Small Craft Advisory 521, NWS Juneau, AK

017 
FZAK51 PAJK 200239 AAB
CWFAJK

COASTAL WATERS FORECAST FOR SOUTHEAST ALASKA...UPDATED
NATIONAL WEATHER SERVICE JUNEAU AK
640 PM AKDT SUN SEP 19 2010

SOUTHEAST ALASKA INSIDE WATERS FROM DIXON ENTRANCE TO SKAGWAY

WIND FORECASTS REFLECT THE PREDOMINANT SPEED AND DIRECTION
EXPECTED. SEA FORECASTS REPRESENT THE AVERAGE OF THE HIGHEST
ONE-THIRD OF THE COMBINED WINDWAVE AND SWELL HEIGHT.

PKZ098-201900-
452 PM AKDT SUN SEP 19 2010
.SYNOPSIS FOR SOUTHEAST ALASKA INNER CHANNELS COASTAL WATERS...
STRONG HIGH PRESSURE OVER THE AREA WILL REMAIN CENTERED OVER
NORTHERN BRITISH COLUMBIA. GALE FORCE GAP WINDS THROUGH COASTAL
MOUNTAIN RANGE WILL SUBSIDE SUN NIGHT. MUCH LIGHTER WIND MON AND
TUE.  

$$

PKZ011-201900-
GLACIER BAY-
452 PM AKDT SUN SEP 19 2010

.TONIGHT...N WIND 20 KT. SEAS 4 FT. 
.MON...N WIND 20 KT BECOMING SE 10 KT IN THE AFTERNOON. SEAS 4
FT. 
.MON NIGHT...VARIABLE WIND 10 KT. SEAS 2 FT OR LESS. 
.TUE...SE WIND 10 KT. SEAS 2 FT OR LESS. 
.TUE NIGHT...N WIND 10 KT. SEAS 2 FT OR LESS. 
.WED...N WIND 15 KT. SEAS 3 FT. 
.THU...N WIND 20 KT. SEAS 4 FT. 
.FRI...N WIND 20 KT. SEAS 5 FT. 



$$

PKZ012-201900-
NORTHERN LYNN CANAL-
452 PM AKDT SUN SEP 19 2010

...SMALL CRAFT ADVISORY THROUGH MON MORNING...

.TONIGHT...N WIND 30 KT DIMINISHING LATE. SEAS 6 FT. 
.MON...N WIND 25 KT DIMINISHING TO 15 KT IN THE AFTERNOON. SEAS 5
FT. 
.MON NIGHT...S WIND 10 KT. SEAS 2 FT OR LESS. 
.TUE...S WIND 20 KT. SEAS 4 FT. 
.TUE NIGHT...S WIND 20 KT DIMINISHING LATE. SEAS 4 FT. 
.WED...N WIND 15 KT. SEAS 3 FT. 
.THU...N WIND 20 KT. SEAS 4 FT. 
.FRI...N WIND 20 KT. SEAS 4 FT. 



$$

PKZ013-201900-
SOUTHERN LYNN CANAL-
452 PM AKDT SUN SEP 19 2010

...SMALL CRAFT ADVISORY THROUGH TONIGHT...

.TONIGHT...N WIND 25 KT. SEAS 5 FT. 
.MON...N WIND 20 KT DIMINISHING IN THE AFTERNOON. SEAS 4 FT. 
.MON NIGHT...N WIND 10 KT. SEAS 2 FT OR LESS. 
.TUE...VARIABLE WIND 10 KT. SEAS 2 FT OR LESS. 
.TUE NIGHT...N WIND 10 KT. SEAS 2 FT OR LESS. 
.WED...N WIND 15 KT. SEAS 3 FT. 
.THU...N WIND 20 KT. SEAS 4 FT. 
.FRI...N WIND 20 KT. SEAS 4 FT. 



$$

PKZ021-201900-
ICY STRAIT-
452 PM AKDT SUN SEP 19 2010

...SMALL CRAFT ADVISORY THROUGH TONIGHT...

