Storm Warning 103, NWS Anchorage, AK

566 
FZAK52 PAFC 110001
CWFALU

COASTAL WATERS FORECAST
NATIONAL WEATHER SERVICE ANCHORAGE ALASKA
400 PM AKDT SAT APR 10 2010

COASTAL WATERS FORECAST FOR SOUTHWEST ALASKA+BRISTOL BAY+THE
ALASKA PENINSULA WATERS AND THE ALEUTIAN ISLANDS UP TO 100 NM OUT.

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.

PKZ199-111400-
400 PM AKDT SAT APR 10 2010
.SYNOPSIS FOR SOUTHWEST ALASKA+BRISTOL BAY+THE ALASKA
PENINSULA WATERS AND THE ALEUTIAN ISLANDS...

A 965 MB LOW 275 NM WEST OF ST MATTHEW ISLAND WILL WEAKEN TO 983 MB
AND MOVE TO 115 NM WEST OF GAMBELL SUN AFTERNOON THEN DISSIPATE SUN
NIGHT. A 988 MB LOW 600 NM WEST OF SHEMYA SAT NIGHT WILL MOVE TO 150
NM NORTH OF SHEMYA AT 983 MB SUN AFTERNOON THEN MOVE TO ST LAWRENCE
ISLAND MON AFTERNOON AT 979 MB.
$$

PKZ150-111400-
COASTAL WATERS SOUTH OF THE ALASKA PENINSULA SITKINAK TO CASTLE
CAPE
400 PM AKDT SAT APR 10 2010

...GALE WARNING TONIGHT...

.TONIGHT...S WIND 35 KT BECOMING SW 25 KT BY MIDNIGHT. SEAS 16 FT.
RAIN AND SNOW. 
.SUN...SW WIND 20 KT. SEAS 13 FT. 
.SUN NIGHT...SW WIND 25 KT. SEAS 11 FT. 
.MON AND MON NIGHT...SW WIND 35 KT. SEAS 13 FT. 
.TUE...SW WIND 35 KT. SEAS 17 FT. 
.WED...SW WIND 20 KT. SEAS 11 FT. 
.THU...SW WIND 20 KT. SEAS 7 FT.  
$$

PKZ155-111400-
COASTAL WATERS SOUTH OF THE ALASKA PENINSULA CASTLE CAPE TO CAPE
SARICHEF
400 PM AKDT SAT APR 10 2010

...GALE WARNING SUNDAY NIGHT...

.TONIGHT...SW WIND 25 KT. SEAS 15 FT. 
.SUN...SW WIND 25 KT. SEAS 13 FT. PATCHY FOG. 
.SUN NIGHT...SW WIND 25 KT INCREASING TO 35 KT AFTER MIDNIGHT. SEAS
13 FT. 
.MON AND MON NIGHT...SW WIND 35 KT. SEAS 16 FT. 
.TUE...W WIND 35 KT. SEAS 17 FT. 
.WED...SW WIND 20 KT. SEAS 10 FT. 
.THU...S WIND 25 KT. SEAS 12 FT.  
$$

PKZ160-111400-
BRISTOL BAY WATERS CAPE NEWENHAM TO PORT HEIDEN
400 PM AKDT SAT APR 10 2010

...GALE WARNING SUNDAY NIGHT...

.TONIGHT...S WIND 30 KT. SNOW IN THE EVENING.
.SUN...S WIND 20 KT. PATCHY FOG. 
.SUN NIGHT...S WIND 20 KT INCREASING TO 35 KT AFTER MIDNIGHT. PATCHY
FOG. 
.MON AND MON NIGHT...SW WIND 40 KT. 
.TUE...W WIND 15 KT. 
.WED...S WIND 15 KT. 
.THU...S WIND 25 KT.  
$$

PKZ165-111400-
PORT HEIDEN TO CAPE SARICHEF
400 PM AKDT SAT APR 10 2010

...GALE WARNING SUNDAY NIGHT...

