Small Craft Advisory 407, NWS Anchorage, AK

729 
FZAK51 PAFC 212330
CWFAER

COASTAL WATERS FORECAST
NATIONAL WEATHER SERVICE ANCHORAGE ALASKA
330 PM AKDT SUN MAY 21 2017

COASTAL WATERS FORECAST FOR THE NORTHERN GULF OF ALASKA COAST
UP TO 100 NM OUT INCLUDING KODIAK ISLAND AND COOK INLET.

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.

PKZ197-221215-
330 PM AKDT SUN MAY 21 2017
.SYNOPSIS FOR THE NORTH GULF COAST+KODIAK ISLAND WATERS+
COOK INLET...
A 996 MB LOW 15 NM SOUTHWEST OF MIDDLETON ISLAND WILL WEAKEN AS 
IT MOVES ONSHORE 25 NM NORTHEAST OF SEWARD TONIGHT. A WEAK FRONT 
WILL ENTER THE SOUTHWEST GULF MON AND DISSIPATE MON NIGHT. A 1011
MB NORTH PACIFIC LOW WILL MOVE TO 300 NM SOUTH OF MIDDLETON 
ISLAND MON AFTERNOON AND MOVE INLAND NORTH OF HAIDA GWAII AT 1008
MB MON NIGHT. A RIDGE OF HIGH PRESSURE WILL BUILD INTO THE GULF 
MON NIGHT THROUGH TUE. 

$$

PKZ119-221215-
CAPE SUCKLING TO CAPE CLEARE-
330 PM AKDT SUN MAY 21 2017

...SMALL CRAFT ADVISORY THROUGH MONDAY NIGHT...

.TONIGHT...S WIND 25 KT. SEAS 11 FT.
.MON...S WIND 20 KT. SEAS 11 FT.
.MON NIGHT...SE WIND 15 KT IN THE EVENING BECOMING VARIABLE 10 KT.
SEAS 9 FT.
.TUE AND TUE NIGHT...SW WIND 25 KT. SEAS 7 FT.
.WED...SW WIND 20 KT. SEAS 7 FT.
.THU...SW WIND 15 KT. SEAS 7 FT.
.FRI...VARIABLE WIND 10 KT. SEAS 6 FT.

$$

PKZ120-221215-
CAPE CLEARE TO GORE POINT-
330 PM AKDT SUN MAY 21 2017

...SMALL CRAFT ADVISORY THROUGH MONDAY...

.TONIGHT...SW WIND 25 KT. SEAS 8 FT.
.MON...SW WIND 20 KT IN THE MORNING BECOMING VARIABLE 10 KT. SEAS
9 FT.
.MON NIGHT...VARIABLE WIND 10 KT. SEAS 7 FT.
.TUE AND TUE NIGHT...SW WIND 25 KT. SEAS 7 FT.
.WED...S WIND 20 KT. SEAS 8 FT.
.THU THROUGH FRI...SW WIND 15 KT. SEAS 7 FT.

$$

PKZ121-221215-
RESURRECTION BAY-
330 PM AKDT SUN MAY 21 2017

.TONIGHT...N WIND 10 KT. SEAS 2 FT. HIGHER SEAS S OF CAINES HEAD.
RAIN.
.MON...S WIND 10 KT INCREASING TO 15 KT IN THE AFTERNOON. SEAS 3
FT. HIGHER SEAS S OF CAINES HEAD.
.MON NIGHT...S WIND 10 KT BECOMING N AFTER MIDNIGHT. SEAS 2 FT.
HIGHER SEAS S OF CAINES HEAD.
.TUE...S WIND 15 KT. SEAS 3 FT.
.TUE NIGHT...S WIND 10 KT. SEAS 2 FT.
.WED THROUGH FRI...S WIND 10 KT. SEAS 2 FT.

$$

PKZ125-221215-
PRINCE WILLIAM SOUND-
330 PM AKDT SUN MAY 21 2017

.TONIGHT...NE WIND 15 KT BECOMING SE 20 KT AFTER MIDNIGHT. SEAS
4 FT. RAIN.
.MON...SE WIND 20 KT. SEAS 4 FT.
.MON NIGHT...SE WIND 15 KT IN THE EVENING BECOMING VARIABLE LESS
THAN 10 KT. SEAS 3 FT.
.TUE...W WIND 10 KT. SEAS 2 FT.
.TUE NIGHT...SE WIND 10 KT. SEAS 2 FT.
.WED...SE WIND 15 KT. SEAS 3 FT.
.THU...S WIND 10 KT. SEAS 2 FT.
.FRI...VARIABLE WIND LESS THAN 10 KT. SEAS 2 FT.

