Storm Warning 218, NWS Anchorage, AK

884 
FZAK52 PAFC 100058
CWFALU

Coastal Waters Forecast
National Weather Service Anchorage Alaska
358 PM AKST Wed Dec 9 2020

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.

PKZ199-101415-
358 PM AKST Wed Dec 9 2020
.SYNOPSIS FOR SOUTHWEST ALASKA+BRISTOL BAY+THE ALASKA
PENINSULA WATERS AND THE ALEUTIAN ISLANDS...

A 971 mb low 185 nm south of Shemya moves around Kiska Thu afternoon
then moves to 190 nm north of Attu at 981 mb Fri afternoon. Its 
front moves over the Aleutians and Bering, then stalls in the 
Eastern Aleutians Thu afternoon. A strong North Pacific low moves 
along the front to 260 nm south of Sand Point at 964 mb by Fri 
afternoon.

$$

PKZ150-101415-
South of the AK Peninsula Sitkinak to Castle Cape-
358 PM AKST Wed Dec 9 2020

...GALE WARNING THURSDAY NIGHT...

.TONIGHT...NW wind 20 kt. Seas 8 ft. Freezing spray.
.THU...E wind up to 20 kt. Seas 5 ft.
.THU NIGHT...E wind 35 kt. Seas 7 ft building to 12 ft after 
midnight.
.FRI AND FRI NIGHT...E wind 40 kt. Seas 22 ft.
.SAT...E wind 30 kt. Seas 16 ft.
.SUN THROUGH MON...NW wind 15 kt. Seas 13 ft.

$$

PKZ155-101415-
South of the AK Peninsula Castle Cape to Cape Sarichef-
358 PM AKST Wed Dec 9 2020

...GALE WARNING THROUGH THURSDAY NIGHT...

.TONIGHT...E wind 25 kt becoming SE 35 kt after midnight. From the
Shumagin Islands E, variable wind 10 kt becoming SE 15 kt after
midnight. Seas 5 ft building to 9 ft except 5 ft from the Shumagin 
Islands E.
.THU...SE wind 40 kt except E 30 kt from the Shumagin Islands E.
Seas 14 ft building to 20 ft except 5ft building to 9 ft from the 
Shumagin Islands E.
.THU NIGHT...E wind 35 kt. Seas 18 ft except 13 ft from the Shumagin
Islands E.
.FRI AND FRI NIGHT...E wind 45 kt. Seas 26 ft.
.SAT...S wind 35 kt. Seas 19 ft.
.SUN THROUGH MON...W wind 15 kt. Seas 12 ft.

$$

PKZ160-101415-
Bristol Bay-
358 PM AKST Wed Dec 9 2020

...HEAVY FREEZING SPRAY WARNING THROUGH THURSDAY NIGHT...
...SMALL CRAFT ADVISORY THURSDAY AND THURSDAY NIGHT...

.TONIGHT...N wind 20 kt becoming NE 15 ft after midnight. Seas 5 ft.
Heavy freezing spray near the coast.
.THU...NE wind 30 kt. Seas 6 ft. Heavy freezing spray.
.THU NIGHT...NE wind 30 kt. Seas 6 ft. Heavy freezing spray.
.FRI...NE wind 30 kt. Seas 7 ft.
.FRI NIGHT...NE wind 35 kt. Seas 8 ft.
.SAT...NE wind 35 kt. Seas 7 ft.
.SUN...NE wind 20 kt. Seas 5 ft.
.MON...NE wind 15 kt. Seas 2 ft.

