Small Craft Advisory 603, NWS Anchorage, AK

216 
FZAK52 PAFC 042334
CWFALU

Coastal Waters Forecast
National Weather Service Anchorage Alaska
334 PM AKDT Wed Aug 4 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.

PKZ199-051245-
334 PM AKDT Wed Aug 4 2021
.SYNOPSIS FOR SOUTHWEST ALASKA+BRISTOL BAY+THE ALASKA
PENINSULA WATERS AND THE ALEUTIAN ISLANDS...

A 983 mb low 275 nm West of St Matthew Island moves to 90 nm 
Southwest of Attu at 1002 mb Fri afternoon. Its front dissipates 
over the Northern Bering Fri afternoon. A 1009 mb North Pacific low 
moves to 100 nm South of Seguam Island at 999 mb Fri afternoon.

$$

PKZ150-051245-
South of the AK Peninsula Sitkinak to Castle Cape-
334 PM AKDT Wed Aug 4 2021

...SMALL CRAFT ADVISORY THURSDAY NIGHT...

.TONIGHT...E wind 15 kt. Seas 5 ft.
.THU...N wind 15 kt. Seas 5 ft.
.THU NIGHT...NW wind 25 kt. Seas 7 ft.
.FRI...W wind 25 kt. Seas 7 ft.
.FRI NIGHT...SW wind 15 kt. Seas 5 ft.
.SAT THROUGH SUN...S wind 25 kt. Seas 9 ft.
.MON...SW wind 25 kt. Seas 15 ft.

$$

PKZ155-051245-
South of the AK Peninsula Castle Cape to Cape Sarichef-
334 PM AKDT Wed Aug 4 2021

.TONIGHT...NW wind 20 kt. Seas 6 ft.
.THU...NW wind 15 kt. Seas 5 ft.
.THU NIGHT...W wind 20 kt. Seas 5 ft.
.FRI...SW wind 15 kt. Seas 5 ft.
.FRI NIGHT...SE wind 25 kt. Seas 7 ft.
.SAT THROUGH SUN...SW wind 25 kt. Seas 10 ft.
.MON...W wind 20 kt. Seas 12 ft.

$$

PKZ160-051245-
Bristol Bay-
334 PM AKDT Wed Aug 4 2021

...SMALL CRAFT ADVISORY THURSDAY NIGHT...

.TONIGHT...W wind 15 kt. Seas 4 ft.
.THU...W wind 20 kt. Seas 5 ft.
.THU NIGHT...W wind 25 kt. Seas 7 ft.
.FRI...W wind 25 kt. Seas 7 ft.
.FRI NIGHT...SW wind 15 kt. Seas 5 ft.
.SAT...SE wind 25 kt. Seas 6 ft.
.SUN...S wind 25 kt. Seas 6 ft.
.MON...SW wind 25 kt. Seas 7 ft.

$$

PKZ165-051245-
Port Heiden to Cape Sarichef-
334 PM AKDT Wed Aug 4 2021

.TONIGHT...W wind 15 kt. Seas 4 ft.
.THU...W wind 15 kt. Seas 4 ft.
.THU NIGHT...Variable wind 10 kt except W 20 kt from Port Moller
E. Seas 4 ft.
.FRI...SW wind 15 kt. Seas 4 ft.
.FRI NIGHT...E wind 25 kt. Seas 6 ft.
.SAT...S wind 30 kt. Seas 8 ft.
.SUN...SW wind 30 kt. Seas 9 ft.
.MON...SW wind 25 kt. Seas 8 ft.

$$

PKZ170-051245-
Cape Sarichef to Nikolski Bering Side-
334 PM AKDT Wed Aug 4 2021

.TONIGHT...S wind 20 kt. Seas 5 ft.
.THU...S wind 15 kt. Seas 4 ft.
.THU NIGHT...Variable wind less than 10 kt becoming SE 15 kt after
midnight. Seas 3 ft.
.FRI...SE wind 25 kt. Seas 7 ft.
.FRI NIGHT...E wind 30 kt. Seas 9 ft.
.SAT THROUGH SUN...SW wind 30 kt. Seas 9 ft.
.MON...W wind 20 kt. Seas 7 ft.

$$

PKZ171-051245-
Unalaska Bay-
334 PM AKDT Wed Aug 4 2021

.TONIGHT...Variable wind less than 10 kt. Seas 3 ft.
.THU...Variable wind less than 10 kt. Seas 2 ft.
.THU NIGHT...Variable wind less than 10 kt. Seas 2 ft.
.FRI...SE wind 20 kt. Seas 3 ft.
.FRI NIGHT...SE wind 25 kt. Seas 3 ft.
.SAT...SW wind 20 kt. Seas 3 ft.
.SUN THROUGH MON...W wind 10 kt. Seas 2 ft.

