Small Craft Advisory 622, NWS Anchorage, AK

736 
FZAK52 PAFC 100210 AAA
CWFALU

Coastal Waters Forecast
National Weather Service Anchorage Alaska
351 PM AKDT Mon Aug 9 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.

PKZ199-101245-
351 PM AKDT Mon Aug 9 2021
.SYNOPSIS FOR SOUTHWEST ALASKA+BRISTOL BAY+THE ALASKA
PENINSULA WATERS AND THE ALEUTIAN ISLANDS...

Semisopochnoi Volcano, 140 nm west of Adak is currently active.

A 988 mb low near Chignik exits into the Gulf tonight. A series 
of weak lows drift across the Bering through Wed afternoon.

$$

PKZ150-101245-
South of the AK Peninsula Sitkinak to Castle Cape-
351 PM AKDT Mon Aug 9 2021

...GALE WARNING TONIGHT...

.TONIGHT...W wind 40 kt diminishing to 30 kt after midnight. Seas 19 ft.
.TUE...SW wind 25 kt diminishing to 15 kt in the afternoon. Seas 14 ft.
.TUE NIGHT...S wind 15 kt. Seas 9 ft.
.WED AND WED NIGHT...NW wind 15 kt. Seas 8 ft.
.THU THROUGH SAT...W wind 15 kt. Seas 6 ft.

$$

PKZ155-101245-
South of the AK Peninsula Castle Cape to Cape Sarichef-
351 PM AKDT Mon Aug 9 2021

...GALE WARNING TONIGHT...

.TONIGHT...W wind 35 kt diminishing to 25 kt after midnight. Seas 16 ft.
.TUE...SW wind 20 kt. Seas 11 ft.
.TUE NIGHT...NW wind 15 kt. Seas 8 ft.
.WED AND WED NIGHT...Variable wind 10 kt. Seas 7 ft.
.THU THROUGH FRI...W wind 15 kt. Seas 6 ft.
.SAT...Variable wind 10 kt. Seas 4 ft.

$$

PKZ160-101245-
Bristol Bay-
351 PM AKDT Mon Aug 9 2021

.TONIGHT...NW wind 20 kt. Seas 5 ft.
.TUE...SW wind 20 kt. Seas 5 ft.
.TUE NIGHT...SW wind 15 kt diminishing to 10 kt after midnight.
Seas 4 ft.
.WED...SW wind 15 kt. Seas 3 ft.
.WED NIGHT...W wind 10 kt. Seas 2 ft.
.THU THROUGH SAT...SW wind 15 kt. Seas 4 ft.

$$

PKZ165-101245-
Port Heiden to Cape Sarichef-
351 PM AKDT Mon Aug 9 2021

...SMALL CRAFT ADVISORY TONIGHT...

.TONIGHT...W wind 25 kt. Seas 6 ft.
.TUE...SW wind 20 kt. Seas 6 ft.
.TUE NIGHT...W wind 15 kt. Seas 5 ft.
.WED...W wind 15 kt. Seas 4 ft.
.WED NIGHT...Variable wind 10 kt. Seas 2 ft.
.THU THROUGH SAT...SW wind 15 kt. Seas 4 ft.

$$

PKZ170-101245-
Cape Sarichef to Nikolski Bering Side-
351 PM AKDT Mon Aug 9 2021

...SMALL CRAFT ADVISORY TONIGHT...

.TONIGHT...W wind 25 kt. Seas 6 ft.
.TUE...W wind 20 kt. Seas 5 ft.
.TUE NIGHT...W wind 15 kt. Seas 5 ft.
.WED AND WED NIGHT...Variable wind 10 kt. Seas 4 ft.
.THU THROUGH FRI...W wind 15 kt. Seas 4 ft.
.SAT...Variable wind 10 kt. Seas 3 ft.

$$

PKZ171-101245-
Unalaska Bay-
351 PM AKDT Mon Aug 9 2021

...SMALL CRAFT ADVISORY TONIGHT...