$$

PKZ165-101415-
Port Heiden to Cape Sarichef-
358 PM AKST Wed Dec 9 2020

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

.TONIGHT...E wind 30 kt except NE 20 kt from Port Moller E. Seas
7 ft. Freezing spray.
.THU...E wind 40 kt except E 30 kt from Port Moller E. Seas 9 ft. 
Freezing spray.
.THU NIGHT...SE wind 40 kt becoming E 30 kt after midnight. From
Port Moller E, E wind 25 kt. Seas 10 ft.
.FRI...E wind 35 kt. Seas 10 ft.
.FRI NIGHT...E wind 40 kt. Seas 15 ft.
.SAT...E wind 40 kt. Seas 13 ft.
.SUN...N wind 15 kt. Seas 6 ft.
.MON...Variable wind 10 kt. Seas 6 ft.

$$

PKZ170-101415-
Cape Sarichef to Nikolski Bering Side-
358 PM AKST Wed Dec 9 2020

...STORM WARNING TONIGHT...

.TONIGHT...E wind 50 kt. Gusts to 65 kt. Seas 12 ft building to 17 
ft after midnight. Snow and rain.
.THU...SE wind 45 kt. Seas 17 ft. Rain.
.THU NIGHT...SE wind 40 kt diminishing to 25 kt after midnight.
Seas 16 ft subsiding to 11 ft after midnight. Rain and widespread 
snow showers.
.FRI...E wind 25 kt. Seas 8 ft.
.FRI NIGHT...NE wind 30 kt. Seas 13 ft.
.SAT...NW wind 25 kt. Seas 12 ft.
.SUN THROUGH MON...W wind 15 kt. Seas 9 ft.

$$

PKZ171-101415-
Unalaska Bay-
358 PM AKST Wed Dec 9 2020

...GALE WARNING THROUGH THURSDAY NIGHT...
 
.TONIGHT...SE wind increasing to 45 kt with gusts to 55 ft after 
midnight. Seas 7 ft. Snow and rain.
.THU...SE wind 45 kt. Seas 7 ft. Rain.
.THU NIGHT...SE wind 35 kt diminishing to 20 kt after midnight.
Seas 5 ft subsiding to 3 ft after midnight. Rain and snow.
.FRI...NE wind 15 kt. Seas 4 ft.
.FRI NIGHT...N wind 15 kt. Seas 5 ft.
.SAT...W wind 15 kt. Seas 5 ft.
.SUN THROUGH MON...W wind 10 kt. Seas 3 ft.

$$

PKZ172-101415-
Cape Sarichef to Nikolski Pacific Side-
358 PM AKST Wed Dec 9 2020

...STORM WARNING TONIGHT...

.TONIGHT...E wind 50 kt. Seas 16 ft building to 24 ft after
midnight. Rain.
.THU...SE wind 45 kt. Seas 25 ft. Rain.
.THU NIGHT...SE wind 35 kt becoming SE 25 kt after midnight. Seas
22 ft subsiding to 16 ft after midnight. Widespread rain showers.
.FRI...NE wind 30 kt. Seas 19 ft.
.FRI NIGHT...NW wind 30 kt. Seas 21 ft.
.SAT...W wind 30 kt. Seas 16 ft.
.SUN...W wind 25 kt. Seas 13 ft.
.MON...W wind 15 kt. Seas 9 ft.

$$

PKZ173-101415-
Nikolski to Seguam Island Bering Side-
358 PM AKST Wed Dec 9 2020

...STORM WARNING TONIGHT...

.TONIGHT...E wind 55 kt. Gusts to 70 kt. Seas 25 ft. Rain and snow.
.THU...S wind 15 kt. Seas 16 ft subsiding to 12 ft by afternoon. 
Rain.
.THU NIGHT...SE wind 25 kt. Seas 12 ft.
.FRI...SE wind 20 kt. Seas 10 ft.
.FRI NIGHT...N wind 15 kt. Seas 7 ft.
.SAT...NW wind 25 kt. Seas 10 ft.
.SUN THROUGH MON...NW wind 20 kt. Seas 11 ft.

$$

PKZ174-101415-
Nikolski to Seguam Island Pacific Side-
358 PM AKST Wed Dec 9 2020

...STORM WARNING TONIGHT...

