Small Craft Advisory 833, NWS Anchorage, AK

452 
FZAK52 PAFC 201200
CWFALU

Coastal Waters Forecast
National Weather Service Anchorage Alaska
400 AM AKDT Wed Oct 20 2021

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.

PKZ199-210115-
400 AM AKDT Wed Oct 20 2021

.SYNOPSIS FOR SOUTHWEST ALASKA+BRISTOL BAY+THE ALASKA
PENINSULA WATERS AND THE ALEUTIAN ISLANDS...

A 983 mb low 40 nm northwest of Hooper Bay moves to the Bering 
Strait at 988 mb Wed night. The low then continues further north 
to the Chukchi Sea through Thu night. A strengthening 976 mb low 
140 nm southwest of Shemya Wed afternoon moves through the Bering 
to 110 nm northwest of Cold Bay at 947 mb early Fri morning.

$$

PKZ150-210115-
South of the AK Peninsula Sitkinak to Castle Cape-
400 AM AKDT Wed Oct 20 2021

...GALE WARNING THURSDAY...

.TODAY...NW wind 30 kt. Seas 13 ft.
.TONIGHT...NW wind 30 kt. Seas 13 ft.
.THU...S wind 25 kt becoming SE 40 kt in the afternoon. Seas 10
ft. Rain.
.THU NIGHT...S wind 45 kt. Seas 17 ft.
.FRI...S wind 30 kt. Seas 22 ft.
.SAT...NW wind 30 kt. Seas 21 ft.
.SUN...NW wind 30 kt. Seas 14 ft.

$$

PKZ155-210115-
South of the AK Peninsula Castle Cape to Cape Sarichef-
400 AM AKDT Wed Oct 20 2021

...GALE WARNING TODAY AND THURSDAY...

.TODAY...NW wind 35 kt. Seas 15 ft.
.TONIGHT...SW wind 30 kt. From the Shumagin Islands E, W wind 30
kt becoming SW 20 kt after midnight. Seas 13 ft.
.THU...S wind 45 kt. From the Shumagin Islands E, S wind 30 kt
becoming SE 45 kt in the afternoon. Seas 16 ft. Rain.
.THU NIGHT...SW wind 60 kt. Seas 28 ft.
.FRI...W wind 65 kt. Seas 36 ft.
.SAT...NW wind 40 kt. Seas 20 ft.
.SUN...NW wind 35 kt. Seas 13 ft.

$$

PKZ160-210115-
Bristol Bay-
400 AM AKDT Wed Oct 20 2021

...GALE WARNING THURSDAY...

.TODAY...W wind 25 kt. Seas 12 ft.
.TONIGHT...W wind 25 kt. Seas 10 ft.
.THU...SE wind 30 kt increasing to 40 kt in the afternoon. Seas
8 ft.
.THU NIGHT...SE wind 45 kt. Seas 10 ft.
.FRI...NE wind 35 kt. Seas 13 ft.
.SAT THROUGH SUN...NW wind 30 kt. Seas 10 ft.

$$

PKZ165-210115-
Port Heiden to Cape Sarichef-
400 AM AKDT Wed Oct 20 2021

...GALE WARNING THURSDAY...

.TODAY...W wind 30 kt. Seas 21 ft.
.TONIGHT...S wind 30 kt except W 25 kt from Port Moller E. Seas
15 ft.
.THU...SE wind 45 kt. From Port Moller E, SE wind 35 kt increasing
to 45 kt in the afternoon. Seas 12 ft. Rain.
.THU NIGHT...SW wind 55 kt. Seas 31 ft.
.FRI...NW wind 50 kt. Seas 31 ft.
.SAT...NW wind 35 kt. Seas 16 ft.
.SUN...NW wind 30 kt. Seas 13 ft.

$$

PKZ170-210115-
Cape Sarichef to Nikolski Bering Side-
400 AM AKDT Wed Oct 20 2021

...STORM WARNING THURSDAY...

