Storm Warning 155, NWS Anchorage, AK

097 
FZAK62 PAFC 131221
OFFALU

Offshore Waters Forecast
National Weather Service Anchorage AK
321 AM AKST Wed Dec 13 2023

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.

PKZ499-140215-
321 AM AKST Wed Dec 13 2023
.SYNOPSIS FOR CENTRAL BERING SEA...

A 971 mb low at 53N 163E moves into Kamchatka at 953 mb for Thu 
morning. Its front sweeps into the Central Aleutians and Bering 
through Thu afternoon.

$$

PKZ411-140215-
Bering Sea Offshore West of 180 and East of the International
Dateline-
321 AM AKST Wed Dec 13 2023

...STORM WARNING THROUGH TONIGHT...

.TODAY...SE wind 35 to 50 kt. Seas 8 to 13 ft building to 11 to
19 ft in the afternoon. Rain and snow.
.TONIGHT...S wind 35 to 50 kt. Seas 15 to 21 ft. Rain and snow.
.THU...SW wind 15 to 25 kt. Seas 15 to 20 ft.
.THU NIGHT...SW wind 10 to 25 kt. Seas 14 to 17 ft.
.FRI THROUGH SAT...W wind 10 to 25 kt. Seas 8 to 16 ft.
.SUN...NE wind 15 to 30 kt. Seas 8 ft.

$$

PKZ412-140215-
Bering Sea Offshore 171W to 180 and North of 56N-
321 AM AKST Wed Dec 13 2023

...STORM WARNING TONIGHT...

.TODAY...NE wind 10 to 25 kt becoming E 20 to 35 kt in the
afternoon. Seas 7 to 12 ft.
.TONIGHT...SE wind 35 to 50 kt. Seas 9 to 17 ft. Snow and rain.
.THU...S wind 30 to 45 kt. Seas 11 to 19 ft. Rain and snow.
.THU NIGHT...W wind 20 to 35 kt. Seas 12 to 17 ft.
.FRI...SW wind 10 to 25 kt. Seas 9 to 14 ft.
.SAT THROUGH SUN...NW wind up to 15 kt. Seas 6 to 10 ft.

$$

PKZ413-140215-
Bering Sea Offshore 171W to 180 and South of 56N-
321 AM AKST Wed Dec 13 2023

...GALE WARNING THROUGH THURSDAY...

.TODAY...NE wind 10 to 25 kt becoming SE 20 to 35 kt in the
afternoon. Seas 7 to 12 ft. Snow and rain.
.TONIGHT...SE wind 25 to 40 kt. Seas 8 to 16 ft. Rain and snow.
.THU...S wind 20 to 35 kt becoming SW 15 to 25 kt in the
afternoon.
Seas 11 to 16 ft. Rain.
.THU NIGHT...W wind 10 to 25 kt. Seas 9 to 14 ft.
.FRI THROUGH SUN...SW wind 10 to 25 kt. Seas 7 to 12 ft.

$$

PKZ414-140215-
Bering Sea Offshore East of 171W-
321 AM AKST Wed Dec 13 2023

...GALE WARNING THROUGH THURSDAY...

.TODAY...N wind 25 to 40 kt. Seas 11 to 19 ft. Freezing spray.
.TONIGHT...N wind 20 to 35 kt becoming NE 10 to 25 kt after
midnight. Seas 8 to 13 ft. Freezing spray.
.THU...E wind 20 to 35 kt. Seas 6 to 11 ft. Freezing spray. Rain.
.THU NIGHT...SE wind 25 to 40 kt. Seas 7 to 12 ft.
.FRI THROUGH SUN...W wind 10 to 25 kt. Seas 6 to 11 ft.

$$

920 
FZAK62 PAFC 140043
OFFALU

Offshore Waters Forecast
National Weather Service Anchorage AK
343 PM AKST Wed Dec 13 2023

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.

PKZ499-141415-
343 PM AKST Wed Dec 13 2023
.SYNOPSIS FOR CENTRAL BERING SEA...

A 960 mb Kamchatka low sweeps its front across the Aleutians and 
Bering through Fri morning. A series of weak lows develop along
the front. 

$$

PKZ411-141415-
Bering Sea Offshore West of 180 and East of the International
Dateline-
343 PM AKST Wed Dec 13 2023

...STORM WARNING TONIGHT...

