Small Craft Advisory 225, NWS Anchorage, AK

985 
FZAK52 PAFC 162346
CWFALU

Coastal Waters Forecast
National Weather Service Anchorage Alaska
346 PM AKDT Tue Mar 16 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.

PKZ199-171230-
346 PM AKDT Tue Mar 16 2021
.SYNOPSIS FOR SOUTHWEST ALASKA+BRISTOL BAY+THE ALASKA
PENINSULA WATERS AND THE ALEUTIAN ISLANDS...

A 1007 mb low 65 nm Southwest of Gambell moves over St Michael at
999 mb then inland on Wed. A 986 mb low 220 nm Southwest of Attu 
moves to 425 nm Southwest of Attu at 987 mb Thu afternoon. Its front
moves over the Aleutians to the Alaskan Peninsula through Thu 
afternoon.

$$

PKZ150-171230-
South of the AK Peninsula Sitkinak to Castle Cape-
346 PM AKDT Tue Mar 16 2021

...SMALL CRAFT ADVISORY THROUGH WEDNESDAY NIGHT...

.TONIGHT...NW wind 25 kt. Seas 8 ft. Freezing spray.
.WED...NW wind 25 kt. Seas 7 ft. Freezing spray.
.WED NIGHT...W wind 25 kt. Seas 6 ft. Freezing spray.
.THU AND THU NIGHT...NW wind 20 kt. Seas 6 ft.
.FRI...SE wind 20 kt. Seas 7 ft.
.SAT...NW wind 20 kt. Seas 10 ft.
.SUN...NW wind 25 kt. Seas 10 ft.

$$

PKZ155-171230-
South of the AK Peninsula Castle Cape to Cape Sarichef-
346 PM AKDT Tue Mar 16 2021

...SMALL CRAFT ADVISORY TONIGHT...

.TONIGHT...NW wind 20 kt. Seas 8 ft.
.WED...W wind 20 kt. Seas 5 ft.
.WED NIGHT...SW wind 20 kt. Seas 4 ft.
.THU...S wind 15 kt. Seas 7 ft.
.THU NIGHT...S wind 20 kt. Seas 8 ft.
.FRI...SW wind 25 kt. Seas 9 ft.
.SAT...W wind 20 kt. Seas 10 ft.
.SUN...NW wind 30 kt. Seas 10 ft.

$$

PKZ160-171230-
Bristol Bay-
346 PM AKDT Tue Mar 16 2021

...HEAVY FREEZING SPRAY WARNING WEDNESDAY NIGHT...
...SMALL CRAFT ADVISORY WEDNESDAY AND WEDNESDAY NIGHT...

.TONIGHT...NW wind 20 kt. Seas in ice free waters 6 ft. Freezing
spray.
.WED...W wind 25 kt. Seas in ice free waters 7 ft. Freezing spray.
.WED NIGHT...W wind 25 kt becoming NW 15 kt after midnight. Seas
in ice free waters 7 ft. Heavy freezing spray.
.THU...N wind 15 kt. Seas in ice free waters 4 ft.
.THU NIGHT...NE wind 20 kt. Seas in ice free waters 3 ft.
.FRI...NE wind 30 kt. Seas in ice free waters 4 ft.
.SAT...N wind 20 kt. Seas in ice free waters 3 ft.
.SUN...NW wind 25 kt. Seas in ice free waters 6 ft.

$$

PKZ165-171230-
Port Heiden to Cape Sarichef-
346 PM AKDT Tue Mar 16 2021

.TONIGHT...NW wind 20 kt. Seas 7 ft. Freezing spray.
.WED...W wind 20 kt. Seas 5 ft. Freezing spray.
.WED NIGHT...Variable wind 10 kt. From Port Moller E, W wind 20 kt
in the evening becoming variable 10 kt. Seas 5 ft. Freezing spray.
.THU...NE wind 15 kt. Seas 4 ft.
.THU NIGHT...SE wind 20 kt. Seas 4 ft.
.FRI...SE wind 25 kt. Seas 5 ft.
.SAT...NW wind 20 kt. Seas 6 ft.
.SUN...NW wind 30 kt. Seas 9 ft.

$$

PKZ170-171230-
Cape Sarichef to Nikolski Bering Side-
346 PM AKDT Tue Mar 16 2021

.TONIGHT...Variable wind 10 kt becoming S 15 kt after midnight.
Seas 7 ft.
.WED...S wind 20 kt. Seas 5 ft.
.WED NIGHT...SE wind 15 kt. Seas 4 ft.
.THU...S wind 20 kt. Seas 4 ft.
.THU NIGHT...S wind 25 kt. Seas 7 ft.
.FRI...W wind 25 kt. Seas 7 ft.
.SAT...NW wind 15 kt. Seas 8 ft.
.SUN...N wind 35 kt. Seas 10 ft.

