Heavy Freezing Spray Warning 6, NWS Anchorage, AK

226 
FZAK62 PAFC 152354
OFFALU

Offshore Waters Forecast
National Weather Service Anchorage AK
254 PM AKST Fri Jan 15 2021

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.

PKZ499-161415-
254 PM AKST Fri Jan 15 2021
.SYNOPSIS FOR CENTRAL BERING SEA...

A 1000 mb compact low in the northwest Bering dissipates near 57N
176W by Sun afternoon. A 971 low at 46N 160W Fri afternoon moves near
56N 156W by Sat afternoon and then moves over Southwest Alaska at
990 mb by Sun afternoon. A front associated with a 957 mb low enters
the western Bering and Aleutians by Sun morning and moves eastward
through Sun afternoon.

$$

PKZ411-161415-
Bering Sea Offshore West of 180 and East of the International
Dateline-
254 PM AKST Fri Jan 15 2021

.TONIGHT...NW wind 15 to 25 kt. Seas 5 to 8 ft. Freezing spray.
.SAT...NW wind 15 to 30 kt. Seas 7 to 10 ft. Freezing spray.
.SAT NIGHT...NW wind 10 to 25 kt becoming SW after midnight. Seas 5 
to 9 ft. Freezing spray.
.SUN...SE wind 20 to 35 kt. Seas 7 to 12 ft.
.SUN NIGHT...SE wind 20 to 35 kt. Seas 9 to 14 ft.
.MON THROUGH TUE...SW wind 15 to 30 kt. Seas 10 to 18 ft.
.WED...NE wind 20 to 35 kt. Seas 11 to 19 ft.

$$

PKZ412-161415-
Bering Sea Offshore 171W to 180 and North of 56N-
254 PM AKST Fri Jan 15 2021

.TONIGHT...NW wind 15 to 30 kt. Seas 7 to 10 ft. Freezing spray.
.SAT...NW wind 15 to 30 kt. Seas 9 to 12 ft. Freezing spray.
.SAT NIGHT...NW wind 20 to 30 kt. Seas 8 to 12 ft. Freezing spray
and areas of blowing snow.
.SUN...NW wind 10 to 25 kt. Seas 6 to 11 ft.
.SUN NIGHT...NE wind 10 to 25 kt. Seas 6 ft.
.MON...E wind 15 to 30 kt. Seas 8 to 13 ft.
.TUE...S wind 15 to 30 kt. Seas 13 to 16 ft.
.WED...E wind 20 to 35 kt. Seas 13 to 21 ft.

$$

PKZ413-161415-
Bering Sea Offshore 171W to 180 and South of 56N-
254 PM AKST Fri Jan 15 2021

...GALE WARNING SATURDAY AND SATURDAY NIGHT...

.TONIGHT...NW wind 15 to 30 kt. Seas 7 to 11 ft. Freezing spray.
.SAT...NW wind 20 to 35 kt. Seas 9 to 14 ft. Freezing spray.
.SAT NIGHT...NW wind 20 to 35 kt. Seas 9 to 16 ft. Freezing spray.
.SUN...W wind 15 to 30 kt. Seas 8 to 13 ft.
.SUN NIGHT...SE wind 15 to 30 kt. Seas 6 to 11 ft.
.MON THROUGH TUE...S wind 15 to 30 kt. Seas 9 to 17 ft.
.WED...E wind 35 kt. Seas 17 to 22 ft.

$$

PKZ414-161415-
Bering Sea Offshore East of 171W-
254 PM AKST Fri Jan 15 2021

...GALE WARNING SATURDAY NIGHT...

.TONIGHT...N wind 15 to 30 kt. Seas 6 to 12 ft. Freezing spray.
.SAT...NW wind 15 to 30 kt. Seas 7 to 14 ft. Freezing spray.
.SAT NIGHT...NW wind 25 to 35 kt. Seas 9 to 16 ft. Freezing spray 
and areas of blowing snow.
.SUN...NW wind 15 to 30 kt. Seas 8 to 16 ft.
.SUN NIGHT...NW wind 10 to 25 kt. Seas 6 to 11 ft.
.MON...SE wind 15 to 30 kt. Seas 9 to 14 ft.
.TUE...SW wind 15 to 30 kt. Seas 11 to 14 ft.
.WED...SE wind 25 to 40 kt. Seas 10 to 18 ft.

$$

Southcentral and Southwest Alaska Forecast Discussion
National Weather Service Anchorage AK
351 PM AKST Thu Jan 14 2021

.ANALYSIS AND UPPER LEVELS...
The main weather feature impacting southern Alaska today is the
large and complex low in the Gulf of Alaska. Satellite shows this
low is extremely elongated with a multiple centers extending
from about 50N to near Kodiak Island. The upper level support is
being provided by the jet stream which is running in serpentine
fashion from around the eastern side of this low and then bends
sharply around the ridge over the Alcan border and into western
Canada. This is producing strong southeasterly flow with a lot of
moisture to move over the eastern Kenai Peninsula and Prince
William Sound. This pattern is also keeping northerly flow over
the Bering Sea region and southwest mainland Alaska.

South of the Aleutians lurks another large low. This one is in a
more favorable position in relation to the jet steam to develop
and move northeastward over the next few days. This low will
become the main low in the Gulf by the weekend.

&&

.MODEL DISCUSSION...
Models are in better agreement with the location of the multiple
low centers within the large low complex in the Gulf region. It
is now likely that the farthest south circulation as seen on
satellite will rotate along the eastern periphery of the low
complex and become the main surface low center Friday as it moves
into Prince William Sound. This solution, or something very
similar, is now shown by the majority of models and seeing this
low on satellite lends credence to this solution.