.TONIGHT...W wind 30 kt becoming SW 20 kt after midnight. Seas 5
ft subsiding to 3 ft after midnight.
.TUE...SW wind 15 kt. Seas 2 ft.
.TUE NIGHT...W wind 15 kt becoming SW after midnight. Seas 2 ft.
.WED AND WED NIGHT...W wind 10 kt. Seas 2 ft.
.THU THROUGH FRI...W wind 10 kt. Seas 2 ft.
.SAT...Variable wind less than 10 kt. Seas 2 ft.

$$

PKZ172-101245-
Cape Sarichef to Nikolski Pacific Side-
351 PM AKDT Mon Aug 9 2021

...SMALL CRAFT ADVISORY THROUGH TUESDAY NIGHT...

.TONIGHT...W wind 25 kt. Seas 12 ft.
.TUE...W wind 10 kt. Seas 9 ft.
.TUE NIGHT...NW wind 15 kt. Seas 8 ft.
.WED AND WED NIGHT...Variable wind 10 kt. Seas 7 ft.
.THU THROUGH FRI...NW wind 15 kt. Seas 6 ft.
.SAT...Variable wind 10 kt. Seas 6 ft.

$$

PKZ173-101245-
Nikolski to Seguam Island Bering Side-
351 PM AKDT Mon Aug 9 2021

.TONIGHT...W wind 20 kt. Seas 7 ft.
.TUE...W wind 15 kt. Seas 7 ft.
.TUE NIGHT...W wind 15 kt. Seas 6 ft.
.WED AND WED NIGHT...Variable wind 10 kt. Seas 5 ft.
.THU...W wind 15 kt. Seas 4 ft.
.FRI...Variable wind 10 kt. Seas 3 ft.
.SAT...Variable wind 10 kt. Seas 6 ft.

$$

PKZ174-101245-
Nikolski to Seguam Island Pacific Side-
351 PM AKDT Mon Aug 9 2021

...SMALL CRAFT ADVISORY THROUGH TUESDAY...

.TONIGHT...W wind 20 kt. Seas 9 ft.
.TUE...W wind 10 kt. Seas 8 ft.
.TUE NIGHT...W wind 10 kt. Seas 7 ft.
.WED AND WED NIGHT...Variable wind 10 kt. Seas 7 ft.
.THU...Variable wind 10 kt. Seas 6 ft.
.FRI THROUGH SAT...E wind 15 kt. Seas 7 ft.

$$

PKZ175-101245-
Seguam Island to Adak Bering Side-
351 PM AKDT Mon Aug 9 2021

.TONIGHT...W wind 15 kt. Seas 6 ft.
.TUE...W wind 15 kt. Seas 5 ft.
.TUE NIGHT...W wind 10 kt. Seas 5 ft.
.WED...W wind 15 kt. Seas 4 ft.
.WED NIGHT...Variable wind 10 kt. Seas 3 ft.
.THU...W wind 15 kt. Seas 3 ft.
.FRI THROUGH SAT...Variable wind 10 kt. Seas 4 ft.

$$

PKZ176-101245-
Seguam Island to Adak Pacific Side-
351 PM AKDT Mon Aug 9 2021

...SMALL CRAFT ADVISORY TONIGHT...

.TONIGHT...W wind 15 kt. Seas 8 ft.
.TUE...W wind 10 kt. Seas 7 ft.
.TUE NIGHT...W wind 10 kt. Seas 6 ft.
.WED...Variable wind 10 kt. Seas 6 ft.
.WED NIGHT...Variable wind 10 kt. Seas 6 ft.
.THU...Variable wind 10 kt. Seas 6 ft.
.FRI...E wind 15 kt. Seas 7 ft.
.SAT...NE wind 20 kt. Seas 10 ft.