$$

PKZ171-171230-
Unalaska Bay-
346 PM AKDT Tue Mar 16 2021

.TONIGHT...NW wind 10 kt in the evening becoming variable less
than 10 kt. Seas 3 ft.
.WED...Variable wind less than 10 kt becoming S 10 kt in the
afternoon. Seas 2 ft.
.WED NIGHT...SE wind 10 kt. Seas 2 ft. Rain and snow.
.THU AND THU NIGHT...S wind 15 kt. Seas 2 ft.
.FRI...SW wind 15 kt. Seas 2 ft.
.SAT...W wind 10 kt. Seas 3 ft.
.SUN...NW wind 25 kt. Seas 8 ft.

$$

PKZ172-171230-
Cape Sarichef to Nikolski Pacific Side-
346 PM AKDT Tue Mar 16 2021

.TONIGHT...NW wind 15 kt becoming SW after midnight. Seas 6 ft.
.WED...S wind 20 kt. Seas 6 ft.
.WED NIGHT...SE wind 20 kt in the evening becoming variable 10 kt.
Seas 7 ft. Rain and snow.
.THU...S wind 20 kt. Seas 9 ft.
.THU NIGHT...S wind 25 kt. Seas 9 ft.
.FRI THROUGH SAT...W wind 25 kt. Seas 11 ft.
.SUN...NW wind 35 kt. Seas 11 ft.

$$

PKZ173-171230-
Nikolski to Seguam Island Bering Side-
346 PM AKDT Tue Mar 16 2021

...SMALL CRAFT ADVISORY THROUGH WEDNESDAY...

.TONIGHT...S wind 25 kt. Seas 7 ft.
.WED...SE wind 25 kt. Seas 7 ft. Rain and snow.
.WED NIGHT...S wind 15 kt. Seas 6 ft.
.THU...S wind 20 kt. Seas 6 ft.
.THU NIGHT...SW wind 25 kt. Seas 8 ft.
.FRI...SW wind 20 kt. Seas 7 ft.
.SAT...NW wind 15 kt. Seas 8 ft.
.SUN...N wind 30 kt. Seas 10 ft.

$$

PKZ174-171230-
Nikolski to Seguam Island Pacific Side-
346 PM AKDT Tue Mar 16 2021

...SMALL CRAFT ADVISORY THROUGH WEDNESDAY NIGHT...

.TONIGHT...S wind 25 kt. Seas 6 ft.
.WED...SE wind 25 kt. Seas 8 ft. Rain and snow.
.WED NIGHT...SW wind 20 kt. Seas 10 ft.
.THU...SW wind 20 kt. Seas 10 ft.
.THU NIGHT...SW wind 25 kt. Seas 11 ft.
.FRI THROUGH SAT...W wind 30 kt. Seas 11 ft.
.SUN...NW wind 35 kt. Seas 10 ft.

$$

PKZ175-171230-
Seguam Island to Adak Bering Side-
346 PM AKDT Tue Mar 16 2021

...SMALL CRAFT ADVISORY THROUGH WEDNESDAY...

.TONIGHT...SE wind 30 kt. Seas 8 ft. Rain and snow.
.WED...SE wind 25 kt. Seas 7 ft. Rain.
.WED NIGHT...S wind 20 kt. Seas 5 ft.
.THU...S wind 20 kt. Seas 6 ft.
.THU NIGHT...SW wind 25 kt. Seas 6 ft.
.FRI...SW wind 20 kt. Seas 6 ft.
.SAT...NW wind 20 kt. Seas 8 ft.
.SUN...N wind 30 kt. Seas 9 ft.

$$

PKZ176-171230-
Seguam Island to Adak Pacific Side-
346 PM AKDT Tue Mar 16 2021

...SMALL CRAFT ADVISORY THROUGH WEDNESDAY NIGHT...

.TONIGHT...SE wind 30 kt. Seas 10 ft. Rain and snow.
.WED...S wind 25 kt. Seas 11 ft.
.WED NIGHT...SW wind 20 kt. Seas 11 ft.
.THU AND THU NIGHT...SW wind 25 kt. Seas 11 ft.
.FRI THROUGH SAT...SW wind 30 kt. Seas 11 ft.
.SUN...NW wind 30 kt. Seas 8 ft.

$$

PKZ177-171230-
Adak to Kiska-
346 PM AKDT Tue Mar 16 2021

...GALE WARNING TONIGHT...