.TONIGHT...S WIND 25 KT. SEAS IN ICE FREE WATERS 12 FT EXCEPT 4 FT
FROM PORT MOLLER E. 
.SUN...S WIND 25 KT. SEAS IN ICE FREE WATERS 12 FT EXCEPT 4 FT FROM
PORT MOLLER E. PATCHY FOG. 
.SUN NIGHT...SW WIND 25 KT BECOMING S 35 KT AFTER MIDNIGHT. SEAS IN
ICE FREE WATERS 11 FT EXCEPT 5 FT FROM PORT MOLLER E. PATCHY FOG.
SNOW AND RAIN. 
.MON...SW WIND 40 KT. SEAS IN ICE FREE WATERS 13 FT. 
.MON NIGHT...SW WIND 30 KT. SEAS IN ICE FREE WATERS 14 FT. 
.TUE...W WIND 20 KT. SEAS IN ICE FREE WATERS 8 FT. 
.WED...SW WIND 15 KT. SEAS IN ICE FREE WATERS 6 FT. 
.THU...S WIND 25 KT. SEAS IN ICE FREE WATERS 8 FT.  

$$

PKZ180-111400-
SOUTHWEST ALASKA WATERS CAPE NEWENHAM TO DALL POINT
400 PM AKDT SAT APR 10 2010

...GALE WARNING TONIGHT AND SUNDAY NIGHT...

.TONIGHT...S WIND 35 KT. PATCHY FOG. 
.SUN...S WIND 25 KT. PATCHY FOG. SNOW SHOWERS. 
.SUN NIGHT...S WIND 20 KT INCREASING TO 35 KT AFTER MIDNIGHT. PATCHY
FOG. 
.MON AND MON NIGHT...SW WIND 45 KT. 
.TUE...SW WIND 20 KT. 
.WED...S WIND 25 KT. 
.THU...S WIND 35 KT.  
$$

PKZ170-111400-
EASTERN ALEUTIANS CAPE SARICHEF TO NIKOLSKI
400 PM AKDT SAT APR 10 2010

...GALE WARNING SUNDAY NIGHT...

.TONIGHT...SW WIND 30 KT. SEAS 19 FT. 
.SUN...SW WIND 30 KT. SEAS 17 FT. 
.SUN NIGHT...SW WIND 40 KT. SEAS 17 FT. PATCHY FOG. RAIN.
.MON...SW WIND 45 KT. SEAS 21 FT. 
.MON NIGHT...SW WIND 30 KT. SEAS 21 FT. 
.TUE...W WIND 25 KT. SEAS 13 FT. 
.WED...SW WIND 25 KT. SEAS 9 FT. 
.THU...S WIND 30 KT. SEAS 15 FT.  
$$

PKZ171-111400-
UNALASKA BAY
400 PM AKDT SAT APR 10 2010

...SMALL CRAFT ADVISORY TONIGHT AND SUNDAY NIGHT...

.TONIGHT...SW WIND 25 KT. SEAS 4 FT. 
.SUN...SW WIND 20 KT. SEAS 3 FT. RAIN AND SNOW. 
.SUN NIGHT...SW WIND 30 KT. SEAS 5 FT. PATCHY FOG. RAIN AND SNOW. 
.MON...SW WIND 30 KT. SEAS 5 FT. 
.MON NIGHT...SW WIND 15 KT. SEAS 2 FT. 
.TUE...W WIND 20 KT. SEAS 3 FT. 
.WED...SW WIND 10 KT. SEAS 2 FT. 
.THU...S WIND 20 KT. SEAS 3 FT.  
$$

PKZ172-111400-
EASTERN ALEUTIANS NIKOLSKI TO ADAK
400 PM AKDT SAT APR 10 2010

...STORM WARNING SUNDAY NIGHT...

.TONIGHT...SW WIND 35 KT. SEAS 20 FT. SNOW AND RAIN SHOWERS. 
.SUN...SW WIND 30 KT INCREASING TO 40 KT IN THE AFTERNOON. SEAS
17 FT. PATCHY FOG. RAIN.
.SUN NIGHT...SW WIND 50 KT. SEAS 23 FT. PATCHY FOG. RAIN AND SNOW. 
.MON...SW WIND 45 KT. SEAS 23 FT. 
.MON NIGHT...W WIND 30 KT. SEAS 18 FT. 
.TUE...W WIND 30 KT. SEAS 14 FT. 
.WED...SW WIND 35 KT. SEAS 14 FT. 
.THU...S WIND 35 KT. SEAS 21 FT.  
$$

PKZ175-111400-
WESTERN ALEUTIANS ADAK TO KISKA
400 PM AKDT SAT APR 10 2010

...STORM WARNING SUNDAY AND SUNDAY NIGHT...

