Small Craft Advisory 975, NWS Anchorage, AK

948 
FZAK52 PAFC 211421 CCA
CWFALU

Coastal Waters Forecast...CORRECTED
National Weather Service Anchorage Alaska
521 AM AKST Thu Dec 21 2017

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.

PKZ199-220200-
521 AM AKST Thu Dec 21 2017
.SYNOPSIS FOR SOUTHWEST ALASKA+BRISTOL BAY+THE ALASKA
PENINSULA WATERS AND THE ALEUTIAN ISLANDS...
A 978 mb low will move to 380 nm southeast of Dutch Harbor this 
afternoon, then it will move to 50 nm east of St. George at 975 
mb Fri morning, then it will move into the northern Bering Fri 
afternoon. A second low will move to 225 nm southeast of Sand
Point at 977 mb Fri night then it will move near 80 nm southeast
of Sand Point at 976 mb Sat morning.

$$

PKZ150-220200-
South of the AK Peninsula Sitkinak to Castle Cape-
521 AM AKST Thu Dec 21 2017

...STORM WARNING THROUGH TONIGHT...

.TODAY...E wind 30 kt increasing to 50 kt in the afternoon. Seas 15 
ft building to 24 ft in the afternoon. Rain.
.TONIGHT...E wind 55 kt. Seas 33 ft. Rain.
.FRI...SE wind 45 kt. Seas 27 ft. Rain.
.FRI NIGHT...SE wind 40 kt. Seas 23 ft.
.SAT...S wind 30 kt. Seas 21 ft.
.SUN...W wind 25 kt. Seas 13 ft.
.MON...NW wind 15 kt. Seas 8 ft.

$$

PKZ155-220200-
South of the AK Peninsula Castle Cape to Cape Sarichef-
521 AM AKST Thu Dec 21 2017

...STORM WARNING THROUGH TONIGHT...

.TODAY...E wind 35 kt increasing to 50 kt in the afternoon. Seas 17 
ft building to 24 ft in the afternoon. Rain.
.TONIGHT...E wind 40 kt becoming SE 30 kt after midnight. From the
Shumagin Islands E, E wind 50 kt. Seas 24 ft except 31 ft from the
Shumagin Islands E. Rain.
.FRI...S wind 25 kt except E 35 kt from the Shumagin Islands E. Seas
23 ft. Rain.
.FRI NIGHT...SE wind 35 kt. Seas 20 ft.
.SAT...W wind 35 kt. Seas 20 ft.
.SUN...W wind 20 kt. Seas 11 ft.
.MON...N wind 20 kt. Seas 8 ft.

$$

PKZ160-220200-
Bristol Bay-
521 AM AKST Thu Dec 21 2017

...STORM WARNING TONIGHT AND FRIDAY...

.TODAY...E wind 30 kt increasing to 45 kt in the afternoon. Seas
building to 11 ft.
.TONIGHT...E wind 55 kt. Seas 15 ft.
.FRI...E wind 50 kt. Seas 14 ft.
.FRI NIGHT...E wind 40 kt. Seas 10 ft.
.SAT...SE wind 40 kt. Seas 10 ft.
.SUN...W wind 20 kt. Seas 8 ft.
.MON...W wind 15 kt. Seas 5 ft.

$$

PKZ165-220200-
Port Heiden to Cape Sarichef-
521 AM AKST Thu Dec 21 2017

...STORM WARNING TONIGHT...

.TODAY...SE wind 35 kt except increasing to E 45 kt from Port Moller
E. Seas 12 ft. Rain with snow.
.TONIGHT...E wind 40 kt except E 50 kt from Port Moller E. Seas
15 ft. Rain.
.FRI...SE wind 40 kt. Seas 13 ft.
.FRI NIGHT...E wind 35 kt. Seas 12 ft.
.SAT...W wind 30 kt. Seas 18 ft.
.SUN...W wind 20 kt. Seas 12 ft.
.MON...N wind 15 kt. Seas 6 ft.

$$

PKZ170-220200-
Cape Sarichef to Nikolski Bering Side-
521 AM AKST Thu Dec 21 2017

...GALE WARNING TODAY AND FRIDAY...

.TODAY...SE wind 35 kt. Seas 15 ft. Rain.
.TONIGHT...E wind 25 kt becoming SW after midnight. Seas 10 ft.
Rain and snow showers.
.FRI...W wind 35 kt except SW 15 kt from Unalaska E. Seas 14 ft 
building to 19 ft in the afternoon. Snow.
.FRI NIGHT...NW wind 40 kt. Seas 22 ft.
.SAT...W wind 35 kt. Seas 22 ft.
.SUN...W wind 20 kt. Seas 10 ft.
.MON...N wind 15 kt. Seas 8 ft.

$$

PKZ171-220200-
Unalaska Bay-
521 AM AKST Thu Dec 21 2017

...GALE WARNING TODAY...

