Heavy Freezing Spray Warning 237, NWS Anchorage, AK

497 
FZAK52 PAFC 311238
CWFALU

Coastal Waters Forecast
National Weather Service Anchorage Alaska
338 AM AKST Fri Dec 31 2021

Coastal Waters Forecast for Southwest Alaska+Bristol Bay+The
Alaska Peninsula Waters and the Aleutian Islands up to 100 nm out.

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.

PKZ199-010145-
338 AM AKST Fri Dec 31 2021
.SYNOPSIS FOR SOUTHWEST ALASKA+BRISTOL BAY+THE ALASKA
PENINSULA WATERS AND THE ALEUTIAN ISLANDS...

A 989 mb low 50 nm east of Saint George moves over the Alaska 
Peninsula Friday afternoon at 992 mb. The low then weakens and exits 
into the western Gulf Friday night. A weak ridge of high pressure 
develops over the central Bering Saturday afternoon.

$$

PKZ150-010145-
South of the AK Peninsula Sitkinak to Castle Cape-
338 AM AKST Fri Dec 31 2021

...HURRICANE FORCE WIND WARNING SATURDAY...
...HEAVY FREEZING SPRAY WARNING TONIGHT AND SATURDAY...

.TODAY...SW wind 30 kt. Seas 13 ft.
.TONIGHT...NW wind 20 kt increasing to 45 kt after midnight. 
Gusts to 60 kt out of bays and passes after midnight. Seas 14 ft. 
Heavy freezing spray.
.SAT...NW wind 65 kt. Gusts to 80 kt out of bays and passes. Seas 23
ft. Heavy freezing spray.
.SAT NIGHT...NW wind 65 kt. Seas 23 ft.
.SUN...NW wind 60 kt. Seas 23 ft.
.MON...N wind 35 kt. Seas 12 ft.
.TUE...NE wind 30 kt. Seas 13 ft.

$$

PKZ155-010145-
South of the AK Peninsula Castle Cape to Cape Sarichef-
338 AM AKST Fri Dec 31 2021

...STORM WARNING SATURDAY...
...HEAVY FREEZING SPRAY WARNING SATURDAY...

.TODAY...SW wind 35 kt. Seas 19 ft.
.TONIGHT...NW wind 45 kt. From the Shumagin Islands E, NW wind 30
kt increasing to 45 kt after midnight. Gusts to 55 kt out of bays 
and passes after midnight. Seas 17 ft. Freezing spray.
.SAT...NW wind 50 kt. Seas 17 ft. Heavy freezing spray from the
Shumagin Islands E.
.SAT NIGHT...NW wind 55 kt. Seas 17 ft.
.SUN...N wind 45 kt. Seas 15 ft.
.MON...N wind 35 kt. Seas 11 ft.
.TUE...NE wind 25 kt. Seas 13 ft.

$$

PKZ160-010145-
Bristol Bay-
338 AM AKST Fri Dec 31 2021

...GALE WARNING TONIGHT AND SATURDAY...
...HEAVY FREEZING SPRAY WARNING TONIGHT AND SATURDAY...

.TODAY...S wind 20 kt becoming SE 10 kt in the afternoon. Seas in
ice free waters 6 ft.
.TONIGHT...N wind 35 kt. Seas in ice free waters 9 ft. Heavy
freezing spray.
.SAT...NW wind 40 kt. Gusts to 60 kt. Seas in ice free waters 10 ft.
Heavy freezing spray.
.SAT NIGHT...NW wind 35 kt. Seas in ice free waters 9 ft.
.SUN...N wind 35 kt. Seas in ice free waters 7 ft.
.MON THROUGH TUE...NE wind 30 kt. Seas in ice free waters 7 ft.

$$

PKZ165-010145-
Port Heiden to Cape Sarichef-
338 AM AKST Fri Dec 31 2021

...GALE WARNING TONIGHT AND SATURDAY...
...HEAVY FREEZING SPRAY WARNING TONIGHT AND SATURDAY...

.TODAY...NW wind 30 kt. Seas 12 ft.
.TONIGHT...NW wind 40 kt. Seas 17 ft. Heavy freezing spray.
.SAT...NW wind 40 kt. Seas 15 ft. Heavy freezing spray.
.SAT NIGHT...N wind 45 kt. Seas 15 ft.
.SUN THROUGH MON...N wind 35 kt. Seas 15 ft.
.TUE...NE wind 30 kt. Seas 12 ft.

$$

PKZ170-010145-
Cape Sarichef to Nikolski Bering Side-
338 AM AKST Fri Dec 31 2021

...GALE WARNING THROUGH TONIGHT...