$$

PKZ177-101245-
Adak to Kiska-
351 PM AKDT Mon Aug 9 2021

.TONIGHT...W wind 15 kt. Seas 7 ft.
.TUE...Variable wind 10 kt. Seas 6 ft.
.TUE NIGHT...Variable wind 10 kt. Seas 6 ft.
.WED AND WED NIGHT...W wind 15 kt. Seas 6 ft.
.THU...S wind 15 kt. Seas 5 ft.
.FRI...NE wind 20 kt. Seas 11 ft.
.SAT...N wind 20 kt. Seas 12 ft.

$$

PKZ178-101245-
Kiska to Attu-
351 PM AKDT Mon Aug 9 2021

.TONIGHT...NW wind 15 kt. Seas 6 ft.
.TUE THROUGH TUE NIGHT...NW wind 15 kt. Seas 6 ft.
.WED AND WED NIGHT...W wind 15 kt. Seas 7 ft.
.THU...SE wind 15 kt. Seas 5 ft.
.FRI...NE wind 20 kt. Seas 12 ft.
.SAT...NW wind 15 kt. Seas 12 ft.

$$

PKZ179-101245-
Pribilof Islands Near Shore Waters-
351 PM AKDT Mon Aug 9 2021

.TONIGHT...NW wind 20 kt. Seas 5 ft.
.TUE...W wind 15 kt. Seas 5 ft.
.TUE NIGHT...Variable wind 10 kt. Seas 5 ft.
.WED AND WED NIGHT...Variable wind 10 kt. Seas 4 ft.
.THU...Variable wind 10 kt. Seas 4 ft.
.FRI THROUGH SAT...SW wind 15 kt. Seas 5 ft.

$$

PKZ180-101245-
Kuskokwim Delta and Etolin Strait-
351 PM AKDT Mon Aug 9 2021

.TONIGHT...NW wind 15 kt. Seas 3 ft.
.TUE...W wind 15 kt. Seas 4 ft.
.TUE NIGHT...W wind 10 kt. Seas 4 ft.
.WED...W wind 10 kt. Seas 3 ft.
.WED NIGHT...NW wind 15 kt. Seas 2 ft.
.THU...NW wind 15 kt. Seas 3 ft.
.FRI...W wind 15 kt. Seas 3 ft.
.SAT...SW wind 20 kt. Seas 6 ft.

$$

PKZ181-101245-
North and West of Nunivak Island-
351 PM AKDT Mon Aug 9 2021

.TONIGHT...NW wind 15 kt. Seas 4 ft.
.TUE...NW wind 15 kt. Seas 4 ft.
.TUE NIGHT...Variable wind 10 kt. Seas 3 ft.
.WED AND WED NIGHT...Variable wind 10 kt. Seas 3 ft.
.THU...NW wind 15 kt. Seas 3 ft.
.FRI...SW wind 20 kt. Seas 4 ft.
.SAT...SW wind 25 kt. Seas 8 ft.

$$

PKZ185-101245-
Saint Matthew Island Waters-
351 PM AKDT Mon Aug 9 2021

.TONIGHT...N wind 20 kt. Seas 7 ft.
.TUE...NW wind 15 kt. Seas 5 ft.
.TUE NIGHT...Variable wind 10 kt. Seas 5 ft.
.WED...Variable wind 10 kt. Seas 4 ft.
.WED NIGHT...Variable wind 10 kt. Seas 3 ft.
.THU...Variable wind 10 kt. Seas 4 ft.
.FRI THROUGH SAT...SW wind 20 kt. Seas 6 ft.

$$

Southcentral and Southwest Alaska Forecast Discussion
National Weather Service Anchorage AK
537 PM AKDT Sun Aug 8 2021

.ANALYSIS AND UPPER LEVELS...Welcome to August. The pattern is
much more dynamic than it was even just a few days ago. From west
to east, there is a very broad trough over the Bering. A fast,
mostly zonal jet is running south of and supporting this trough.
Winds at 300 mb (30,000') are about 150 kts moving from west to
east and keeping the pattern dynamic. Within the trough is a
vigorous upper level low. Various pieces of energy (some of them
remnant Tropical Storms from the W Pacific) are moving quickly to
the north and east as they get caught in the 300 mb jet. As they
near the Alaska Peninsula, the upper level low is helping to grab
the energy and the moisture and sling it into Southcentral.