.TODAY...W wind 35 kt. Seas 21 ft.
.TONIGHT...SW wind 30 kt becoming S 45 kt after midnight. Seas
15 ft. Rain.
.THU...SW wind 55 kt. Seas 15 ft building to 22 ft in the
afternoon. Widespread rain showers.
.THU NIGHT...W wind 70 kt. Seas 48 ft.
.FRI...W wind 70 kt. Seas 45 ft.
.SAT...W wind 40 kt. Seas 19 ft.
.SUN...NE wind 25 kt. Seas 11 ft.

$$

PKZ171-210115-
Unalaska Bay-
400 AM AKDT Wed Oct 20 2021

...GALE WARNING TONIGHT AND THURSDAY...

.TODAY...W wind 30 kt. Seas 5 ft. Rain.
.TONIGHT...SW wind 15 kt becoming S 35 kt after midnight. Seas 2
ft building to 5 ft after midnight. Rain.
.THU...S wind 35 kt becoming W 45 kt in the afternoon. Seas 7 ft.
Rain.
.THU NIGHT...W wind 70 kt. Seas 10 ft.
.FRI...W wind 70 kt. Seas 10 ft.
.SAT...W wind 35 kt. Seas 5 ft.
.SUN...N wind 20 kt. Seas 3 ft.

$$

PKZ172-210115-
Cape Sarichef to Nikolski Pacific Side-
400 AM AKDT Wed Oct 20 2021

...STORM WARNING THURSDAY...

.TODAY...W wind 35 kt. Seas 15 ft.
.TONIGHT...SW wind 30 kt becoming S 45 kt after midnight. Seas
13 ft. Rain.
.THU...W wind 50 kt. Seas 17 ft building to 25 ft in the
afternoon.
.THU NIGHT...W wind 60 kt. Seas 33 ft.
.FRI...W wind 65 kt. Seas 35 ft.
.SAT...W wind 40 kt. Seas 16 ft.
.SUN...NE wind 30 kt. Seas 14 ft.

$$

PKZ173-210115-
Nikolski to Seguam Island Bering Side-
400 AM AKDT Wed Oct 20 2021

...STORM WARNING THURSDAY...

.TODAY...W wind 35 kt. Seas 19 ft.
.TONIGHT...S wind 45 kt. Seas 16 ft. Widespread rain showers.
.THU...W wind 55 kt. Seas 19 ft building to 31 ft in the
afternoon. Rain showers.
.THU NIGHT...W wind 65 kt. Seas 41 ft.
.FRI...W wind 60 kt. Seas 39 ft.
.SAT...W wind 35 kt. Seas 18 ft.
.SUN...NE wind 30 kt. Seas 11 ft.

$$

PKZ174-210115-
Nikolski to Seguam Island Pacific Side-
400 AM AKDT Wed Oct 20 2021

...STORM WARNING THURSDAY...

.TODAY...W wind 30 kt. Seas 16 ft. Rain.
.TONIGHT...S wind 45 kt. Seas 16 ft. Rain.
.THU...W wind 50 kt. Seas 23 ft building to 29 ft in the
afternoon. Rain showers.
.THU NIGHT...W wind 55 kt. Seas 32 ft.
.FRI...W wind 55 kt. Seas 32 ft.
.SAT...W wind 35 kt. Seas 15 ft.
.SUN...E wind 30 kt. Seas 17 ft.

$$

PKZ175-210115-
Seguam Island to Adak Bering Side-
400 AM AKDT Wed Oct 20 2021

...STORM WARNING THURSDAY...

.TODAY...SW wind 30 kt. Seas 17 ft. Rain.
.TONIGHT...S wind 45 kt. Seas 14 ft. Widespread rain showers.
.THU...W wind 55 kt. Seas 20 ft building to 28 ft in the
afternoon.
.THU NIGHT...W wind 50 kt. Seas 31 ft.
.FRI...NW wind 45 kt. Seas 27 ft.
.SAT...W wind 30 kt. Seas 14 ft.
.SUN...NE wind 35 kt. Seas 12 ft.

$$

PKZ176-210115-
Seguam Island to Adak Pacific Side-
400 AM AKDT Wed Oct 20 2021

...STORM WARNING THURSDAY...