.TODAY...W wind 30 kt becoming NW 40 kt in the afternoon. Seas
17 ft.
.TONIGHT...NW wind 35 kt. Seas 19 ft.
.SAT...N wind 30 kt. Seas 13 ft. Freezing spray.
.SAT NIGHT...NE wind 25 kt. Seas 11 ft.
.SUN...NE wind 30 kt. Seas 12 ft.
.MON THROUGH TUE...NE wind 30 kt. Seas 17 ft.

$$

PKZ171-010145-
Unalaska Bay-
338 AM AKST Fri Dec 31 2021

...GALE WARNING THROUGH TONIGHT...

.TODAY...NW wind 35 kt. Gusts to 45 kt. Seas 4 ft building to 13 ft 
in the afternoon. Rain showers.
.TONIGHT...NW wind 40 kt. Gusts to 50 kt. Seas 16 ft.
.SAT...NW wind 30 kt diminishing to 20 kt in the afternoon. Seas
10 ft.
.SAT NIGHT...N wind 20 kt. Seas 7 ft.
.SUN...NE wind 20 kt. Seas 7 ft.
.MON...N wind 25 kt. Seas 10 ft.
.TUE...NE wind 20 kt. Seas 7 ft.

$$

PKZ172-010145-
Cape Sarichef to Nikolski Pacific Side-
338 AM AKST Fri Dec 31 2021

...GALE WARNING THROUGH SATURDAY...

.TODAY...W wind 40 kt. Seas 23 ft.
.TONIGHT...NW wind 40 kt. Seas 16 ft.
.SAT...NW wind 35 kt. Seas 12 ft.
.SAT NIGHT...N wind 30 kt. Seas 9 ft.
.SUN...NE wind 30 kt. Seas 9 ft.
.MON...N wind 25 kt. Seas 11 ft.
.TUE...NE wind 25 kt. Seas 16 ft.

$$

PKZ173-010145-
Nikolski to Seguam Island Bering Side-
338 AM AKST Fri Dec 31 2021

...GALE WARNING TODAY...

.TODAY...NW wind 45 kt. Seas 22 ft.
.TONIGHT...NW wind 30 kt. Seas 18 ft.
.SAT...N wind 15 kt. Seas 11 ft.
.SAT NIGHT...E wind 25 kt. Seas 7 ft.
.SUN...E wind 35 kt. Seas 13 ft.
.MON THROUGH TUE...NE wind 30 kt. Seas 19 ft.

$$

PKZ174-010145-
Nikolski to Seguam Island Pacific Side-
338 AM AKST Fri Dec 31 2021

...GALE WARNING THROUGH TONIGHT...

.TODAY...W wind 45 kt. Seas 23 ft.
.TONIGHT...NW wind 40 kt diminishing to 30 kt after midnight. Seas
17 ft.
.SAT...N wind 20 kt in the morning becoming variable 10 kt. Seas
10 ft.
.SAT NIGHT...E wind 25 kt. Seas 9 ft.
.SUN...E wind 35 kt. Seas 14 ft.
.MON THROUGH TUE...NE wind 30 kt. Seas 17 ft.

$$

PKZ175-010145-
Seguam Island to Adak Bering Side-
338 AM AKST Fri Dec 31 2021

...GALE WARNING TODAY...

.TODAY...NW wind 45 kt diminishing to 35 kt in the afternoon. Seas
22 ft.
.TONIGHT...NW wind 25 kt becoming SE after midnight. Seas 14 ft.
.SAT...SE wind 25 kt. Seas 10 ft.
.SAT NIGHT...SE wind 30 kt. Seas 9 ft.
.SUN THROUGH MON...E wind 40 kt. Seas 18 ft.
.TUE...NE wind 35 kt. Seas 20 ft.

$$

PKZ176-010145-
Seguam Island to Adak Pacific Side-
338 AM AKST Fri Dec 31 2021

...GALE WARNING TODAY...

.TODAY...NW wind 45 kt. Seas 20 ft.
.TONIGHT...NW wind 25 kt becoming SE 15 kt after midnight. Seas
11 ft.
.SAT...SE wind 25 kt. Seas 9 ft.
.SAT NIGHT...SE wind 35 kt. Seas 12 ft.
.SUN THROUGH MON...E wind 45 kt. Seas 26 ft.
.TUE...NE wind 35 kt. Seas 21 ft.

$$

PKZ177-010145-
Adak to Kiska-
338 AM AKST Fri Dec 31 2021

...GALE WARNING THROUGH SATURDAY...

