Gale Warning 679, NWS Anchorage, AK

532 
FZAK62 PAFC 200004
OFFALU

Offshore Waters Forecast
National Weather Service Anchorage AK
304 PM AKST Thu Dec 19 2019

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-
304 PM AKST Thu Dec 19 2019
.SYNOPSIS FOR CENTRAL BERING SEA...

A front continues moving across the Bering and into western 
Alaska by Fri afternoon. A 977 mb low at 45N 172E Fri night moves
to 52N 180W at 960 mb low for Sat afternoon.

$$

PKZ411-201415-
Bering Sea Offshore West of 180 and East of the International
Dateline-
304 PM AKST Thu Dec 19 2019

...GALE WARNING TONIGHT AND FRIDAY NIGHT...

.TONIGHT...W wind 25 to 35 kt. Seas 16 to 21 ft. Snow showers.
.FRI...SW wind 20 to 30 kt. Seas 14 to 20 ft.
.FRI NIGHT...S wind 20 to 35 kt. Seas 9 to 16 ft.
.SAT...E wind 30 to 45 kt. Seas 11 to 19 ft.
.SAT NIGHT...NE wind 30 to 45 kt. Seas 14 to 27 ft.
.SUN...NW wind 40 to 55 kt. Seas 17 to 30 ft.
.MON...NW wind 20 to 35 kt. Seas 16 to 24 ft.
.TUE...N wind 10 to 25 kt. Seas 12 to 16 ft.

$$

PKZ412-201415-
Bering Sea Offshore 171W to 180 and North of 56N-
304 PM AKST Thu Dec 19 2019

...GALE WARNING TONIGHT...

.TONIGHT...SW wind 35 kt. Seas 11 to 19 ft building to 17 ft after
midnight. Rain.
.FRI...W wind 20 to 30 kt. Seas 15 to 19 ft. Snow showers.
.FRI NIGHT...SW wind 15 to 30 kt. Seas 12 to 17 ft.
.SAT...SE wind 30 to 45 kt. Seas 8 to 16 ft.
.SAT NIGHT...E wind 40 to 55 kt. Seas 16 to 24 ft.
.SUN...E wind 35 to 50 kt. Seas 18 to 28 ft.
.MON...N wind 15 to 30 kt. Seas 15 to 22 ft.
.TUE...N wind 15 to 25 kt. Seas 12 ft.

$$

PKZ413-201415-
Bering Sea Offshore 171W to 180 and South of 56N-
304 PM AKST Thu Dec 19 2019

.TONIGHT...W wind 30 kt. Seas 11 to 18 ft. Rain.
.FRI...W wind 15 to 25 kt. Seas 11 to 16 ft.
.FRI NIGHT...W wind 10 to 25 kt becoming SE after midnight. Seas
9 to 15 ft.
.SAT...SE wind 40 to 55 kt. Seas 12 to 20 ft.
.SAT NIGHT...SE wind 35 to 50 kt. Seas 15 to 23 ft.
.SUN THROUGH MON...NW wind 35 to 50 kt. Seas 17 to 32 ft.
.TUE...N wind 10 to 25 kt. Seas 10 to 15 ft.

$$

PKZ414-201415-
Bering Sea Offshore East of 171W-
304 PM AKST Thu Dec 19 2019

.TONIGHT...SW wind 15 to 30 kt. Seas 6 to 11 ft. Rain and snow.
.FRI...W wind 25 kt. Seas 9 to 14 ft.
.FRI NIGHT...NW wind 10 to 25 kt. Seas 9 to 14 ft.
.SAT...SW wind 25 to 40 kt. Seas 7 to 12 ft.
.SAT NIGHT...SE wind 35 to 50 kt. Seas 8 to 16 ft.
.SUN...SE wind 30 to 45 kt. Seas 13 to 28 ft.
.MON...NW wind 15 to 30 kt. Seas 13 to 28 ft.
.TUE...NE wind up to 20 kt. Seas 9 to 14 ft.

$$

321 
FZAK62 PAFC 201236
OFFALU

Offshore Waters Forecast
National Weather Service Anchorage AK
336 AM AKST Fri Dec 20 2019

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.

PKZ499-210230-
336 AM AKST Fri Dec 20 2019
.SYNOPSIS FOR CENTRAL BERING SEA...

A front over the eastern Bering moves into Southwest Alaska today.
A 970 mb low near 48N 178E late tonight moves to 55N 175W at 959 
mb late Sat night.

$$

PKZ411-210230-
Bering Sea Offshore West of 180 and East of the International
Dateline-
336 AM AKST Fri Dec 20 2019

...GALE WARNING SATURDAY...

