Gale Warning 495, NWS Anchorage, AK

549 
FZAK52 PAFC 221018
CWFALU

Coastal Waters Forecast
National Weather Service Anchorage Alaska
218 AM AKDT Tue Sep 22 2020

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.

PKZ199-222345-
218 AM AKDT Tue Sep 22 2020
.SYNOPSIS FOR SOUTHWEST ALASKA+BRISTOL BAY+THE ALASKA
PENINSULA WATERS AND THE ALEUTIAN ISLANDS...

A strong low will persist over the Gulf while high pressure sits
over the western to central Bering Sea through Wed. A Pacific low
will track to 120 nm S of Shemya Wed night at 1006 mb.

$$

PKZ150-222345-
South of the AK Peninsula Sitkinak to Castle Cape-
218 AM AKDT Tue Sep 22 2020

...SMALL CRAFT ADVISORY THROUGH WEDNESDAY...

.TODAY...N wind 30 kt. Seas 11 ft.
.TONIGHT...N wind 30 kt. Seas 11 ft.
.WED...NW wind 25 kt. Seas 10 ft.
.WED NIGHT...NW wind 25 kt. Seas 9 ft.
.THU...NW wind 25 kt. Seas 9 ft.
.FRI...W wind 20 kt. Seas 8 ft.
.SAT...W wind 15 kt. Seas 7 ft.

$$

PKZ155-222345-
South of the AK Peninsula Castle Cape to Cape Sarichef-
218 AM AKDT Tue Sep 22 2020

...GALE WARNING TONIGHT...

.TODAY...NW wind 30 kt. Seas 11 ft.
.TONIGHT...NW wind 35 kt. Seas 11 ft.
.WED...NW wind 30 kt. Seas 10 ft.
.WED NIGHT...NW wind 30 kt. Seas 9 ft.
.THU...NW wind 25 kt. Seas 7 ft.
.FRI THROUGH SAT...W wind 20 kt. Seas 8 ft.

$$

PKZ160-222345-
Bristol Bay-
218 AM AKDT Tue Sep 22 2020

...SMALL CRAFT ADVISORY THROUGH TONIGHT...

.TODAY...N wind 25 kt. Seas 6 ft.
.TONIGHT...N wind 25 kt. Seas 5 ft.
.WED...N wind 20 kt. Seas 5 ft.
.WED NIGHT...N wind 25 kt. Seas 5 ft.
.THU...N wind 20 kt. Seas 4 ft.
.FRI...NW wind 15 kt. Seas 4 ft.
.SAT...NW wind 10 kt. Seas 5 ft.

$$

PKZ165-222345-
Port Heiden to Cape Sarichef-
218 AM AKDT Tue Sep 22 2020

...SMALL CRAFT ADVISORY THROUGH WEDNESDAY...

.TODAY...N wind 30 kt. Seas 10 ft.
.TONIGHT...NW wind 30 kt. Seas 11 ft.
.WED...NW wind 30 kt. Seas 11 ft.
.WED NIGHT...NW wind 25 kt. Seas 9 ft.
.THU THROUGH FRI...NW wind 20 kt. Seas 8 ft.
.SAT...NW wind 25 kt. Seas 9 ft.

$$

PKZ170-222345-
Cape Sarichef to Nikolski Bering Side-
218 AM AKDT Tue Sep 22 2020

...SMALL CRAFT ADVISORY THROUGH WEDNESDAY...

.TODAY...NW wind 30 kt. Seas 12 ft.
.TONIGHT...NW wind 30 kt. Seas 12 ft.
.WED...NW wind 25 kt. Seas 10 ft.
.WED NIGHT...NW wind 20 kt. Seas 7 ft.
.THU...NW wind 20 kt. Seas 5 ft.
.FRI...NW wind 20 kt. Seas 9 ft.
.SAT...NW wind 25 kt. Seas 9 ft.

$$

PKZ171-222345-
Unalaska Bay-
218 AM AKDT Tue Sep 22 2020

...SMALL CRAFT ADVISORY THROUGH TONIGHT...

.TODAY...NW wind 30 kt. Seas 10 ft. Rain showers.
.TONIGHT...NW wind 25 kt. Seas 10 ft.
.WED...NW wind 20 kt. Seas 7 ft.
.WED NIGHT...NW wind 20 kt. Seas 6 ft.
.THU THROUGH SAT...NW wind 15 kt. Seas 4 ft.

$$

PKZ172-222345-
Cape Sarichef to Nikolski Pacific Side-
218 AM AKDT Tue Sep 22 2020

...GALE WARNING TODAY...