$$

PKZ126-221215-
PORT VALDEZ-
330 PM AKDT SUN MAY 21 2017

.TONIGHT...VARIABLE WIND LESS THAN 10 KT BECOMING NE 10 KT AFTER
MIDNIGHT. SEAS 2 FT. RAIN.
.MON...VARIABLE WIND LESS THAN 10 KT BECOMING SW 15 KT IN THE
AFTERNOON. SEAS 3 FT. RAIN SHOWERS.
.MON NIGHT...SW WIND 10 KT IN THE EVENING BECOMING VARIABLE LESS
THAN 10 KT. SEAS 2 FT.
.TUE...SW WIND 15 KT. SEAS 3 FT.
.TUE NIGHT...E WIND 10 KT. SEAS 2 FT.
.WED...VARIABLE WIND 10 KT. SEAS 2 FT.
.THU...VARIABLE WIND LESS THAN 10 KT. SEAS 2 FT.
.FRI...VARIABLE WIND LESS THAN 10 KT. SEAS 2 FT.

$$

PKZ127-221215-
VALDEZ NARROWS-
330 PM AKDT SUN MAY 21 2017

...SMALL CRAFT ADVISORY TONIGHT...

.TONIGHT...NE WIND INCREASING TO 25 KT. SEAS 3 FT. RAIN.
.MON...NE WIND 15 KT BECOMING SW IN THE AFTERNOON. SEAS 3 FT. RAIN
SHOWERS.
.MON NIGHT...SW WIND 15 KT BECOMING NE 10 KT AFTER MIDNIGHT. SEAS
3 FT.
.TUE...SW WIND 15 KT. SEAS 3 FT.
.TUE NIGHT...NE WIND 15 KT. SEAS 3 FT.
.WED...VARIABLE WIND 10 KT. SEAS 2 FT.
.THU...VARIABLE WIND 10 KT. SEAS 2 FT.
.FRI...N WIND 10 KT. SEAS 2 FT.

$$

PKZ128-221215-
VALDEZ ARM-
330 PM AKDT SUN MAY 21 2017

.TONIGHT...NE WIND 20 KT. SEAS 4 FT. RAIN.
.MON...NE WIND 15 KT BECOMING S IN THE AFTERNOON. SEAS 3 FT. RAIN
SHOWERS.
.MON NIGHT...SW WIND 15 KT IN THE EVENING BECOMING VARIABLE LESS
THAN 10 KT. SEAS 3 FT.
.TUE...SW WIND 10 KT. SEAS 2 FT.
.TUE NIGHT...NE WIND 10 KT. SEAS 2 FT.
.WED...NE WIND 10 KT. SEAS 2 FT.
.THU...VARIABLE WIND LESS THAN 10 KT. SEAS 2 FT.
.FRI...VARIABLE WIND LESS THAN 10 KT. SEAS 2 FT.

$$

PKZ129-221215-
PASSAGE CANAL-
330 PM AKDT SUN MAY 21 2017

.TONIGHT...W WIND 10 KT. SEAS 2 FT. RAIN.
.MON...W WIND 15 KT BECOMING E IN THE AFTERNOON. SEAS 2 FT. RAIN
SHOWERS.
.MON NIGHT...E WIND 20 KT DIMINISHING TO 10 KT AFTER MIDNIGHT.
SEAS 3 FT.
.TUE...W WIND 10 KT. SEAS 2 FT.
.TUE NIGHT...E WIND 10 KT. SEAS 2 FT.
.WED...E WIND 10 KT. SEAS 2 FT.
.THU...VARIABLE WIND LESS THAN 10 KT. SEAS 2 FT.
.FRI...E WIND 10 KT. SEAS 2 FT.

$$

PKZ130-221215-
WEST OF BARREN ISLANDS INCLUDING KAMISHAK BAY-
330 PM AKDT SUN MAY 21 2017

.TONIGHT...SW WIND 20 KT. SEAS 5 FT.
.MON...SW WIND 15 KT. SEAS 4 FT.
.MON NIGHT...W WIND 20 KT. SEAS 5 FT.
.TUE...SW WIND 25 KT. SEAS 6 FT.
.TUE NIGHT...S WIND 25 KT. SEAS 9 FT.
.WED...S WIND 25 KT. SEAS 8 FT.
.THU...SW WIND 15 KT. SEAS 5 FT.
.FRI...VARIABLE WIND 10 KT. SEAS 3 FT.

$$

PKZ131-221215-
BARREN ISLANDS EAST-
330 PM AKDT SUN MAY 21 2017

...SMALL CRAFT ADVISORY THROUGH MONDAY...

