Storm Warning 80, NWS Anchorage, AK

360 
FZAK61 PAFC 261157
OFFAER

Offshore Waters Forecast
National Weather Service Anchorage AK
357 AM AKDT Sat Sep 26 2020

Offshore waters forecast for the Gulf of Alaska West of 144W

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.

PKZ399-270045-
357 AM AKDT Sat Sep 26 2020
.SYNOPSIS FOR THE WESTERN GULF OF ALASKA...

A 996 mb low at 58N 148W moves to 59N 152W Sat afternoon at 998 mb and
dissipates. A 965 mb low at 54N 149W moves to 60N 145W at 989 mb
by Sun night.

$$

PKZ351-270045-
Gulf of Alaska Offshore North of 57N and West of 144W-
357 AM AKDT Sat Sep 26 2020

...STORM WARNING TONIGHT...

.TODAY...W wind up to 20 kt becoming SE in the afternoon. Seas 4 to 
7 ft.
.TONIGHT...SE wind 15 to 30 kt becoming E 40 to 55 kt after
midnight. Gusts to 65 kt after midnight. Seas 4 to 8 ft building to 
11 to 19 ft after midnight. Rain.
.SUN...SE wind 25 to 40 kt becoming SW 20 to 35 kt in the afternoon.
Seas 15 to 23 ft. Rain.
.SUN NIGHT...SW wind 35 to 50 kt. Seas 19 to 34 ft.
.MON...S wind 20 to 35 kt. Seas 13 to 21 ft.
.TUE...E wind 25 to 40 kt. Seas 9 to 17 ft.
.WED...SE wind 30 kt. Seas 15 to 19 ft.

$$

PKZ352-270045-
Gulf of Alaska Offshore South of 57N North of 55N and West of
144W-
357 AM AKDT Sat Sep 26 2020

...STORM WARNING TONIGHT AND SUNDAY...

.TODAY...W wind 10 to 20 kt becoming SE. Seas 5 to 9 ft.
.TONIGHT...SE wind 35 to 50 kt. Seas 8 to 16 ft. Rain.
.SUN...SW wind 25 to 40 kt increasing to 35 to 50 kt in the
afternoon. Gusts to 65 kt in the afternoon. Seas 15 to 23 ft 
building to 21 to 36 ft in the afternoon. Rain.
.SUN NIGHT...SW wind 35 to 50 kt. Seas 19 to 34 ft.
.MON...SE wind 15 to 30 kt. Seas 11 to 19 ft.
.TUE...E wind 20 to 35 kt. Seas 9 to 17 ft.
.WED...S wind 30 kt. Seas 16 to 20 ft.

$$

068 
FZAK61 PAFC 262300
OFFAER

Offshore Waters Forecast
National Weather Service Anchorage AK
300 PM AKDT Sat Sep 26 2020

Offshore waters forecast for the Gulf of Alaska West of 144W

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.

PKZ399-271400-
300 PM AKDT Sat Sep 26 2020
.SYNOPSIS FOR THE WESTERN GULF OF ALASKA...

A 965 mb North Pacific low moves to 55N 147W Sun morning at 962 
mb. The low then moves to 60N 146W Sun night at 978 mb before 
heading onshore and dissipating early Mon.

$$

PKZ351-271400-
Gulf of Alaska Offshore North of 57N and West of 144W-
300 PM AKDT Sat Sep 26 2020

...STORM WARNING TONIGHT AND SUNDAY NIGHT...

.TONIGHT...SE wind 15 to 30 kt becoming E 35 to 50 kt after
midnight. Seas 4 to 8 ft building to 10 to 18 ft after midnight.
Rain.
.SUN...SE wind 25 to 40 kt becoming SW 20 to 35 kt in the
afternoon. Seas 14 to 22 ft. Rain.
.SUN NIGHT...SW wind 35 to 50 kt. Seas 19 to 32 ft. Rain.
.MON...SW wind 20 to 35 kt. Seas 14 to 27 ft.
.MON NIGHT...SE wind 10 to 20 kt. Seas 9 to 14 ft.
.TUE...E wind 25 to 40 kt. Seas 9 to 17 ft.
.WED THROUGH THU...SE wind 20 to 30 kt. Seas 12 to 19 ft.

$$

PKZ352-271400-
Gulf of Alaska Offshore South of 57N North of 55N and West of
144W-
300 PM AKDT Sat Sep 26 2020

...STORM WARNING THROUGH SUNDAY NIGHT...