At the surface, this results in showers over Southwest AK with
widespread moderate to heavy steady rain from the Kenai Peninsula
through the Gulf Coast into the Copper River Basin. As of 00z/4pm
AKDT, the forecast office measured 0.88" of rain. Gusty winds are
also moving in with this system. Winds over the marine areas over
the Northern Gulf are pushing into small craft range (23 kts)
already this afternoon and should continue to climb in advance of
the surface front. As the surface low is developing on the
southern end of the Cook Inlet, we will see some wrap around,
ageostrophic influence behind the low. Kodiak and Kachemak Bay are
the first to see this influence this afternoon with gusty west to
southwest winds.

&&

.MODEL DISCUSSION...Models are doing ok with the dynamic pattern,
but are displaying some of their usual struggles for this time of
year. The primary concern is the location of the next triple point
low Mon night into Tue. The GFS had been the furthest east and
strongest with this feature. Through this morning though, even
while it remains on the stronger end of guidance, the track has
shifted further west and a bit north. This puts it in better
alignment with the rest of the models. This will impacts exactly
where the strongest winds will develop over the Gulf late Mon. The
other subtleties revolve around where the most precipitation will
fall and the exact timing of wind shifts. This forecast package
relied mostly on hi- res guidance in handling these.

&&

.AVIATION...
PANC...A combination of MVFR to IFR ceilings will persist through
Mon morning. They will predominantly remain MVFR dropping to IFR
when a heavier band of rain moves in. The best chance for this
will be this afternoon and evening before rain starts to taper off
overnight. As the front lifts through, expect some gusty southeast
to southwest winds to develop at the terminal. With weaker flow
aloft and minimal dry air behind the front, we expect low ceilings
to linger around Cook Inlet through the period.

&&

.SHORT TERM FORECAST SOUTHCENTRAL ALASKA (Days 1 through 3/Tonight
through Wednesday night)...

A pre-Fall seasonal pattern has arrived and it should not come as
a surprise as more tropical moisture combined with a series of
upper level shortwaves pushes across the Gulf and Southcentral
through the next couple days. A train of former tropical cyclones
from the Northwest Pacific aims for the Gulf of Alaska through
Southcentral, leading to more rainfall with the heaviest episode
expected across Prince William Sound tonight and again from Monday
afternoon through Tuesday morning.

A broad frontal system from this morning is still making its way
across the northeastern Gulf and the rest of Southcentral, where
the influx of moisture and precipitation is consistent with the
model solutions. Rainfall observations from across the region
continues to soar into 0.50" to 1.25" range since this morning,
with more rainy clouds approaching Southcentral tonight. Steady
light to moderate rain has moved to across the Gulf to as far as
Copper River Basin, Mat-Su Valley, and through PWS and Anchorage
Bowl since this morning. This afternoon's RAOB atmospheric profile
near Ted Stevens International Airport was pretty saturated and
enhanced with tropical moisture up to near 10,000 ft, with the
precipitable water at 0.94".

The next low will bring strong gales over the Gulf with the
potential of storm force winds as early as Tuesday morning. NAM
and ECMWF carried mainly gales while GFS maintained storm force
winds. The path of the expected low could make a difference in
strong wind coverage should it veer off from its current path, but
for now, strong winds associated with the low will remain south-
southeast of Cordova and portion of the east PWS waters on
Tuesday. Overall, winds and widespread rain will remain in the
short term forecast, with a few breaks in shower activity.

&&

.SHORT TERM FORECAST SOUTHWEST ALASKA (Days 1 through 3: Sunday
night through Wednesday)...