.TONIGHT...SE wind 55 kt with gusts to 70 kt becoming S 35 kt after 
midnight. Seas 25 ft subsiding to 21 ft after midnight. Rain and 
snow.
.THU...SW wind 15 kt. Seas 19 ft subsiding to 16 ft by afternoon.
.THU NIGHT...S wind 20 kt. Seas 18 ft.
.FRI...S wind 15 kt. Seas 17 ft.
.FRI NIGHT...W wind 20 kt. Seas 16 ft.
.SAT...W wind 30 kt. Seas 17 ft.
.SUN...W wind 25 kt. Seas 15 ft.
.MON...NW wind 20 kt. Seas 10 ft.

$$

PKZ175-101415-
Seguam Island to Adak Bering Side-
358 PM AKST Wed Dec 9 2020

...STORM WARNING TONIGHT...

.TONIGHT...SE wind 55 kt with gusts to 65 kt becoming S 25 kt after 
midnight. Seas 23 ft subsiding to 17 ft after midnight. Rain and 
snow.
.THU...S wind 25 kt. Seas 15 ft.
.THU NIGHT...SE wind 25 kt. Seas 12 ft.
.FRI...S wind 20 kt. Seas 11 ft.
.FRI NIGHT...S wind 15 kt. Seas 7 ft.
.SAT THROUGH MON...NW wind 20 kt. Seas 11 ft.

$$

PKZ176-101415-
Seguam Island to Adak Pacific Side-
358 PM AKST Wed Dec 9 2020

...STORM WARNING TONIGHT...

.TONIGHT...S wind 50 kt with gusts to 60 kt diminishing to 25 kt 
after midnight. Seas 25 ft subsiding to 21 ft after midnight. Rain.
.THU...S wind 30 kt. Seas 21 ft.
.THU NIGHT...S wind 25 kt. Seas 20 ft.
.FRI...SW wind 20 kt. Seas 17 ft.
.FRI NIGHT...W wind 30 kt. Seas 17 ft.
.SAT...W wind 30 kt. Seas 17 ft.
.SUN...NW wind 25 kt. Seas 16 ft.
.MON...NW wind 20 kt. Seas 11 ft.

$$

PKZ177-101415-
Adak to Kiska-
358 PM AKST Wed Dec 9 2020

...GALE WARNING TONIGHT...

.TONIGHT...S wind 35 kt diminishing to 25 kt after midnight. Seas
18 ft.
.THU...S wind 30 kt. Seas 16 ft except 20 ft Pacific side. Rain 
showers.
.THU NIGHT...S wind 20 kt. Seas 16 ft except 12 ft Bering Side.
.FRI...SW wind 25 kt. Seas 17 ft.
.FRI NIGHT...W wind 30 kt. Seas 17 ft.
.SAT THROUGH SUN...NW wind 30 kt. Seas 16 ft.
.MON...N wind 15 kt. Seas 10 ft.

$$

PKZ178-101415-
Kiska to Attu-
358 PM AKST Wed Dec 9 2020

...SMALL CRAFT ADVISORY THROUGH THURSDAY NIGHT...

.TONIGHT...NE wind 30 kt. Seas 17 ft except 13 ft Pacific side.
.THU...NE wind 25 kt except NW 20 kt Pacific Side. Seas 17 ft except
13 ft Pacific side.
.THU NIGHT...NE wind 20 kt except W 20 Pacific Side. Seas 18 ft
except 14 ft Pacific side.
.FRI...NW wind 25 kt. Seas 16 ft.
.FRI NIGHT...W wind 30 kt. Seas 15 ft.
.SAT THROUGH SUN...NW wind 30 kt. Seas 14 ft.
.MON...NE wind 25 kt. Seas 13 ft.

$$

PKZ179-101415-
Pribilof Islands Near Shore Waters-
358 PM AKST Wed Dec 9 2020

...STORM WARNING THROUGH THURSDAY NIGHT...