.TONIGHT...S wind 40 to 55 kt. Seas 15 to 22 ft. Rain and snow.
.THU...SW wind 15 to 25 kt. Seas 15 to 19 ft. Snow showers.
.THU NIGHT...SW wind 15 to 25 kt. Seas 14 to 18 ft.
.FRI...SW wind up to 20 kt. Seas 11 to 15 ft.
.FRI NIGHT...SW wind 10 to 20 kt. Seas 11 ft.
.SAT...W wind up to 20 kt. Seas 8 to 11 ft.
.SUN...NE wind 15 to 30 kt. Seas 8 ft.
.MON...N wind 20 to 35 kt. Seas 10 to 18 ft.

$$

PKZ412-141415-
Bering Sea Offshore 171W to 180 and North of 56N-
343 PM AKST Wed Dec 13 2023

...STORM WARNING THROUGH THURSDAY...

.TONIGHT...SE wind 35 to 50 kt. Seas 10 to 18 ft. 
Freezing spray N of 57N. Snow.
.THU...S wind 35 to 50 kt. Seas 12 to 20 ft. 
Freezing spray N of 57N in the morning. Snow.
.THU NIGHT...W wind 20 to 35 kt. Seas 12 to 16 ft.
.FRI...SW wind 10 to 25 kt. Seas 9 to 15 ft.
.FRI NIGHT...SW wind 15 kt. Seas 8 to 12 ft.
.SAT THROUGH SUN...NW wind up to 15 kt. Seas 6 to 10 ft.
.MON...NE wind 20 to 30 kt. Seas 8 to 13 ft.

$$

PKZ413-141415-
Bering Sea Offshore 171W to 180 and South of 56N-
343 PM AKST Wed Dec 13 2023

...GALE WARNING THROUGH THURSDAY...

.TONIGHT...SE wind 30 to 45 kt. Seas 9 to 16 ft. Rain and snow.
.THU...SW wind 25 to 40 kt becoming W 15 to 25 kt in the
afternoon. Seas 10 to 16 ft. Rain.
.THU NIGHT...SW wind 20 kt. Seas 9 to 13 ft.
.FRI...SW wind up to 20 kt. Seas 8 to 13 ft.
.FRI NIGHT...W wind 10 to 20 kt. Seas 8 to 11 ft.
.SAT THROUGH SUN...SW wind 10 to 25 kt. Seas 6 to 10 ft.
.MON...SE wind 20 to 30 kt. Seas 9 to 14 ft.

$$

PKZ414-141415-
Bering Sea Offshore East of 171W-
343 PM AKST Wed Dec 13 2023

...GALE WARNING THURSDAY AND THURSDAY NIGHT...

.TONIGHT...NE wind 15 to 30 kt. Seas 8 to 13 ft. Freezing spray N of 56N.
.THU...E wind 20 to 35 kt. Seas 6 to 11 ft. Freezing spray N of 56N. Snow.
.THU NIGHT...SE wind 25 to 40 kt becoming SW 20 to 35 kt after
midnight. Seas 7 to 12 ft. Freezing spray N of 56N. Snow.
.FRI...SW wind 10 to 25 kt. Seas 7 to 11 ft.
.FRI NIGHT...SW wind 10 to 20 kt. Seas 5 to 10 ft.
.SAT THROUGH SUN...W wind 10 to 20 kt. Seas 7 to 11 ft.
.MON...SE wind 15 to 30 kt. Seas 6 to 10 ft.

$$

806 
FZAK62 PAFC 141218
OFFALU

Offshore Waters Forecast
National Weather Service Anchorage AK
318 AM AKST Thu Dec 14 2023

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.

PKZ499-150200-
318 AM AKST Thu Dec 14 2023
.SYNOPSIS FOR CENTRAL BERING SEA...

A Bering front located over the Central Aleutians continues 
eastward into Bristol Bay through early Fri. A developing 995 mb 
low near Adak Fri morning moves to 58N 173W at 984 mb by Sat 
morning.

$$

PKZ411-150200-
Bering Sea Offshore West of 180 and East of the International
Dateline-
318 AM AKST Thu Dec 14 2023

.TODAY...SW wind 15 to 25 kt. Seas 14 to 19 ft.
.TONIGHT...SW wind 15 to 25 kt. Seas 14 to 18 ft.
.FRI...SW wind 15 kt becoming SW 20 kt in the afternoon. Seas 14 ft.
.FRI NIGHT...SW wind up to 20 kt. Seas 12 ft.
.SAT...W wind up to 20 kt. Seas 7 to 12 ft.
.SUN...NE wind 15 to 30 kt. Seas 5 to 10 ft.
.MON...NE wind 20 to 35 kt. Seas 13 to 21 ft.

$$

PKZ412-150200-
Bering Sea Offshore 171W to 180 and North of 56N-
318 AM AKST Thu Dec 14 2023

...STORM WARNING TODAY...