.TODAY...SE wind 35 kt diminishing to 25 kt in the afternoon. Gusts
to 45 kt in the morning. Seas 5 ft. Rain.
.TONIGHT...NE wind 10 kt becoming W after midnight. Seas 3 ft.
Widespread rain and snow showers.
.FRI...W wind 20 kt. Seas 2 ft. Snow.
.FRI NIGHT...NW wind 35 kt. Seas 13 ft.
.SAT...W wind 35 kt. Seas 5 ft.
.SUN...W wind 15 kt. Seas 2 ft.
.MON...N wind 10 kt. Seas 3 ft.

$$

PKZ172-220200-
Cape Sarichef to Nikolski Pacific Side-
521 AM AKST Thu Dec 21 2017

...GALE WARNING TODAY AND FRIDAY...

.TODAY...SE wind 35 kt diminishing to 25 kt in the afternoon. Seas 
19 ft. Rain.
.TONIGHT...N wind 30 kt. Seas 20 ft. Rain.
.FRI...W wind 40 kt. Seas 21 ft. Snow showers and rain showers.
.FRI NIGHT...NW wind 40 kt. Seas 19 ft.
.SAT...W wind 35 kt. Seas 18 ft.
.SUN...W wind 20 kt. Seas 8 ft.
.MON...N wind 15 kt. Seas 7 ft.

$$

PKZ173-220200-
Nikloski to Seguam Island Bering Side-
521 AM AKST Thu Dec 21 2017

...GALE WARNING THROUGH FRIDAY...

.TODAY...SE wind 40 kt becoming W 30 kt in the afternoon. Seas
18 ft. Rain.
.TONIGHT...W wind 30 kt increasing to 45 kt after midnight. Seas
15 ft building to 22 ft after midnight. Snow showers and rain
showers.
.FRI...W wind 45 kt. Seas 26 ft. Snow showers.
.FRI NIGHT...NW wind 35 kt. Seas 22 ft.
.SAT...W wind 25 kt. Seas 16 ft.
.SUN...W wind 20 kt. Seas 9 ft.
.MON...Variable wind 10 kt. Seas 9 ft.

$$

PKZ174-220200-
Nikolski to Seguam Island Pacific Side-
521 AM AKST Thu Dec 21 2017

...GALE WARNING THROUGH FRIDAY...

.TODAY...S wind 40 kt becoming W 30 kt in the afternoon. Seas 23
ft. Rain.
.TONIGHT...W wind 30 kt increasing to 40 kt after midnight. Seas
21 ft. Snow and rain showers.
.FRI...W wind 45 kt. Seas 25 ft. Snow showers.
.FRI NIGHT...NW wind 35 kt. Seas 20 ft.
.SAT...W wind 30 kt. Seas 15 ft.
.SUN...W wind 15 kt. Seas 10 ft.
.MON...Variable wind 10 kt. Seas 7 ft.

$$

PKZ175-220200-
Seguam Island to Adak Bering Side-
521 AM AKST Thu Dec 21 2017

...GALE WARNING THROUGH FRIDAY...

.TODAY...NW wind 35 kt. Seas 17 ft.
.TONIGHT...NW wind 45 kt. Seas 17 ft building to 24 ft after
midnight.
.FRI...NW wind 45 kt. Seas 25 ft.
.FRI NIGHT...W wind 30 kt. Seas 17 ft.
.SAT...W wind 25 kt. Seas 12 ft.
.SUN...SW wind 20 kt. Seas 11 ft.
.MON...S wind 15 kt. Seas 7 ft.

$$

PKZ176-220200-
Seguam Island to Adak Pacific Side-
521 AM AKST Thu Dec 21 2017

...GALE WARNING THROUGH FRIDAY...

.TODAY...NW wind 40 kt becoming W 30 kt in the afternoon. Seas
20 ft.
.TONIGHT...NW wind 30 kt increasing to 40 kt after midnight. Seas
20 ft. Snow showers.
.FRI...NW wind 40 kt. Seas 19 ft.
.FRI NIGHT...W wind 25 kt. Seas 14 ft.
.SAT...W wind 25 kt. Seas 12 ft.
.SUN...SW wind 15 kt. Seas 10 ft.
.MON...SE wind 15 kt. Seas 8 ft.

$$

PKZ177-220200-
Adak to Kiska-
521 AM AKST Thu Dec 21 2017

...GALE WARNING TODAY...

.TODAY...W wind 35 kt...except 25 kt Bering Side. Bering side, seas 
10 ft building to 15 ft in the afternoon. Pacific side, seas 23 ft. 
Snow showers.
.TONIGHT...NW wind 30 kt. Seas 15 ft bering side...22 ft Pacific 
side.
.FRI...NW wind 20 kt. Seas 15 ft.
.FRI NIGHT...W wind 25 kt. Seas 12 ft.
.SAT THROUGH SUN...W wind 25 kt. Seas 12 ft.
.MON...N wind 20 kt. Seas 9 ft.

$$

PKZ178-220200-
Kiska to Attu-
521 AM AKST Thu Dec 21 2017

...GALE WARNING TODAY...