.TONIGHT...SW WIND 25 KT. SEAS 8 FT.
.MON...SW WIND 20 KT IN THE MORNING BECOMING VARIABLE 10 KT. SEAS
8 FT.
.MON NIGHT...W WIND 15 KT. SEAS 7 FT.
.TUE...W WIND 20 KT. SEAS 6 FT.
.TUE NIGHT...SW WIND 25 KT. SEAS 8 FT.
.WED...S WIND 25 KT. SEAS 9 FT.
.THU...SW WIND 20 KT. SEAS 8 FT.
.FRI...VARIABLE WIND 10 KT. SEAS 6 FT.

$$

PKZ132-221215-
MARMOT ISLAND TO SITKINAK-
330 PM AKDT SUN MAY 21 2017

...SMALL CRAFT ADVISORY THROUGH MONDAY NIGHT...

.TONIGHT...SW WIND 25 KT. SEAS 8 FT.
.MON...SW WIND 15 KT. SEAS 8 FT.
.MON NIGHT...W WIND 25 KT. SEAS 7 FT.
.TUE AND TUE NIGHT...SW WIND 25 KT. SEAS 9 FT.
.WED...SW WIND 25 KT. SEAS 11 FT.
.THU...SW WIND 20 KT. SEAS 11 FT.
.FRI...SW WIND 15 KT. SEAS 6 FT.

$$

PKZ136-221215-
CHINIAK BAY-
330 PM AKDT SUN MAY 21 2017

.TONIGHT...W WIND 15 KT. SEAS 2 FT.
.MON...S WIND 10 KT. SEAS 2 FT.
.MON NIGHT...VARIABLE WIND LESS THAN 10 KT BECOMING W 10 KT AFTER
MIDNIGHT. SEAS 2 FT.
.TUE...SW WIND 15 KT. SEAS 2 FT.
.TUE NIGHT...S WIND 20 KT. SEAS 3 FT.
.WED...S WIND 20 KT. SEAS 3 FT.
.THU...SW WIND 15 KT. SEAS 2 FT.
.FRI...SW WIND 10 KT. SEAS 1 FOOT.

$$

PKZ137-221215-
MARMOT BAY-
330 PM AKDT SUN MAY 21 2017

.TONIGHT...W WIND 20 KT. SEAS 4 FT.
.MON...S WIND 10 KT. SEAS 3 FT.
.MON NIGHT...SW WIND 10 KT BECOMING W 15 KT AFTER MIDNIGHT. SEAS
3 FT.
.TUE...SW WIND 10 KT. SEAS 2 FT.
.TUE NIGHT...SW WIND 15 KT. SEAS 3 FT.
.WED THROUGH THU...SW WIND 15 KT. SEAS 3 FT.
.FRI...SW WIND 10 KT. SEAS 2 FT.

$$

PKZ138-221215-
SHELIKOF STRAIT-
330 PM AKDT SUN MAY 21 2017

...SMALL CRAFT ADVISORY TONIGHT...

.TONIGHT...SW WIND 30 KT. SEAS 10 FT.
.MON...SW WIND 20 KT. SEAS 5 FT.
.MON NIGHT...SW WIND 20 KT. SEAS 5 FT.
.TUE...SW WIND 25 KT. SEAS 8 FT.
.TUE NIGHT...SW WIND 25 KT. SEAS 9 FT.
.WED...SW WIND 25 KT. SEAS 9 FT.
.THU...SW WIND 15 KT. SEAS 3 FT.
.FRI...VARIABLE WIND 10 KT. SEAS 2 FT.

$$

PKZ139-221215-
COOK INLET KALGIN ISLAND TO POINT BEDE-
330 PM AKDT SUN MAY 21 2017

...SMALL CRAFT ADVISORY MONDAY NIGHT...

.TONIGHT...S WIND 10 KT BECOMING SW 20 KT AFTER MIDNIGHT. SEAS 2
FT BUILDING TO 5 FT AFTER MIDNIGHT.
.MON...S WIND 20 KT. SEAS 5 FT.
.MON NIGHT...S WIND 25 KT. SEAS 7 FT.
.TUE AND TUE NIGHT...S WIND 20 KT. SEAS 6 FT.
.WED...S WIND 20 KT. SEAS 6 FT.
.THU...S WIND 15 KT. SEAS 3 FT.
.FRI...S WIND 10 KT. SEAS 2 FT.

$$

PKZ140-221215-
COOK INLET NORTH OF KALGIN ISLAND-
330 PM AKDT SUN MAY 21 2017

...SMALL CRAFT ADVISORY MONDAY NIGHT...