.TODAY...SW wind 30 kt. Seas 12 ft. Rain.
.TONIGHT...S wind 45 kt. Seas 15 ft building to 22 ft after
midnight. Widespread rain showers.
.THU...W wind 50 kt. Seas 26 ft.
.THU NIGHT...W wind 45 kt. Seas 25 ft.
.FRI...NW wind 40 kt. Seas 21 ft.
.SAT...W wind 35 kt. Seas 10 ft.
.SUN...NE wind 40 kt. Seas 18 ft.

$$

PKZ177-210115-
Adak to Kiska-
400 AM AKDT Wed Oct 20 2021

...GALE WARNING THROUGH THURSDAY...

.TODAY...SW wind 25 kt becoming S 35 kt in the afternoon. Seas
13 ft. Rain.
.TONIGHT...W wind 45 kt. Seas 17 ft Bering side...22 ft Pac side.
Widespread rain showers.
.THU...NW wind 45 kt. Seas 23 ft.
.THU NIGHT...W wind 40 kt. Seas 22 ft.
.FRI...NW wind 30 kt. Seas 16 ft.
.SAT...S wind 40 kt. Seas 12 ft.
.SUN...N wind 40 kt. Seas 15 ft.

$$

PKZ178-210115-
Kiska to Attu-
400 AM AKDT Wed Oct 20 2021

...GALE WARNING THROUGH THURSDAY...

.TODAY...S wind 25 kt becoming SE 35 kt in the afternoon. Seas
11 ft. Rain.
.TONIGHT...N wind 40 kt. Seas 18 ft.
.THU...NW wind 40 kt. Seas 19 ft.
.THU NIGHT...W wind 35 kt. Seas 17 ft.
.FRI...NW wind 20 kt. Seas 11 ft.
.SAT...SE wind 35 kt. Seas 9 ft.
.SUN...NW wind 35 kt. Seas 10 ft.

$$

PKZ179-210115-
Pribilof Islands Near Shore Waters-
400 AM AKDT Wed Oct 20 2021

...GALE WARNING THROUGH THURSDAY...

.TODAY...W wind 35 kt. Seas 19 ft.
.TONIGHT...S wind 15 kt becoming SE 35 kt after midnight. Seas
13 ft. Rain.
.THU...SE wind 45 kt. Seas 16 ft. Widespread rain showers.
.THU NIGHT...NW wind 50 kt. Seas 26 ft.
.FRI...NW wind 50 kt. Seas 21 ft.
.SAT...W wind 35 kt. Seas 14 ft.
.SUN...N wind 25 kt. Seas 9 ft.

$$

PKZ180-210115-
Kuskokwim Delta and Etolin Strait-
400 AM AKDT Wed Oct 20 2021

...GALE WARNING THURSDAY...

.TODAY...W wind 30 kt. Seas 17 ft.
.TONIGHT...W wind 25 kt. Seas 13 ft.
.THU...E wind 45 kt. Seas 9 ft building to 15 ft in the afternoon.
Rain.
.THU NIGHT...E wind 45 kt. Seas 17 ft.
.FRI...NE wind 35 kt. Seas 19 ft.
.SAT THROUGH SUN...NW wind 30 kt. Seas 12 ft.

$$

PKZ181-210115-
North and West of Nunivak Island-
400 AM AKDT Wed Oct 20 2021

...GALE WARNING THURSDAY...

.TODAY...W wind 30 kt. Seas 17 ft.
.TONIGHT...W wind 20 kt. Seas 11 ft.
.THU...SE wind 35 kt becoming E 45 kt in the afternoon. Seas 8 ft
building to 13 ft in the afternoon. Rain.
.THU NIGHT...E wind 45 kt. Seas 16 ft.
.FRI...N wind 30 kt. Seas 14 ft.
.SAT...NW wind 30 kt. Seas 10 ft.
.SUN...NW wind 25 kt. Seas 9 ft.

$$

PKZ185-210115-
Saint Matthew Island Waters-
400 AM AKDT Wed Oct 20 2021

...GALE WARNING THURSDAY...

.TODAY...W wind 30 kt. Seas 17 ft.
.TONIGHT...SW wind 20 kt becoming SE after midnight. Seas 11 ft.
.THU...NE wind 35 kt increasing to 45 kt in the afternoon. Seas 9
ft building to 16 ft in the afternoon. Rain.
.THU NIGHT...N wind 45 kt. Seas 19 ft.
.FRI...N wind 30 kt. Seas 15 ft.
.SAT...W wind 30 kt. Seas 10 ft.
.SUN...NW wind 25 kt. Seas 8 ft.

$$

Southcentral and Southwest Alaska Forecast Discussion
National Weather Service Anchorage AK
514 AM AKDT Tue Oct 19 2021

.ANALYSIS AND UPPER LEVELS...