.TODAY...NW wind 35 kt. Seas 21 ft. Snow showers.
.TONIGHT...NW wind 25 kt becoming W 15 kt after midnight. Seas
14 ft.
.FRI...W wind 15 kt increasing to 25 kt in the afternoon. Seas
10 ft.
.FRI NIGHT...W wind 25 kt. Seas 11 ft.
.SAT THROUGH SUN...W wind 25 kt. Seas 12 ft.
.MON...SE wind 30 kt. Seas 11 ft.

$$

PKZ179-220200-
Pribilof Islands Near Shore Waters-
521 AM AKST Thu Dec 21 2017

...GALE WARNING TODAY...

.TODAY...SE wind 40 kt. Seas 21 ft. Rain.
.TONIGHT...E wind 30 kt diminishing to 20 kt after midnight. Seas
15 ft. Rain.
.FRI...Variable wind 10 kt. Seas 11 ft.
.FRI NIGHT...NW wind 35 kt. Seas 18 ft.
.SAT...W wind 35 kt. Seas 18 ft.
.SUN...NW wind 20 kt. Seas 10 ft.
.MON...Variable wind 10 kt. Seas 9 ft.

$$

PKZ180-220200-
Kuskokwim Delta and Etolin Strait-
521 AM AKST Thu Dec 21 2017

...STORM WARNING TONIGHT AND FRIDAY...

.TODAY...SE wind 45 kt. Seas 17 ft. Rain.
.TONIGHT...E wind 55 kt. Seas 20 ft. Rain and snow.
.FRI...SE wind 55 kt. Seas 19 ft. Rain.
.FRI NIGHT...E wind 40 kt. Seas 15 ft.
.SAT...S wind 40 kt. Seas 13 ft.
.SUN...W wind 25 kt. Seas 11 ft.
.MON...W wind 15 kt. Seas 6 ft.

$$

PKZ181-220200-
North and West of Nunivak Island-
521 AM AKST Thu Dec 21 2017

...GALE WARNING THROUGH FRIDAY...

.TODAY...SE wind 40 kt. Seas 17 ft. Snow and rain.
.TONIGHT...SE wind 40 kt. Seas 16 ft. Snow and rain.
.FRI...SE wind 45 kt. Seas 18 ft. Rain and snow.
.FRI NIGHT...SE wind 40 kt. Seas 14 ft.
.SAT...SE wind 30 kt. Seas 11 ft.
.SUN...NW wind 25 kt. Seas 11 ft.
.MON...W wind 15 kt. Seas 8 ft.

$$

PKZ185-220200-
Saint Matthew Island Waters-
521 AM AKST Thu Dec 21 2017

...GALE WARNING THROUGH FRIDAY...

.TODAY...SE wind 35 kt. Seas 18 ft. Snow and rain.
.TONIGHT...E wind 35 kt. Seas 17 ft. Freezing spray. Snow.
.FRI...NE wind 40 kt. Seas 18 ft. Widespread snow showers and
rain.
.FRI NIGHT...W wind 30 kt. Seas 15 ft.
.SAT...W wind 30 kt. Seas 12 ft.
.SUN...NW wind 25 kt. Seas 10 ft.
.MON...NW wind 15 kt. Seas 9 ft.

$$

Southcentral and Southwest Alaska Forecast Discussion
National Weather Service Anchorage AK
408 PM AKST Wed Dec 20 2017

.ANALYSIS AND UPPER LEVELS...
The remnants of a once powerful Bering Sea low is moving east as
a low amplitude (and deamplifying still) shortwave trough tracks
across the ALCAN. Weak upper ridging is building over Southwest
Alaska ahead of a digging upper level trough over the western
Bering Sea and into the North Pacific. There is a ridge over the
northeast Pacific and a cutoff low to it's west near 38N. Closer
to home, a storm force front is stalled over the central Bering.
At the surface across Southcentral, the dichotomy in the pattern
is clear as there is a weak but obvious up-inlet flow over Cook
Inlet while a subtle offshore flow remains from Prince William
Sound eastward.

&&

.MODEL DISCUSSION...
The numerical models are in excellent agreement with the large
scale general synoptic pattern through the weekend. A duo of
powerful surface lows are expected to reinforce a strong
baroclinic zone over the eastern Bering Sea Thursday night and
Friday night, and while there remains some disagreement still with
the exact track of the second low, the models are now largely in
good agreement with increase forecast confidence of impacts across
Southwest Alaska and the eastern Bering Sea. The NAM hi-res was
favored over Southcentral for local gap winds while the GFS was
favored for the strong front over the Bering Sea and Southwest
Alaska.

