFIC...SO DO NOT EXPECT WARNING LEVEL WINDS. THE FRONTAL SYSTEM
WILL MOVE FAR OUT AHEAD OF THE LOW FROM THE WESTERN ALEUTIANS
WEDNESDAY AFTERNOON TO SOUTHWEST ALASKA FRIDAY...WITH WINDS
EXPECTED TO MAX OUT AT STORM FORCE. RIGHT NOW IT LOOKS LIKE AIRMASS
ALONG THE FRONT WILL BE TOO WARM FOR BLIZZARD CONDITIONS...BUT
THIS WILL NEED TO BE RE-EVALUATED AS WE GET CLOSER.

.LONG TERM FORECAST...A RIDGE WILL BUILD OUT AHEAD OF THE RAPIDLY
INTENSIFYING NORTHWEST PACIFIC LOW ON WEDNESDAY AND THEN MERGE
WITH THE HIGH OVER THE BERING STRAIT WEDNESDAY NIGHT AND THURSDAY...
CREATING A VERY HIGH AMPLITUDE RIDGE OVER MAINLAND ALASKA THURSDAY
NIGHT INTO FRIDAY. MEDIUM RANGE MODELS DIFFER ON THE EASTWARD
PROGRESSION OF THIS RIDGE...AND THUS ON WHETHER THE FRONT EVER
MAKES IT ANY FURTHER THAN SOUTHWEST ALASKA BEFORE FALLING APART.
THERE IS EVEN LARGER DIFFERENCES IN MODEL SOLUTIONS WITH HANDLING
OF NEXT LOW MOVING UP FROM THE PACIFIC OVER THE WEEKEND. BOTTOM
LINE THOUGH...THIS MAJOR PATTERN CHANGE WILL LIKELY BRING A RETURN
OF CLOUDS AND PRECIPITATION BACK TO MAINLAND ALASKA SOMETIME LATE
THIS WEEK OR EARLY NEXT WEEK.

.AER/ALU...WATCH/WARNING SUMMARY
PUBLIC...NONE.
MARINE...STORM WARNING 175 176.
         GALE WARNING...172.
FIRE WEATHER...NONE.

SEB MAR 11