.TODAY...NW wind 35 kt. Seas 12 ft.
.TONIGHT...NW wind 30 kt. Seas 10 ft.
.WED...NW wind 25 kt. Seas 7 ft.
.WED NIGHT...NW wind 25 kt. Seas 5 ft.
.THU...NW wind 20 kt. Seas 4 ft.
.FRI THROUGH SAT...NW wind 20 kt. Seas 8 ft.

$$

PKZ173-222345-
Nikolski to Seguam Island Bering Side-
218 AM AKDT Tue Sep 22 2020

...SMALL CRAFT ADVISORY THROUGH TONIGHT...

.TODAY...NW wind 30 kt diminishing to 20 kt in the afternoon. Seas
12 ft.
.TONIGHT...NW wind 20 kt. Seas 9 ft.
.WED...N wind 15 kt. Seas 7 ft.
.WED NIGHT...NW wind 15 kt. Seas 6 ft.
.THU THROUGH FRI...NW wind 15 kt. Seas 7 ft.
.SAT...NW wind 20 kt. Seas 10 ft.

$$

PKZ174-222345-
Nikolski to Seguam Island Pacific Side-
218 AM AKDT Tue Sep 22 2020

...SMALL CRAFT ADVISORY TODAY...

.TODAY...NW wind 30 kt. Seas 11 ft.
.TONIGHT...NW wind 20 kt. Seas 7 ft.
.WED...N wind 15 kt. Seas 5 ft.
.WED NIGHT...NW wind 15 kt. Seas 4 ft.
.THU...NW wind 15 kt. Seas 5 ft.
.FRI...NW wind 15 kt. Seas 10 ft.
.SAT...NW wind 20 kt. Seas 9 ft.

$$

PKZ175-222345-
Seguam Island to Adak Bering Side-
218 AM AKDT Tue Sep 22 2020

...SMALL CRAFT ADVISORY TODAY...

.TODAY...NW wind 25 kt. Seas 10 ft.
.TONIGHT...N wind 15 kt. Seas 7 ft.
.WED...Variable wind 10 kt. Seas 6 ft.
.WED NIGHT...Variable wind 10 kt. Seas 4 ft.
.THU THROUGH FRI...NW wind 15 kt. Seas 5 ft.
.SAT...NW wind 20 kt. Seas 11 ft.

$$

PKZ176-222345-
Seguam Island to Adak Pacific Side-
218 AM AKDT Tue Sep 22 2020

.TODAY...NW wind 20 kt. Seas 7 ft.
.TONIGHT...N wind 15 kt. Seas 6 ft.
.WED...NE wind 15 kt. Seas 4 ft.
.WED NIGHT...Variable wind 10 kt. Seas 4 ft.
.THU THROUGH FRI...W wind 15 kt. Seas 7 ft.
.SAT...NW wind 20 kt. Seas 9 ft.

$$

PKZ177-222345-
Adak to Kiska-
218 AM AKDT Tue Sep 22 2020

.TODAY...E wind 20 kt. Seas 7 ft.
.TONIGHT...E wind 20 kt. Seas 7 ft.
.WED...E wind 20 kt. Seas 7 ft.
.WED NIGHT...SE wind 15 kt. Seas 6 ft.
.THU...NW wind 15 kt. Seas 5 ft.
.FRI...W wind 20 kt. Seas 7 ft.
.SAT...NW wind 25 kt. Seas 10 ft.

$$

PKZ178-222345-
Kiska to Attu-
218 AM AKDT Tue Sep 22 2020

...SMALL CRAFT ADVISORY WEDNESDAY...

.TODAY...E wind 20 kt. Seas 6 ft.
.TONIGHT...E wind 20 kt. Seas 7 ft.
.WED...SE wind 15 kt. Seas 8 ft.
.WED NIGHT...SE wind 20 kt. Seas 7 ft.
.THU...NW wind 20 kt. Seas 6 ft.
.FRI THROUGH SAT...NW wind 30 kt. Seas 10 ft.

$$

PKZ179-222345-
Pribilof Islands Near Shore Waters-
218 AM AKDT Tue Sep 22 2020

...SMALL CRAFT ADVISORY THROUGH TONIGHT...