.TONIGHT...NE WIND 25 KT BECOMING 20 KT LATE. SEAS 5 FT. 
.MON...NE WIND 20 KT BECOMING E 10 KT IN THE AFTERNOON. SEAS 3
FT. 
.MON NIGHT...NE WIND 10 KT. SEAS 2 FT OR LESS. 
.TUE...NE WIND 10 KT. SEAS 2 FT OR LESS. 
.TUE NIGHT...NE WIND 15 KT. SEAS 3 FT. 
.WED...E WIND 15 KT. SEAS 3 FT. 
.THU...E WIND 20 KT. SEAS 4 FT. 
.FRI...E WIND 30 KT. SEAS 6 FT. 



$$

PKZ022-201900-
CROSS SOUND-
640 PM AKDT SUN SEP 19 2010

UPDATED TONIGHT

.REST OF TONIGHT...E WIND 20 KT. SEAS 4 FT.
.MON...E WIND 15 KT DIMINISHING IN THE AFTERNOON. SEAS 3 FT. 
.MON NIGHT...NE WIND 10 KT. SEAS 2 FT OR LESS. 
.TUE...E WIND 10 KT. SEAS 2 FT OR LESS. 
.TUE NIGHT...E WIND 15 KT. SEAS 3 FT. 
.WED...NE WIND 15 KT. SEAS 3 FT. 
.THU...E WIND 20 KT. SEAS 4 FT. 
.FRI...E WIND 30 KT. SEAS 6 FT. 



$$

PKZ031-201900-
STEPHENS PASSAGE-
452 PM AKDT SUN SEP 19 2010

...SMALL CRAFT ADVISORY THROUGH MON MORNING...

.TONIGHT...N WIND 25 KT. SEAS 5 FT.
.MON...N WIND 25 KT DIMINISHING TO 15 KT IN THE AFTERNOON. SEAS 5
FT SUBSIDING TO 3 FT IN THE AFTERNOON. 
.MON NIGHT...N WIND 10 KT. SEAS 2 FT OR LESS. 
.TUE...N WIND 10 KT. SEAS 2 FT OR LESS. 
.TUE NIGHT...N WIND 10 KT. SEAS 2 FT OR LESS. 
.WED...N WIND 15 KT. SEAS 3 FT. 
.THU...N WIND 15 KT. SEAS 3 FT. 
.FRI...N WIND 25 KT. SEAS 5 FT. 



$$

PKZ032-201900-
NORTHERN CHATHAM STRAIT-
452 PM AKDT SUN SEP 19 2010

.TONIGHT...N WIND 20 KT. SEAS 4 FT. 
.MON...N WIND 20 KT DIMINISHING IN THE AFTERNOON. SEAS 4 FT. 
.MON NIGHT...LIGHT WINDS. SEAS 2 FT OR LESS. 
.TUE...LIGHT WINDS. SEAS 2 FT OR LESS. 
.TUE NIGHT...N WIND 10 KT. SEAS 2 FT OR LESS. 
.WED...N WIND 15 KT. SEAS 3 FT. 
.THU...N WIND 15 KT. SEAS 3 FT. 
.FRI...N WIND 25 KT. SEAS 5 FT. 



$$

PKZ033-201900-
SOUTHERN CHATHAM STRAIT-
452 PM AKDT SUN SEP 19 2010

.TONIGHT...NE WIND 20 KT. SEAS 4 FT. 
.MON...SE WIND 20 KT BECOMING N 15 KT IN THE AFTERNOON. SEAS 4
FT. 
.MON NIGHT...NE WIND 10 KT. SEAS 2 FT OR LESS. 
.TUE...LIGHT WINDS. SEAS 2 FT OR LESS. 
.TUE NIGHT...SE WIND 10 KT. SEAS 2 FT OR LESS. 
.WED...SE WIND 15 KT. SEAS 3 FT. 
.THU...SE WIND 20 KT. SEAS 4 FT. 
.FRI...SE WIND 30 KT. SEAS 6 FT. 



$$

PKZ034-201900-
FREDERICK SOUND-
452 PM AKDT SUN SEP 19 2010

...SMALL CRAFT ADVISORY TONIGHT...