.TONIGHT...W WIND 35 KT. SEAS 21 FT. SNOW SHOWERS. 
.SUN...SW WIND 40 KT INCREASING TO 50 KT IN THE AFTERNOON. SEAS
21 FT. PATCHY FOG. RAIN AND SNOW. 
.SUN NIGHT...SW WIND 50 KT. SEAS 27 FT. PATCHY FOG. RAIN AND SNOW. 
.MON...W WIND 40 KT. SEAS 25 FT. 
.MON NIGHT AND TUE...W WIND 30 KT. SEAS 18 FT. 
.WED...S WIND 35 KT. SEAS 17 FT. 
.THU...SW WIND 35 KT. SEAS 28 FT.  

$$

PKZ176-111400-
WESTERN ALEUTIANS KISKA TO ATTU
400 PM AKDT SAT APR 10 2010

...STORM WARNING SUNDAY AND SUNDAY NIGHT...

.TONIGHT...W WIND 35 KT. SEAS 21 FT. SNOW SHOWERS. PATCHY FOG. 
.SUN...SW WIND 40 KT INCREASING TO 50 KT IN THE AFTERNOON. SEAS
17 FT BUILDING TO 24 FT IN THE AFTERNOON. PATCHY FOG. SNOW AND RAIN.
.SUN NIGHT...SW WIND 50 KT BECOMING W 35 KT AFTER MIDNIGHT. SEAS 30
FT. PATCHY FOG. SNOW SHOWERS. 
.MON...W WIND 35 KT. SEAS 23 FT. 
.MON NIGHT...W WIND 35 KT. SEAS 18 FT. 
.TUE...W WIND 30 KT. SEAS 16 FT. 
.WED...S WIND 45 KT. SEAS 21 FT. 
.THU...SW WIND 40 KT. SEAS 31 FT.  

$$

PKZ185-111400-
ST MATTHEW ISLAND WATERS
400 PM AKDT SAT APR 10 2010

...STORM WARNING TONIGHT...

.TONIGHT...S WIND 50 KT. E OF SAINT MATTHEW ISLAND...S WIND 35 KT.
PATCHY FOG. SNOW SHOWERS. 
.SUN...SW WIND 35 KT. SNOW SHOWERS. 
.SUN NIGHT...S WIND 25 KT. PATCHY FOG. SNOW.
.MON...W WIND 35 KT. 
.MON NIGHT...W WIND 30 KT. 
.TUE...W WIND 20 KT. 
.WED AND THU...S WIND 35 KT. 
$$

PKZ179-111400-
PRIBILOF ISLANDS NEAR-SHORE WATERS
400 PM AKDT SAT APR 10 2010

...GALE WARNING TONIGHT AND SUNDAY NIGHT...

.TONIGHT...SW WIND 35 KT. SNOW SHOWERS. 
.SUN...SW WIND 20 KT. 
.SUN NIGHT...SW WIND 40 KT. PATCHY FOG. SNOW.
.MON...SW WIND 45 KT. 
.MON NIGHT...SW WIND 30 KT. 
.TUE...W WIND 25 KT. 
.WED...SW WIND 25 KT. 
.THU...S WIND 35 KT.  
$$

AREA FORECAST DISCUSSION...UPDATED WARNINGS
SOUTHCENTRAL AND SOUTHWEST ALASKA
500 PM AKDT FRI APR 9 2010

.ANALYSIS AND UPPER LEVELS...
A PERSISTENT LARGE UPPER LEVEL TROUGH STILL ENCOMPASSES MUCH OF
EASTERN AND NORTHERN ALASKA...BUT IS LOSING THE BATTLE TO A
STRENGTHENING UPPER LEVEL RIDGE BUILDING NORTHWARD ACROSS THE AKPEN
AND WESTERN ALASKA. THE 170 KT JET STREAM RIDES AROUND THIS
RIDGE...ARCING NORTH ACROSS THE CENTRAL BERING TO THE BERING STRAIT
BEFORE DIVING SOUTH AGAIN OVER SOUTHWESTERN ALASKA. A NEGATIVELY
TILTED UPPER LEVEL TROUGH FOLLOWS QUICKLY ON THE HEELS OF THIS RIDGE
OVER THE WESTERN BERING SEA.