.TONIGHT...E wind 35 to 50 kt becoming S 20 to 35 kt late. 
Seas 9 to 14 ft. Rain.
.SUN...SW wind 25 to 40 kt increasing to 40 to 55 kt in the
afternoon. Seas 13 to 21 ft building to 20 to 33 ft in the
afternoon. Rain.
.SUN NIGHT...SW wind 35 to 50 kt. Seas 18 to 33 ft.
.MON...SW wind 15 to 30 kt. Seas 12 to 20 ft.
.MON NIGHT...SE wind 10 to 25 kt. Seas 8 to 13 ft.
.TUE...E wind 25 to 35 kt. Seas 10 to 18 ft.
.WED THROUGH THU...SE wind 30 kt. Seas 14 to 20 ft.

$$

070 
FZAK61 PAFC 271209
OFFAER

Offshore Waters Forecast
National Weather Service Anchorage AK
409 AM AKDT Sun Sep 27 2020

Offshore waters forecast for the Gulf of Alaska West of 144W

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.

PKZ399-280130-
409 AM AKDT Sun Sep 27 2020
.SYNOPSIS FOR THE WESTERN GULF OF ALASKA...

A 961 mb low at 53N 150W and moves to 60N 147W at 986 mb Monday
morning. A front approaches the southern Gulf Tuesday morning.

$$

PKZ351-280130-
Gulf of Alaska Offshore North of 57N and West of 144W-
409 AM AKDT Sun Sep 27 2020

...STORM WARNING TONIGHT...

.TODAY...SE wind 30 to 45 kt diminishing to 10 to 25 kt in the
afternoon. Seas 13 to 21 ft. Rain.
.TONIGHT...SW wind 25 to 40 kt increasing to 35 to 50 kt with gusts
to 60 kt after midnight. Seas 19 to 31 ft. Rain.
.MON...SW wind 25 to 40 kt diminishing to 20 to 30 kt in the
afternoon. Seas 15 to 28 ft.
.MON NIGHT...SE wind 10 to 20 kt. Seas 9 to 15 ft.
.TUE...E wind 30 to 45 kt. Seas 10 to 18 ft.
.WED THROUGH THU...SE wind 25 to 40 kt. Seas 12 to 19 ft.

$$

PKZ352-280130-
Gulf of Alaska Offshore South of 57N North of 55N and West of
144W-
409 AM AKDT Sun Sep 27 2020

...STORM WARNING THROUGH TONIGHT...

.TODAY...SE wind 20 to 35 kt becoming SW 35 to 50 kt with gusts to 65
kt in the afternoon. Seas 12 to 20 ft building to 17 to 31 ft in the
afternoon. Rain.
.TONIGHT...SW wind 35 to 50 kt with gusts to 60 kt. Seas 18 to 33 
ft.
.MON...SW wind 20 to 35 kt diminishing to 10 to 25 kt in the
afternoon. Seas 13 to 21 ft.
.MON NIGHT...SE wind up to 20 kt. Seas 8 to 13 ft.
.TUE...E wind 35 to 50 kt. Seas 9 to 17 ft.
.WED THROUGH THU...SE wind 25 to 35 kt. Seas 12 to 20 ft.

$$

401 
FZAK61 PAFC 271818 AAA
OFFAER

Offshore Waters Forecast...UPDATED
National Weather Service Anchorage AK
1018 AM AKDT Sun Sep 27 2020

Updated zones 351 and 352

Offshore Waters Forecast for the Gulf of Alaska West of 144W

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.

PKZ399-280330-
1018 AM AKDT Sun Sep 27 2020
.SYNOPSIS FOR THE WESTERN GULF OF ALASKA...

A 961 mb low at 53N 150W and moves to 60N 147W at 986 mb Monday
morning. A front approaches the southern Gulf Tuesday morning.

$$

PKZ351-280330-
Gulf of Alaska Offshore North of 57N and West of 144W-
1018 AM AKDT Sun Sep 27 2020

...STORM WARNING TONIGHT...