.TONIGHT...NE WIND 25 KT. GUSTS TO 40 KT OUT OF INTERIOR PASSES.
SEAS 5 FT. 
.MON...NE WIND 20 KT DIMINISHING IN THE AFTERNOON. OUT OF
INTERIOR PASSES...GUSTS TO 40 KT IN THE MORNING. SEAS 4 FT. 
.MON NIGHT...NE WIND 15 KT. SEAS 3 FT. 
.TUE...NE WIND 10 KT. SEAS 2 FT OR LESS. 
.TUE NIGHT...NE WIND 10 KT. SEAS 2 FT OR LESS. 
.WED...NE WIND 15 KT. SEAS 3 FT. 
.THU...SE WIND 20 KT. SEAS 4 FT. 
.FRI...SE WIND 30 KT. SEAS 6 FT. 



$$

PKZ035-201900-
SUMNER STRAIT-
452 PM AKDT SUN SEP 19 2010

.TONIGHT...E WIND 20 KT. SEAS 4 FT. 
.MON...E WIND 20 KT BECOMING NE 15 KT IN THE AFTERNOON. SEAS 4
FT.
.MON NIGHT...W WIND 10 KT. SEAS 2 FT OR LESS. 
.TUE...E WIND 10 KT. SEAS 2 FT OR LESS. 
.TUE NIGHT...E WIND 15 KT. SEAS 3 FT. 
.WED...E WIND 15 KT. SEAS 3 FT. 
.THU...E WIND 20 KT. SEAS 4 FT. 
.FRI...E WIND 30 KT. SEAS 6 FT. 



$$

PKZ036-201900-
CLARENCE STRAIT-
452 PM AKDT SUN SEP 19 2010

UPDATED

.REST OF TONIGHT...NE WIND 20 KT. SEAS 4 FT. 
.MON...NW WIND 20 KT DIMINISHING IN THE AFTERNOON. SEAS 4 FT. 
.MON NIGHT...NW WIND 15 KT. SEAS 3 FT. 
.TUE...SE WIND 10 KT. SEAS 2 FT OR LESS. 
.TUE NIGHT...SE WIND 10 KT. SEAS 2 FT OR LESS. 
.WED...SE WIND 20 KT. SEAS 4 FT. 
.THU...SE WIND 20 KT. SEAS 4 FT. 
.FRI...SE WIND 30 KT. SEAS 6 FT. 



$$

SOUTHEAST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE JUNEAU AK
110 PM AKDT SUN SEP 19 2010

.SHORT TERM...MAIN FORECAST ISSUE TODAY IS WIND EVENT ACROSS
MAINLY THE EASTERN HALF OF THE PANHANDLE. DRY BUT SHARPLY
CYCLONIC UPPER LEVEL SYSTEM IS MOVING SOUTH DOWN COASTAL RANGE.
WATER VAPOR SATELLITE IMAGERY OUTLINES THIS SYSTEM AND PLACES
CENTER OVER MISTY FJORDS AT 18Z. MID LEVEL COLD AIR ADVECTION IN
ITS WAKE OVER WRN BC HELPED WITH SFC PRESSURE RISES EAST OF MTNS
AND ENHANCING OFFSHORE PRESSURE GRADIENTS. NE WND ABOVE RIDGES IS
CAUSING SOME LEE /COASTAL/ SIDE TROUGHING. 12Z NAM AND WRF MODELS
HIGHLIGHT SFC TROUGHS EAST OF GLACIER BAY AND EAST OF PAPG/PAWG.
MSAS ANALYSIS DECENT BUT MAYBE NOT DEEP ENOUGH ALG SOME SECTIONS
OF THE TROUGH. BOTTOM LINE IS EASTERLY GAP WINDS FROM NORTH OF
JUNEAU TO ERN DIXON ENTRANCE. SMALL CRAFT ADV ALL ERN MOST
CHANNELS AND GALES THRU THIS AFTERNOON FOR N LYNN AND CROSS SND.