.TODAY...N wind 25 kt. Seas 9 ft.
.TONIGHT...NW wind 25 kt. Seas 8 ft.
.WED...NW wind 20 kt. Seas 6 ft.
.WED NIGHT...NW wind 15 kt. Seas 5 ft.
.THU...Variable wind 10 kt. Seas 4 ft.
.FRI...N wind 20 kt. Seas 7 ft.
.SAT...NW wind 25 kt. Seas 8 ft.

$$

PKZ180-222345-
Kuskokwim Delta and Etolin Strait-
218 AM AKDT Tue Sep 22 2020

...SMALL CRAFT ADVISORY THROUGH WEDNESDAY...

.TODAY...N wind 30 kt. Seas 8 ft.
.TONIGHT...N wind 30 kt. Seas 8 ft.
.WED...N wind 30 kt. Seas 8 ft.
.WED NIGHT...N wind 25 kt. Seas 7 ft.
.THU THROUGH SAT...NW wind 25 kt. Seas 6 ft.

$$

PKZ181-222345-
North and West of Nunivak Island-
218 AM AKDT Tue Sep 22 2020

...SMALL CRAFT ADVISORY THROUGH WEDNESDAY...

.TODAY...N wind 25 kt. Seas 7 ft.
.TONIGHT...N wind 25 kt. Seas 7 ft.
.WED...N wind 25 kt. Seas 7 ft.
.WED NIGHT...N wind 20 kt. Seas 6 ft.
.THU...N wind 20 kt. Seas 5 ft.
.FRI THROUGH SAT...NW wind 25 kt. Seas 6 ft.

$$

PKZ185-222345-
Saint Matthew Island Waters-
218 AM AKDT Tue Sep 22 2020

.TODAY...N wind 20 kt. Seas 7 ft.
.TONIGHT...NW wind 20 kt. Seas 6 ft.
.WED...NW wind 15 kt. Seas 4 ft.
.WED NIGHT...NW wind 15 kt. Seas 4 ft.
.THU...N wind 15 kt. Seas 4 ft.
.FRI THROUGH SAT...NW wind 25 kt. Seas 8 ft.

$$

Southcentral and Southwest Alaska Forecast Discussion
National Weather Service Anchorage AK
427 AM AKDT Mon Sep 21 2020

.ANALYSIS AND UPPER LEVELS...

On the synoptic scale, the jetstream is fairly zonal (straight-
lined from west to east) between 40N and 50N across the North
Pacific. An upper level low is currently located in the left-exit
region (area that is conducive to storm development) of this jet
over the western AKPEN. This upper low is moving eastward towards
the Gulf of Alaska. Scatterometry (ASCAT) data shows widespread
gale force winds in the eastern Aleutians and along the AKPEN
associated with this low. On the southern flank of this low, ASCAT
data shows winds nearing storm force.

On the mesoscale, radar imagery shows showers moving northwestward
across the northern Gulf of Alaska into Prince William Sound.
There is another area of isolated showers moving northwestward in
Cook Inlet and across the Anchorage Bowl. Over southwest Alaska,
radar imagery shows bands of rain associated with the
aforementioned low moving northeastward across Bristol Bay.

&&

.MODEL DISCUSSION...

Guidance is in good agreement with the placement and intensity of
synoptic scale features. Deterministic models show a similar
pattern to the ensembles with regards to the jetstream remaining
south of the Alaska mainland. Due to the high degree of
consistency, forecast confidence is high. High resolution models
were favored for local effects.

&&

.AVIATION...
PANC...VFR conditions and light winds will persist for this TAF
package. There are a few clouds between 500ft and 1000ft this
morning. Confidence is low that this low cloud deck will become
the ceiling.

&&

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

What is left of the low that had been in the Gulf of Alaska the
past two days is near Middleton Island early this morning and
heading northward. While this low is dissipating, the energy
associated with it will move through Prince William Sound and the
Copper River Basin today bringing some rain to that area. The
passes in the Copper River Basin such as near Eureka, Paxon, and
the eastern Denali Highway may see snow this morning with this
system as temperatures in those areas have dropped below freezing
overnight. Warmer air is moving in with the precipitation, so snow
should not persist, but it could start as snow in those areas.

The next low is in the Aleutians, but the front associated with
it is swinging into the western Gulf today and already bringing
rain to Kodiak Island. This low will be slow to move to the north
Gulf coast, arriving tonight into Tuesday due to the low
undercutting it to the south of the Gulf which will stall its
northward progression. Therefore, from Tuesday through Wednesday,
there will be a bit of rain along the immediate coast. Some
easterly wave may develop in this flow and bring periods of
showers with them, but it is a bit unclear as to timing their
development and movement right now.

