Small Craft Advisory 893, NWS Anchorage, AK

162 
FZAK52 PAFC 231243
CWFALU

Coastal Waters Forecast
National Weather Service Anchorage Alaska
343 AM AKST Thu Nov 23 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.

PKZ199-240115-
343 AM AKST Thu Nov 23 2017
.SYNOPSIS FOR SOUTHWEST ALASKA+BRISTOL BAY+THE ALASKA
PENINSULA WATERS AND THE ALEUTIAN ISLANDS...
A 969 mb low 50 nm southeast of Kipnuk will move over Chignik at 
979 mb by this afternoon, then it will move into the western Gulf 
at 984 mb by this evening. A front pushing into the western 
Aleutians Fri morning will continue east to arrive in the eastern 
Aleutians by Sat morning.

$$

PKZ150-240115-
South of the AK Peninsula Sitkinak to Castle Cape-
343 AM AKST Thu Nov 23 2017

...STORM WARNING TONIGHT AND FRIDAY...

.TODAY...NW wind 45 kt. Gusts to 65 kt out of bays and passes. 
Seas 21 ft. Widespread rain showers.
.TONIGHT...NW wind 50 kt. Seas 21 ft.
.FRI...NW wind 50 kt. Seas 20 ft.
.FRI NIGHT...N wind 45 kt. Seas 16 ft.
.SAT...NW wind 30 kt. Seas 12 ft.
.SUN...SE wind 30 kt. Seas 16 ft.
.MON...SW wind 25 kt. Seas 16 ft.

$$

PKZ155-240115-
South of the AK Peninsula Castle Cape to Cape Sarichef-
343 AM AKST Thu Nov 23 2017

...STORM WARNING THROUGH TONIGHT...

.TODAY...NW wind 55 kt. Gusts to 80 kt out of bays and passes. 
Seas 28 ft. Widespread rain and snow showers.
.TONIGHT...NW wind 55 kt diminishing to 45 kt after midnight. 
Gusts to 70 kt out of bays and passes through midnight. Seas 26 ft 
subsiding to 19 ft after midnight.
.FRI...NW wind 40 kt. Seas 15 ft.
.FRI NIGHT...NW wind 40 kt. Seas 13 ft.
.SAT...S wind 30 kt. Seas 12 ft.
.SUN...S wind 35 kt. Seas 18 ft.
.MON...W wind 30 kt. Seas 17 ft.

$$

PKZ160-240115-
Bristol Bay-
343 AM AKST Thu Nov 23 2017

...GALE WARNING THROUGH FRIDAY...

.TODAY...W wind 40 kt becoming N in the afternoon. Seas 20 ft.
Widespread rain showers.
.TONIGHT...N wind 40 kt. Seas 14 ft. Freezing spray.
.FRI...NW wind 35 kt. Seas 11 ft. Freezing spray.
.FRI NIGHT...N wind 30 kt. Seas 8 ft.
.SAT...E wind 30 kt. Seas 6 ft.
.SUN...E wind 35 kt. Seas 8 ft.
.MON...E wind 20 kt. Seas 5 ft.

$$

PKZ165-240115-
Port Heiden to Cape Sarichef-
343 AM AKST Thu Nov 23 2017

...STORM WARNING THROUGH TONIGHT...

.TODAY...NW wind 60 kt. Gusts to 75 kt. Seas 38 ft. Widespread rain 
showers.
.TONIGHT...NW wind 50 kt diminishing to 40 kt after midnight. 
Gusts to Seas 29 ft subsiding to 21 ft after midnight.
.FRI...NW wind 35 kt. Seas 16 ft.
.FRI NIGHT...NW wind 30 kt. Seas 13 ft.
.SAT...SE wind 30 kt. Seas 9 ft.
.SUN...SE wind 35 kt. Seas 10 ft.
.MON...W wind 20 kt. Seas 11 ft.

$$

PKZ170-240115-
Cape Sarichef to Nikolski Bering Side-
343 AM AKST Thu Nov 23 2017

...STORM WARNING TODAY...

.TODAY...NW wind 55 kt. Gusts to 70 kt east of Unalaska. Seas 37 ft.
.TONIGHT...NW wind 45 kt diminishing to 30 kt after midnight. 
Seas28 ft subsiding to 19 ft after midnight.
.FRI...NW wind 30 kt. Seas 14 ft.
.FRI NIGHT...SW wind 30 kt. Seas 10 ft.
.SAT...S wind 30 kt. Seas 9 ft.
.SUN THROUGH MON...W wind 35 kt. Seas 22 ft.

$$

PKZ171-240115-
Unalaska Bay-
343 AM AKST Thu Nov 23 2017

...STORM WARNING TODAY...