.TODAY...W wind 35 kt becoming SW 20 kt in the afternoon. Seas
15 ft.
.TONIGHT...S wind 35 kt. Seas 14 ft.
.SAT...SE wind 40 kt. Seas 17 ft.
.SAT NIGHT...SE wind 40 kt. Seas 18 ft.
.SUN THROUGH MON...E wind 45 kt. Seas 30 ft.
.TUE...NE wind 35 kt. Seas 24 ft.

$$

PKZ178-010145-
Kiska to Attu-
338 AM AKST Fri Dec 31 2021

...STORM WARNING TONIGHT...

.TODAY...S wind 35 kt. Seas 13 ft building to 19 ft in the
afternoon. Rain.
.TONIGHT...SE wind 50 kt. Seas 21 ft building to 28 ft after
midnight. Rain.
.SAT...S wind 45 kt. Seas 30 ft.
.SAT NIGHT...SE wind 45 kt. Seas 27 ft.
.SUN THROUGH MON...E wind 45 kt. Seas 27 ft.
.TUE...NE wind 40 kt. Seas 24 ft.

$$

PKZ179-010145-
Pribilof Islands Near Shore Waters-
338 AM AKST Fri Dec 31 2021

...GALE WARNING TODAY...

.TODAY...N wind 40 kt. Seas 17 ft.
.TONIGHT...N wind 30 kt. Seas 13 ft. Freezing spray.
.SAT...N wind 20 kt. Seas 8 ft. Freezing spray.
.SAT NIGHT...E wind 15 kt. Seas 6 ft.
.SUN...E wind 25 kt. Seas 8 ft.
.MON...NE wind 30 kt. Seas 13 ft.
.TUE...NE wind 35 kt. Seas 15 ft.

$$

PKZ180-010145-
Kuskokwim Delta and Etolin Strait-
338 AM AKST Fri Dec 31 2021

...GALE WARNING THROUGH SATURDAY...
...HEAVY FREEZING SPRAY WARNING THROUGH SATURDAY...

.TODAY...N wind 35 kt. Seas 10 ft. Heavy freezing spray.
.TONIGHT...N wind 40 kt. Seas 11 ft. Heavy freezing spray.
.SAT...N wind 40 kt. Seas 10 ft. Heavy freezing spray.
.SAT NIGHT...N wind 45 kt. Seas 11 ft.
.SUN THROUGH TUE...NE wind 35 kt. Seas 9 ft.

$$

PKZ181-010145-
North and West of Nunivak Island-
338 AM AKST Fri Dec 31 2021

...GALE WARNING TODAY...
...HEAVY FREEZING SPRAY WARNING THROUGH SATURDAY...

.TODAY...N wind 40 kt. Seas 12 ft. Heavy freezing spray.
.TONIGHT...N wind 30 kt. Seas 10 ft. Heavy freezing spray.
.SAT...N wind 30 kt. Seas 9 ft. Heavy freezing spray.
.SAT NIGHT...N wind 20 kt. Seas 5 ft.
.SUN...E wind 20 kt. Seas 7 ft.
.MON...NE wind 30 kt. Seas 7 ft.
.TUE...NE wind 35 kt. Seas 10 ft.

$$

PKZ185-010145-
Saint Matthew Island Waters-
338 AM AKST Fri Dec 31 2021

...GALE WARNING TODAY AND SATURDAY...
...HEAVY FREEZING SPRAY WARNING THROUGH SATURDAY...

.TODAY...N wind 40 kt. Seas 16 ft. Heavy freezing spray.
.TONIGHT...N wind 30 kt. Seas 10 ft. Heavy freezing spray.
.SAT...E of Saint Matthew Island, N wind 25 kt. W of Saint Matthew
Island, E wind 30 kt becoming SE 40 kt in the afternoon. Seas 9
ft. Heavy freezing spray.
.SAT NIGHT...SE wind 40 kt. Seas 17 ft.
.SUN...SE wind 30 kt. Seas 17 ft.
.MON...E wind 30 kt. Seas 14 ft.
.TUE...NE wind 35 kt. Seas 14 ft.

$$

Southcentral and Southwest Alaska Forecast Discussion
National Weather Service Anchorage AK
545 AM AKST Thu Dec 30 2021

.ANALYSIS AND UPPER LEVELS...

The main synoptic feature is a negatively tilted shortwave trough
with a strong surface low lifting north of the Western Aleutians.
Based on the CIMSS MIMIC imagery, a deep fetch of southerly
moisture of 0.5-1.00 inch of precipitable water is extending
northward to Nunivak Island. A warm front extending east from this
low is accessing this moisture source, providing precipitation
across the Aleutians, Pribilofs, Alaska Peninsula, and southern
portions of Bristol Bay. Northwesterly gale force winds can be
seen on the ASCAT passes in response to a thermal gradient as
polar air wraps around the low. Meanwhile, a ridge of high
pressure extends from eastern Siberia southeastward along the
Southwest AK coast and into the northwestern Gulf.