.TODAY...SE wind 35 to 50 kt becoming SW 25 to 40 kt in the
afternoon. Seas 12 to 20 ft. Rain and snow.
.TONIGHT...W wind 15 to 30 kt. Seas 11 to 16 ft.
.FRI...SW wind 10 to 20 kt. Seas 9 to 14 ft.
.FRI NIGHT...W wind up to 20 kt. Seas 8 to 13 ft.
.SAT THROUGH SUN...NW wind up to 20 kt. Seas 6 to 11 ft.
.MON...E wind 15 to 30 kt. Seas 9 to 14 ft.

$$

PKZ413-150200-
Bering Sea Offshore 171W to 180 and South of 56N-
318 AM AKST Thu Dec 14 2023

...GALE WARNING TODAY...

.TODAY...SW wind 25 to 40 kt becoming W 15 to 25 kt in the
afternoon. Seas 10 to 16 ft. Rain.
.TONIGHT...SW wind 20 kt. Seas 9 to 13 ft.
.FRI...SW wind 10 to 25 kt. Seas 9 to 14 ft. Snow and rain showers.
.FRI NIGHT...W wind 20 kt. Seas 9 to 15 ft.
.SAT THROUGH SUN...W wind 10 to 20 kt. Seas 6 to 11 ft.
.MON...SE wind 15 to 30 kt. Seas 8 to 13 ft.

$$

PKZ414-150200-
Bering Sea Offshore East of 171W-
318 AM AKST Thu Dec 14 2023

...GALE WARNING THROUGH TONIGHT...

.TODAY...E wind 20 to 35 kt. Seas 6 to 11 ft. Freezing spray. Rain
and snow.
.TONIGHT...S wind 20 to 35 kt. Seas 7 to 12 ft. Freezing spray.
Rain and snow.
.FRI...SW wind 10 to 25 kt. Seas 8 to 11 ft.
.FRI NIGHT...SW wind 10 to 25 kt. Seas 8 to 13 ft.
.SAT THROUGH SUN...W wind 10 to 25 kt. Seas 9 to 14 ft.
.MON...SE wind 15 to 30 kt. Seas 6 to 11 ft.

$$

798 
FZAK62 PAFC 150048
OFFALU

Offshore Waters Forecast
National Weather Service Anchorage AK
348 PM AKST Thu Dec 14 2023

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.

PKZ499-151545-
348 PM AKST Thu Dec 14 2023
.SYNOPSIS FOR CENTRAL BERING SEA...

A 965 mb Central Kamchatka low extends a front across the 
Aleutians and Bering that moves into Western Alaska for Midday 
Friday. A 993 mb low forms on the front at 50N 173W Fri afternoon 
and moves along the front to 59N 162W by Sat afternoon.

$$

PKZ411-151545-
Bering Sea Offshore West of 180 and East of the International
Dateline-
348 PM AKST Thu Dec 14 2023

.TONIGHT...SW wind 10 to 25 kt. Seas 13 to 17 ft.
.FRI...SW wind 10 to 20 kt. Seas 12 to 15 ft.
.FRI NIGHT...SW wind 10 to 20 kt. Seas 9 to 13 ft.
.SAT...W wind up to 15 kt. Seas 7 to 11 ft.
.SAT NIGHT...NW wind 10 to 20 kt. Seas 7 to 10 ft.
.SUN...NE wind 15 to 30 kt. Seas 5 to 10 ft.
.MON...NE wind 20 to 35 kt. Seas 13 to 21 ft.
.TUE...NW wind 20 to 30 kt. Seas 14 to 20 ft.

$$

PKZ412-151545-
Bering Sea Offshore 171W to 180 and North of 56N-
348 PM AKST Thu Dec 14 2023

