Small Craft Advisory 621, NWS Anchorage, AK

197 
FZAK52 PAFC 292323
CWFALU

Coastal Waters Forecast
National Weather Service Anchorage Alaska
323 PM AKDT Thu Aug 29 2019

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.

PKZ199-301145-
323 PM AKDT Thu Aug 29 2019
.SYNOPSIS FOR SOUTHWEST ALASKA+BRISTOL BAY+THE ALASKA
PENINSULA WATERS AND THE ALEUTIAN ISLANDS...

A 1001 mb low 335 nm northeast of Shemya weakens by Sat morning. A 
999 mb north Pacific low deepens to 980 mb 360 nm southwest of Adak 
then moves to 145 nm southwest of Dutch Harbor by Sat afternoon at 
970 mb.

$$

PKZ150-301145-
South of the AK Peninsula Sitkinak to Castle Cape-
323 PM AKDT Thu Aug 29 2019

...SMALL CRAFT ADVISORY THROUGH FRIDAY...

.TONIGHT...E wind increasing to 25 kt. Seas 7 ft. Rain.
.FRI...E wind 25 kt becoming W in the afternoon. Seas 7 ft.
.FRI NIGHT...W wind 15 kt. Seas 6 ft.
.SAT...S wind 30 kt. Seas 7 ft.
.SAT NIGHT...SE wind 35 kt. Seas 12 ft.
.SUN...S wind 35 kt. Seas 23 ft.
.MON...SW wind 30 kt. Seas 21 ft.
.TUE...W wind 20 kt. Seas 11 ft.

$$

PKZ155-301145-
South of the AK Peninsula Castle Cape to Cape Sarichef-
323 PM AKDT Thu Aug 29 2019

...SMALL CRAFT ADVISORY FRIDAY NIGHT...

.TONIGHT...SE wind 20 kt. Seas 7 ft.
.FRI...NW wind 15 kt. Seas 6 ft.
.FRI NIGHT...SW wind 15 kt becoming S 25 kt after midnight. From
the Shumagin Islands E, variable wind 10 kt. Seas 6 ft.
.SAT...SE wind 35 kt. Seas 13 ft.
.SAT NIGHT...S wind 40 kt. Seas 24 ft.
.SUN...SW wind 40 kt. Seas 25 ft.
.MON...SW wind 35 kt. Seas 21 ft.
.TUE...SW wind 20 kt. Seas 9 ft.

$$

PKZ160-301145-
Bristol Bay-
323 PM AKDT Thu Aug 29 2019

.TONIGHT...SE wind increasing to 20 kt. Seas 3 ft.
.FRI...E wind 15 kt. Seas 3 ft.
.FRI NIGHT...SW wind 10 kt. Seas 2 ft.
.SAT...SE wind 30 kt. Seas 5 ft.
.SAT NIGHT...SE wind 45 kt. Seas 10 ft.
.SUN...SE wind 40 kt. Seas 8 ft.
.MON THROUGH TUE...SW wind 30 kt. Seas 12 ft.

$$

PKZ165-301145-
Port Heiden to Cape Sarichef-
323 PM AKDT Thu Aug 29 2019

...SMALL CRAFT ADVISORY TONIGHT...

.TONIGHT...SE wind 25 kt. Seas 4 ft.
.FRI...SW wind 15 kt. Seas 3 ft.
.FRI NIGHT...SE wind 20 kt after midnight. Variable wind 10 kt in
the evening. From Port Moller E, variable 10 kt. Seas 4 ft.
.SAT...E wind 45 kt. Seas 10 ft.
.SAT NIGHT...SE wind 40 kt. Seas 9 ft.
.SUN...S wind 30 kt. Seas 12 ft.
.MON...SW wind 35 kt. Seas 18 ft.
.TUE...SW wind 25 kt. Seas 15 ft.

$$

PKZ170-301145-
Cape Sarichef to Nikolski Bering Side-
323 PM AKDT Thu Aug 29 2019

...SMALL CRAFT ADVISORY FRIDAY NIGHT...