&&

.SHORT TERM FORECAST SOUTHWEST ALASKA (Days 1 through 3)...

A frontal system is pivoting over the coastal regions of Bristol
Bay this morning bringing some light rain. Any rain will taper off
by late morning as the front drifts southward. However, as the
front drifts south, a tight pressure gradient will develop
creating breezy conditions for much of Southwest for the next
couple of days. With this wind will come cooler air especially
for the Kuskokwim Delta and Middle Kuskokwim Valley. But with the
wind, this help to keep a mixed atmosphere even though cold air
advection will be ongoing bringing in cooler air. This will
prevent temperatures from falling to freezing and below for valley
areas at night but the higher elevations will have the best
chance of falling to freezing and below. With the colder air mass,
a piece of upper level energy near Kodiak Island will move
northwestward that may send enough moisture over the Alaska Range
into the Middle Kuskokwim Valley for some showers. The highest
elevations of the Alaska Range will most likely be cold enough for
snow.

&&

.SHORT TERM FORECAST BERING SEA/ALEUTIANS (Days 1 through 3)...

A broad low pressure continues moving southeastward this morning
with the center currently moving over Sand Point west to Dutch
Harbor. This low will continue moving out of the area and into the
North Pacific later this morning. As a result, gusty northwesterly
winds and widespread rain showers are expected. A steadier rain is
expected for Dutch Harbor though this morning through Tuesday
morning as a piece of upper level energy rotating around the main
upper level low moves through the area. Winds are also expected to
become quite gusty in and around Dutch Harbor with gusts upwards
of 50 kts or 58 mph possible this afternoon as cold air advection
begins to move through. Wave heights will also remain high today
south of the central to eastern Aleutian in the 20-25 foot range
and 12-18 feet on Bering side. Wave will subside moving into the
overnight hours and early Tuesday morning as the low continues
moving into the North Pacific.

Areas west of Atka will remain relatively dry today as a weak
upper level ridge builds into the region west to Attu Island. The
next weak system moves into the western Aleutians Wednesday
morning with another round of unsettled weather though not nearly
as strong as this last storm.

Lastly, much of the Bering Sea will be enduring weak cold air
advection over the next 3 days becoming slightly colder each day.
This will create an unstable atmospheric profile causing scattered
rain showers over the Bering Sea as well as continued breezy
conditions.

&&

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

The large and complex low over the Gulf on Wednesday will break
down and move onshore over Southeast Alaska on Thursday. There is
high confidence that winds will remain calm over the Gulf through
Friday. Northerly winds over the eastern Bering will subside
throughout the day Wednesday and return to calm conditions
Thursday morning. Models have come to better agreement that the
next storm system will stay south of the Aleutian Chain, resulting
in higher confidence of calm conditions for the Bering through
Friday.

&&

.LONG TERM FORECAST (Days 4 through 7/Thursday through
Sunday)...

The broad longwave trough is expected to continue the fall pattern
for most of the AOR with colder temperatures coming into the
Bering on Friday. The main weather story for the start of the
forecast period is a broad low pressure complex over the Gulf.
Multiple meso-low centers are expected to revolve around one
another in the Gulf through Friday as the system weakens. This
will bring rain to coastal areas of Southcentral, while a series
of upper level vortices provide chances for rain to inland areas
Thursday and Friday.

A slight pattern change will occur by Friday afternoon as a polar
trough drops in over the Bering Strait and into the central Bering
Sea. 850 mb temperatures ranging from -5C to -10C are expected to
move over the Bering through Sunday. This may bring some snow or
mixed precipitation types to the Bering and western Aleutian Chain.
For Southwest this could mean high temperatures in the upper 20s
to low 30s on Friday. Highs should rebound into the 40s by
Saturday as the next storm system moves into Gulf. Model consensus
has improved considerably since yesterday's deterministic runs.
Solutions have trended more toward yesterday's EC run, with a
much weaker system moving quickly east to the south of the
Aleutian Chain on Friday before moving north into Gulf on
Saturday. Guidance still has considerable spread in intensity and
timing of this feature, but it should return heavier rainfall to
coastal areas of Southcentral on Saturday and Sunday.

&&

.AFC WATCHES/WARNINGS/ADVISORIES...
PUBLIC...NONE.
MARINE...Storm Warning 119 120 131.
Gale Warning 130 132 138 139 351 352 155 160 170 171 172 173 174 180 414.
FIRE WEATHER...NONE.

&&

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