.TONIGHT...E wind 40 kt increasing to 50 kt with gusts to 60 kt 
after midnight. Seas 12 ft building to 18 ft after midnight.
.THU...E wind 50 kt. Gusts to 65 kt. Seas 23 ft. Snow and rain.
.THU NIGHT...E wind 50 kt with gusts to 60 kt becoming SE 20 kt 
after midnight. Seas 23 ft subsiding to 15 ft after midnight. Rain.
.FRI...E wind 25 kt. Seas 11 ft.
.FRI NIGHT...E wind 30 kt. Seas 12 ft.
.SAT...NE wind 30 kt. Seas 14 ft.
.SUN THROUGH MON...N wind 20 kt. Seas 12 ft.

$$

PKZ180-101415-
Kuskokwim Delta and Etolin Strait-
358 PM AKST Wed Dec 9 2020

...GALE WARNING THURSDAY AND THURSDAY NIGHT...
...HEAVY FREEZING SPRAY WARNING THROUGH THURSDAY NIGHT...

.TONIGHT...NE wind 30 kt. Seas 6 ft. Heavy freezing spray.
.THU...E wind 35 kt. Seas 10 ft. Heavy freezing spray.
.THU NIGHT...E wind 35 kt. Seas 11 ft. Heavy freezing spray..
.FRI...E wind 30 kt. Seas 9 ft.
.FRI NIGHT...NE wind 35 kt. Seas 11 ft.
.SAT...NE wind 40 kt. Seas 11 ft.
.SUN...NE wind 30 kt. Seas 9 ft.
.MON...NE wind 20 kt. Seas 6 ft.

$$

PKZ181-101415-
North and West of Nunivak Island-
358 PM AKST Wed Dec 9 2020

...GALE WARNING THURSDAY AND THURSDAY NIGHT...
...HEAVY FREEZING SPRAY WARNING THROUGH THURSDAY NIGHT...

.TONIGHT...NE wind 20 kt becoming E 30 kt after midnight. Seas 6 ft.
Heavy freezing spray after midnight.
.THU...E wind 40 kt. Seas 12 ft. Heavy freezing spray.
.THU NIGHT...E wind 40 kt. Seas 12 ft. Heavy freezing spray.
.FRI AND FRI NIGHT...NE wind 30 kt. Seas 11 ft.
.SAT THROUGH MON...NE wind 30 kt. Seas 11 ft.

$$

PKZ185-101415-
Saint Matthew Island Waters-
358 PM AKST Wed Dec 9 2020

...STORM WARNING THURSDAY AND THURSDAY NIGHT...
...HEAVY FREEZING SPRAY WARNING THURSDAY NIGHT...

.TONIGHT...E wind 35 kt E of Saint Matthew Island...E 45 kt W of
Saint Matthew Island. Seas 12 ft building to 18 ft after midnight.
Freezing spray.
.THU...E wind 50 kt. Gusts to 65 kt. Seas 29 ft. Freezing spray.
.THU NIGHT...E wind 55 kt. Gusts to 65 kt. Seas 32 ft. Heavy 
freezing spray. Widespread snow showers.
.FRI...E wind 50 kt. Seas 27 ft.
.FRI NIGHT...E wind 35 kt. Seas 18 ft.
.SAT...NE wind 35 kt. Seas 16 ft.
.SUN THROUGH MON...NE wind 30 kt. Seas 17 ft.

$$

Southcentral and Southwest Alaska Forecast Discussion
National Weather Service Anchorage AK
516 AM AKST Wed Dec 9 2020

.ANALYSIS AND UPPER LEVELS...