AT THE SURFACE...ALL EYES ARE FIXED ON A VERY POWERFUL AND MOISTURE
LADEN STORM SYSTEM CURRENTLY AFFECTING MUCH OF THE BERING SEA WITH
STRONG WINDS...AND SOME REGIONS IN THE EASTERN BERING WITH NEAR
BLIZZARD CONDITIONS. THE NORTHWARD TRACKING 954 MB PARENT LOW IS
CURRENTLY POSITIONED 150 MILES NORTH OF SHEMYA WHILE THE WARM FRONTAL
BAND EXTENDS TO THE SOUTHEAST ACROSS THE PRIBILOFS AND THE WESTERN
AKPEN. PRECIPITATION ACROSS THE ALEUTIANS IS MOSTLY RAIN AT THE
MOMENT WITH THE REGION STILL UNDER THE INFLUENCE OF WARM AIR
ADVECTION...BUT THE TRAILING COLD FRONT IS QUICKLY SWEEPING WESTWARD
ACROSS THE ISLAND CHAIN. MEANWHILE...THE MAINLAND IS ENJOYING WHAT
COULD BEST BE DESCRIBED AS THE CALM BEFORE THE STORM...WITH A SURFACE
HIGH PRESSURE RIDGE IN CONTROL OF THE WEATHER PATTERN AND CLEAR SKIES
PREVAILING FOR YET ANOTHER DAY.

.MODEL DISCUSSION...
MODELS OVERALL ARE IN VERY GOOD AGREEMENT ONCE AGAIN TODAY...BUT
ISSUES THAT CROPPED UP YESTERDAY ARE STILL CONTINUING TODAY. THE NAM
STILL LAGS A GOOD THREE TO SIX HOURS BEHIND THE GFS AND ECMWF IN
BRINGING THE FRONTAL SYSTEM INTO SOUTHWESTERN ALASKA TONIGHT. THE
MODELS ARE ALSO SLIGHTLY STRONGER WITH THE BERING SEA LOW...DROPPING
ITS PRESSURE BY A FEW MORE MILLIBARS ON SATURDAY COMPARED TO WHAT WAS
PREVIOUSLY FORECAST. THE MODELS ARE ALSO NOT QUITE IN AGREEMENT OVER
THE TRACK OF THE LOW OVER THE NEXT 24 TO 32 HOURS...BUT THESE ISSUES
WILL HAVE LITTLE IMPACT ON THE FORECAST.

OUT PAST 32 HOURS THE GFS ACCELERATES THE LOW TO THE NORTH AND
DISSIPATES IT OVER FAR EASTERN RUSSIA WHILE THE NAM AND ECMWF
MAINTAIN THE LOW IN THE NORTH CENTRAL BERING BEFORE EVENTUALLY TAKING
IT ON A SIMILAR COURSE 18 HOURS LATER. THE MODELS THOUGH ARE ALL IN
AGREEMENT THAT PORTIONS OF SOUTHWESTERN ALASKA WILL SEE HEAVY
PRECIPITATION...BUT THE QUESTION REMAINS AS TO WHETHER THIS WILL FALL
AS RAIN OR SNOW. MODEL SOUNDINGS OVER SOUTHWEST ALASKA INDICATE THAT
THE LOWER LEVELS OF THE ATMOSPHERE WILL REMAIN JUST BELOW
FREEZING...BUT STRONG SOUTHEASTERLY SURFACE WINDS MAY BOOST
TEMPERATURES AND MIX THE LOWER ATMOSPHERE ENOUGH TO CHANGE THE
PRECIPITATION OVER TO RAIN...AT LEAST IN THE SOUTHERN SECTIONS OF
SOUTHWEST ALASKA.

.SHORT TERM FORECAST...
.SOUTHCENTRAL ALASKA...FORECAST CHALLENGES IN THE EASTERN DOMAIN WILL
CENTER AROUND THE EFFECTS OF THE REMNANTS OF THE CURRENT SYSTEM AS IT
APPROACHES SOUTHCENTRAL. ABUNDANT MOISTURE AND SOUTHWESTERLY FLOW
ALOFT WILL INSURE PRECIPITATION WILL FALL...DESPITE THE SURFACE
PRESSURE GRADIENT INDICATING A SOUTHEASTERLY DOWNSLOPE COMPONENT. THE
DOWNSLOPING COMPONENT WILL LIMIT PRECIPITATION IN ANCHORAGE AND THE
WESTERN KENAI...BUT WILL NOT BE SIGNIFICANT ENOUGH TO KEEP US DRY AS
THE NAM IS SUGGESTING. CONSIDERING SNOW ADVISORY LEVEL TOTALS FOR
KACHEMAK BAY AREA AND SUSITNA VALLEY...ESPECIALLY WEST OF THE PARKS
HIGHWAY.