.TONIGHT...SW wind 15 kt. Seas 5 ft.
.FRI...SW wind 15 kt. Seas 4 ft.
.FRI NIGHT...SE wind 20 kt increasing to 30 kt after midnight.
Seas 6 ft.
.SAT...SE wind 45 kt. Seas 12 ft.
.SAT NIGHT...SE wind 35 kt. Seas 9 ft.
.SUN...W wind 40 kt. Seas 18 ft.
.MON...W wind 35 kt. Seas 18 ft.
.TUE...SW wind 25 kt. Seas 13 ft.

$$

PKZ171-301145-
Unalaska Bay-
323 PM AKDT Thu Aug 29 2019

...SMALL CRAFT ADVISORY FRIDAY NIGHT...

.TONIGHT...W wind 15 kt diminishing to 10 kt after midnight. Seas
2 ft.
.FRI...SW wind 10 kt in the morning becoming variable less than
10 kt. Seas 2 ft.
.FRI NIGHT...SE wind 15 kt increasing to 25 kt after midnight.
Seas 2 ft building to 4 ft after midnight.
.SAT...SE wind 40 kt. Seas 5 ft.
.SAT NIGHT...SE wind 25 kt. Seas 4 ft.
.SUN THROUGH MON...SW wind 30 kt. Seas 5 ft.
.TUE...SW wind 10 kt. Seas 2 ft.

$$

PKZ172-301145-
Cape Sarichef to Nikolski Pacific Side-
323 PM AKDT Thu Aug 29 2019

...SMALL CRAFT ADVISORY FRIDAY NIGHT...

.TONIGHT...W wind 20 kt. Seas 7 ft.
.FRI...W wind 15 kt. Seas 6 ft.
.FRI NIGHT...S wind 20 kt becoming SE 30 kt after midnight. Seas
5 ft building to 9 ft after midnight.
.SAT...SE wind 40 kt. Seas 17 ft.
.SAT NIGHT...S wind 40 kt. Seas 26 ft.
.SUN...W wind 40 kt. Seas 24 ft.
.MON...W wind 35 kt. Seas 18 ft.
.TUE...SW wind 20 kt. Seas 8 ft.

$$

PKZ173-301145-
Nikolski to Seguam Island Bering Side-
323 PM AKDT Thu Aug 29 2019

...GALE WARNING FRIDAY NIGHT...

.TONIGHT...W wind 20 kt. Seas 6 ft.
.FRI...SW wind 15 kt. Seas 5 ft.
.FRI NIGHT...SE wind 30 kt becoming E 40 kt after midnight. Seas
6 ft building to 11 ft after midnight. Rain.
.SAT...E wind 40 kt. Seas 12 ft.
.SAT NIGHT...NW wind 35 kt. Seas 12 ft.
.SUN...W wind 40 kt. Seas 17 ft.
.MON...W wind 30 kt. Seas 15 ft.
.TUE...S wind 20 kt. Seas 9 ft.

$$

PKZ174-301145-
Nikolski to Seguam Island Pacific Side-
323 PM AKDT Thu Aug 29 2019

...GALE WARNING FRIDAY NIGHT...

.TONIGHT...W wind 20 kt. Seas 6 ft.
.FRI...S wind 20 kt. Seas 5 ft.
.FRI NIGHT...SE wind 30 kt increasing to 40 kt after midnight.
Seas 12 ft. Rain.
.SAT...S wind 40 kt. Seas 20 ft.
.SAT NIGHT...W wind 40 kt. Seas 21 ft.
.SUN...W wind 45 kt. Seas 20 ft.
.MON...W wind 30 kt. Seas 15 ft.
.TUE...S wind 15 kt. Seas 8 ft.

$$

PKZ175-301145-
Seguam Island to Adak Bering Side-
323 PM AKDT Thu Aug 29 2019

...GALE WARNING FRIDAY NIGHT...