$$

PKZ172-051245-
Cape Sarichef to Nikolski Pacific Side-
334 PM AKDT Wed Aug 4 2021

.TONIGHT...SW wind 15 kt. Seas 6 ft.
.THU...SW wind 15 kt. Seas 5 ft.
.THU NIGHT...SW wind 15 kt. Seas 5 ft.
.FRI AND FRI NIGHT...SE wind 30 kt. Seas 9 ft.
.SAT THROUGH SUN...SW wind 25 kt. Seas 10 ft.
.MON...W wind 20 kt. Seas 9 ft.

$$

PKZ173-051245-
Nikolski to Seguam Island Bering Side-
334 PM AKDT Wed Aug 4 2021

.TONIGHT...S wind 20 kt. Seas 6 ft.
.THU...Variable wind 10 kt. Seas 5 ft.
.THU NIGHT...SE wind 20 kt. Seas 5 ft.
.FRI...E wind 30 kt. Seas 8 ft.
.FRI NIGHT...NE wind 25 kt. Seas 8 ft.
.SAT...SW wind 25 kt. Seas 7 ft.
.SUN...W wind 20 kt. Seas 6 ft.
.MON...W wind 15 kt. Seas 6 ft.

$$

PKZ174-051245-
Nikolski to Seguam Island Pacific Side-
334 PM AKDT Wed Aug 4 2021

.TONIGHT...S wind 20 kt. Seas 7 ft.
.THU...SW wind 15 kt. Seas 6 ft.
.THU NIGHT...S wind 20 kt. Seas 6 ft.
.FRI...SE wind 30 kt. Seas 9 ft.
.FRI NIGHT...SW wind 25 kt. Seas 11 ft.
.SAT...SW wind 25 kt. Seas 8 ft.
.SUN...SW wind 20 kt. Seas 8 ft.
.MON...W wind 15 kt. Seas 8 ft.

$$

PKZ175-051245-
Seguam Island to Adak Bering Side-
334 PM AKDT Wed Aug 4 2021

.TONIGHT...SW wind 15 kt. Seas 4 ft.
.THU...S wind 15 kt. Seas 4 ft.
.THU NIGHT...SE wind 20 kt. Seas 4 ft.
.FRI...E wind 20 kt. Seas 5 ft.
.FRI NIGHT...W wind 15 kt. Seas 4 ft.
.SAT...W wind 20 kt. Seas 5 ft.
.SUN...NW wind 15 kt. Seas 6 ft.
.MON...SW wind 15 kt. Seas 6 ft.

$$

PKZ176-051245-
Seguam Island to Adak Pacific Side-
334 PM AKDT Wed Aug 4 2021

...SMALL CRAFT ADVISORY TONIGHT AND THURSDAY NIGHT...

.TONIGHT...SW wind 25 kt diminishing to 15 kt after midnight. Seas
7 ft.
.THU...Variable wind 10 kt. Seas 6 ft.
.THU NIGHT...SE wind 15 kt increasing to 25 kt after midnight.
Seas 7 ft.
.FRI...NE wind 30 kt. Seas 9 ft.
.FRI NIGHT...W wind 20 kt. Seas 10 ft.
.SAT...SW wind 20 kt. Seas 8 ft.
.SUN THROUGH MON...W wind 15 kt. Seas 6 ft.

$$

PKZ177-051245-
Adak to Kiska-
334 PM AKDT Wed Aug 4 2021

.TONIGHT...SW wind 20 kt. Seas 5 ft.
.THU...S wind 20 kt. Seas 5 ft.
.THU NIGHT...SE wind 20 kt. Seas 5 ft.
.FRI...SE wind 15 kt. Seas 4 ft.
.FRI NIGHT...SW wind 15 kt. Seas 6 ft.
.SAT...W wind 20 kt. Seas 7 ft.
.SUN...Variable wind 10 kt. Seas 6 ft.
.MON...SW wind 15 kt. Seas 5 ft.

$$

PKZ178-051245-
Kiska to Attu-
334 PM AKDT Wed Aug 4 2021

...SMALL CRAFT ADVISORY TONIGHT...