THE ENE FLOW ACROSS RIDGES AND STABLE AIR MASS SET UP A MTN WAVE
EVENT IN THE JNU AREA SUN MORNING. VERTICAL PROFILER DATA ALL
MORNING INDICATING OSCILLATING WAVES PASSING E TO W THRU AREA.
RIDGE TOP WINDS PEAKED JUST OVER 80 KTS AT 0830 ADT ON SHEEP MTN
JUST NORTH OF TAKU INLET. WINDS MEASURED 20-30 KTS AT EAGLECREST
AND AT TRAM. AS THESE RIDGE TOP WINDS RIDE ALONG THE OSCILLATING
WAVES IT DESCENDS TO NEAR THE SFC AND CAUSES THE WINDY CONDS
TODAY. WIND ADVISORY IN EFFECT THRU 1 PM. BOTH WRF AND NAM MODELS
HAVE THESE MTN WAVE INGREDIENTS WEAKENING SUN AFTERNOON AND
DISSIPATING SUN EVE. CONFIDENCE FAIRLY HIGH WIND SPEEDS WILL
SLACKEN QUICKLY BY LATE AFTERNOON.

HIGH PRESSURE BUILDS IN AT SFC AND ALOFT TONIGHT AND MON. A
WEAKER NLY WIND FLOW THROUGH MON WILL PROLONG UNSEASONABLY DRY AND
MILD WEATHER PATTERN ACROSS PANHANDLE. PRESSURE GRADIENTS IN ALL
MODELS MUCH WEAKER MON. I DID INCLUDE FOG IN THE PAPG AND PAWG
TAFS FOR A FEW HRS MON MORNING BASED ON GFS LOCAL AVIATION
STATISTICAL OUTPUT BUT WILL BE DEPENDENT ON MIN TEMPS TONIGHT. THE
AIR IS SO DRY AND DEW POINTS ARE SO LOW IT MAY BE HARD TO SATURATE
AIR INTO FOG.

.LONG TERM...AFTERNOON MODEL RUNS REMAIN CONSISTENT ON THE COMING
PATTERN CHANGE FOR THE PANHANDLE FROM THE UNSEASONABLY WARM AND DRY
PATTERN TO A MORE FALL-LIKE AND WET PATTERN. THE EXACT DETAILS OF
HOW STRONG EACH FRONTAL BOUNDARY MOVING ACROSS THE PANHANDLE FROM
THURSDAY INTO NEXT WEEKEND REMAINS THE MAIN FORECAST PROBLEM
DURING THE LONG TERM PERIOD. THE BLOCKING MID LEVEL RIDGE PATTERN
THAT HAS BEEN PROTECTING THE PANHANDLE FROM WET WEATHER WILL
FINALLY BREAK DOWN BY TUESDAY NIGHT AND A GALE FORCE SURFACE LOW
WILL DEVELOP IN THE NORTHEASTERN PACIFIC AND BE 200 NM SOUTHWEST
OF DIXON ENTRANCE BY WEDNESDAY NIGHT. THIS GALE FORCE LOW WILL BE
THE FIRST TO ENCOUNTER THE DEPARTING MID LEVEL RIDGE AND SO AS THE
ASSOCIATED FRONTAL BOUNDARY TRIES TO MOVE ACROSS THE PANHANDLE
MUCH OF ITS ENERGY AND STRUCTURE WILL BE SHEARED APART...AND SO
KEPT MOST OF THE PRECIP SOUTH OF FREDERICK SOUND THROUGH THURSDAY
NIGHT. ON FRIDAY 12Z OPERATIONAL MODEL DIFFERENCES BECOME QUITE
LARGE AS A DEVELOPING TRIPLE POINT LOW WILL FORM IN THE EASTERN
GULF BUT ITS EXACT TIMING AND STRENGTH ARE QUITE DIFFERENT ON EACH
MODEL RUN. THE 12Z GFS REMAINS MOST CONSISTENT WITH ITS PREVIOUS
RUN WITH THE TRIPLE POINT LOW MOVING THROUGH EASTERN GULF FRIDAY
AFTERNOON NEAR 960 MB. WHILE THE 12Z ECMWF AND 12Z UKMET ARE 24
HOURS QUICKER ON THE DEVELOPMENT OF THE TRIPLE POINT LOW FROM
THEIR PREVIOUS RUNS WITH THE GALE TO STORM FORCE LOW MOVING
THROUGH THE EASTERN GULF FRIDAY MORNING. DUE TO MODEL RUN TO RUN
CONSISTENCY ISSUES PREFERRED THE HPC SOLUTION DAY 4 ONWARD WITH
THE CONSISTENCY OF THE GFS SOLUTION FOR THE DEVELOPING GALE TO
STORM FORCE LOW ON FRIDAY. IN COORDINATION WITH PAFC USED THE 12Z
NAM FOR DAYS 2 AND 3 TO KEEP THE STRONGER WINDS IN THE EASTERN
GULF WITH THE MARINE LAYER.