A stacked low over the Gulf ushers strong winds and rain across
the Gulf this morning. A robust frontal system anchored across the
eastern Gulf through Prince William Sound is latched to the
aforementioned low, creating a vigorous barrier jet leading to
much stronger high-end gales and low-end storm force gusts mainly
south of Cordova and Valdez overnight. Over the Bering, a broad
frontal system from the North Pacific extends across the eastern Bering
to a complex low west of Saint Matthew Island. Meanwhile, an upper
level ridge extends from the western Gulf through the north-
northeast flank of the Gulf low. Multiple shortwaves associated
with these two separate upper lows increased the potential for
more clouds, rain and gusty winds especially for Prince William
Sound, eastern Aleutians and Southwest Coast today.

&&

.MODEL DISCUSSION...

Model solutions show favorable agreement between surface and
upper-level features moving across the Bering and Gulf of Alaska
through the week until Friday morning. A robust front wrapped
across the eastern Gulf through Prince William Sound is well
advertised among the models, creating multiple micro-scale lows to
en route north-northwest through the northern Gulf until the front
tapers off Wed afternoon. Over the Bering, solutions are still on
track with the placement of the existing Bering low and its
associated front today through Tue night. As the next Northwest
Pacific low enters the Bering Sea Wed night, most guidance
highlights a broad area of strong gales and potentially storm-
force winds on the west and south flank of the low. After Friday
morning, synoptic patterns begins to fizzle out for both the
Bering and Gulf which creates a low forecast confidence.
Essentially, the aforementioned short-term pattern will still
bring active weather across the region especially along the
coastal areas.

&&

.AVIATION...

PANC...VFR conditions will persist, with gentle northerly winds
continuing this morning. As Turnagain winds pick up a notch this
afternoon, gusts could make its way near the airfield in the
evening. The potential for reduced ceiling and light rain could
occur around 03Z Wed, leading to a low end MVFR conditions.

&&
.SHORT TERM FORECAST SOUTHCENTRAL ALASKA (Days 1 and 2)...

A tightly-wrapped low is moving rapidly through the Gulf of
Alaska from Southeast to Northwest today. This low is just to the
south of Middleton Island early this morning can be seen quite
well on both satellite and radar. There has been some uncertainty
as to where this low will make its landfall over the kenai
Peninsula, with the difference between a northerly track and on e
off the southern tip having a large difference in today and
tonight's weather from Kodiak Island through the Anchorage area.
It has taken a while, but it does appear that this system should
take the more northerly track as was discussed yesterday morning.
This will bring it just south of Seward and then it will rapidly
weaken as it moves over Kenai and then farther northwest. Winds
will be strong especially to the north of this low, but the winds
around the low will rapidly weaken today as it loses strength.
The Whittier and Portage areas will be interesting to watch as
this low moves through. Lows taking a track similar, but just a
little farther north (coming onshore between Seward and Whittier
have sometimes brought a periods of very strong winds to these
areas. In this case, the little bit farther south track and the
lack of strong pressure rises behind the low (due to the weakened
stationary front along the north Gulf coast, this one probably
will not be a strong as the one from about three years ago in
October. However, still went with a Gale warning for Passage Canal
and increased winds there and in Portage above all model
guidance.

The next weather feature to track will be the 500 mb longwave trough
as it slowly moves into and through Southcentral Wednesday
through Thursday night. This will keep south-to-southeast flow
aloft over Southcentral with some embedded shortwaves in the flow
aloft that may bring some additional shots of precipitation. With
the Southerly flow, most of the precipitation at sea level should
be rain, but will need to see how this develops as these short
waves are rather weak and not well defined at this point.

&&

.SHORT TERM FORECAST SOUTHWEST ALASKA (Days 1 and 2)...