.TODAY...SE wind 30 to 45 kt diminishing to 10 to 25 kt in the
afternoon. Seas 13 to 21 ft. Showers with isolated thunderstorms.
.TONIGHT...SW wind 25 to 40 kt increasing to 35 to 50 kt with
gusts to 60 kt after midnight. Seas 19 to 31 ft. Showers with
isolated thunderstorms in the evening.
.MON...SW wind 25 to 40 kt diminishing to 20 to 30 kt in the
afternoon. Seas 15 to 28 ft. 
.MON NIGHT...SE wind 10 to 20 kt. Seas 9 to 15 ft. 
.TUE...E wind 30 to 45 kt. Seas 10 to 18 ft. 
.WED THROUGH THU...SE wind 25 to 40 kt. Seas 12 to 19 ft.

$$

PKZ352-280330-
Gulf of Alaska Offshore South of 57N North of 55N and West of
144W-
1018 AM AKDT Sun Sep 27 2020

...STORM WARNING THROUGH TONIGHT...

.TODAY...SE wind 20 to 35 kt becoming SW 35 to 50 kt with gusts
to 65 kt in the afternoon. Seas 12 to 20 ft building to 17 to
31 ft in the afternoon. Showers with isolated thunderstorms.
.TONIGHT...SW wind 35 to 50 kt with gusts to 60 kt. Seas 18 to
33 ft. Showers with isolated thunderstorms in the evening.
.MON...SW wind 20 to 35 kt diminishing to 10 to 25 kt in the
afternoon. Seas 13 to 21 ft. 
.MON NIGHT...SE wind up to 20 kt. Seas 8 to 13 ft. 
.TUE...E wind 35 to 50 kt. Seas 9 to 17 ft. 
.WED THROUGH THU...SE wind 25 to 35 kt. Seas 12 to 20 ft.

$$

294 
FZAK61 PAFC 280003
OFFAER

Offshore Waters Forecast
National Weather Service Anchorage AK
403 PM AKDT Sun Sep 27 2020

Offshore waters forecast for the Gulf of Alaska West of 144W

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.

PKZ399-281245-
403 PM AKDT Sun Sep 27 2020

.SYNOPSIS FOR THE WESTERN GULF OF ALASKA...

A 967 mb low at 57N 146W moves to 60N 147W at 990 mb Monday morning. 
This low then moves inland and dissipates Monday afternoon. A front 
approaches the southern Gulf of Alaska Tuesday afternoon.

$$

PKZ351-281245-
Gulf of Alaska Offshore North of 57N and West of 144W-
403 PM AKDT Sun Sep 27 2020

...GALE WARNING THROUGH MONDAY...

.TONIGHT...SW wind 20 to 35 kt increasing to 30 to 45 kt after
midnight. Seas 19 to 31 ft. Showers with isolated thunderstorms.
.MON...SW wind 25 to 40 kt diminishing to 20 to 30 kt in the
afternoon. Seas 15 to 28 ft.
.MON NIGHT...SE wind 10 to 20 kt. Seas 9 to 15 ft.
.TUE...E wind 25 to 40 kt. Seas 8 to 12 ft.
.TUE NIGHT...E wind 30 to 45 kt. Seas 12 to 20 ft.
.WED...SE wind 25 to 40 kt. Seas 16 to 20 ft.
.THU THROUGH FRI...SE wind 20 to 30 kt. Seas 12 to 18 ft.

$$

PKZ352-281245-
Gulf of Alaska Offshore South of 57N North of 55N and West of
144W-
403 PM AKDT Sun Sep 27 2020

...GALE WARNING THROUGH MONDAY...

.TONIGHT...SW wind 30 to 45 kt. Seas 18 to 33 ft. Showers with
isolated thunderstorms.
.MON...SW wind 25 to 35 kt diminishing to 10 to 25 kt in the
afternoon. Seas 13 to 21 ft.
.MON NIGHT...S wind up to 15 kt becoming E 10 to 25 kt after
midnight. Seas 8 to 13 ft.
.TUE...E wind 30 to 45 kt. Seas 8 to 16 ft.
.TUE NIGHT...SE wind 30 to 45 kt. Seas 15 to 19 ft.
.WED THROUGH FRI...S wind 20 to 35 kt. Seas 12 to 20 ft.

$$

Southcentral and Southwest Alaska Forecast Discussion
National Weather Service Anchorage AK
524 AM AKDT Fri Sep 25 2020

.ANALYSIS AND UPPER LEVELS...