An upper-level trough pushes northeast across the Southern
portion of the state through Thursday afternoon. A band of snow
ahead of the trough with travel across the Kenai Peninsula towards
Anchorage and the North Gulf Coast, also hitting parts of the
Mat-Su Valleys as well. A ridge of high pressure will build
behind the trough and encompass Southern Alaska Thursday and
Friday. Thus, expect clear and dry conditions towards the end of
the week. Out west, a storm force low pressure system with
multiple embedded surface lows continues to bombard the Western
Bering as its front progresses towards the Southwest Coast
through Thursday night. This front will have occluded before
reaching the coast and is not expected to have significant impact
and will likely diminish before making it onshore. By the end of
the week, a second strong system out of the North Pacific is
expected to approach the Southern AKPEN.

&&

.MODEL DISCUSSION...

There is relatively good model agreement in the short term.
Solutions have come into better agreement on the orientation of
the upper-level trough moving northeast across the state today
and tomorrow. Decent model agreement as well for the upper-level
ridge that moves across Southern Alaska Thursday and Friday. By
Friday, models begin to disagree across for a seemingly strong
North Pacific low approaching the Southern AKPEN Friday afternoon.
There is some similarity on the general track but distinct
differences on speed, location, and strength. NAM/ECMWF puts this
low around 968 mb on Friday while the GFS is stronger (963 mb) and
the Canadian- NH is weaker (975 mb).

&&

.AVIATION...
PANC...VFR conditions will persist throughout today. A band of
snow showers are expected to pass through this evening, bringing
conditions back down to marginal. Conditions should improve by
Thursday morning.

&&

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

A cold upper trough over Southwest Alaska moves slowly across
Southcentral tonight and early Thursday. Snow showers, perhaps
mixed at times along the North Gulf Coast, will remain fairly
persistent over the Southern/Eastern Kenai Peninsula and North
Gulf until trough passage tonight. Inland areas will see some
isolated snow shower activity today, becoming more persistent as
the trough moves through tonight. Drier conditions are expected
on Thursday/Thursday night with the onset of broad offshore flow
and weak gap winds over the North Gulf Coast and Eastern Kenai
Peninsula. Conditions may also become favorable for low stratus
and fog to develop along Turnagain Arm and Anchorage Bowl
Thursday night with generally light flow and low level temperature
inversions.

&&

.SHORT TERM FORECAST SOUTHWEST ALASKA (Days 1 through 3: Wednesday
morning through Saturday morning)...

Weak circulation over the Bristol Bay area this morning will
continue to bring light snow showers as the dissipating area of
low pressure moves east. A very cold airmass has begun to move in
from the north across the Kuskokwim Delta and Lower Kuskokwim
Valley and temperatures across much of the northern parts of
Southwest will not climb above single digits today. Overnight
temperatures will drop tonight to 10 to 15 degrees below zero
across the north while overnight lows will be in the single digits
below zero across the Bristol Bay region. Clear conditions are
expected for Thursday as an upper level ridge of high pressure
builds ahead of an advancing front. By Thursday evening, cloud
cover will spread in overhead as the leading front associated with
a storm force low in the Bering approaches the coast Friday
morning. In response to this approaching front, offshore winds
will pick up along the coast late Thursday. A North Pacific low
approaches the Alaska Peninsula Friday morning, bringing easterly
gale force winds. Models continue to struggle with this low, so
there is less confidence in track and strength at this time.
Precipitation with this system will spread northward across the
Alaska Peninsula and the Bristol Bay region Friday into Saturday.
Given southerly flow and a warmer airmass with this low, a
rain/snow mix, or all rain is the more likely form of
precipitation this weekend with snow accumulations expected at
higher elevations.

&&

.SHORT TERM FORECAST BERING SEA/ALEUTIANS (Days 1 through 3:
Wednesday morning through Saturday morning)...

