Small Craft Advisory 581, NWS Anchorage, AK

527 
FZAK52 PAFC 091155
CWFALU

Coastal Waters Forecast
National Weather Service Anchorage Alaska
355 AM AKDT Wed Aug 9 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.

PKZ199-100100-
355 AM AKDT Wed Aug 9 2017
.SYNOPSIS FOR SOUTHWEST ALASKA+BRISTOL BAY+THE ALASKA
PENINSULA WATERS AND THE ALEUTIAN ISLANDS...

Bogoslof volcano, 53 nm northwest of Dutch Harbor, is currently 
active. 

A 1003 mb low 90 nm south of Sand Point will shift to 60 nm north
of Cold Bay at 1000 mb tonight...then remain stationary through 
Thu night as it weakens to 1005 mb. High pressure will build over 
the western Bering through Thu night. 

$$

PKZ150-100100-
South of the AK Peninsula Sitkinak to Castle Cape-
355 AM AKDT Wed Aug 9 2017

.TODAY...SE wind increasing to 20 kt. Seas 7 ft.
.TONIGHT...S wind 20 kt. Seas 7 ft.
.THU...SE wind 20 kt. Seas 6 ft.
.THU NIGHT...SE wind 15 kt. Seas 5 ft.
.FRI THROUGH SAT...W wind 20 kt. Seas 6 ft.
.SUN...W wind 15 kt. Seas 6 ft.

$$

PKZ155-100100-
South of the AK Peninsula Castle Cape to Cape Sarichef-
355 AM AKDT Wed Aug 9 2017

.TODAY...NW wind 15 kt except S 10 kt E of the Shumagin Islands. 
Seas 6 ft. Patchy fog.
.TONIGHT...SW wind 20 kt. Seas 6 ft.
.THU...SW wind 20 kt. Seas 6 ft.
.THU NIGHT...SW wind 15 kt. Seas 6 ft.
.FRI...NW wind 20 kt. Seas 5 ft.
.SAT...SW wind 20 kt. Seas 5 ft.
.SUN...Variable wind 10 kt. Seas 11 ft.

$$

PKZ160-100100-
Bristol Bay-
355 AM AKDT Wed Aug 9 2017

...SMALL CRAFT ADVISORY TONIGHT AND THURSDAY...

.TODAY...E wind increasing to 20 kt. Seas 4 ft.
.TONIGHT...SE wind 25 kt. Seas 4 ft.
.THU...E wind 25 kt. Seas 4 ft.
.THU NIGHT...SE wind 20 kt. Seas 4 ft.
.FRI THROUGH SAT...W wind 20 kt. Seas 4 ft.
.SUN...NE wind 10 kt. Seas 3 ft.

$$

PKZ165-100100-
Port Heiden to Cape Sarichef-
355 AM AKDT Wed Aug 9 2017

.TODAY...N wind 15 kt . Seas 4 ft. Patchy fog. Rain.
.TONIGHT...Variable wind 15 kt except becoming S 25 kt E of Port
Moller after midnight. Seas 3 ft. Patchy fog. Rain.
.THU...S wind 20 kt except W 15 kt W of Port Moller in the afternoon.
Seas 4 ft.
.THU NIGHT...S wind 15 kt. Seas 3 ft.
.FRI THROUGH SAT...W wind 20 kt. Seas 4 ft.
.SUN...NE wind 15 kt. Seas 5 ft.

$$

PKZ170-100100-
Cape Sarichef to Nikolski Bering Side-
355 AM AKDT Wed Aug 9 2017

.TODAY...N wind 15 kt. Seas 4 ft. Patchy fog.
.TONIGHT...NW wind 15 kt. Seas 4 ft. Patchy fog.
.THU...W wind 20 kt. Seas 4 ft. Patchy fog.
.THU NIGHT...NW wind 15 kt. Seas 4 ft.
.FRI...NW wind 20 kt. Seas 4 ft.
.SAT...SE wind 20 kt. Seas 4 ft.
.SUN...NE wind 20 kt. Seas 8 ft.