.TONIGHT...SW wind 25 kt. Seas 7 ft.
.THU...SW wind 20 kt. Seas 6 ft.
.THU NIGHT...S wind 20 kt. Seas 6 ft.
.FRI...S wind 15 kt. Seas 5 ft.
.FRI NIGHT...NW wind 15 kt. Seas 5 ft.
.SAT THROUGH MON...NW wind 15 kt. Seas 6 ft.

$$

PKZ179-051245-
Pribilof Islands Near Shore Waters-
334 PM AKDT Wed Aug 4 2021

.TONIGHT...S wind 15 kt. Seas 6 ft.
.THU...S wind 15 kt. Seas 5 ft.
.THU NIGHT...Variable wind 10 kt. Seas 4 ft.
.FRI...SE wind 15 kt. Seas 4 ft.
.FRI NIGHT...E wind 20 kt. Seas 5 ft.
.SAT...NE wind 30 kt. Seas 9 ft.
.SUN THROUGH MON...W wind 25 kt. Seas 7 ft.

$$

PKZ180-051245-
Kuskokwim Delta and Etolin Strait-
334 PM AKDT Wed Aug 4 2021

.TONIGHT...W wind 15 kt. Seas 5 ft.
.THU...W wind 20 kt. Seas 4 ft.
.THU NIGHT...W wind 20 kt. Seas 4 ft.
.FRI...W wind 15 kt. Seas 3 ft.
.FRI NIGHT...SE wind 15 kt. Seas 3 ft.
.SAT...SE wind 25 kt. Seas 6 ft.
.SUN...S wind 35 kt. Seas 9 ft.
.MON...SW wind 25 kt. Seas 7 ft.

$$

PKZ181-051245-
North and West of Nunivak Island-
334 PM AKDT Wed Aug 4 2021

.TONIGHT...SW wind 15 kt. Seas 7 ft.
.THU...SW wind 15 kt. Seas 5 ft.
.THU NIGHT...W wind 15 kt. Seas 3 ft.
.FRI...W wind 15 kt. Seas 3 ft.
.FRI NIGHT...Variable wind 10 kt. Seas 2 ft.
.SAT THROUGH SUN...NE wind 25 kt. Seas 6 ft.
.MON...W wind 20 kt. Seas 6 ft.

$$

PKZ185-051245-
Saint Matthew Island Waters-
334 PM AKDT Wed Aug 4 2021

...SMALL CRAFT ADVISORY THROUGH THURSDAY...

.TONIGHT...S wind 20 kt E of Saint Matthew Island...S 30 kt W of
Saint Matthew Island. Seas 10 ft.
.THU...Variable wind 10 kt E of Saint Matthew Island... SE 20 kt W
of Saint Matthew Island. Seas 8 ft.
.THU NIGHT...S wind 15 kt. Seas 5 ft.
.FRI...Variable wind 10 kt. Seas 5 ft.
.FRI NIGHT...Variable wind 10 kt. Seas 4 ft.
.SAT THROUGH SUN...N wind 25 kt. Seas 8 ft.
.MON...NW wind 20 kt. Seas 7 ft.

$$

Southcentral and Southwest Alaska Forecast Discussion
National Weather Service Anchorage AK
418 PM AKDT Tue Aug 3 2021

.ANALYSIS AND UPPER LEVELS...

Another day of very little change. High pressure is now firmly
embedded over Alaska, with low pressure being held in place over
the Bering Sea, creating southerly flow there. Low pressure also
remains stalled in the Gulf of Alaska. An easterly wave from this
low is currently inbound into the Copper River Basin. Hazy
conditions are also present in Southcentral Alaska from elevated
smoke being wrapped into Southcentral from the Northeast. The
source for this smoke is difficult to determine, but satellite
indicates it is coming from Siberia and wrapping around the high
pressure located over the state.

&&

.MODEL DISCUSSION...

Synoptically models remain in good agreement. They are struggling
a bit to handle the easterly wave coming into the Copper River
Basin. This does not affect overall forecast confidence too much,
however we did need to adjust the forecast as a result. But as
stated, confidence in the models is still high.

&&

.AVIATION...

PANC...VFR conditions and light winds will persist.

&&

.SHORT TERM FORECAST SOUTHCENTRAL ALASKA (Days 1 through 3: Today
through Friday evening)...