Satellite imagery this morning shows a 971 mb storm force low
centered south of Shemya. Several smaller mesolows are embedded
within the leading front as it gradually moves eastward across the
Chain. Easterly to southeasterly storm force winds are expected
across the western and central Bering waters this afternoon as
the front advances eastward, reaching the Central Aleutians by
this evening. Given a much warmer airmass, precipitation is
expected to fall as a rain/snow mix initially with a quick change
to all rain along the Aleutian Chain. Across the northern Bering,
precipitation will like be all snow, with the Pribilof Islands
also likely to see more snow until a change to rain by late
Thursday. Overall, this is a pretty moist system, so expecting
higher QPF values with this front. Storm force winds are expected
to persist across the Northern Bering waters through Thursday
night before diminishing Friday morning. The weakened parent low
will remain in place over the western Bering, keeping snow showers
likely across the western Aleutians for Friday. Another low
approaches from the North Pacific Friday morning and tracks
northward toward the Alaska Peninsula and Eastern Bering. Models
continue to struggle with this low, so there is lower confidence
in the track and strength at this time.

&&

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

Bering: A broad area of low pressure over the Western Bering will
produce some easterly Gales across the Northern Bering early on
Friday before weakening late day. Friday night into Saturday there
is model disagreement as to how quickly a strong low will
cross the Eastern Aleutians into the Eastern Bering, with risks
being towards stronger easterly winds than currently forecasted.
While the positioning of this low is uncertain heading into Sunday
there is general agreement on winds falling below gales across
most of the Bering.

Gulf of Alaska: A North Pacific low lifting towards the Eastern
Aleutians may generate some easterly Gales across the Southwestern
Gulf of Alaska on Friday before this system moves west of the
area and weakens. Later on Saturday into Sunday another low in the
North Pacific looks to lift into the eastern Gulf of Alaska.
Currently the winds look to remain below gale force across the
Western/Central Gulf, but if this storm takes a further westward
track there could be a period of Gales late Sunday before the
storm weakens.

&&

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

On Saturday we kick things off with a strong low just to the
south of the AKPEN. Most guidance points towards this low crossing
into the Bering Saturday morning and then eventually
weakening/being absorbed into a broader low complex. This storm
should bring a rain/snow mix to start, but a quick transition to
all rain for the eastern Aleutians and southern AKPEN.

Late Saturday another storm looks to lift out of the North
Pacific and into the Bering, ultimately aiming for the Northern
Gulf Coast by Sunday, but with jet support staying well south of
the area,this low looks to be weakening rapidly as it approaches
and it seems most of the precipitation impacts will remain
confined to coastal areas, with the interior staying quiet.

By Monday and Tuesday model agreement falls apart, with little
left in the way of coherent signal to work with. That being said
the primary jet looks to remain well to our south, so odds are the
pattern will remain relatively quiet across much of Mainland
Alaska, with the storm track generally remaining out over the
North Pacific.

&&

.AFC WATCHES/WARNINGS/ADVISORIES...
PUBLIC...NONE.
MARINE...Storm: 411-414, 173-176, 179, 185
		 Gale: 352, 130-131, 155, 165, 170-172, 177-178, 180-181
		 Heavy Freezing Spray: 130, 160, 180-181
FIRE WEATHER...NONE.

&&

SYNOPSIS AND MODEL DISCUSSION...KM
SOUTHCENTRAL ALASKA...RMC
SOUTHWEST ALASKA/BERING SEA/ALEUTIANS...KO
MARINE/LONG TERM...BG

SPECIAL WEATHER STATEMENT
National Weather Service ANCHORAGE AK
357 AM AKST Wed Dec 9 2020

AKZ125-100400-
Western Prince William Sound-
Including the cities of Whittier, Seward, Girdwood,
and Moose Pass
357 AM AKST Wed Dec 9 2020

...HEAVY SNOW POSSIBLE ALONG THE SEWARD HIGHWAY FROM MOOSE PASS
TO SEWARD THROUGH EARLY THIS EVENING...

Snow showers are expected across the southern Kenai Peninsula
with bands of locally heavy snow at times through early this
evening. Snowfall rates of 1 to 2 inches per hour are possible
along the Seward Highway from Moose Pass to Seward in the heavier
snow bands with visibility dropping to as low as one quarter mile.
Up to one foot of snow is possible before the snow tapers off
this evening.