.TODAY...W wind 15 to 30 kt. Seas 14 to 19 ft.
.TONIGHT...SW wind 10 to 25 kt becoming SE 20 to 30 kt after
midnight. Seas 10 to 15 ft.
.SAT...E wind 30 to 45 kt. Seas 10 to 13 ft building to 11 to 19
ft in the afternoon. Snow.
.SAT NIGHT...N wind 40 to 55 kt. Seas 16 to 24 ft.
.SUN...NW wind 40 to 55 kt. Seas 15 to 30 ft.
.MON...W wind 20 to 35 kt. Seas 13 to 21 ft.
.TUE...W wind 10 to 25 kt. Seas 7 to 12 ft.

$$

PKZ412-210230-
Bering Sea Offshore 171W to 180 and North of 56N-
336 AM AKST Fri Dec 20 2019

...STORM WARNING SATURDAY...

.TODAY...W wind 30 kt. Seas 15 to 19 ft. Snow showers.
.TONIGHT...W wind 15 to 25 kt becoming variable up to 15 kt. Seas 12
to 16 ft.
.SAT...SE wind 20 to 35 kt becoming E 35 to 50 kt in the
afternoon. Seas 10 to 13 ft building to 11 to 19 ft in the 
afternoon.
.SAT NIGHT...E wind 40 to 55 kt. Seas 15 to 23 ft.
.SUN...NE wind 35 to 50 kt. Seas 16 to 26 ft.
.MON...NE wind 15 to 30 kt. Seas 12 to 20 ft.
.TUE...N wind 10 to 20 kt. Seas 9 ft.

$$

PKZ413-210230-
Bering Sea Offshore 171W to 180 and South of 56N-
336 AM AKST Fri Dec 20 2019

...STORM WARNING SATURDAY...

.TODAY...W wind 15 to 30 kt. Seas 11 to 17 ft.
.TONIGHT...W wind 10 to 25 kt becoming SE 15 to 30 kt after
midnight. Seas 10 to 16 ft.
.SAT...E wind 40 to 55 kt. Seas 13 to 21 ft. Rain and snow.
.SAT NIGHT...SE wind 40 to 55 kt. Seas 14 to 27 ft.
.SUN...W wind 45 to 60 kt. Seas 21 to 36 ft.
.MON...NW wind 30 to 45 kt. Seas 14 to 29 ft.
.TUE...NW wind 15 to 30 kt. Seas 9 to 15 ft.

$$

PKZ414-210230-
Bering Sea Offshore East of 171W-
336 AM AKST Fri Dec 20 2019

...GALE WARNING SATURDAY...

.TODAY...W wind 25 kt. Seas 9 to 14 ft.
.TONIGHT...W wind 15 to 25 kt. Seas 10 to 14 ft.
.SAT...NW wind up to 20 kt becoming E 30 to 45 kt in the
afternoon. Seas 8 to 12 ft.
.SAT NIGHT...SE wind 30 to 45 kt. Seas 9 to 17 ft.
.SUN...E wind 30 to 45 kt. Seas 15 to 30 ft.
.MON...N wind 20 to 35 kt. Seas 14 to 22 ft.
.TUE...NW wind 10 to 20 kt. Seas 7 to 10 ft.

$$

Southcentral and Southwest Alaska Forecast Discussion
National Weather Service Anchorage AK
510 PM AKST Wed Dec 18 2019

.ANALYSIS AND UPPER LEVELS...

A vertically stacked 970mb low continues to slowly drift eastward
across the southern Gulf of Alaska. A series of upper-level
shortwaves is pinwheeling around the northern periphery of the
parent low, all moving east to west. The first spun up a tight
surface low near Middleton Island this morning. This feature
continues to produce some gales and bands of rain showers as it
tracks southwest toward Kodiak Island. The second is producing
some clouds and very light rain and snow showers from Prince
William Sound and the eastern Kenai Peninsula north across the
Chugach Range. The third is spinning up a surface low south of
Yakutat. This feature is tracking northwest towards the Copper
River Delta.

Farther west, a shortwave stretching across the Y-K Delta is
producing some clouds and widely scattered snow showers along the
immediate coast. Along the AKPEN and eastern Aleutians, yet
another shortwave is producing gusty northerly winds and scattered
rain/snow showers as it continues to drop south into the north
Pacific. A gale-force front is also moving over the western
Aleutians this afternoon as a Kamchatka low continues to deepen
off the Russian coast.

