Storm Warning 135, NWS Anchorage, AK

189 
FZAK62 PAFC 192348
OFFALU

Offshore Waters Forecast
National Weather Service Anchorage AK
248 PM AKST Thu Nov 19 2020

Offshore Waters Forecast for the Bering Sea

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.

PKZ499-201415-
248 PM AKST Thu Nov 19 2020
.SYNOPSIS FOR CENTRAL BERING SEA...

A 967 mb low at 55N 170W moves to 59N 170W at 972 mb Fri
afternoon. The low then moves to 61N 177W at 972 mb Sat afternoon.

$$

PKZ411-201415-
Bering Sea Offshore West of 180 and East of the International
Dateline-
248 PM AKST Thu Nov 19 2020

.TONIGHT...W wind 10 to 20 kt. Seas 7 to 12 ft.
.FRI...W wind 10 to 20 kt. Seas 8 to 11 ft.
.FRI NIGHT...W wind 15 to 25 kt. Seas 7 to 10 ft.
.SAT...W wind 15 to 25 kt. Seas 7 ft.
.SAT NIGHT...W wind 15 to 25 kt. Seas 7 to 11 ft.
.SUN...SW wind 20 to 30 kt. Seas 8 to 16 ft.
.MON THROUGH TUE...SW wind 25 to 40 kt. Seas 16 to 25 ft.

$$

PKZ412-201415-
Bering Sea Offshore 171W to 180 and North of 56N-
248 PM AKST Thu Nov 19 2020

...GALE WARNING THROUGH FRIDAY NIGHT...

.TONIGHT...N wind 25 to 40 kt. Seas 9 to 16 ft. Rain and snow.
.FRI...NW wind 30 to 45 kt. Seas 10 to 17 ft. Snow showers and
rain showers.
.FRI NIGHT...W wind 25 to 40 kt. Seas 10 to 16 ft.
.SAT...W wind 20 to 35 kt. Seas 9 to 16 ft.
.SAT NIGHT...SW wind 10 to 20 kt. Seas 8 to 12 ft.
.SUN...W wind 15 to 30 kt. Seas 9 to 14 ft.
.MON THROUGH TUE...SW wind 20 to 35 kt. Seas 10 to 18 ft.

$$

PKZ413-201415-
Bering Sea Offshore 171W to 180 and South of 56N-
248 PM AKST Thu Nov 19 2020

...STORM WARNING TONIGHT...

.TONIGHT...NW wind 30 to 50 kt east of 175W. NW wind 25 kt 
elsewhere. Seas 10 to 17 ft.
.FRI...W wind 25 to 40 kt. Seas 10 to 17 ft.
.FRI NIGHT...W wind 15 to 30 kt becoming 25 kt after midnight.
Seas 9 to 14 ft.
.SAT...W wind 10 to 25 kt. Seas 7 to 12 ft.
.SAT NIGHT...W wind up to 20 kt. Seas 7 to 12 ft.
.SUN...W wind 15 to 30 kt. Seas 8 to 13 ft.
.MON THROUGH TUE...SW wind 25 to 40 kt. Seas 11 to 19 ft.

$$

PKZ414-201415-
Bering Sea Offshore East of 171W-
248 PM AKST Thu Nov 19 2020

...STORM WARNING TONIGHT...

.TONIGHT...S wind 35 to 50 kt. Seas 14 to 22 ft. Snow and 
widespread rain showers.
.FRI...SW wind 30 to 45 kt. Seas 12 to 20 ft.
.FRI NIGHT...SW wind 25 to 40 kt. Seas 10 to 18 ft.
.SAT...SW wind 20 to 30 kt. Seas 11 to 16 ft.
.SAT NIGHT...SW wind up to 20 kt. Seas 7 to 12 ft.
.SUN...NW wind 15 to 30 kt. Seas 7 to 12 ft.
.MON THROUGH TUE...SW wind 20 to 35 kt. Seas 8 to 13 ft.

$$

314 
FZAK62 PAFC 201241
OFFALU

Offshore Waters Forecast
National Weather Service Anchorage AK
341 AM AKST Fri Nov 20 2020

Offshore Waters Forecast for the Bering Sea

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.

PKZ499-210145-
341 AM AKST Fri Nov 20 2020
.SYNOPSIS FOR CENTRAL BERING SEA...