The front off a large broad system in the Bering has pushed
over the Southwest Coast early this morning. Snow has pushed as
far inland as Bethel, and will likely continue through the rest of
the morning before tapering off. Precipitation reaches the Bristol
bay area later this morning, and will likely consist of primarily
rain for the lower elevations, with a rain/snow mix or all snow
along the higher elevation and foothills of the Kilbuck Mountains.
The front continues across the Southwest Mainland, fizzling out as
it approaches the Alaska Range late this afternoon. Inland areas
of Southwest, such as Sleetmute and Iliamna will see daytime
temperatures above freezing today, meaning any precipitation that
falls this afternoon will be rain and then transition to a
rain/snow mix or all snow for the overnight hours. Conditions
behind the longwave trough are drier, but will remain cool and
cloudy Wednesday and Thursday. The next front off a new incoming
Bering low reaches the Southwest Coast by Thursday evening. There
are still a few inconsistencies yet with this system, but
current guidance shows the main impacts and brunt of impactful
weather may be confined to the Coastal areas.

&&

.SHORT TERM FORECAST BERING SEA/ALEUTIANS (Days 1 and 2)...

A broad low pressure system is set up in the northern Bering,
while a high pressure ridge enters the western Bering today. The
two are creating a tight pressure gradient and creating gusty gale
force northwesterly winds across the western and central Bering
today and tonight. Winds die down to widespread small craft by
tomorrow morning once the transient ridge moves into the central
Bering. A new system develops west of Attu and moves into the
western Bering by late Wednesday night. Model guidance is hinting
as strong cyclogenesis as the low tracks eastward across the
Bering, meaning it is strengthening as it travels. Anticipate
strong storm force winds along the front as well as the back side
of the system beginning early Thursday morning. Significant cold
air advection is pulled behind the low, aiding in the
strengthening of the winds behind it, with models hinting towards
at least hurricane force gusts Thursday evening and Thursday night
between the Pribilof Islands and the Eastern Aleutians.
Additionally, expect heavy precipitation (mostly rain) along the
frontal boundary tracking from the Western Aleutians to the
Southern AKPen starting tomorrow evening and persisting through
Thursday evening.

&&

.MARINE (Days 3 through 5/Thursday through Saturday)...

Bering/Aleutians

Forecast confidence is moderate during the 3-5 day period as a
strong low pressure system moves through the southern Bering Sea
on Thursday and Friday. Minor differences exist between guidance
with respect to the placement and intensity of this low. There is
high confidence that widespread gale force winds will occur during
this period. In addition to the strong winds, large long period
northwesterly swell is expected along the coastal waters on the
north side of the Aleutian Islands Thursday and Friday. These
winds and seas will gradually ease and abate on Saturday.

Gulf of Alaska

Forecast confidence remains above average for Thursday with winds
remaining under gale force and no high seas. Confidence decreases
on Friday as the next low moves in from the North Pacific. Gale
force winds are possible along the coastal waters throughout the
northern Gulf on Friday and Saturday.

&&

.LONG TERM FORECAST (Days 4 through 7/Friday through Monday)...

A cloudy, cool and wet pattern is expected for Southcentral Friday
through Monday as upper-level troughing extends from the northern
Bering Sea into the central Gulf. This orientation of the upper
trough will allow for moisture to enter Southcentral as the
trough-axis remains southwest of the Kenai Peninsula and thus
resulting in broad south-southeasterly flow from the Gulf. With
respect to precipitation type, the chance for snow increases with
elevation.

The Bering/Aleutians will be in a cloudy and cool pattern as broad
upper level troughing continues to extend across the region.
Strong northwesterly gap winds are expected in the eastern
Aleutians and western Alaska Peninsula on Friday and Saturday in
the wake of a strong low pressure system moving into the Gulf.
These winds will eased Sunday and Monday.

&&

.AFC WATCHES/WARNINGS/ADVISORIES...
PUBLIC...NONE.
MARINE...Gale Warning: 119, 120, 125, 129, 131, 155, 165,
					   170-179, 185, 351, 411-414
FIRE WEATHER...NONE.

&&

SYNOPSIS AND MODEL DISCUSSION...CB
SOUTHCENTRAL ALASKA...EZ
SOUTHWEST ALASKA/BERING SEA/ALEUTIANS...KM
MARINE/LONG TERM...ED