.TONIGHT...SW WIND 10 KT BECOMING S 15 KT AFTER MIDNIGHT. SEAS 3
FT. RAIN.
.MON...S WIND 20 KT. SEAS 4 FT.
.MON NIGHT...SW WIND 25 KT. SEAS 6 FT.
.TUE...S WIND 20 KT. SEAS 4 FT.
.TUE NIGHT...S WIND 15 KT. SEAS 3 FT.
.WED...S WIND 20 KT. SEAS 4 FT.
.THU...S WIND 15 KT. SEAS 3 FT.
.FRI...S WIND 10 KT. SEAS 2 FT.

$$

PKZ141-221215-
KACHEMAK BAY-
330 PM AKDT SUN MAY 21 2017

.TONIGHT...VARIABLE WIND LESS THAN 10 KT BECOMING S 15 KT AFTER
MIDNIGHT. SEAS 2 FT.
.MON...S WIND 15 KT. SEAS 2 FT.
.MON NIGHT...SW WIND 15 KT. SEAS 4 FT.
.TUE...SW WIND 15 KT. SEAS 4 FT.
.TUE NIGHT...S WIND 20 KT. SEAS 3 FT.
.WED...S WIND 20 KT. SEAS 3 FT.
.THU THROUGH FRI...SW WIND 10 KT. SEAS 2 FT.

$$

Southcentral and Southwest Alaska Forecast Discussion...UPDATED
National Weather Service Anchorage AK
527 PM AKDT Sat May 20 2017

.ANALYSIS AND UPPER LEVELS...
Water vapor imagery shows a very dynamic and amplified pattern.
A broad trough and closed upper level low are centered over the
north central Pacific (due south of the Alaska Peninsula) with an
amplifying ridge downstream over the far east Pacific. This has
led to development of an atmospheric river, with moisture
streaming northward to the eastern Gulf and Southeast Alaska. A
low has formed at the surface and is being led into the eastern
Gulf by a warm front. This will be the major weather maker for
Southcentral tonight through Monday.

Meanwhile, an elongated upper low is centered along Shelikof Strait
with a trough rotating northwestward across Southcentral leading
to fairly extensive cloud cover and showers. With abundant sunshine
over interior Southwest Alaska to start the day, it appears very
favorable for development of showers (and perhaps a few thunderstorms)
this afternoon and evening as the upper trough continues westward
across the Alaska Range.

Out west, benign weather dominates much of the Bering Sea and
Aleutians. This is about to change; a strong upper level jet
streak is driving a deep upper trough eastward across the western
Bering Sea, with a sweeping cold front at the surface. Expect
steady rain and strong winds as this continues eastward.

&&

.MODEL DISCUSSION...
Looking at the 12z model guidance, the NAM remains an outlier with
a faster and farther east track of the low crossing the Gulf.
Prefer a consensus of the other solutions which track the low to
near Cape Cleare Sunday night, then inland Monday. There has not
been great run-to-run consistency with the timing and track of
this low, but based on good agreement with all but the NAM and
the fact that we are so close in time, confidence is increasing
and forecast will be adjusted to reflect the latest solution.
Elsewhere, models are in good agreement with major features and
forecast confidence is high.

&&

.AVIATION...
PANC...Expect Turnagain winds this afternoon, but they should cut
off pretty quickly early this evening as pressure gradients
slacken ahead of the surface low crossing the Gulf. Ceilings will
also improve this evening as the mean flow shifts around to
northerly. Ceilings will then quickly lower as steady rain moves
in Sunday, with a possibility of dropping to MVFR Sunday
afternoon or evening as the low levels continue to moisten under
weak flow and falling rain.