A 969 mb low at 58N 165W this morning will move to 61N 170W at 968
mb Saturday morning. The low then moves to 64N 179E at 973 mb
Sunday morning. 

$$

PKZ411-210145-
Bering Sea Offshore West of 180 and East of the International
Dateline-
341 AM AKST Fri Nov 20 2020

.TODAY...W wind 10 to 20 kt. Seas 8 to 11 ft.
.TONIGHT...W wind 15 to 25 kt. Seas 8 ft.
.SAT...W wind 15 to 25 kt. Seas 7 ft.
.SAT NIGHT...W wind 15 to 25 kt. Seas 7 to 11 ft.
.SUN...SW wind 20 to 35 kt. Seas 8 to 16 ft.
.MON THROUGH TUE...SW wind 20 to 35 kt. Seas 13 to 21 ft.

$$

PKZ412-210145-
Bering Sea Offshore 171W to 180 and North of 56N-
341 AM AKST Fri Nov 20 2020

...GALE WARNING THROUGH SATURDAY...

.TODAY...NW wind 25 to 40 kt. Seas 9 to 15 ft.
.TONIGHT...W wind 25 to 40 kt. Seas 9 to 15 ft.
.SAT...W wind 20 to 35 kt. Seas 9 to 15 ft.
.SAT NIGHT...SW wind 10 to 20 kt. Seas 8 to 12 ft.
.SUN...W wind 15 to 30 kt. Seas 9 to 14 ft.
.MON THROUGH TUE...SW wind 20 to 35 kt. Seas 14 to 22 ft.

$$

PKZ413-210145-
Bering Sea Offshore 171W to 180 and South of 56N-
341 AM AKST Fri Nov 20 2020

...GALE WARNING TODAY...

.TODAY...W wind 20 to 35 kt. Seas 10 to 15 ft.
.TONIGHT...W wind 15 to 30 kt becoming 25 kt after midnight. Seas
9 to 13 ft.
.SAT...W wind 10 to 25 kt. Seas 7 to 11 ft.
.SAT NIGHT...W wind up to 20 kt. Seas 7 to 12 ft.
.SUN...W wind 15 to 30 kt. Seas 8 to 13 ft.
.MON...S wind 25 to 40 kt. Seas 13 to 21 ft.
.TUE...SW wind 20 to 30 kt. Seas 14 to 21 ft.

$$

PKZ414-210145-
Bering Sea Offshore East of 171W-
341 AM AKST Fri Nov 20 2020

...GALE WARNING THROUGH TONIGHT...

.TODAY...SW wind 30 to 45 kt. Seas 11 to 19 ft.
.TONIGHT...SW wind 25 to 40 kt. Seas 12 to 20 ft.
.SAT...SW wind 20 to 30 kt. Seas 11 to 17 ft.
.SAT NIGHT...SW wind up to 20 kt. Seas 7 to 12 ft.
.SUN...NW wind 20 to 35 kt. Seas 7 to 12 ft.
.MON...SW wind 20 to 35 kt. Seas 9 to 14 ft.
.TUE...S wind 20 to 35 kt. Seas 14 to 22 ft.

$$

Southcentral and Southwest Alaska Forecast Discussion
National Weather Service Anchorage AK
429 PM AKST Wed Nov 18 2020

.ANALYSIS AND UPPER LEVELS...
The strong low remains in the northwest Bering Sea with a front
that stretches from the Gulf of Anadyr to the Alaska Peninsula and
then to the southwest from there. What is notable on the GOES-17
satellite IR imagery is the convective nature of the showers
behind the front in the central Bering Sea. This is due to cold
air that is streaming into the low off Kamchatka and is fueling
this system.

South of Attu there is an area of clouds moving rapidly to the
east due to the jet steam. Under the front left quadrant of the
jet max, the system is rapidly developing a surface low that will
be the strong low that moves into the Southern Bering Sea
tomorrow. This development can be seen beginning in the clouds
beginning to hook northward out of the main areas of clouds.

Southcentral Alaska remain under a large dome of high pressure
which is still bringing some areas of fog and some gusty winds
through channeled terrain.

&&

.MODEL DISCUSSION...
Models are struggling quite a bit with this pattern and the
numerous lows that will develop in both the Gulf and Bering Sea
into the weekend. We have good model information for only about a
day and a half and then they start to break down. The good news is
that the strong low that is just developing south of Attu this
afternoon and will rapidly strengthen as it moves into the Bering
Sea Thursday is in much better agreement through Thursday night.
Unfortunately, the handling of this low becomes problematic by
Friday afternoon and consensus on both track and strength
completely break down by Friday night in both the Bering Sea and
Gulf of Alaska.

&&

.AVIATION...
PANC...Fog will remain a possibility around the airport through
Thursday. As it has been the past few days, it will likely come
and go and conditions will vary from VFR to LIFR.