$$

PKZ171-100100-
Unalaska Bay-
355 AM AKDT Wed Aug 9 2017

.TODAY...NW wind 10 kt increasing to 15 kt in the afternoon. Seas
2 ft. Patchy fog.
.TONIGHT...NW wind 15 kt. Seas 2 ft.
.THU...NW wind 20 kt. Seas 2 ft. Rain.
.THU NIGHT...NW wind 20 kt. Seas 4 ft.
.FRI...NW wind 15 kt. Seas 4 ft.
.SAT...SE wind 10 kt. Seas 2 ft.
.SUN...E wind 10 kt. Seas 3 ft.

$$

PKZ172-100100-
Cape Sarichef to Nikolski Pacific Side-
355 AM AKDT Wed Aug 9 2017

.TODAY...NW wind increasing to 20 kt. Seas building to 5 ft. Patchy 
fog.
.TONIGHT...W wind 20 kt. Seas 6 ft. Patchy fog.
.THU...W wind 15 kt. Seas 6 ft. Patchy fog.
.THU NIGHT...W wind 20 kt. Seas 6 ft.
.FRI...NW wind 15 kt. Seas 5 ft.
.SAT...SE wind 15 kt. Seas 5 ft.
.SUN...SE wind 15 kt. Seas 10 ft.

$$

PKZ173-100100-
Nikloski to Seguam Island Bering Side-
355 AM AKDT Wed Aug 9 2017

.TODAY...Variable wind 10 kt. Seas 4 ft. Patchy fog.
.TONIGHT...N wind 15 kt. Seas 3 ft. Patchy fog.
.THU...NW wind 15 kt. Seas 4 ft. Patchy fog.
.THU NIGHT...NW wind 15 kt. Seas 4 ft.
.FRI...NW wind 15 kt. Seas 4 ft.
.SAT...E wind 15 kt. Seas 5 ft.
.SUN...NE wind 20 kt. Seas 9 ft.

$$

PKZ174-100100-
Nikolski to Seguam Island Pacific Side-
355 AM AKDT Wed Aug 9 2017

.TODAY...Variable wind 10 kt. Seas 5 ft. Patchy fog.
.TONIGHT...NE wind 15 kt. Seas 5 ft. Patchy fog.
.THU...N wind 15 kt. Seas 5 ft. Patchy fog.
.THU NIGHT...NW wind 15 kt. Seas 5 ft.
.FRI...N wind 15 kt. Seas 5 ft.
.SAT...SE wind 15 kt. Seas 7 ft.
.SUN...SE wind 15 kt. Seas 11 ft.

$$

PKZ175-100100-
Seguam Island to Adak Bering Side-
355 AM AKDT Wed Aug 9 2017

.TODAY...SE wind 20 kt. Seas 4 ft. Patchy fog.
.TONIGHT...NE wind 20 kt. Seas 4 ft. Patchy fog.
.THU...NE wind 15 kt. Seas 3 ft. Patchy fog.
.THU NIGHT...N wind 15 kt. Seas 4 ft.
.FRI...N wind 15 kt. Seas 4 ft.
.SAT...E wind 20 kt. Seas 6 ft.
.SUN...NE wind 25 kt. Seas 10 ft.

$$

PKZ176-100100-
Seguam Island to Adak Pacific Side-
355 AM AKDT Wed Aug 9 2017

.TODAY...SE wind 15 kt except SW wind 10 kt W of Atka. Seas 5 ft. 
Patchy fog.
.TONIGHT...E wind 20 kt. Seas 5 ft. Patchy fog.
.THU...NE wind 20 kt. Seas 5 ft. Patchy fog.
.THU NIGHT...N wind 15 kt. Seas 4 ft.
.FRI...NE wind 15 kt. Seas 5 ft.
.SAT...SE wind 15 kt. Seas 7 ft.
.SUN...NE wind 15 kt. Seas 9 ft.

$$

PKZ177-100100-
Adak to Kiska-
355 AM AKDT Wed Aug 9 2017

.TODAY...Variable wind 10 kt becoming NE 15 kt in the afternoon.
Seas 4 ft. Patchy fog. Rain.
.TONIGHT...NE wind 20 kt. Seas 6 ft. Patchy fog.
.THU...NE wind 20 kt. Seas 6 ft. Patchy fog.
.THU NIGHT...NE wind 20 kt. Seas 5 ft.
.FRI THROUGH SAT...NE wind 20 kt. Seas 6 ft.
.SUN...NE wind 25 kt. Seas 11 ft.