The cold air at the surface over the northern half of the state is
also showing up quite well on infra-red satellite imagery this
afternoon. This colder air mass is moving southward as the trough
over the Y-K delta dives into the eastern Bering. Temperatures
this afternoon across the middle and upper Kuskokwim Delta remain
near or just below zero. Even colder air is entrenched in the
Copper River Basin, where temperatures remain near -15F in
places.

&&

.MODEL DISCUSSION...

Models are still in fairly good agreement through Friday. Some
notable differences from previous runs are a slight slowdown in
the front moving across the Bering and a more sheared and slower
progression of a shortwave diving south across Southcentral late
Thursday. There is also some variance in timing and areal coverage
of precipitation over coastal Southcentral and the Copper River
Basin tonight through early Friday. However, subtleties between
the various guidance do little to significantly influence the
expected sensible weather.

&&

.AVIATION...

PANC...VFR conditions and light northerly winds will persist.

&&

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

A low continues to spin in the northern Gulf this evening, which
will bring an increased chance of precipitation to inland areas,
including a chance of light snow for the Copper Basin. As this low
exits the area on Thursday, chances for precipitation diminishes
across the region through Friday. The biggest difference in
today's forecast is the Arctic trough that will be a pattern
change for much of the Southcentral region. Models are in better
agreement that the trough will dig farther south over the area,
which delays the initial start of the strong cold air advection
moving in Thursday night into Friday afternoon. This change will
result in stronger winds for Kamishak Bay through the Barren
Islands as well as bays and passes along Shelikof Strait starting
on Thursday afternoon and diminishing through the night. The
cooling trend across Southcentral will continue through Friday as
the cold air advection brings in some of the coldest temperatures
seen so far this winter.

&&

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

A continental polar air mass will bring much cooler temperatures
across the Southwest tonight through Saturday. Gusty northerly
flow combined with temperatures dropping into the low teens or
below, cause winds chills in the 20 below to 35 below range late
Thursday into Friday. A front moves to the coast Friday morning,
bringing increased chances for snow. The front diminishes quickly
as it out runs the parent low, but a re-enforcing wave may provide
enough forcing to bring light snow across to Bethel to just west
of Dillingham late Friday into Saturday.

&&

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

A gale force low move into the western Bering tonight, weakening
on an eastward track to the central waters Thursday afternoon.
Rain mixed with snow will develop along the boundary as it moves
through, with snow showers in its wake and cold air advection. The
next front is expected to be much stronger, moving up from the
North Pacific Friday night. The associated low deepens to 965 mb
as it crosses to the southern Bering, between Adak and Shemya,
late Saturday. Winds were increased for the afternoon package to
storms around the core of the low and expanded rain coverage as
models are in better agreement on the the track of this system.

&&

.MARINE (Days 3 through 5 Friday through Sunday)...

We are still on track and confident that the outflow pattern will
be setting up along the North Gulf Coast to Kamishak Bay Thursday
night and Friday. These winds will likely be in the gale force
range through Saturday. The models are in relatively good
agreement with the next storm to approach the western Aleutians
Friday night and Saturday that will likely bring a strong storm
force low to the Bering Sea and western and central Aleutians
Friday night and Saturday. Mariners should stay tuned to this low
as it will likely have high seas and powerful winds associated
with it.

&&

.LONG TERM FORECAST (Days 3 through 7 Friday through Tuesday)...

Friday features the remnants of a front moving in along the Bering
Sea coast while another low is in the eastern Gulf of Alaska. A
weak ridge of high pressure is over the mainland between these
lows. Under this ridge, deep cold air moves in over the interior,
establishing favorable conditions for the typical outflow gap
winds through the mountains across southern Alaska. Progressing
through the weekend, cold air deepens over the eastern mainland,
while warmer air is pushed over western Alaska preceding a
deepening low and associated front that is moving into the Bering
Sea. This is where guidance is struggling however, thus forecast
uncertainty is high beginning Sunday. The differences in the model
solutions results in very different resulting sensible weather
across southern Alaska Monday and Tuesday. Thus we will maintain
the current forecast trend until model guidance comes into better
agreement.

&&

.AFC WATCHES/WARNINGS/ADVISORIES...
PUBLIC...NONE.
MARINE...GALE WARNING 127 130 131 138 150 177 178 185 411
         HEAVY FREEZING SPRAY WARNING 160 180 181
FIRE WEATHER...NONE.

&&

SYNOPSIS AND MODEL DISCUSSION...TM
SOUTHCENTRAL ALASKA...AH
SOUTHWEST ALASKA/BERING SEA/ALEUTIANS...KH
MARINE/LONG TERM...SA