&&

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

A pattern shift is expected across Southcentral. A weak low and
associated front will move over Kodiak Island Thursday. Brief
periods of snow in the morning will change to mostly rain by the
afternoon in Kodiak City. The will likewise be the case for the
southern Kenai Peninsula, including Seward. Light mixed
precipitation will track eastward into Prince William Sound as
well by Thursday evening as the front weakens. Forecast confidence
degrades into Friday, however a series of low pressure systems
will allow the active pattern to persist the Gulf/Kodiak. Gusty
southeasterly winds will develop in the western Gulf by Friday
evening and move along the coast into Saturday. Precipitation
should be confined to near the coast and over Kodiak Island. If
the surface flow pattern remains consistent, Anchorage and the
Mat-Su look to remain dry. Given the increased southerly flow and
cloud cover, temperatures will rise back to near seasonal
normals.

&&

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

High pressure over interior Southwest Alaska will keep cold
temperatures and dry conditions in the forecast through the
night. Towards the coast, chances for precipitation increase this
afternoon into the overnight hours as a front associated with a
weak low in the Bering moves inland. The Alaska Peninsula will
start off as rain, but could transition to a mix of rain and snow
as temperatures cool overnight. The Southwest mainland should see
snow as the dominant precipitation type associated with this
system as it continues to move farther inland through Thursday
evening.

Another system approaches the Southwest coast early Friday
morning, bringing a second round of precipitation for the region.
However, the there is still some uncertainty in the track of this
low and how far inland snow will move. Expect stronger winds
along the coastal areas and the Alaska Peninsula with this next
system.

&&

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

The active weather pattern across the Bering and Aleutians will
continue through the end of the week starting with an occluded
front in the eastern Bering today. This system will continue to
move into the Southwest mainland overnight and into Thursday
morning, with cold air advection moving in behind it.

Attention quickly focuses in on the next low feature moving over
the central Aleutians early Thursday morning. This system will
bring sustained storm for winds, with the possibility of hurricane
force gusts north of the Chain throughout the day as the center of
the low moves over the Pribilofs overnight Thursday into Friday
morning.

There is confidence in this system for the first 48 hours of the
forecast, but models quickly start to diverge late Friday morning
with the next developing low south of the Alaska Peninsula. Stay
tuned as this system continues to be evaluated over the next few
forecast packages.

&&

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

Gulf of Alaska:

There is increasing confidence in a strong low moving into the
Gulf Saturday with the potential for storm force winds, however
there continues to be extremely low confidence in the track of
this low. By Saturday night, conditions look to improve with sub
small craft wind levels expected. By Sunday, there is some
potential for another low to arrive over the Gulf from the south,
however a wide variety in model solutions has kept confidence very
low regarding track and strength of this low over the Gulf
through Monday.

Bering Sea:

There is potential for a strong low to impact the eastern Bering
Saturday, however there is extremely low confidence as model
solutions are vastly different. One solution places a storm force
low over the eastern Bering while another depicts the low centered
south of the Alaska Peninsula. The only insight at this time for
the weekend is that it will be an active pattern over the Bering
through Monday with the potential for storm force winds. By
Monday, another low enters the western Bering introducing
southerly gale force winds over the western Aleutians.

&&

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

The long term continues to show plenty of uncertainty, however
model solutions have still keyed in on several features. A broad
upper level trough looks to maintain its hold over the eastern
Bering/western mainland on Sunday while upstream, a ridge builds
over the Kamchatka Peninsula/western Bering. An upper level jet in
place just south of the Aleutian Chain will shift eastward late
Sunday, allowing for a more amplified pattern to develop Monday. A
strong Kamchatka low approaches the Bering Monday, forcing the
ridge to amplify and the broad upper level low to shift eastward
over the mainland, resulting in several upper level shortwaves
that will likely keep an active pattern across Southcentral. As
this pattern becomes more amplified, the increased pressure
gradients will likely bring a gusty northwesterly outflow wind to
the Alaska Peninsula Monday, especially given the signatures of
ample cold air advection at this time. By Tuesday, the ridge
continues eastward while the Kamchatka low deepens and its
associated front pushes eastward across the Bering through
midweek.

&&

.AFC WATCHES/WARNINGS/ADVISORIES...
PUBLIC...NONE.
MARINE...Storms 155 165 170 172-175 414.
         Gales 130 132 150 160 171 176 179-181 185 412 413.
FIRE WEATHER...NONE.

&&

SYNOPSIS AND MODEL DISCUSSION...EZ
SOUTHCENTRAL ALASKA...AP
SOUTHWEST ALASKA/BERING SEA/ALEUTIANS...AH
MARINE/LONG TERM...KO