.TONIGHT...W wind 20 kt. Seas 5 ft. Patchy fog.
.FRI...SE wind 20 kt. Seas 4 ft.
.FRI NIGHT...E wind 40 kt. Seas 8 ft building to 13 ft after
midnight. Rain.
.SAT...NE wind 45 kt. Seas 15 ft.
.SAT NIGHT...NW wind 45 kt. Seas 18 ft.
.SUN...W wind 40 kt. Seas 17 ft.
.MON...SW wind 30 kt. Seas 12 ft.
.TUE...S wind 25 kt. Seas 8 ft.

$$

PKZ176-301145-
Seguam Island to Adak Pacific Side-
323 PM AKDT Thu Aug 29 2019

...GALE WARNING FRIDAY NIGHT...

.TONIGHT...W wind 20 kt. Seas 6 ft. Patchy fog.
.FRI...S wind 15 kt becoming SE 30 kt in the afternoon. Seas 7 ft.
.FRI NIGHT...SE wind 40 kt. Seas 15 ft. Rain.
.SAT AND SAT NIGHT...NW wind 45 kt. Seas 18 ft.
.SUN...W wind 45 kt. Seas 17 ft.
.MON...SW wind 25 kt. Seas 10 ft.
.TUE...S wind 20 kt. Seas 6 ft.

$$

PKZ177-301145-
Adak to Kiska-
323 PM AKDT Thu Aug 29 2019

...STORM WARNING FRIDAY NIGHT...

.TONIGHT...SW wind 15 kt. Seas 5 ft. Patchy fog.
.FRI...SE wind 15 kt becoming E 35 kt in the afternoon. Seas 7 ft.
Rain.
.FRI NIGHT...N wind 50 kt. Seas 14 ft. Rain.
.SAT...NW wind 50 kt. Seas 16 ft.
.SAT NIGHT...NW wind 40 kt. Seas 14 ft.
.SUN...W wind 30 kt. Seas 13 ft.
.MON...SW wind 25 kt. Seas 8 ft.
.TUE...S wind 25 kt. Seas 7 ft.

$$

PKZ178-301145-
Kiska to Attu-
323 PM AKDT Thu Aug 29 2019

...GALE WARNING FRIDAY NIGHT...

.TONIGHT...Variable wind 10 kt. Seas 4 ft. Patchy fog.
.FRI...NE wind 15 kt becoming N 25 kt in the afternoon. Seas 5 ft.
.FRI NIGHT...N wind 35 kt. Seas 8 ft.
.SAT AND SAT NIGHT...NW wind 30 kt. Seas 11 ft.
.SUN...W wind 25 kt. Seas 9 ft.
.MON THROUGH TUE...S wind 25 kt. Seas 7 ft.

$$

PKZ179-301145-
Pribilof Islands Near Shore Waters-
323 PM AKDT Thu Aug 29 2019

.TONIGHT...S wind 20 kt. Seas 7 ft.
.FRI...SW wind 20 kt. Seas 6 ft.
.FRI NIGHT...SE wind 20 kt. Seas 5 ft.
.SAT...E wind 40 kt. Seas 14 ft.
.SAT NIGHT...NE wind 35 kt. Seas 13 ft.
.SUN...NW wind 30 kt. Seas 11 ft.
.MON...W wind 35 kt. Seas 14 ft.
.TUE...SW wind 25 kt. Seas 11 ft.

$$

PKZ180-301145-
Kuskokwim Delta and Etolin Strait-
323 PM AKDT Thu Aug 29 2019

.TONIGHT...SE wind 20 kt. Seas 6 ft.
.FRI...SE wind 20 kt. Seas 6 ft.
.FRI NIGHT...SW wind 10 kt. Seas 4 ft.
.SAT...SE wind 30 kt. Seas 7 ft.
.SAT NIGHT...E wind 45 kt. Seas 13 ft.
.SUN...SE wind 35 kt. Seas 10 ft.
.MON THROUGH TUE...SW wind 30 kt. Seas 13 ft.

$$

PKZ181-301145-
North and West of Nunivak Island-
323 PM AKDT Thu Aug 29 2019

...SMALL CRAFT ADVISORY TONIGHT...