Low pressure in Bristol Bay is creating showery activity for
Southwest AK behind a front that pushed though last night. This
low is expected to exit tonight. Tomorrow, the next system that is
currently moving through the Aleutians will clip Southwest AK as
it moves into the Western Gulf of Alaska. This will provide
another round of steady rain for Southwest Alaska. We have a high
confidence level in this forecast through tomorrow. As we go through
the week, lingering instability in Southwest AK will cause showery
activity and cloud cover to persist. A train of tropical typhoons
moving into the North Pacific is decreasing model performance,
but we have enough confidence in the forecast to say it will stay
wet and cool in Southwest AK. However, do stay tuned to the
forecast with models having trouble with the weather right now.

&&

.SHORT TERM FORECAST BERING SEA/ALEUTIANS (Days 1 through 3:
Sunday night through Wednesday)...

Low pressure that has been working its way through the Bering is
currently located in Bristol Bay. It is on track to exit tonight.
As it does, another system is quickly traversing along the Aleutian
Islands, bringing another round of rain and wind to the island
chain. After the exit of this system, the Bering appears to quiet
for the rest of the short term. There is plenty of model discrepancy
as remnants of tropical systems are really having an adverse
affect on model performance. However, it appears that these
systems will stay south of the Aleutians in the North Pacific as
they work towards Alaska. So, expect conditions to settle but stay
tuned with increasing forecast uncertainty by midweek.

&&

.MARINE (Days 3 through 5: Wednesday through Friday)...

The forecast period from Wednesday through Friday remains active
initially southeast of the Alaska Peninsula northeast through the
Gulf of Alaska. Another low is expected to follow a similar track
on Wednesday that the previous systems took. Models have come into
better agreement on where the center of this low will track. Most
now track the low from somewhere near/just east of Kodiak Island
north and east towards Prince William Sound with its front slowly
traversing eastward across the Gulf through Thursday. There
remains average to high confidence in gale force winds and seas 12
to 18 ft to the Gulf of Alaska Wednesday, especially in any
barrier jet that develops along the North Gulf of Alaska coast.
There also may be small craft winds through the Barren Islands on
Friday due to a tightening pressure gradient. Lastly, expect winds
less than 30 kts and seas less than 7 ft for much of the Bering
Sea through the forecast period.

Long Term Discussion (Days 4 through 7: Thursday through
Sunday)...

The start of the long term period will feature a positively-tilted
longwave trough positioned over the western half of the AK
mainland and eastern Bering. Both operational and ensemble
guidance suggest the trough axis will begin to advance east
through the end of the week as it also lifts and becomes less
amplified, eventually leading to a potentially drier and more
zonal flow setting up across the southern half of the state. The
deep tap of tropical moisture following the strong southwest flow
out ahead of the trough will likely be shunted east more into the
Southeast from Thursday to Friday. This should help bring an end
to the very wet pattern that will be in place for the first half
of the week. However, there would unlikely be a hard transition
back to clear and sunny weather, with cool low level temperatures
and a showery/cloudy regime lingering near the longwave trough
overhead. There is also quite a bit of spread between models for
the track of a couple smaller shortwaves that will move through
the base of the trough between the eastern Bering and towards the
Gulf from Friday to Sunday. The GFS is the most progressive with
the first of these waves, bringing it quickly into the Gulf by
Friday night. The Canadian is much slower with this system,
lagging nearly a day behind the GFS. Bottom line, expect a trend
towards a less active pattern by the end of the week with more
widely scattered/intermittent showers with passing systems.

&&

.AFC WATCHES/WARNINGS/ADVISORIES...
PUBLIC...NONE.
MARINE...Gale Warning 132 352.
FIRE WEATHER...NONE.

&&

SYNOPSIS AND MODEL DISCUSSION...MSO
SOUTHCENTRAL ALASKA...CB
SOUTHWEST ALASKA/BERING SEA/ALEUTIANS...BJB
MARINE/LONG TERM...AS