MONDAY NIGHT THROUGH WEDNESDAY MORNING WILL SEE RELATIVELY LIGHT
MID LEVEL TO SURFACE FLOW ACROSS THE PANHANDLE AND THIS WILL LEAD
TO THE MARINE LAYER...LOW CLOUDS AND WEAK ONSHORE FLOW EACH DAY.
BELIEVE WILL SEE EXTENSIVE CLOUD COVER DEVELOP ALONG THE OUTER
COAST BY TUESDAY MORNING BUT WEAK SOUTHEASTERLY SURFACE FLOW
ACROSS THE CENTRAL INNER CHANNELS SHOULD KEEP MOST OF THE LOW
CLOUDS AND MARINE LAYER AWAY THROUGH WEDNESDAY. ALONG THE OUTER
COAST ON THE OTHER HAND SHOULD SEE CLOUD COVER INCREASE BY EARLY
TUESDAY MORNING WITH AREAS OF DRIZZLE AND FOG.

THE MORE FALL-LIKE PATTERN WILL BEGIN BY THURSDAY MORNING WITH THE
FIRST OF THE FRONTAL BOUNDARIES MOVING ACROSS THE PANHANDLE FROM
SOUTH TO NORTH. THIS FRONTAL BOUNDARY WILL SPREAD LOCALLY BREEZY
CONDITIONS ALONG THE OUTER COAST WITH MOST OF THE PRECIP REMAINING
SOUTH OF FREDERICK SOUND. BY FRIDAY AFTERNOON A DEVELOPING TRIPLE
POINT SURFACE LOW WILL MOVE INTO THE EASTERN GULF AND WITH LLJ 850
MB WINDS NEAR 90 KNOTS WILL HAVE THE POSSIBILITY OF WARNING LEVEL
WIND GUSTS ACROSS THE OUTER COAST. THIS SITUATION BEARS WATCHING IN
FUTURE MODEL RUNS.

INTO NEXT WEEKEND SEVERAL MORE BUT WEAKER FRONTAL BOUNDARIES WILL
MOVE ACROSS THE PANHANDLE AS A LONG WAVE TROUGH REMAINS IN THE
CENTRAL GULF AND EXPECT LOCALLY BREEZY CONDITIONS ALONG THE OUTER
COAST THROUGH SUNDAY WITH MOST OF THE RAINFALL REMAINING ACROSS
THE SOUTHERN PANHANDLE WHERE THE INCREASE UPPER LEVEL JET SUPPORT
IS.

FORECAST CONFIDENCE IS ABOVE AVERAGE THROUGH WEDNESDAY AFTERNOON
AT WHICH POINT OPERATIONAL MODELS DIVERGE SIGNIFICANTLY ON THE
TIMING AND STRENGTH OF THE FRONTAL BOUNDARIES MOVING ACROSS THE
PANHANDLE. EXPECT DRY CONDITIONS ACROSS THE PANHANDLE THROUGH
WEDNESDAY AND THEN THE BEGINNING OF A WET AND WINDY PATTERN. THE
STRONG TRIPLE POINT LOW DEVELOPMENT ON FRIDAY BEARS WATCHING
THROUGH THE WEEK.

.AJK WATCHES/WARNINGS/ADVISORIES...
MARINE...GALE WARNING FOR PKZ012-022.
SMALL CRAFT ADVISORY FOR PKZ013-021-031-032-036-043.
SMALL CRAFT ADVISORY DUE TO SEAS FOR PKZ042.

&&

TA/PSS