&&

.SHORT TERM FORECAST SOUTHCENTRAL ALASKA (Days 1 and 2)...
After a partial break in the clouds this evening, widespread
rains will return to the region for Sunday and Monday. Before this
rain begins, showers and gusty winds through Turnagain Arm/west
Anchorage, as well as the Knik and Copper River valleys will
continue through the early evening hours as the remnants of the
shortwave moves overhead. Afterwards, widespread rain will begin
along the north Gulf coast late tonight and then spread westward
into most of Southcentral by Sunday afternoon. This rain will
cause afternoon/evening gap winds to be much weaker than recent
days, and instead winds are expected to increase through these
areas late Sunday night where they will persist into Monday as the
surface low makes landfall. Confidence in the timing of these
winds improved significantly today, especially as the 18z GFS and
NAM came into much better agreement in the timing of the gulf low.
Conditions throughout the area will then begin to improve from
south to north on Monday afternoon, providing a brief break in the
rain to most areas that should persist into Tuesday.

&&

.SHORT TERM FORECAST SOUTHWEST ALASKA (Days 1 and 2)...
An upper level wave extending northward from an upper level low
along the Alaska Range is moving westward across the mountains
towards the Lower Kuskokwim Valley and interior Bristol Bay this
afternoon. As the wave becomes and additional source of lift for
an already moist, unstable atmosphere above that region, isolated
thunderstorms will be possible this afternoon. As the sun sets,
the activity will wane and partly cloudy to mainly clear skies
will return to Southwest Alaska tonight.

A similar scenario plays out on Sunday though this time the wave
will have moved to near the Kilbucks, where upon meeting the
approaching upper level signature of a front pushing eastward from
off the Bering, the two features colliding will be the source of
lift for the isolated thunderstorms on Sunday afternoon and
evening. Thus it is expected that any isolated thunderstorms will
be a bit further west on Sunday across the lower Kuskokwim Valley,
but in many of the same areas of Bristol Bay due to the front
hanging up the upper level wave further east across that region.
Slightly warmer air over the area, especially interior sections of
Southwest Alaska, will allow high temperatures to return to the
60s Sunday afternoon.

Then on Sunday night into Monday, the aforementioned Bering front
moves into Southwest Alaska from coast to interior, bringing some
rainfall to nearly all areas of Southwest Alaska as it passes
through. The front will also reinforce the cool air already in
place, with no sign of summer-like weather anywhere in sight.

&&

.SHORT TERM FORECAST BERING SEA/ALEUTIANS (Days 1 and 2)...
A front moving across the central Bering this afternoon will
continue to press eastward until making landfall in Southwest
Alaska Sunday night. Any areas dealing with the usual fog and
stratus across the eastern Bering will see that kind of weather
end with the frontal passage. Another strong wave of energy will
bring gale force winds to the western Bering Sunday afternoon, but
will be unable to keep favorable upper level atmospheric
conditions with it long enough to maintain itself as it tries to
move eastward and will subsequently die out over the central
Bering on Monday. The aftermath of this second wave will be a
period of solid south to southwest winds over nearly all of the
Bering by Monday afternoon. Warmer air may sneak into the
Aleutians Monday afternoon, but it will be very short-lived as
most of that air mass gets shunted to the east and a much colder
air mass dives into the Bering next week.

&&

.LONG TERM FORECAST (Days 3 through 7)...
An amplifying trough over the Bering Sea will bring a wet and
windy period of weather to Southwest Alaska starting late Tuesday
morning. Models have been slowly coming into better agreement
bringing an unseasonably moist airmass (based on progged PWAT
values) to mainland Alaska. Very impressive jet dynamics along the
west side of the trough will act as a lifting mechanism which
will create some very favorable rain processes. While rainfall
amounts vary from model to model, it looks quite likely that
coastal locations of Southwest Alaska could see over an inch of
rain while inland locations could see a quarter of an inch to
three quarters of an inch.

One of the biggest struggles in the extended forecast is just how
far east the rainfall makes it. Latest model runs suggest a
further eastward track which would allow Southcentral Alaska to be
impacted by the southwesterly flow aloft. This would allow
rainfall to begin possibly as early as Wednesday morning and
persist through Friday. However, it appears that this wet pattern
will begin to dissipate during the Memorial Day weekend, as models
are now in quite good agreement with bringing a ridge of high
pressure over the Northern gulf from Pacific Northwest coast.
This would potentially bring warmer and drier conditions to
Southcentral Alaska over the weekend and into Monday. The big
question is: will the rain end on Saturday or on Sunday? Stay
tuned.

&&

.AFC WATCHES/WARNINGS/ADVISORIES...
PUBLIC...NONE.
MARINE...Gale Warning 178.
FIRE WEATHER...NONE.

&&

SYNOPSIS AND MODEL DISCUSSION...SB
SOUTHCENTRAL ALASKA...DEK
SOUTHWEST ALASKA/BERING SEA/ALEUTIANS...JW
LONG TERM...MC/TP