.TONIGHT...SE wind 35 kt. Seas 12 ft. Rain and snow.
.WED...SW wind 20 kt. Seas 12 ft.
.WED NIGHT...S wind 25 kt. Seas 12 ft.
.THU AND THU NIGHT...SW wind 25 kt. Seas 11 ft.
.FRI...SW wind 25 kt. Seas 11 ft.
.SAT...NW wind 20 kt. Seas 10 ft.
.SUN...NW wind 25 kt. Seas 10 ft.

$$

PKZ178-171230-
Kiska to Attu-
346 PM AKDT Tue Mar 16 2021

...GALE WARNING TONIGHT...

.TONIGHT...SE wind 40 kt becoming S 30 kt after midnight. Seas
18 ft. Rain and snow.
.WED...S wind 20 kt. Seas 14 ft.
.WED NIGHT...S wind 30 kt. Seas 12 ft. Rain showers.
.THU AND THU NIGHT...SW wind 25 kt. Seas 12 ft.
.FRI...NW wind 25 kt. Seas 11 ft.
.SAT...N wind 20 kt. Seas 11 ft.
.SUN...NW wind 25 kt. Seas 10 ft.

$$

PKZ179-171230-
Pribilof Islands Near Shore Waters-
346 PM AKDT Tue Mar 16 2021

.TONIGHT...SW wind 15 kt. Seas 6 ft. Freezing spray.
.WED...SW wind 15 kt. Seas 4 ft. Freezing spray.
.WED NIGHT...E wind 20 kt. Seas 5 ft.
.THU AND THU NIGHT...SE wind 30 kt. Seas 8 ft.
.FRI...W wind 20 kt. Seas 9 ft.
.SAT...N wind 20 kt. Seas 9 ft.
.SUN...N wind 30 kt. Seas 9 ft.

$$

PKZ180-171230-
Kuskokwim Delta and Etolin Strait-
346 PM AKDT Tue Mar 16 2021

...HEAVY FREEZING SPRAY WARNING WEDNESDAY AND WEDNESDAY NIGHT...
...SMALL CRAFT ADVISORY THROUGH WEDNESDAY...

.TONIGHT...W wind 25 kt. Seas in ice free waters 5 ft. Freezing
spray.
.WED...W wind 25 kt. Seas in ice free waters 6 ft. Heavy freezing
spray.
.WED NIGHT...N wind 15 kt. Seas in ice free waters 5 ft. Heavy
freezing spray.
.THU...NE wind 15 kt. Seas in ice free waters 3 ft.
.THU NIGHT...E wind 25 kt. Seas in ice free waters 4 ft.
.FRI...E wind 35 kt. Seas in ice free waters 9 ft.
.SAT...N wind 20 kt. Seas in ice free waters 6 ft.
.SUN...NW wind 30 kt. Seas in ice free waters 7 ft.

$$

PKZ181-171230-
North and West of Nunivak Island-
346 PM AKDT Tue Mar 16 2021

...HEAVY FREEZING SPRAY WARNING THROUGH WEDNESDAY NIGHT...
...BRISK WIND ADVISORY TONIGHT...

.TONIGHT...SW wind 25 kt. Heavy freezing spray. Snow.
.WED...NW wind 20 kt. Heavy freezing spray.
.WED NIGHT...N wind 15 kt. Heavy freezing spray.
.THU...NE wind 15 kt.
.THU NIGHT...E wind 30 kt.
.FRI...NE wind 30 kt.
.SAT...N wind 20 kt.
.SUN...NW wind 30 kt.

$$

PKZ185-171230-
Saint Matthew Island Waters-
346 PM AKDT Tue Mar 16 2021

...HEAVY FREEZING SPRAY WARNING THROUGH WEDNESDAY NIGHT...
...SMALL CRAFT ADVISORY THROUGH WEDNESDAY NIGHT...

.TONIGHT...W wind 25 kt. Seas 7 ft. Heavy freezing spray.
.WED...N wind 15 kt E of Saint Matthew Island... NE 25 kt W of
Saint Matthew Island. Seas 6 ft. Heavy freezing spray.
.WED NIGHT...NE wind 20 kt E of Saint Matthew Island...NE 30 kt W
of Saint Matthew Island. Seas 7 ft. Heavy freezing spray.
.THU...E wind 35 kt. Seas 10 ft.
.THU NIGHT...E wind 35 kt. Seas 15 ft.
.FRI...NE wind 35 kt. Seas 15 ft.
.SAT...N wind 25 kt. Seas 10 ft.
.SUN...NW wind 25 kt. Seas 6 ft.

$$

Southcentral and Southwest Alaska Forecast Discussion
National Weather Service Anchorage AK
504 PM AKDT Mon Mar 15 2021

.ANALYSIS AND UPPER LEVELS...