PRECIP TYPE...AN OCCLUSION WILL DEVELOP AND MOVE SOUTHEAST ACROSS THE
ALASKA PENINSULA SATURDAY NIGHT. THIS WILL PINCH OFF THE WARM AIR
FROM PROGRESSING NORTHWARD AND GIVE ANCHORAGE THE POSSIBILITY FOR
SNOW RATHER THAN RAIN. STILL SUSPECT COASTAL AREAS WILL REMAIN JUST
ABOVE FREEZING BUT INLAND WILL STAY SNOW...OR AT LEAST MOSTLY
SNOW...THROUGH THIS EVENT. MODELS ARE ALSO NOW STALLING THE OLD
FRONTAL BOUNDARY AND PROLONGING THE PRECIPITATION JUST A BIT LONGER
DUE TO THE AMPLIFIED DOWNSTREAM RIDGE. ACCUMULATING SNOWFALL IN
ANCHORAGE IS LOOKING MORE AND MORE LIKELY WITH THIS PATTERN.

.SOUTHWEST ALASKA...CHALLENGING FORECAST AS THE DEVELOPING OCCLUSION
AND HEAVY PRECIPITATION COULD LEAD TO SEVERAL DIFFERENT SCENARIOS
PLAYING OUT. FEEL CONFIDENT THAT BLIZZARD CONDITIONS WILL DEVELOP
ALONG THE COAST OF THE KUSKOKWIM DELTA LATER THIS EVENING. THE
FORECAST FOR THE BRISTOL BAY ZONE IS NOT AS CLEAR AS WARM AIR GETS
PINCHED OFF AND HAS A HARD TIME MAKING IT INLAND. WINDS AT THE
SURFACE WILL INCREASE WHICH WILL HELP MIX WHATEVER WARMER AIR ALOFT
EXISTS DOWN TO THE SURFACE. MOS GUIDANCE IS SHOWING TEMPERATURES WELL
ABOVE FREEZING ALTHOUGH PRECIP TYPE IS STILL INDICATING SNOW. CURRENT
THINKING IS THAT TEMPERATURES WILL BE JUST ABOVE FREEZING WHICH WILL
LIMIT THE POSSIBILITY FOR BLIZZARD CONDITIONS AS WELL AS ACCUMULATING
SNOWFALL. STILL HAVE MENTIONED SOME RESPECTABLE ACCUMULATIONS ACROSS
THE BRISTOL BAY ZONE AS SOME AREAS MIGHT NOT SEE THE WARM AIR
INTRUSION THAT OTHERS WILL.

.ALEUTIANS/BERING SEA...STRONG LOW AND ASSOCIATED FRONTAL BOUNDARY
MAKING EASTWARD PROGRESS EARLY THIS AFTERNOON. WIDESPREAD STORM FORCE
WINDS ARE BEING REPORTED FROM THE PRIBILOFS BACK TO ATTU ISLAND. RAIN
WILL CHANGE BACK OVER TO SNOW AS THE COLD AIR WRAPS AROUND THE
BACKSIDE OF THE LOW.

.LONG TERM FORECAST...
AN AMPLIFIED AND PROGRESSIVE UPPER LEVEL JET WILL REMAIN OVER THE
REGION THROUGH LATE NEXT WEEK...BRINGING WITH IT A SERIES OF STORMS
INTO THE CENTRAL BERING. THE NEXT LOW MARCHES INTO THE WESTERN BERING
LATE IN THE WEEKEND AND FOLLOWS A COURSE SIMILAR TO ITS
PREDECESSOR...DISSIPATING IN THE NORTHERN BERING MIDWEEK. ANOTHER LOW
MIGRATES INTO THE BERING ON WEDNESDAY...BUT SIGNIFICANT TRACK
DIFFERENCES EXIST WITH THIS LOW BETWEEN THE MODELS. THESE STORMS WILL
HAVE THE GREATEST IMPACT ON THE BERING SEA AND SOUTHWESTERN
ALASKA...BUT COULD ALSO IMPACT SOUTHCENTRAL AS WELL...THOUGH
IN A WEAKER STATE.

.AER/ALU...WATCH/WARNING SUMMARY
PUBLIC...BLIZZARD WARNING...155.
         HIGH WIND WARNING...181.
MARINE...STORM WARNING...175 176.
         GALE WARNING...130 132 136 137 138 140 150 155 160 165 170
                        171 172 179 180 185.
FIRE WEATHER...NONE.

KS/AB APR 10