Looking at the current satellite and water vapor imagery, the jet
stream remains far off to the south of Alaska with the core of the
energy being aimed at southern British Columbia and the northwest
United States. As a result, a broad longwave trough is currently
in place across much of Alaska with little waves of upper level
energy embedded within this longwave trough. No significant upper
level shortwaves are present. This is resulting in low ceilings
currently across the Anchorage Bowl and the Kenai Peninsula with
occasional showers from time to time. More rigorous showers were
observed south of Cordova moving westward towards Prince William
Sound this morning. Patchy fog has also been observed around the
Anchorage Bowl especially Birchwood where visibility dropped to
1/4 to 1/2 mile at times. Gulkana and some areas in the Copper
River Basin and Palmer in the Matanuska Valley also observed some
time periods of fog. With the persistence of the pattern in place,
expect this to linger around for a time this morning.

Further west, the weather remains quiet with general northerly
flow across Southwest keeping the area mainly dry. The only area
where reflectivity was showing up on current radar was the Bristol
Bay area from Iliamna to King Salmon where a light brief shower
could occur. Over the Bering, cool air continues to flow
southward keeping the region quiet with just cumulus clouds
covering a decent portion of the area especially the western and
central Bering. A weak low south of Adak will continue moving
southward and away from the central Aleutians this morning and not
be much of a factor.

&&

.MODEL DISCUSSION...

Model guidance remains in agreement on a broad longwave trough
over much of Alaska and the Bering for the next two days. However,
there are very subtle shortwaves rotating around a dissipating low
currently in the Gulf. Due to how subtle these upper level
shortwaves are it will be challenging to forecast exactly how each
one will affect Southcentral and when any rain will occur.
Basically, expect the cloudy and wet pattern to continue with the
occasional showers. Confidence continues to improve and increase
with the significant low that will move up into the Gulf of Alaska
Saturday through Sunday as model guidance continues to come
together on a solution. The main issue remains the exact placement
of the low which have impacts down to the local level on what
occurs. This will continue to be fine-tuned as we get closer.

&&

.AVIATION...
PANC...LIFR to IFR ceilings have moved over the terminal
overnight. The threat for patchy fog is also possible across the
terminal this morning with nearby areas reporting fog. This is
expected to continue through the late morning before lifting up to
MVFR conditions for the late morning into the afternoon. Any
showers that move over the terminal late morning into the
afternoon hours have the capability to give a better chance for
the MVFR conditions for ceiling or even VFR conditions for a time.
The risk for low ceilings to maybe IFR again exists for Saturday
morning after the showers end.

&&

.SHORT TERM FORECAST SOUTHCENTRAL ALASKA (Days 1 through 3: Today
through Sunday Night)...

A weak, diffuse low in the Gulf continues to direct Gulf moisture
and associated rainfall into Southcentral this morning. The
easterly flow is mostly favoring the mountains, Prince William
Sound, and the western Susitna Valley. An occasional spritz of
light rain has been making it over the Chugach to wet the roads as
well this morning. The primary weather concern this morning is
patchy dense fog that has been developing and dissipating across
portions of Anchorage, the Glenn Highway, and the Matanuska
Valley. Anywhere light rain develops, the fog situation improves.
Expect the patchy dense fog to persist into the mid-morning,
dissipating by midday. Otherwise, today will be similar to
yesterday, though with additional dry time. Nevertheless,
scattered showers will persist throughout the day. Tonight, the
weak low in the Gulf drifts west into southern Cook Inlet. As it
passes, precipitation chances will increase for tonight from
Anchorage south, then increasing everywhere on Saturday as the
low and associated front move north into the coast.

Late Saturday afternoon into Saturday night, all eyes turn south,
to a strong North Pacific low that will be moving into the
southern Gulf. The latest model trends have shifted the track of
the center further west since yesterday, and most of them now
strengthen the low into the lower 960s mb area as it approaches
the Gulf. This means the low is now forecast to produce at least
storm force winds both ahead of the low along the coast with the
barrier jet and the offshore southern Gulf behind the low as a
cooler air mass works in behind the storm. The low center will
move into the northern Gulf, somewhere near Middleton Island on
Sunday, then drift into Prince William Sound Sunday night. Along
this track, periods of heavy rain are likely in Kodiak Saturday
night into Sunday. The strong easterly flow north of the low will
also produce a few inches of rain across most Prince William Sound
locations as well. There looks to be a brief period the winds
through Turnagain Arm will increase Saturday afternoon and evening
with the leading front, but fortunately the strong low staying
east of the area, heading into Prince William Sound should mean
the winds across the Hillside will stay well below damaging
levels. This of course assumes the eventual track of the low
remains where it is. Thus, right now the primary threats
associated with the low will be very strong winds across the open
waters of the Gulf, and heavy rain over the eastern Kenai
Peninsula, Prince William Sound, and Kodiak Island.