.TODAY...NW wind 50 kt. Gusts to 70 kt. Seas 28 ft. Widespread snow 
showers.
.TONIGHT...NW wind 40 kt diminishing to 25 kt after midnight. 
Seas 20 ft subsiding to 10 ft after midnight.
.FRI...NW wind 25 kt. Seas 10 ft subsiding to 4 ft in the
afternoon.
.FRI NIGHT...SW wind 15 kt. Seas 2 ft.
.SAT...S wind 20 kt. Seas 3 ft.
.SUN...W wind 25 kt. Seas 4 ft.
.MON...W wind 30 kt. Seas 4 ft.

$$

PKZ172-240115-
Cape Sarichef to Nikolski Pacific Side-
343 AM AKST Thu Nov 23 2017

...STORM WARNING TODAY...

.TODAY...NW wind 50 kt. Gusts to 75 kt east of Unalaska. Seas 21 ft.
.TONIGHT...NW wind 45 kt diminishing to 35 kt after midnight. Seas
18 ft subsiding to 12 ft after midnight.
.FRI...NW wind 30 kt. Seas 9 ft.
.FRI NIGHT...W wind 25 kt. Seas 6 ft.
.SAT...SW wind 30 kt. Seas 15 ft.
.SUN THROUGH MON...W wind 40 kt. Seas 18 ft.

$$

PKZ173-240115-
Nikloski to Seguam Island Bering Side-
343 AM AKST Thu Nov 23 2017

...GALE WARNING TODAY...

.TODAY...NW wind 45 kt diminishing to 35 kt in the afternoon. 
Seas 28 ft.
.TONIGHT...NW wind 30 kt becoming W 20 kt after midnight. 
Seas 21 ft subsiding to 15 ft after midnight.
.FRI...SW wind 20 kt. Seas 11 ft.
.FRI NIGHT...S wind 35 kt. Seas 11 ft.
.SAT...W wind 35 kt. Seas 23 ft.
.SUN...NW wind 45 kt. Seas 30 ft.
.MON...W wind 40 kt. Seas 24 ft.

$$

PKZ174-240115-
Nikolski to Seguam Island Pacific Side-
343 AM AKST Thu Nov 23 2017

...GALE WARNING TODAY...

.TODAY...NW wind 40 kt. Seas 19 ft.
.TONIGHT...NW wind 30 kt diminishing to 20 kt after midnight. 
Seas 15 ft.
.FRI...SW wind 20 kt. Seas 9 ft.
.FRI NIGHT...S wind 30 kt. Seas 14 ft.
.SAT...SW wind 40 kt. Seas 18 ft.
.SUN...W wind 50 kt. Seas 31 ft.
.MON...W wind 40 kt. Seas 27 ft.

$$

PKZ175-240115-
Seguam Island to Adak Bering Side-
343 AM AKST Thu Nov 23 2017

...GALE WARNING FRIDAY...

.TODAY...NW wind 30 kt diminishing to 20 kt in the afternoon. 
Seas 19 ft.
.TONIGHT...W wind 15 kt. Seas 16 ft subsiding to 11 ft after
midnight.
.FRI...S wind 25 kt increasing to 35 kt in the afternoon. 
Seas 9 ft.
.FRI NIGHT...S wind 35 kt. Seas 10 ft.
.SAT...NW wind 35 kt. Seas 21 ft.
.SUN...NW wind 45 kt. Seas 28 ft.
.MON...SW wind 35 kt. Seas 20 ft.

$$

PKZ176-240115-
Seguam Island to Adak Pacific Side-
343 AM AKST Thu Nov 23 2017

...GALE WARNING FRIDAY...

.TODAY...NW wind 25 kt. Seas 10 ft.
.TONIGHT...NE wind 15 kt becoming SE after midnight. Seas 7 ft.
.FRI...S wind 35 kt. Seas 9 ft building to 15 ft in the afternoon.
.FRI NIGHT...S wind 30 kt. Seas 16 ft.
.SAT...W wind 30 kt. Seas 17 ft.
.SUN...NW wind 45 kt. Seas 20 ft.
.MON...SW wind 40 kt. Seas 31 ft.

$$

PKZ177-240115-
Adak to Kiska-
343 AM AKST Thu Nov 23 2017

...GALE WARNING FRIDAY...

.TODAY...N wind 15 kt becoming SE in the afternoon. Seas 12 ft.
.TONIGHT...SE wind 20 kt increasing to 30 kt after midnight. 
Seas 9 ft.
.FRI...SE wind 35 kt. Seas 17 ft. Rain.
.FRI NIGHT...SW wind 30 kt. Seas 17 ft.
.SAT...N wind 35 kt. Seas 13 ft.
.SUN...NW wind 35 kt. Seas 17 ft.
.MON...SW wind 30 kt. Seas 35 ft.

$$

PKZ178-240115-
Kiska to Attu-
343 AM AKST Thu Nov 23 2017

...GALE WARNING TONIGHT AND FRIDAY...