Over Southcentral, a weak upper level wave moving downstream of
the ridge is beginning to develop a surface low south of the Kenai
Peninsula, with light precipitation remaining primarily offshore.
This wave will have minimal impact and expected to exit into the
southern Gulf later today. Otherwise, mid to high level clouds are
streaming ahead of the frontal system for areas of south of
Anchorage. Latest observations are reporting benign conditions
with overnight temperatures ranging anywhere between the teens to
the low 30s. Lastly, a trough with an embedded polar low centered
over the Beaufort Sea extends across the North Slope.

&&

.MODEL DISCUSSION...

The latest operational model runs are in good agreement with the
placement and intensity of synoptic scale features at both the
surface and in the upper levels. As the warm front advances east
today, some uncertainty remains for a wintry mix of precipitation
for parts of the northern Alaska Peninsula and Bristol Bay. This
includes the potential for a brief period of freezing rain, sleet,
and snow between Pilot Point and King Salmon. For Southcentral,
model solutions are in a consensus with a triple point low forming
along the frontal boundary near the southern coast of the Kenai
Peninsula on Friday morning. The differences, however, is the
exact precipitation timing and storm total amounts, but confidence
is high that this will be a snow event. Models are also keying on
an Arctic outbreak of cold air across the Alaska mainland,
leading to gusty winds for the bays and passes, heavy freezing
spray, as well as cold wind chills as we head into the weekend.

&&

.AVIATION...
PANC...VFR conditions and light winds will persist into this
evening. Snow will move into the area tonight, bringing MVFR to
IFR reductions to ceiling and visibility at the terminal.

&&

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

A warm front moving into the Kodiak area today will bring some
rainfall there by this afternoon. This front will develop a
triple point low south of the Kenai Peninsula this afternoon
which will keep the bulk of the warmer air from moving inland or
even to the north Gulf coast. With this low moving near Middleton
Island overnight, it will allow colder air to move into
Southcentral as a cold upper level trough moves into the area from
the west. The front aloft will override the colder surface air
over Southcentral tonight bringing in some snowfall. This snowfall
is expected to be generally light.

The pattern get a little more interesting Friday as the main
upper level low digs into Southcentral bringing much colder air to
the region. This will keep the snowfall going for most of the day
Friday. Most of this snowfall will also be light and general
amounts across Southcentral should be 2 to 4 inches for the
entire event. There is some disagreement on the timing of the
upper level low moving through. That matters since the snowfall
will generally end for an areas after the low moves past.

For Saturday, the pattern changes to a cold and windy one. Expect
skies to clear out, but gusty northerly winds will develop in the
normal places as the 850 mb temperatures plunge 15 to 20 degrees
from Friday to Saturday. This will also cause large areas of Heavy
freezing spray from Cook Inlet southward through Shelikof Strait
and the Alaska Peninsula.

&&

.SHORT TERM FORECAST SOUTHWEST ALASKA (Days 1 through 2: Today
through Friday night)...

A strong low moving across the Bering will send a front onshore
with light to moderate snowfall moving inland from southwest to
northeast through this evening. Across the Y-K Delta, easterly
winds will gust up to 40 mph will combine with falling snow and
produce significant areas of blowing snow and cause significantly
reduced visibility, especially along the immediate coastline. A
Winter Weather Advisory remains in effect for the Y-K Delta beginning
by noon today for the expected snow and blowing snow with the
front. Snowfall totals with the main round of snow continue to be
anticipated in the 4 to 6 inch range for the Y-K Delta, with lower
amounts of 2 to 4 inches expected across northern portions of
Bristol Bay.

Looking to the south closer to the Alaska Peninsula, the details
remain elusive for a more wintry mixed precipitation event that
will unfold in several short stages today. Current thinking is
that the leading edge of frontal precipitation will still start
out as snow over the northernmost parts of the Alaska Peninsula
and southern Bristol Bay later this morning. However, a weak nose
of warm air aloft is expected to move north just ahead of the
front above surface temperatures likely still hovering at or just
below freezing, setting up the potential for a myriad of
precipitation types ranging from snow, sleet, freezing rain and
rain. This wintry mix is most likely to occur with a transition
zone that will work north between near Pilot Point and King Salmon
over the course of the day. Fortunately, the layer of cold air at
the surface will remain shallow, and temperatures should easily
warm above the freezing mark and change the mix over to rain by
late this afternoon. Very little ice/sleet accumulations are
expected due to the short duration of the event for the areas
impacted.