Showers and isolated thunderstorms will continue to track
westward over the southern Copper River Basin tonight along the
northern periphery of an upper low in the Gulf. As cloud cover is
more widespread across Southcentral and the Mat-Su this afternoon,
highs will be lower than originally expected today and
consequently sea breezes slightly weaker. Shortwave troughs
ejecting from the aforementioned upper low will continue to bring
forecast challenges for Wednesday. Generally warm and sunny
conditions are expected across lower terrain, with scattered
showers/thunderstorms possible near higher terrain. If cloud cover
decreases, high temperatures will reach the upper 70s in the
interior helping to increase sea breezes in the usual locations
near the coast. Less shortwave activity is expected on Thursday,
leading to mostly sunny and warmer conditions over much of the
region with the exception of a front brining moderate rain to
Kodiak by Thursday evening. The longwave pattern will begin to
change on Friday with a weakening upper trough moving into
Southcentral. Although precipitation will be scattered, increased
cloud cover will result in high temperatures returning to the 60s
for areas west of the Copper River Delta.

&&

.SHORT TERM FORECAST SOUTHWEST ALASKA (Tuesday afternoon through
Thursday night)...
Another bluebird afternoon and evening is in store for the
mainland. Temperatures will peak in the mid-80s for the Kuskokwim
Valley with 70s inland. Clear sky will prevail save for some fair
weather cumulus. Some patchy fog is possible Wednesday morning for
low-lying areas. Wednesday brings some changes in a couple ways.
First, some showers and thunderstorms will likely pop off in the
Kuskokwim Valley as ridging gives way to a shortwave trough in the
afternoon and evening. Secondly, the remains of a Bering Sea
front will move ashore, bringing in a much cooler airmass to the
Kuskokwim Delta and Bristol Bay areas. Steadier rain is possible
as these two features collide late Wednesday night into Thursday
morning. The front may linger over interior Bristol Bay Thursday
and Thursday night keeping rain over the area.

&&

.SHORT TERM FORECAST BERING SEA/ALEUTIANS (Days 1 and 2)...
A very moist frontal boundary sits from north to south over the
Bering Sea, dividing two distinct air masses. Warmer and winder
conditions to the eastern Bering and cooler and calmer conditions
for the western Bering Sea. These converging air masses will
slowly shift rain eastward, however the front falls apart quickly
on Wednesday as it approaches the mainland. The responsible low
pressure moves northwestward into the cold air aloft. Behind the
front a weak showery pattern sets up with light winds and cooler
temperatures.

&&

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

Good agreement on Friday among models across the Bering and
Aleutians, however Saturday and Sunday large differences emerge
on the track of a low pressure system moving into the Bering by
Saturday. So forecast confidence is low for Saturday and Sunday. A
low pressure system will move towards the central Aleutians and
central Bering Friday night this could potentially bring Gale
force winds out of bays and passes north of the AKPEN mainly from
Port Heiden down to around Cold Bay. Otherwise expect areas of
small craft winds near this low pressure. Seas may approach 10
feet near the low especially on Pacific side of the Aleutians, but
low confidence on seas after Friday. Across the Gulf better model
agreement with a front that will move across the area late
Saturday into Sunday, so good forecast confidence for this area.
Friday a trough will move across the western Gulf with winds less
than small crafts. Then by Saturday night a front moves into the
southern Gulf and tracks north on Sunday there is some slight
difference on how fast it moves into northern Gulf by late Sunday,
but overall just minor at this time. Expect small craft winds
mainly near Kodiak Island, Shelikof Strait and the Barren Islands
Saturday night and Sunday, there is a chance of near Gale force
winds in the Barren Islands. Otherwise seas will remain below 10
feet.

&&

.LONG TERM FORECAST (Days 3 through 7: Saturday through Tuesday)...

The long term will feature a broad area of low pressure over the
Bering with the upper trough extending inland with several
shortwaves as well as frontal systems moving across the Bering and
into Southwest and Southcentral through the long term as south
westerly flow aloft sets up Sunday across Southcentral. This will
bring cooler temperatures with mostly cloudy conditions and
periods of rain. On Saturday an upper level shortwave will swing
across Southcentral bringing showers. While a front moves out of
the Bering into the Southwest Saturday bringing rain and winds to
that area, this front will move across Kodiak and towards
Southcentral bringing rain to this area late Saturday and Sunday.
Monday and Tuesday will feature periods of rain as shortwave
energy moves across the Southwest and Southcentral. Overall good
confidence with the overall long wave pattern but low confidence
on timing of shortwaves and low pressure systems embedded in the
long wave pattern.
&&

.AFC WATCHES/WARNINGS/ADVISORIES...
PUBLIC...NONE.
MARINE...Gale 165 170 181 185.
FIRE WEATHER...NONE.

&&

SYNOPSIS AND MODEL DISCUSSION...BB
SOUTHCENTRAL ALASKA...AP
SOUTHWEST ALASKA/BERING SEA/ALEUTIANS...MTL
MARINE/LONG TERM...RC