.TODAY...S wind 25 kt. Seas 9 ft.
.TONIGHT...SE wind 35 kt. Seas 11 ft.
.FRI...SE wind 35 kt. Seas 15 ft. Rain.
.FRI NIGHT...NW wind 20 kt. Seas 13 ft.
.SAT...NW wind 25 kt. Seas 10 ft.
.SUN...W wind 30 kt. Seas 15 ft.
.MON...N wind 40 kt. Seas 32 ft.

$$

PKZ179-240115-
Pribilof Islands Near Shore Waters-
343 AM AKST Thu Nov 23 2017

...STORM WARNING TODAY...

.TODAY...NW wind 55 kt diminishing to 40 kt in the afternoon. Gusts
to 70 kt through the morning. Seas 33 ft subsiding to 26 ft in the 
afternoon.
.TONIGHT...NW wind 30 kt. Seas 19 ft subsiding to 12 ft after
midnight.
.FRI...W wind 25 kt. Seas 11 ft.
.FRI NIGHT...S wind 30 kt. Seas 8 ft.
.SAT...E wind 30 kt. Seas 13 ft.
.SUN...N wind 30 kt. Seas 15 ft.
.MON...N wind 25 kt. Seas 12 ft.

$$

PKZ180-240115-
Kuskokwim Delta and Etolin Strait-
343 AM AKST Thu Nov 23 2017

...STORM WARNING TODAY...

.TODAY...NW wind 55 kt. Gusts to 70 kt. Seas 25 ft. Widespread rain 
showers.
.TONIGHT...NW wind 45 kt diminishing to 35 kt after midnight. 
Seas 17 ft.
.FRI...NW wind 30 kt. Seas 12 ft.
.FRI NIGHT...NE wind 25 kt. Seas 8 ft.
.SAT THROUGH SUN...E wind 35 kt. Seas 13 ft.
.MON...NE wind 25 kt. Seas 8 ft.

$$

PKZ181-240115-
North and West of Nunivak Island-
343 AM AKST Thu Nov 23 2017

...GALE WARNING THROUGH TONIGHT...

.TODAY...N wind 45 kt becoming NW 35 kt in the afternoon. 
Seas 20 ft.
.TONIGHT...NW wind 35 kt diminishing to 25 kt after midnight.
Seas 15 ft subsiding to 10 ft after midnight. Snow showers.
.FRI...NW wind 30 kt diminishing to 20 kt in the afternoon. 
Seas 10 ft.
.FRI NIGHT...SE wind 25 kt. Seas 7 ft.
.SAT...SE wind 30 kt. Seas 10 ft.
.SUN...NE wind 30 kt. Seas 10 ft.
.MON...NE wind 25 kt. Seas 9 ft.

$$

PKZ185-240115-
Saint Matthew Island Waters-
343 AM AKST Thu Nov 23 2017

...GALE WARNING TODAY...

.TODAY...NW wind 45 kt becoming W 35 kt in the afternoon. 
Seas 23 ft subsiding to 17 ft in the afternoon.
.TONIGHT...W wind 30 kt. Seas 13 ft.
.FRI...W wind 25 kt E of Saint Matthew Island...SW 30 kt W of
Saint Matthew Island. Seas 12 ft.
.FRI NIGHT...S wind 30 kt. Seas 13 ft.
.SAT...N wind 30 kt. Seas 14 ft.
.SUN...NE wind 30 kt. Seas 12 ft.
.MON...NE wind 25 kt. Seas 10 ft.

$$

Southcentral and Southwest Alaska Forecast Discussion
National Weather Service Anchorage AK
527 AM AKST Wed Nov 22 2017

.ANALYSIS AND UPPER LEVELS...
The next incoming surface low is rapidly deepening as it crosses
the 180 degree longitude line and speeds to the northeast across
the Bering. The associated rather strong warm/occluding front is
pushing across the Pribilof Islands early this morning with the
trailing cold front moving into the central Aleutians. Further to
the east, a shearing apart upper level trough is tracking east
across southcentral Alaska while a transient ridge builds in
behind it.

&&

.MODEL DISCUSSION...
Model agreement continues to improve with regards to the strong
low tracking towards Nunivak Island this afternoon/evening,
increasing confidence in the various high wind and winter weather
impacts expected across Southwest Alaska, the eastern Bering and
Alaska Peninsula. Additionally there is good agreement with the
trough and surface low rotating into the Gulf of Alaska Wednesday
night and Thursday and the resulting increasing offshore flow.

&&

.AVIATION...
PANC...While there are a few patchy low clouds drifting around this
morning VFR conditions are expected to prevail.