In the upper levels, a complex pattern has set up with a broad,
longwave trough with embedded shortwaves moving over the
Bering/Aleutians, AKPEN, and Southern Mainland. Coupled with a
cold, northwesterly flow aloft and interacting with the
relatively warm waters, these shortwaves are bringing widespread,
convective snow showers over parts of the Aleutian Chain, Pribilof
Islands, and Coastal Southwest AK. Further west, a high amplitude
ridge extends along its axis from the North Pacific, western
Bearing Sea, and into eastern Siberia. The Nighttime Microphysics
this morning showed the Southwest and AKPEN completely blanketed
with low fog/stratus with many stations reporting a reduction in
ceiling and visibility.

At the surface, a rapidly, intensifying low with a well defined
circulation and wrap-around moisture is currently moving
southeastward of Sand Point. Additionally, a Gulf low that has
been responsible for spreading snow showers over much Southcentral
since early this morning is slowly weakening as it moves onshore
in the vicinity of the Copper River Delta. The 12Z ANC sounding
has an impressive steep, moist profile above the warm nose at 1,500
feet, with variable winds near the boundary layer and increasing,
southeasterly winds aloft.

&&

.MODEL DISCUSSION...

Models are overall in good agreement with the synoptic scale
features and still on track for continued snow showers today
associated with the aforementioned Gulf low with conditions
improving tomorrow over the Southern Mainland. Moreover, model
solutions are in agreement with a low and associated front moving
toward the western Aleutians on Tuesday, and a transient shortwave
and associated surface low moving southeastward toward coastal
Southwest AK on Wednesday.

&&

.AVIATION...

PANC...Light snow is expected to continue through Tuesday morning
with generally IFR ceilings and visibility. A few breaks in the
cloud cover and precipitation are possible this afternoon through
this evening which could allow for some improvement to MVFR
conditions. However, steadier snow is expected to move back over
the terminal by later this evening, continuing through Tuesday
morning before tapering to flurries.

&&

.SHORT TERM FORECAST SOUTHCENTRAL ALASKA (Days 1 through 3:
Tonight through Thursday night)...

Snow will persist into early this evening, with the weather
conditions improving later tonight into Tuesday morning over much
of Southcentral. A weakening low over Prince William Sound (PWS)
combined with a shortwave aloft will continue to produce snow
showers, particularly for eastern Prince William Sound. As this
low dissipates Tuesday afternoon, it transitions into a surface
trough mainly over the eastern end of PWS with very minimal to no
effects over Cordova and Valdez.

A developing stacked low will move over the northern Gulf between
Wednesday night and Thursday morning. This combined feature may
stay farther south of PWS but it could also induce a bit of
weather to move near Cordova by Thursday morning. Upper level
wind direction at 500 mb seems to disagree for the first 24 hour-
period in response to the upper low, but by Wednesday morning,
model solutions all come into agreement on direction and speed.
The cold air advection will remain present over the area, but not
significantly strong for most areas. Strong northwest winds at
850 mb extends from Susitna Valley through Kenai Peninsula into
Wednesday morning. The -20 degrees Celsius (at 850 mb) will spread
east of Talkeetna Tuesday night, then spreading southeast toward
Thompson Pass through Wednesday morning. Colder temperatures will
settle in across nearly all of Southcentral. Diurnal ranges will
be fairly large due to the rapid increase in amount of daylight,
but temperatures will remain below normal for this time of year.

&&

.SHORT TERM FORECAST SOUTHWEST ALASKA (Days 1 through 3: Monday
afternoon through Thursday)...

A broad upper level trough in place over much of the mainland is
keeping active weather across Southwest. A weakening low centered
south of the Alaska Peninsula is keeping snow showers in place
across the southern AKPEN. Snow will taper off this evening as
the low gradually moves southward. Meanwhile across the Bristol
Bay coast, persistent fog this morning has lifted to stratus, and
will likely stick around during the overnight hours. Patchy fog
can be expected along coastal locations again for Tuesday morning.

Lingering snow showers across the Kuskokwim Delta will eventually
diminish by the evening hours tonight. By Tuesday night, a
shortwave trough moves in from the north, bringing a quick shot of
snow and gusty northerly winds. A brief period of blowing snow
with limited visibility are possible Tuesday night through early
Wednesday morning. As this shortwave quickly moves southeastward,
a quick burst of snowfall is expected with a couple inches
possible across higher elevations, especially over the Kilbuck
Mountains. By Thursday morning, quieter conditions are expected
across the region, ahead of an incoming front arriving by the end
of the work-week.