&&

.AVIATION...
PANC...VFR conditions will develop late this afternoon. Some
patchy fog and/or low stratus is possible over the terminal
beginning around midnight, and clearing by early Thursday
afternoon.

&&

.SHORT TERM FORECAST SOUTHCENTRAL ALASKA (Days 1 and 2)...
A weak upper level trough will move across the Copper River Basin
this evening providing enough instability to trigger some snow
showers in the residual moisture left from the previous system
than moved through overnight. This will be followed by rapidly
diminishing cloud cover and the onset of a strong radiational
cooling inversion over the Basin that will likely result in low
stratus and fog throughout much of the low lying areas in the
Basin. Over the Kenai Peninsula and Cook Inlet we should also see
an inversion with areas of fog, however, the down Inlet flow will
help to mix out some of the inversion, thus the fog should be
limited to wind protected areas. There is a chance the fog will
persist well into the day tomorrow under a ridge aloft that will
build over the Copper River Basin.

Another storm will move to south of the Alaska Peninsula Thursday
resulting in a tight gradient and strong wind extending northeast
to the Barren Islands. This will also push rain to Kodiak Island.
We will back off on the onset of the rain along the outer coast of
the Kenai Peninsula to account for a slightly slower progression
of the storm and precipitation field in the latest model run.

&&

.SHORT TERM FORECAST SOUTHWEST ALASKA (Days 1 and 2)...
Sensible weather-wise, much of the southwest will be dry for the
ensuing 24 hr period which will prove to be a lull before the next
storm. Thursday evening, the precipitation shield will move into
the AKPEN, Eastern Bristol Bay and up the Kuskokwim Delta. The
projected thermal profiles suggest another wintry mix at the onset
of the storm. However, by Friday morning the precip type will
change over to rain along the coast. The models are in sync with
the tight pressure gradient over the AKPEN and Bristol Bay
Thursday afternoon and Friday. Gaps and downslope wind prone
areas along the AK pen will get hammered with winds. Confidence
begins to wane over the weekend due to the placement of a
secondary low but there is potential that this secondary low could
bring a prolonged period of strong/gusty winds to Bristol Bay and
the Kuskokwim Delta into Saturday. Stay tuned for more details.

&&

.SHORT TERM FORECAST BERING SEA/ALEUTIANS (Days 1 and 2)...
Unsettled weather will continue as a series of lows trek across
the region. The forecast period commences with a surface low near
Adak. This low will continue to produce gusty winds across the
Aleutians. As time elapses, a second system will move into the
region from the southwest/North Pacific which will keep the tight
pressure gradient over the Eastern Aleutians. In addition to gusty
winds, the models ping into a deep fetch of moisture associated
with the warm sector. By Friday, a new disturbance will approach
Attu Island and Shemya.

&&

.LONG TERM FORECAST (Friday through Tuesday)...
By Friday, southern Alaska will be in the thick of things
weather-wise, with a low pressure system in the northern Bering
and another one close on its heels south of the AK Pen. This will
bring a strong series of fronts through Southwest Alaska, and
Bristol Bay and the Bering side of the AK Pen can expect some very
windy conditions. Precipitation on the Pacific side of the AK Pen
and Kodiak Island will also be significant, although not as much
as initially shown several days ago. On the western or backside of
these low pressure systems, some strong cold air advection will
move into the Pribilofs and Eastern Aleutians, which will bring
some heavy snow showers and possible blowing snow through Saturday
night.

On Saturday, the ridge holding those lows in place will weaken,
allowing the front over Kodiak to slide eastward and bring
precipitation to the southern Kenai peninsula. A secondary low is
forecast to form just south of the Kenai and move into the Gulf of
Alaska, which should keep down-inlet windflow for Southcentral and
keep the weekend cool. Unfortunately, this northerly flow looks to
remain pretty dry, decreasing any chances of snow for the
northern portions of Southcentral. Tuesday looks like it will
clear out over most of the mainland. By Wednesday, the forecast
models are struggling to agree on a solution. Currently, the GFS,
EC and Canadian agree on bringing a strong low up toward the AK
Pen from the north Pacific. However, previous runs have shown
significantly different solutions, so confidence in the day 7
forecast is low.

&&

.AFC WATCHES/WARNINGS/ADVISORIES...
PUBLIC...High Wind Watch 161.
MARINE...Storm Warning 130>132 150 155 160 165 180 181 185.
 Gale Warning 119 120 136>139 170>179.

&&

SYNOPSIS AND MODEL DISCUSSION...JA
SOUTHCENTRAL ALASKA...SA
SOUTHWEST ALASKA/BERING SEA/ALEUTIANS...PJS
LONG TERM...LF