&&

.AVIATION...
PANC...It is becoming more likely that there will be some MVFR or
even IFR conditions at times early Friday morning into Friday
evening as some light snow moves into the area.

&&

.SHORT TERM FORECAST SOUTHCENTRAL ALASKA (Days 1 through 3/Tonight
through Sunday)...
A large low complex moving into the Gulf this afternoon has
reached its maximum strength, so winds across the Gulf waters will
diminish as we head through tonight. A surface wave along the
portion of the front over the eastern Gulf will develop into a
closed low and track just south of Cordova late tonight before
dissipating. This will maintain strong pressure gradient driven
winds through Thompson Pass. Have continued to the Blizzard
Warning for the Pass, but delayed the start as snow will not make
it in there until later this evening. The low and associated
frontal system will push onshore Friday, followed by the upper
level trough. Expect light snow to spread inland, especially
across the Kenai Peninsula and north to Anchorage and the Mat-Su.
Snowfall will be light so generally expect an inch or two of
accumulation for most inland locations.

Another large and deep low, currently over the North Central
Pacific, will track into the Gulf Friday night through Saturday.
This storm will track farther west than the current storm, which
means will see a more significant warm-up across the region and
primarily rain along the coast. Otherwise, the weather and
associated impacts will be very similar to the current storm, with
widespread gale to storm force winds across the Gulf and heavy
precipitation focused over Kodiak Island and the eastern Kenai
Peninsula. Downslope flow will initially keep inland areas dry,
though could see some precipitation spread inland Saturday night
through Sunday as some weak upper level short-waves lift northward
across Southcentral.

&&

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

An upper level ridge moving across Southwest Alaska today will be
replaced with a weakening upper level low which will move over the
Alaska Range tonight and into Southwest Alaska tomorrow this low
will produce a few snow showers mainly across the Bristol Bay
region. Saturday a stronger low pressure will move across the
AKPEN Saturday evening and into Bristol Bay this will bring
slightly warmer air across Bristol Bay. Rain and snow are likely
with this low with minor snow accumulations. The AKPEN will likely
get the most snow with a few inches possible, but below advisory
criteria. Winds will also increase with this low creating
localized areas of blowing snow across coastal areas of Bristol
Bay. Sunday this low will track across Southwest Alaska bringing a
couple of inches of snow to most locations.

&&

.SHORT TERM FORECAST BERING SEA/ALEUTIANS (Days 1 through 3: Thursday
Afternoon through Sunday)...

A broad area of troughing at 500mb dominates much of the Bering
and Aleutians with a few minor shortwaves enhancing precipitation
across the area. The most notable shortwave is near the Pribilofs
and across the northern Bering drifting westward. The low levels
are producing northerly flow keeping colder temperatures in place
with snow the precipitation type. This pattern will continue on
Friday. However on Saturday the pressure gradient tightens up
across the central and eastern Aleutians in response to a low
pressure system moving across the AKPEN into Bristol Bay Saturday
evening. This will bring in cold air advection and increasing
winds from the north with 850 temperatures dropping a few degrees
through Sunday. Much of the central and eastern Aleutians will
see snow and blowing snow from Saturday morning through Sunday. We
will need to monitor this system closely as a winter weather
advisory may be needed for snow and/or blowing snow mainly for
zones 185 and 181 from Dutch Harbor to Cold Bay. Still some model
differences on QPF amounts as well as the exact track of the low
across Bristol Bay. Additionally, upper level support is not
strong enough to favor heavier bands of snow, so confidence is
low for an advisory. Finally a gale force front with possible
storm force gusts will move across the western Aleutians Sunday.

&&

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

Gulf of Alaska: A strong North Pacific low moves over Kodiak
Island into the Alaska Peninsula for Mon. Model tracks and
development vary somewhat, but forecast confidence is good.
Widespread high end easterly gale force winds and waves move
northward over the Gulf with the front and diminish Sunday. A new
North Pacific low enters the Gulf bringing gale force gusts over
the Southeast Gulf Monday. This system will bring rough seas with
wave heights peaking near 20 feet.

Aleutians/Bering: A strong Kamchatka low and front moves east
through Tuesday. Widespread high end gale force winds anticipated
with this system as the front moves to the Central Aleutians and
across the Bering. Enhanced seas expected with this system as wave
heights are forecast to reach 19 feet for the Bering side, and
the Pacific side.

&&

.LONG TERM FORECAST (Days 3 through 7: Sunday through
Thursday)...

A progressive pattern is on tap for this forecast period. The
longwave trough extends from NE Russia to SE Alaska. There are
numerous embedded shortwaves. Expect a parade of lows for the
Bering, North Pacific and Gulf Of Alaska. Sunday there will be
surface low near the AKPEN/Bristol Bay and a second one west of
Attu Island. The steering flow is steadily eastward for both
systems. Expect snow in portions of SW AK and the Western Alaska
Range. The front associated with the other low will push directly
over the Central Aleutians. The models spin up a third surface
low south of Kodiak early Monday. This low will move directly into
the Gulf and South Central AK. By Tuesday the front over the
chain will be near Cold Bay. Past Tuesday, divergence has emerged
in the models but they are all showing a continuation of the wet
pattern.

&&

.AFC WATCHES/WARNINGS/ADVISORIES...
PUBLIC...WSW 125 131.
MARINE...Storms 130 131 139.
         Gales 119 120 132 138 150 170 173 174 351 352.
FIRE WEATHER...NONE.

&&

SYNOPSIS AND MODEL DISCUSSION...EZ
SOUTHCENTRAL ALASKA...SEB
SOUTHWEST ALASKA/BERING SEA/ALEUTIANS...RC
MARINE/LONG TERM...PS