$$

PKZ178-100100-
Kiska to Attu-
355 AM AKDT Wed Aug 9 2017

.TODAY...N wind increasing to 20 kt. Seas 6 ft. Patchy fog.
.TONIGHT...NE wind 20 kt. Seas 6 ft. Patchy fog.
.THU...NE wind 20 kt. Seas 6 ft. Areas of fog.
.THU NIGHT...NE wind 20 kt. Seas 6 ft.
.FRI THROUGH SAT...NE wind 20 kt. Seas 6 ft.
.SUN...NE wind 25 kt. Seas 8 ft.

$$

PKZ179-100100-
Pribilof Islands Near Shore Waters-
355 AM AKDT Wed Aug 9 2017

.TODAY...N wind 15 kt. Seas 4 ft. Areas of fog.
.TONIGHT...N wind 20 kt. Seas 4 ft. Patchy fog. Rain.
.THU...N wind 15 kt. Seas 4 ft. Patchy fog.
.THU NIGHT...N wind 15 kt. Seas 4 ft.
.FRI...W wind 20 kt. Seas 5 ft.
.SAT THROUGH SUN...NE wind 20 kt. Seas 6 ft.

$$

PKZ180-100100-
Kuskokwim Delta and Etolin Strait-
355 AM AKDT Wed Aug 9 2017

...SMALL CRAFT ADVISORY TONIGHT AND THURSDAY...

.TODAY...NE wind 20 kt. Seas 4 ft. Patchy fog. Rain.
.TONIGHT...E wind 25 kt. Seas 4 ft.
.THU...E wind 25 kt. Seas 5 ft.
.THU NIGHT...E wind 15 kt. Seas 4 ft.
.FRI...W wind 25 kt. Seas 5 ft.
.SAT...N wind 25 kt. Seas 5 ft.
.SUN...N wind 20 kt. Seas 4 ft.

$$

PKZ181-100100-
North and West of Nunivak Island-
355 AM AKDT Wed Aug 9 2017

.TODAY...N wind 20 kt. Seas 4 ft. Patchy fog.
.TONIGHT...N wind 20 kt. Seas 6 ft. Patchy fog.
.THU...NE wind 20 kt in the morning becoming variable 10 kt. Seas
5 ft. Patchy fog.
.THU NIGHT...W wind 15 kt. Seas 3 ft.
.FRI...W wind 25 kt. Seas 8 ft.
.SAT...N wind 25 kt. Seas 7 ft.
.SUN...N wind 20 kt. Seas 7 ft.

$$

PKZ185-100100-
Saint Matthew Island Waters-
355 AM AKDT Wed Aug 9 2017

.TODAY...N wind increasing to  20 kt E of Saint Matthew 
Island...variable 10 kt W of Saint Matthew Island. Seas 4 ft. Areas 
of fog.
.TONIGHT...N wind 20 kt E of Saint Matthew Island...N 10 kt W of 
Saint Matthew Island. Seas 5 ft. Areas of fog.
.THU...N wind 20 kt except NW 10 kt W of Saint Matthew Island. Seas 
5 ft. Areas of fog.
.THU NIGHT...W wind 20 kt. Seas 4 ft.
.FRI...NW wind 25 kt. Seas 7 ft.
.SAT THROUGH SUN...NE wind 20 kt. Seas 7 ft.

$$

Southcentral and Southwest Alaska Forecast Discussion
National Weather Service Anchorage AK
444 AM AKDT Tue Aug 8 2017

.ANALYSIS AND UPPER LEVELS...
The synoptic pattern features broad cyclonic flow extending from
the Bering Sea to the North Pacific. In satellite imagery, there
are three distinct features including the remnants of a frontal
boundary that are south of the AK peninsula, a new system pushing
into the Western Aleutians and a cold front draped over the north
slope. The vortex south of the AK peninsula continues to kick
vort lobes out of it...ushering precipitation into the central
Aleutians...AK peninsula and south central.

&&

.MODEL DISCUSSION...
Models are in good agreement with the longwave pattern with a pair
of lows impacting the Aleutians and the ridge holding steadfast
over SE AK in the short term. However, a major transition is
gearing up as Arctic air begins to push south of the Brooks Range
this weekend. Both the GFS and the ECMWF depict this intrusion of
cold air.