&&

.SHORT TERM FORECAST BERING SEA/ALEUTIANS (Days 1 through 3:
Monday afternoon through Thursday)...

Northwesterly flow and a showery pattern will continue across much
of the Bering as an upper level ridge in place over the western
Aleutians gradually builds in. Snow showers will persist for much
of the central and eastern Aleutians and Pribilofs tonight before
diminishing early Tuesday morning. Fair conditions are expected
across the Bering waters with the ridge in place Tuesday. By
Tuesday night, another front approaches the western Aleutians.
Warmer southerly flow and rain will spread in from west to east
across the Chain as the front reaches the central Bering Wednesday
afternoon and weakens considerably. By Wednesday night, model
solutions suggest a reinforcing upper level low arrives over the
western Bering. This stronger low will likely phase with the
weaker one, and will send a stronger front eastward by the end of
the week.

&&

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

Gulf: A low moves across the Northern Gulf and dissipates Sat.
Forecast confidence is good. Widespread small craft winds and
waves south of the low move across the Gulf, dissipating Fri. Gale
force gap winds exit into the Gulf from the Barren Islands and
Sitkinak areas, and dissipate Fri as the low moves east. A new
front approaches the Southwest Gulf late Fri into Sat.

Bering: A Western Bering low moves to the Central Bering by Sat.
Its front extends through the Eastern Bering and Alaska Peninsula
through Sat. Forecast confidence is good. Widespread high end
small craft winds and waves with areas of gale force winds
wrapping the low and front across the Bering through Sat. Winds
dissipate south of the low and front, but remain across the
Northern Bering through Sat. Seas to 22 feet over the Western
Bering, 18 feet on the Pacific side, subsiding through Sat.

&&

.LONG TERM FORECAST (Days 4 through 7)...

The long term forecast begins late Thursday with a persistent
broad trough over much of Mainland Alaska. Meanwhile, a ridge
situated over the eastern Bering and Southwest AK coast begins to
breakdown as a low moves east across the Aleutian Chain. By
Sunday, models diverge greatly as to how far eastward this system
progresses and how it interacts with the aforementioned ridge. The
GFS pushes this system into the southern Gulf by Sunday while the
EC and GEM keep the low farther west, with some semblance of a
ridge remaining in place. The GEM goes so far as to establish an
omega block, with an amplified ridge extending to the Chukchi
Sea. The latter solutions would allow a second shortwave to move
underneath the aforementioned Aleutian low and steer it north into
the Gulf by Monday. The GFS collapses the ridge by dropping a
shortwave southeast from the northern Bering. The interesting
thing of note, is that while these solutions are different in the
evolution of the shortwaves through the weekend, they are
convergent on the solution of the upper-level trough re-establishing
itself over the state with an amplified ridge over the Bering by
the start of next week. In terms of sensible weather, the EC and
GEM would keep conditions cooler and drier over the Southern
Mainland through the weekend, while the GFS would allow for some
precipitation to develop from the AKPEN east across Bristol Bay
and perhaps the immediate Southcentral coast beginning Saturday.

&&

.AFC WATCHES/WARNINGS/ADVISORIES...
PUBLIC...NONE.
MARINE...Gale Warning 130 138 177 178.
         Heavy Freezing Spray Warning 121 130 139 180 181 185.
FIRE WEATHER...NONE.

&&

SYNOPSIS AND MODEL DISCUSSION...MF
SOUTHCENTRAL ALASKA...CB
SOUTHWEST ALASKA/BERING SEA/ALEUTIANS...KO
MARINE/LONG TERM...MK/TM

SPECIAL WEATHER STATEMENT
National Weather Service ANCHORAGE AK
423 AM AKDT Tue Mar 16 2021

AKZ155-170100-
Kuskokwim Delta-
Including the cities of Bethel, Hooper Bay, and Nunivak Island
423 AM AKDT Tue Mar 16 2021

...BRIEF PERIOD OF SNOW AND BLOWING SNOW WEDNESDAY MORNING...

A fast moving front is expected to move south from Norton Sound
early Wednesday morning. Westerly winds up to 25 mph with gusts to
40 mph combined with snow will reduce visibility to one half mile
at times. These conditions are not expected to last more than 2 to 3
hours at any one location. The front is expected to reach Hooper
Bay around 2 am and move south of Quinhagak by 10 am. Snow
accumulation up to 2 inches is expected. Northerly winds up 20 mph
behind the front may cause areas of blowing snow through the
afternoon.