By Friday morning, the front will become fully occluded as the
parent Bering low approaches from the west. Cooling temperatures
aloft will mostly put an end to any mixed precip, with more
showery snow drifting across the entire region on Friday as the
low weakens and drifts southeast towards the Alaska Peninsula.
Still, areas of freezing drizzle/mist will be possible in some
areas with the mid levels (including the dendritic growth zone,
an important layer for snow formation) drying out while low levels
remain saturated. Snow and any freezing drizzle will end from
north to south as drier air filters in and as the low crosses into
the Gulf. Expect rapidly falling temperatures as the snow and
cloud cover clear out by Friday evening as strong northerly flow
develops and quickly ushers a frigid, Arctic air mass south,
plunging the entire area back into a deep freeze (below 0F) to
kick off the new year.

&&

.SHORT TERM FORECAST BERING SEA/ALEUTIANS (Days 1 through 2:
Today through Friday night)...

A large low pressure system has made its way from the North
Pacific into the Bering this morning, with its attendant front
spiraling to the east and south across the Pribilofs and out into
the Alaska Peninsula. This will send mainly rain across the
eastern Aleutians and Pribilof Islands through this afternoon,
with a mix of rain and snow progressing across the western
aleutians on the back side of the low. Winds around the low and
it's associated front will peak later this afternoon and evening,
with storm force winds developing over the western Aleutians and
southwest Bering, as well as near St Matthew Island, through late
tonight. Cold air wrapping into the low from the low just above
the surface will help destabilized the marine layer near the
corridor of strongest winds, supporting Hurricane force gusts
roughly between Adak and Atka with gusts to 70 mph over land. The
low will weaken to gale force as it moves into the eastern Bering
and dives across the Alaska Peninsula on Friday, with rain showers
becoming snow showers across the entire Aleutian chain with much
colder air filtering in with strong northerly flow developing.
This will set the stage for strengthening gap winds through the
eastern Aleutians and Alaska Peninsula, with gusts increasing to
storm force by late Friday night. At the same time, another front
will bring southerly winds increasing to storm force over the far
western Aleutians/Bering. Heavy freezing spray will also become
increasingly widespread over the northern and eastern Bering
through Friday night.

&&

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

Bering...A low that tracks across the AKPEN Friday will bring
northerly winds across the Central and Eastern Bering Saturday.
Winds will peak at high- end gales on the backside of the low. As
the low exits into the Gulf, storm- force gap winds and heavy
freezing spray are possible south of the AKPEN Saturday through
early Sunday. In the Western Bering, a strong front will bring
southerly gales and areas of storm-force winds Saturday through
Sunday. Seas will be mostly 8-15 ft except 15-25 ft where gales
are expected. A ridge of high pressure will build over the Bering
Sunday night through Monday.

Gulf of Alaska...Gusty outflow winds intensify to gales early
Saturday and persist through Sunday, with storm-force winds likely
through Kamishak Gap. Heavy freezing spray is possible with these
strong and cold outflow winds that will continue through Monday.
Seas will increase to 15-25 ft Saturday though Monday.

&&

.LONG TERM FORECAST (Days 4 through 8: Sunday through Wednesday)...

An upper-level ridge in the Bering moves eastward into Alaska
through Tuesday, transitioning the weather towards cold and mostly
dry conditions. As a surface low, developed by an upper-level
trough located over Alaska, moves out of the Gulf through
Saturday, snow will slowly taper off. Cold, northerly gap winds
out of the AKPEN and northern Gulf Coast will continue through
Monday due to high pressure over the interior and ridging in the
Eastern Bering. Cold air advection and clearer skies at night will
allow temperatures to drop below negative during the weekend.

Behind the upper-level ridge, a strong warm front brings rain and
southerly winds as it tracks across the Aleutians through
Tuesday. Some uncertainty remains with how quickly the front will
move east. However, temperatures warm by Tuesday/Wednesday across
Southwest as the front approaches.

.AFC WATCHES/WARNINGS/ADVISORIES...
PUBLIC...Winter Weather Advisory: 155.
MARINE...Storm Warning: 155 165 170 172-174 178 185 411 413.
Gale Warning: 175-177 179 180 181 412 414.
Heavy Freezing Spray Warning: 180 181 185.
FIRE WEATHER...NONE.

&&

SYNOPSIS AND MODEL DISCUSSION...MF
SOUTHCENTRAL ALASKA...EZ
SOUTHWEST ALASKA/BERING SEA/ALEUTIANS...AS
MARINE/LONG TERM...NS