.TONIGHT...SW wind 15 to 30 kt. Seas 12 to 16 ft.
.FRI...SW wind 10 to 25 kt becoming N 15 to 30 kt in the
afternoon. Seas 10 to 14 ft.
.FRI NIGHT...NW wind 15 to 30 kt. Seas 8 to 13 ft.
.SAT...NW wind up to 20 kt. Seas 7 to 10 ft.
.SAT NIGHT...NW wind up to 15 kt. Seas 6 to 10 ft.
.SUN...NW wind 10 to 20 kt. Seas 6 to 10 ft.
.MON...E wind 15 to 30 kt. Seas 9 to 14 ft.
.TUE...N wind 15 to 30 kt. Seas 13 to 20 ft.

$$

PKZ413-151545-
Bering Sea Offshore 171W to 180 and South of 56N-
348 PM AKST Thu Dec 14 2023

...GALE WARNING FRIDAY...

.TONIGHT...SW wind 10 to 25 kt. Seas 9 to 14 ft.
.FRI...SW wind 20 to 35 kt. Seas 10 to 15 ft.
.FRI NIGHT...W wind 15 to 30 kt. Seas 9 to 14 ft.
.SAT...W wind 10 to 20 kt. Seas 8 to 11 ft.
.SAT NIGHT...W wind 15 kt. Seas 7 to 10 ft.
.SUN...W wind 10 to 20 kt. Seas 5 to 10 ft.
.MON...SE wind 15 to 30 kt. Seas 8 to 13 ft.
.TUE...W wind 10 to 20 kt. Seas 13 to 17 ft.

$$

PKZ414-151545-
Bering Sea Offshore East of 171W-
348 PM AKST Thu Dec 14 2023

...GALE WARNING TONIGHT...

.TONIGHT...SW wind 20 to 35 kt. Seas 8 to 13 ft. Freezing spray N of
56N. Snow.
.FRI...SW wind 15 to 30 kt. Seas 8 to 12 ft. Freezing spray N of 56N
in the morning.
.FRI NIGHT...SW wind 15 to 30 kt. Seas 8 to 13 ft. Rain and snow.
.SAT...W wind 15 to 25 kt. Seas 8 to 13 ft.
.SAT NIGHT...W wind 15 to 25 kt. Seas 9 to 15 ft.
.SUN...W wind 10 to 25 kt. Seas 9 to 13 ft.
.MON THROUGH TUE...SE wind 15 to 30 kt. Seas 7 to 12 ft.

$$

Southcentral and Southwest Alaska Forecast Discussion
National Weather Service Anchorage AK
431 AM AKST Tue Dec 12 2023

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

A high amplitude, longwave trough remains in place over western
Alaska, extending south of Kodiak Island where it is anchored by a
510 dm upper-level low. Stout, southerly flow downstream of these
features is drawing both copious amounts of moisture and a
surface low north toward Prince William Sound this morning. The
surface low is moving north-northwest along a stalled frontal
boundary that is has been the focus for the heavy precipitation
stretching from the central Gulf over the Central Chugach and
Copper River Basin for the past 24 to 36 hours. To the west,
conditions are quieter; however, residual moisture over Cook Inlet
and a weak trough beginning to usher in colder air aloft has
resulted in the redevelopment of scattered showers from Homer
north to Anchorage.

Snow levels did drop slightly overnight with rain changing to snow
for Valdez, Cordova, and around the junction of the Edgerton and
Richardson Highways in the southern Copper River Basin. Snow
levels will likely remain steady through the day as the low
tracks inland by mid morning and precipitation intensity during
the afternoon and evening hours wanes. The exception to this is
likely Cordova, where enough warmer air will work back in this
morning to change snow, or mixed rain/snow, back to all rain for a
time before colder air works back in later today. Farther west,
the main challenge will not only be the extent of snow shower
activity this morning across Cook Inlet, but whether the western
edge of the precipitation shield makes it far enough over the
Chugach to allow for some light snow for places like Anchorage and
Palmer. The best chance for any light snow through the afternoon
hours is over the Matanuska Valley.

The parade of surface lows continues this evening as the next
follows a similar track to the previous and moves toward Prince
William Sound. Another round of heavy precipitation will move over
the Central Chugach and across the Copper River Basin through
Wednesday morning. Again, the biggest challenge will be the
western extent of the precipitation. This system appears more
likely to bring a round of steady, light snow to the Mat-Su
Valleys, Anchorage Bowl and parts of the Kenai Peninsula Wednesday
morning as the anchoring upper-level low to the west dips south
and becomes more negatively tilted, drawing the surface feature
and attendant shortwave back to the west. Snowfall amounts for
these locations should be light, on the order of 1 to 3 inches.