&&

.AVIATION...
PANC...There is an area of disturbed weather that is moving
towards PANC...but the models keep the CIGs above 5,000 ft.
Cautiously anticipate VFR conditions to persist. The gradient
associated with this system merit keeping gusty winds in the TAF.

&&

.SHORT TERM FORECAST SOUTHCENTRAL ALASKA (Days 1 and 2)...
With south to southeast flow aloft over Southcentral Alaska the
next few days there will be continued periods of rain along the
coast with some of it occasionally spilling over the mountains to
the inland areas. A front moving into the Gulf of Alaska will also
increase winds to Gale force around Kodiak Island, particularly
in Shelikof Strait and the Barren Islands. These strong winds will
go a long way to keeping the precipitation on the windward side
of the mountains with downslope protecting the leeward sides of
the kenai and Chugach ranges. As the winds diminish late Wednesday
into Wednesday night the possibility of rain making it into
Anchorage, the Mat-Su and western Kenai Peninsula increase. The
Copper River Basin very well may not see much if any precipitation
as the areas of deep moisture will be west of there. This will
help keep temperatures warm in the Copper River Basin but there
should be enough increased moisture to help increase the Relative
Humidity today.

&&

.SHORT TERM FORECAST SOUTHWEST ALASKA (Days 1 and 2)...
The showery pattern over the mainland will diminish today as
instability wanes and a front approaches from the Pacific. An
upper jet will punch in with the front, carrying above average
moisture for this time of year. Widespread rain will affect the
Bristol Bay area this evening into the overnight hours. The low
pressure system that is responsible is very fall-like, and will
contain a moderate amount of cross-barrier wind behind the front.
The wind will create some downslope drying along the
Alaska/Aleutian Range. The main upper level disturbance will
continue to curve into the Bering Sea, taking the bulk of the
precipitation there as well. The mainland will be left in a deep-
layer southeasterly flow on Wednesday and Thursday, leading to a
showery/sprinkle pattern.

&&

.SHORT TERM FORECAST BERING SEA/ALEUTIANS (Days 1 and 2)...
Two different low pressure systems will enter the Bering, one from
the northwest, another from the southeast. The front to the west
is weakening, hence no major wind or precipitation issues, while
the one entering from the southeast will be stronger, bringing
widespread precipitation in on late Tuesday night. Otherwise,
another normal day in the Bering...low stratus and fog.

&&

.LONG TERM FORECAST (Days 3 through 7/Wednesday night through
Monday)...
Beginning Wednesday night the large upper level low is lifting
northward in the vicinity of the Alaska Peninsula, with a short-
wave on the east side of the low lifting northward across the
Gulf and Southcentral. There are model differences in timing and
amplitude of the short-wave. In any case, with weakening low level
flow over Southcentral, rain looks likely during this period for
all except the Copper River Basin. Some of this rain will also
spread into interior Southwest Alaska. Otherwise, expect showery
conditions for the eastern Bering/SW Alaska region underneath the
upper low. As we head into the weekend this upper low begin to
exit across the Gulf/NE Pacific, with lingering clouds and showers
over the southern mainland.

Models are in quite good agreement with the large scale evolution
through the weekend and into early next week, though as is usual
there are some key differences in the details. A deep and cold
trough will drop out of the Arctic and interact with another
closed low along the Aleutians. The extent to which individual
short-waves phase (or not) will determine the mean trough position
and areas most likely to see rain. Models tend to take a while to
lock on to timing and phasing details for these types of scenarios,
so expect continued large variation with each new model cycle.
Based on the larger scale pattern, it is generally favorable for
deep south to southwest flow into mainland Alaska, so there is
potential for much wetter weather by early next week.

&&

.AFC WATCHES/WARNINGS/ADVISORIES...
PUBLIC...NONE.
MARINE...NONE.
FIRE WEATHER...NONE.

&&

SYNOPSIS AND MODEL DISCUSSION...PJS
SOUTHCENTRAL ALASKA...EZ
SOUTHWEST ALASKA/BERING SEA/ALEUTIANS...ML
LONG TERM...SEB