.TONIGHT...E wind 25 kt. Seas 6 ft.
.FRI...SE wind 20 kt. Seas 6 ft.
.FRI NIGHT...S wind 15 kt. Seas 5 ft.
.SAT...SE wind 25 kt. Seas 4 ft.
.SAT NIGHT...E wind 35 kt. Seas 9 ft.
.SUN...E wind 30 kt. Seas 9 ft.
.MON...W wind 25 kt. Seas 7 ft.
.TUE...SW wind 20 kt. Seas 8 ft.

$$

PKZ185-301145-
Saint Matthew Island Waters-
323 PM AKDT Thu Aug 29 2019

...SMALL CRAFT ADVISORY THROUGH FRIDAY...

.TONIGHT...E wind 25 kt. Seas 9 ft.
.FRI...E wind 25 kt. Seas 8 ft.
.FRI NIGHT...SE wind 20 kt. Seas 6 ft.
.SAT...E wind 20 kt. Seas 5 ft.
.SAT NIGHT...NE wind 35 kt. Seas 8 ft.
.SUN...N wind 30 kt. Seas 9 ft.
.MON...W wind 25 kt. Seas 9 ft.
.TUE...S wind 25 kt. Seas 8 ft.

$$

Southcentral and Southwest Alaska Forecast Discussion
National Weather Service Anchorage AK
544 PM AKDT Wed Aug 28 2019

.ANALYSIS AND UPPER LEVELS...

Weak upper level flow dominates the Southern Mainland this
afternoon with continued warm and mostly sunny weather over
Southcentral. More clouds exist over Southwest as some moisture
from the Bering moves inland, but is blocked by the mighty Alaska
Range from moving eastward. There is a very subtle shortwave
trough moving east across Southcentral, but with heights rising
behind it, this feature is mostly further promoting subsidence and
mostly clear skies. Out west, there is an amplifying shortwave
trough and associated deepening surface low bringing increased
southerly winds and rain to the Pribilof Islands and to the
Central Aleutians.

&&

.MODEL DISCUSSION...

Models are in excellent overall synoptic agreement through the
weekend as the pattern changes to wetter and rainier across
drought stricken Southern Alaska. The first low to impact
Southwest, Kodiak, and the Kenai Peninsula comes on Friday and
Friday night. Discrepancy exists still with the numerical guidance
on how far west and north precipitation moves, mostly due to
differences in the upper level shortwave the models are progging.
For now a middle ground approach is favored as the models are all
similar but have key differences, so this forecast will favor most
rain over Kodiak, the coast, and inland Bristol Bay with lighter
rain along the northern Kenai and the Swan Lake fire.

The next storm force low, which will be the strongest of the
season at or around 970 mb, will move into the Bering Sea Friday
night and move east through Sunday, with the front reaching
Southcentral on Sunday. Models are well clustered on track and
strength, but the GFS was favored due to its higher resolution
wind fields.

&&

.AVIATION...
PANC...VFR conditions and light winds will persist through early
afternoon. After this time, an up-inlet flow will allow a
strengthening Turnagain Arm wind to develop over the northern
Inlet, just south of the airport. There may be an increase in
smoke transport with this wind. The question is whether enough
smoke moves in to reduce visibility. The current line of thought
is that the stronger Turnagain Arm wind during the afternoon hours
will allow for enough mixing and no reduction of visibility.
However, once the wind settles down a bit and we move into the
overnight hours, conditions will become more stable allowing the
smoke to settle and reduce the visibility to MVFR. As stated
previously, the amount of smoke and resultant visibility is
difficult to forecast, so confidence in the exact timing and
visibility is low but it is increasing enough that the lowest
visibility is expected Thursday morning.