The weakening low will gradually drift into mainland Southcentral
Sunday night, but most of the rainfall will remain along the
coastal mountains. Looking ahead, the pattern remains active with
another strong front expected Tuesday night. As far as
temperatures go, this active pattern and storm track will keep
temperatures much warmer than average, especially with overnight
lows. Each low and front from Saturday through the upcoming week
will bring a reinforcing warm air mass into the area, which should
mean even lows in the 30s will be few and far between except over
the Copper River Basin.

&&

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

The low over the Gulf of Alaska is continuing to bring northerly
flow and cool temperatures to the Southwest. Scattered showers
will remain possible with this pattern through Saturday afternoon.
After this time, the low will weaken as it moves inland, bringing
showers across the Alaska Peninsula and further northwest towards
Bristol Bay and the Kuskokwim Valley. By Sunday afternoon, drier
conditions should prevail, with a slight increase in temperatures
for the area as these conditions are shunted into the area by a
low in the Gulf.

&&

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

A low in the northwestern Bering, with shortwaves surrounding it,
will continue to bring showery activity to the area. Winds should
not exceed small craft criteria as this system propagates into
the North Pacific late Saturday. Saturday morning, a low moving
north into the Gulf of Alaska will cause northerly flow on the
backside of this low, into the north and eastern Bering. Expect
small craft criteria winds with this feature and an increase in
precipitation through Sunday as it moves into the central Bering
and Aleutians.

&&

.MARINE (Days 3 through 5/Sunday through Tuesday)...

There has been a large change in the forecast for this weekend.
It now looks like a large deep storm system will develop over
the Pacific and track right into the heart of the Gulf of Alaska
Saturday night through Sunday. Expect widespread gale to storm
force winds across all of the Gulf waters, with a chance of small
areas of hurricane force winds. This storm will rapidly weaken as
it pushes onshore along the north Gulf coast Sunday night/Monday
morning, with winds coming down fast across the Gulf. However, a
second storm system will follow not far behind. This storm will
take a farther west track toward the Alaska Peninsula. There is
quite a bit of uncertainty in the exact track and strength, but
would expect a good chance of gale to storm force winds from the
Gulf to Alaska Peninsula and Bristol Bay.

Looking west to the Bering Sea and Aleutians, a polar shortwave
drives southward across the eastern Bering into the North Pacific,
with gusty small craft northerlies Sunday through Monday. A
low will then pass south of the western Aleutians Monday through
Tuesday. For now the forecast reflects small craft winds, but
there is potential for gales right along the western Aleutian
chain.

&&

.LONG TERM FORECAST (Days 4 through 7/Monday through Thursday)...
Expect active weather with large and strong storm systems during
the extended forecast period thanks to a highly amplified pattern.
Beginning on Monday, a deep low which moves into the Gulf Sunday
will rapidly weaken and push onshore along the north Gulf coast.
This will likely bring a quick shot of moderate to heavy rain to
the Gulf coast and Prince William Sound. Meanwhile, the next
short-wave rounding the base of the trough over the North Pacific
will cause the downstream ridge to amplify. This will shift the
jet and storm track westward. As a result, expect the next storm
system to approach the Alaska Peninsula and Kodiak Island Monday
night through Tuesday. While there is some uncertainty in
strength and track of this system, all solutions indicate a large
storm system affecting the southern Mainland of Alaska Tuesday
night through Wednesday night. Widespread strong winds and heavy
rain are likely. This low then exits into the Bering Sea while the
next storm system moves up out of the Pacific. The spread in
solutions is even larger with this low, but chances are it will
also impact the southern Alaska Mainland.

Out west, the remnants of Tropical Storm Dolphin will transition
to an extratropical low and pass just south of the western
Aleutians Monday through Tuesday. This will bring a quick shot
of rain and wind. Otherwise, with the primary storm track much
farther east, conditions across the western Bering and Aleutian
Chain will remain relatively quiet.

&&

.AFC WATCHES/WARNINGS/ADVISORIES...
PUBLIC...NONE.
MARINE...NONE.
FIRE WEATHER...NONE.

&&

SYNOPSIS AND MODEL DISCUSSION...MV
SOUTHCENTRAL ALASKA...JPW
SOUTHWEST ALASKA/BERING SEA/ALEUTIANS...CK
MARINE/LONG TERM...MK/BG/SEB