&&

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

A sharp shortwave trough is moving through the area this morning.
This feature is dragging cold air with it (12z Anchorage UA
sounding shows -12C 850 hpa temperatures) and is pushing this cold
air through the gaps along the North Gulf Coast. Winds will peak
midday then begin to weaken as the pressure gradient weakens with
the eastward progression of the trough. Light snow today will
mainly be over the Alaska Range, Talkeetna Mountains, and Wrangell
Mountains, but some light snow will continue across the Copper
Basin.

Attention quickly turns to a fast moving front which will move
into the Gulf of Alaska, bringing a quick shot of accumulating
snow to western Kodiak Island before turning to a mix of rain and
snow. The front will reach the southern Kenai Peninsula tonight,
bringing accumulating snow to the area through morning before the
main low tracks south. Temperatures aloft will be quite cold, so
offshore winds look to really ramp up Thursday night into Friday.
The Matanuska Valley, Thompson Pass, Valdez, Kodiak, Copper
Delta, etc. will all blow hard as a reinforcing upper trough digs
in.

&&

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

The forecast remains largely on track with few changes made this
forecast package. A strong area of low pressure will reach Kipnuk
around midnight tonight, before dropping southeast into Bristol
Bay. An attendant cold front will sweep westward across the
Bering through the afternoon before reaching the coast of
southwest Alaska around sunset. Widespread precipitation will
develop along the front.

Taking a closer look at the model data, widespread snow will
develop ahead of the front with periods of moderate to heavy
snowfall likely. The front will eventually stall near a Bethel to
King Salmon line. Where this front stalls is important as warmer
air will push inland following frontal passage for a few hours,
before colder air advects into the region from the northwest as
the low moves along the coast. This has impacts on how much
snowfall will be seen near the coast, as a slower frontal
progression could allow for mesoscale banding to develop in the
precipitation, thus putting out higher snowfall totals. This is
something we'll keep an eye on as the system evolves.

Otherwise, look for snow to change to a rain/snow mix along the
coast, with perhaps some of the western most portions of the coast
briefly seeing all rain. Snowfall accumulations look similar to
the previous forecast package. Strong southerly winds ahead of the
front may also bring some coastal flood concerns, and the
previous headlines for this were unchanged as the models remain
consistent with this potential. Drier air will advect into the
region by Thursday night. However, gusty northwest winds will keep
blowing snow concerns in our picture.

&&

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

Abrupt changes are coming over the next 24 hours as a strong cold
front sweeps eastward from the west central Aleutians this
morning to eastern portions of the AKPEN tonight. Look for
widespread precipitation to develop along the front before
northwesterly winds move in behind the front. These winds will
rapidly increase in strength with some hurricane force gusts
likely. Only minor temporal changes were made to the headlines for
the Pribilof Islands, while upgrading the watch to a warning for
zone 181 along the peninsula while adjusting the timing for both
locations. The winds will gradually diminish for all areas from
west to east for the Bering and the Aleutian chain by Friday
morning.

&&

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

Beginning the extended period forecast on Friday, there will be a
longwave trough over the state of Alaska, extending into the Gulf
of Alaska, with a transient ridge over the Bering Sea. Deep cold
air and a strong offshore pressure gradient over Southcentral will
continue a strong gap wind event over that region. Otherwise, most
of Southern Alaska will be dry, and rather cold, through Saturday
night into Sunday.

The forecast quickly becomes complicated as a large and very cold
trough over Eastern Siberia pinwheels a series of shortwaves into
the Bering Sea for the weekend. The first of these looks to
develops over the Bering late Saturday into Sunday then move a
front into Southwest Alaska sometime on Sunday. This will bring a
mix of rain and snow threats to Southwest before the energy moves
into the Gulf of Alaska Sunday night through Tuesday. Meanwhile, a
series of powerful lows looks poised to move through the western
Bering Sea and North Pacific along the Aleutian Chain, but huge
uncertainty develops from Monday onward. It does seem the net
effect of this pattern shift, alluded to in all the global model
guidance, is that the deep northerly flow and cold pattern over
the state will wane (at least for Southern Alaska) Monday through
midweek.

&&

.AFC WATCHES/WARNINGS/ADVISORIES...
PUBLIC...High Wind Warning 181 195.
         Coastal Flood Advisory 155 161.
         Winter Weather Advisory 155 161.
MARINE...Gale 120 127 130-132 150 160 173-178 351 352 411
         Storm 155 165 170 171 172 179 180 181 185 412-414.

&&

SYNOPSIS AND MODEL DISCUSSION...JR
SOUTHCENTRAL ALASKA...Ahsenmacher
SOUTHWEST ALASKA/BERING SEA/ALEUTIANS...P Doll
LONG TERM...Ahsenmacher