&&

.FIRE WEATHER...

Southcentral...Continued warm and dry conditions will persist
through Friday. The next chance for rain is looking increasingly
likely for Friday evening and overnight as a weak front moves
toward Kodiak Island and lifts north. The best chances for light
wetting rain will be along the Kenai Peninsula and coast with much
lighter rain and lower chances inland as the front weakens.

The next likely time for rain will be Sunday as a powerful front
moves inland, which will likely be accompanied by strong mountain
gap winds. Wetting rain chances will once again be most likely
along the coast and the Kenai Peninsula with somewhat of a
downslope drying for inland locations, although those details are
still not clear this far out.

Southwest...High pressure will keep conditions seasonably mild
and dry across Southwest Alaska through Thursday night. The next
rain chance is Friday as a weak front moves inland, although it
will likely be weakening as it moves inland so chances for wetting
rains do not look high, and will favor Bristol Bay and the lower
Kusko Valley. Widespread rain moves in Sunday and Monday as a
powerful low moves inland.

&&

.SHORT TERM FORECAST SOUTHCENTRAL ALASKA (Days 1 and 2/Wednesday
night through Friday)...

High pressure will hold in place through Friday for most of
Southcentral AK, meaning current conditions will persist for the
mainland. On Friday, a frontal system will begin to move up the
western Gulf of Alaska, impacting Kodiak as it travels northeast.
This will bring the first precipitation to the area in quite some
time.

Smoke from the Swan Lake fire will continue to be the weather
impact for the forecast area. Of note, we are expecting a wind
shift tonight to a southerly flow moving up Turnagain Arm. This is
expected to push smoke from the Kenai into the Anchorage Bowl and
Mat-Su Valleys, increasing smoke density for those locations.
However, it will give places around Seward some reprieve from dense
smoke. As such, we have lifted the dense smoke advisory for Seward
and the eastern Kenai Peninsula. Still expect dense smoke around
Cooper Landing, so a dense smoke advisory remains in effect
there.

&&

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

Mostly cloudy and dry conditions will continue across Southwest
Alaska this evening as the upper level ridge begins to exit the
region eastward through tomorrow afternoon. A front approaching
the Southwest coast Thursday evening will bring a pattern shift
across the region as southeasterly flow and rain moves inland. As
this front weakens, a second feature lifting northward from the
Gulf will bring a stronger band of precipitation to the Bristol
Bay region as it merges with the weakening front Friday afternoon.

&&

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

A front over the central Bering and Aleutians associated with a
low in the western Bering will continue to push eastward through
tomorrow afternoon. A swath of gale force winds are expected
through early Thursday morning, before weakening to small crafts
tomorrow afternoon as it lifts northward on Friday.

While the eastern Bering becomes relatively quiet on Friday
afternoon, the western Bering can expect its first strong storm
system of the season, bringing strong winds and rainfall along its
path. Gale force winds are forecasted as this low approaches the
western Aleutians on Friday afternoon, which will intensify
heading into the extended forecast.

&&

.MARINE (Days 3 through 5: Saturday through Monday)...

By far the primary weather story in the marine forecast is a
strong low near the Aleutians Saturday morning producing
widespread gales across most of the central and eastern Aleutians,
with possible storm force winds south of Adak. Gales will move
north and east with time, moving into Bristol Bay and much of the
eastern Bering by Saturday evening. Any storm force winds on the
Pacific side of the Aleutians should diminish below those
thresholds Sunday morning. The gales will persist over the central
Bering through the Pribilofs southeastward to the southern Alaska
Peninsula into the day Monday. The models are in good agreement
with the low and widespread gales, with a bit less certainty on
exact track and timing of those winds, and also how widespread any
storm force winds will be.