The southerly flow across the Gulf persists into Thursday with
showers rotating around the lows. Much colder air will also advect
in, bringing snow levels down to sea level across the Southcentral
coast by Wednesday afternoon.

TM

&&

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

Conditions across the Bering Sea and Southwest Alaska remain
largely driven by a large low pressure system in the Gulf of
Alaska and a ridge set-up in the Western Bering Sea. The influence
from these two systems is driving the strong influx of cold air
from the northern Arctic down into the the Southwest coastline,
Alaska Peninsula, and eastern Aleutians. This strong plunge of
cold air will continue to produce gusty winds in the Eastern
Bering, and across the the Alaska Peninsula through Wednesday.
Storm-force gusts through gaps and passes along the Alaska
Peninsula and Eastern Aleutians are expected during this time.
Areas of blowing snow reducing visibility will be likely along the
coastline from Bethel to Cold Bay. Similarly, this area will
likely see new snowfall from persistent snow showers with the
strong northerly winds diminishing only by Wednesday evening. The
easing wind flow will weaken the presence of blowing snow across
the aforementioned areas, however not out of the realm of
possibility until about Thursday afternoon.

The system that will eventually break the hold of this cold air
flow will be a new low pressure system pushing in from the western
Bering sea. This low pressure system will be initially noted by a
leading frontal passage that will bring warmer southerly air
arriving to the western-most Aleutians by Wednesday morning. The
front will bring with it another round of precipitation, however
this will likely come in the form of liquid rain due to the warmer
temperatures. The front will be producing Gale-force southerly
winds with some Storm-force winds possible further north into the
Central Bering sea, however will likely be less "gusty" in nature
due to the temperature of the air coming in being warmer than
whats currently in place. The front will advance steadily
eastward, reaching Unalaska by Thursday morning. As the front
approaches, precipitation may initially begin as snowfall, but is
expected to transition within a few hours to plain rain. By this
time, the tight pressure gradient driving strong winds through the
Eastern Aleutians will have relaxed, and the strong winds eased
significantly. By Thursday morning, the parental low pressure
center will enter the Western Bering sea, re-initializing the
precipitation over the western- most Aleutians, however this time
likely in the form of snowfall due to more colder air entrained in
the system.

CL

&&

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

The long-term forecast continues to feature general agreement on
the continuation of the active pattern Friday through at least
Monday. For Friday, a new deep upper trough drops into the
western/central Bering Sea while a shortwave ridge moves over the
eastern Bering and Southwest Alaska. The upper low that provided
Southcentral Alaska with very active weather in the short-term
continues to move eastward towards Southeast Alaska as the
shortwave ridge builds over Southcentral. However, any break in
weather associated with the ridge will not last long. Later on
Friday and into Saturday, the deep trough in the Bering moves
eastward and puts all of mainland Southern Alaska back in moist
southerly to southwesterly flow. A front over then central and
eastern Bering moves to the coast of Southwest later in the day on
Friday and eventually to Southcentral on Saturday. There is lots
of uncertainty exactly where a secondary low will spin up along
the front in the Gulf on Saturday. All ensemble and deterministic
guidance all show different solutions. However, generally
speaking, coastal Southcentral chances for moderate to heavy
precipitation are average. Southwest flow in the middle to upper
levels continues for Monday as additional shortwaves lift
northward through the Gulf and into Southcentral. The Bering Sea
and Aleutians stay active Saturday through Monday as shortwaves
pivot around the main trough. An additional low coming from
Kamchatka looks to send its gale-force front from the western
Aleutians Sunday afternoon to the central Aleutians by Monday
morning. This will spread gusty winds and precipitation across the
Aleutian Chain early next week.

&&

.AVIATION...

PANC...Expect scattered snow showers to continue through mid to
late Tuesday morning. These snow showers could cause temporary
reductions to ceilings and vis, especially between 12z and 15z.
MVFR conditions are most likely in snow showers, but conditions
could briefly drop as low as IFR. Conditions will improve during
the morning hours on Tuesday, with dry conditions and VFR ceilings
likely until snow with the next storm arrives sometime late
Tuesday night or early Wednesday morning.

Expect northerly winds to continue throughout the day, with the
strongest winds, around 10 kt, through 18z.

&&