Over the Gulf, any hazardous winds and seas will be associated
with the eastern side of the aforementioned Bering low. Thus,
Saturday looks quiet. Southeasterly winds will gradually increase
with localized gales through southern Shelikof Strait and the
Barren Islands to Kamishak Gap during the day Sunday. When the
leading front reaches the north Gulf Coast on Monday, gale force
easterly winds associated with the barrier jet are possible. Those
winds will diminish Monday night.

&&

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

The weather pattern looks to finally take a turn for the wetter
across Southcentral through the long-term forecast period. The
first chance of rain comes Friday night into Saturday morning.
Unfortunately there is considerable model uncertainty with this
feature. The upper level forcing for the rain, which will be the
primary driver, will be weakening. Whether it weakens as a wave,
or splits into a cutoff low in the Gulf will determine how much
rain gets into Anchorage and points north. For the most part,
rains of 0.05 inches to one quarter inch is decently agreed upon
for the Kenai Peninsula, including over the Swan Lake fire and
other drought-stricken communities. By late Saturday morning, the
rain will shift east to the Gulf coast.

On Sunday, a strong front associated with a strong Bering low
(more on the Bering low below), will move into the Gulf. This will
bring another round of wetting rains to portions of Southcentral.
Light rain will begin very early Sunday morning at Kodiak,
spreading north to the southern Kenai Peninsula by mid-morning.
Heavier rain will spread north and east through the day across
all of Southcentral except the Copper River Basin. Strong
Turnagain Arm winds may make for some downsloping, but at least
initially, some light rain should get into both Anchorage and the
Mat-Su Valleys Sunday afternoon and evening. Downsloping and
splitting energy will end the rain for Anchorage and the Mat
Valley for the day Monday, but some shower activity will still be
around. Meanwhile, the stronger winds and rains will have
competing effects at the Swan Lake fire. A trailing trough behind
the low moves through Tuesday, with more widespread shower
activity across much of Southcentral expected.

Out west, a strong low will be moving into the Aleutians Saturday
morning. The low will produce widespread gales, with potential for
storm force winds to the west and south of the low center on the
Pacific side of the islands. The center will cross the chain west
of Dutch Harbor Saturday evening and slow down as it moves
northeastward to near Kuskokwim Bay over to Nunivak Island by
Monday morning. Associated wetting rain will move into
Southwest Alaska Saturday night, overspreading much of the area on
Sunday. Gusty southeast winds are also expected with the rain.
Thus, in the usual downslope areas, from King Salmon to Iliamna
and the west-facing slopes of the Kuskokwim Mountains, less rain
is expected. Once the winds turn more southerly on Monday, all of
Southwest Alaska will get into light to moderate rain. The winds
turn southwesterly to westerly on Tuesday as the rain generally
diminishes from west to east.

The strong southeasterly winds begin Saturday night in Southwest
Alaska, and will persist into the day on Sunday. Coastal villages
with exposure to the southeast such as Kwigillingok should be on
alert for potential coastal flooding from Saturday night through
Sunday. Strong south to southwest winds and onshore flow in
Bristol Bay may also cause coastal flooding concerns during the
day on Monday. There still remains some uncertainty as to the
exact storm track. If the center moves further west, towards
Nunivak Island, there is potential for a longer period of onshore
winds and potential for coastal flooding concerns in Kuskokwim Bay
and the Kuskokwim Delta coast. In that scenario, concerns in
Bristol Bay would be lessened.

&&

.AFC WATCHES/WARNINGS/ADVISORIES...
PUBLIC...Dense Smoke Advisory 121.
MARINE...Gale Warning 170 173.
FIRE WEATHER...NONE.

&&

SYNOPSIS AND MODEL DISCUSSION...JA
SOUTHCENTRAL ALASKA...BB
SOUTHWEST ALASKA/BERING SEA/ALEUTIANS...AH
MARINE/LONG TERM...JW