Small Craft Advisory 598, NWS Anchorage, AK

997 
FZAK51 PAFC 141140
CWFAER

Coastal Waters Forecast
National Weather Service Anchorage Alaska
340 AM AKDT Mon Aug 14 2017

Coastal Waters Forecast for the Northern Gulf of Alaska Coast
up to 100 nm out including Kodiak Island and Cook Inlet.

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.

PKZ197-150100-
340 AM AKDT Mon Aug 14 2017
.SYNOPSIS FOR THE NORTH GULF COAST+KODIAK ISLAND WATERS+
COOK INLET...
A 1003 mb low 65 nm South of Cordova dissipates Mon night. A front
precedes a 1000 mb low 170 nm South of Chignik Mon afternoon and 
moves to 200 nm Southwest of Yakutat at 1004 mb by Wed morning. 
The trailing front lies across the Gulf through Wed morning. 

$$

PKZ119-150100-
Cape Suckling to Cape Cleare-
340 AM AKDT Mon Aug 14 2017

.TODAY...Variable wind 10 kt. Seas 5 ft.
.TONIGHT...SE wind 15 kt. Seas 4 ft.
.TUE...E wind 15 kt. Seas 5 ft.
.TUE NIGHT...Variable wind 10 kt. Seas 8 ft.
.WED THROUGH THU...S wind 15 kt. Seas 8 ft.
.FRI...Variable wind 10 kt. Seas 9 ft.

$$

PKZ120-150100-
Cape Cleare to Gore Point-
340 AM AKDT Mon Aug 14 2017

.TODAY...SW wind 15 kt. Seas 5 ft.
.TONIGHT...Variable wind 10 kt. Seas 4 ft.
.TUE...Variable wind 10 kt. Seas 4 ft.
.TUE NIGHT...Variable wind 10 kt. Seas 6 ft.
.WED...S wind 15 kt. Seas 6 ft.
.THU...Variable wind 10 kt. Seas 6 ft.
.FRI...W wind 15 kt. Seas 7 ft.

$$

PKZ121-150100-
Resurrection Bay-
340 AM AKDT Mon Aug 14 2017

.TODAY...Variable wind less than 10 kt becoming S 10 kt in the
afternoon. Seas 2 ft. Patchy fog.
.TONIGHT...S wind 10 kt becoming N after midnight. Seas 2 ft.
.TUE...Variable wind less than 10 kt becoming S 10 kt in the
afternoon. Seas 2 ft.
.TUE NIGHT...Variable wind 10 kt. Seas 2 ft.
.WED THROUGH THU...S wind 10 kt. Seas 2 ft.
.FRI...Variable wind 10 kt. Seas 2 ft.

$$

PKZ125-150100-
Prince William Sound-
340 AM AKDT Mon Aug 14 2017

.TODAY...E wind 15 kt in the morning becoming variable less than
10 kt. Seas 3 ft. Patchy fog.
.TONIGHT...Variable wind less than 10 kt becoming NE 10 kt after
midnight. Seas 2 ft.
.TUE...NE wind 10 kt in the morning becoming variable less than
10 kt. Seas 2 ft.
.TUE NIGHT...E wind 10 kt. Seas 2 ft.
.WED THROUGH THU...E wind 10 kt. Seas 2 ft.
.FRI...Variable wind less than 10 kt. Seas 2 ft.

$$

PKZ126-150100-
Port Valdez-
340 AM AKDT Mon Aug 14 2017

.TODAY...Variable wind less than 10 kt becoming W 10 kt in the
afternoon. Seas 2 ft. Patchy fog.
.TONIGHT...Variable wind 10 kt in the evening becoming variable
less than 10 kt. Seas 2 ft.
.TUE...Variable wind less than 10 kt becoming W 10 kt in the
afternoon. Seas 2 ft.
.TUE NIGHT...E wind 10 kt. Seas 2 ft.
.WED...Variable wind 10 kt. Seas 2 ft.
.THU...Variable wind less than 10 kt. Seas 2 ft.
.FRI...Variable wind less than 10 kt. Seas 2 ft.

$$

PKZ127-150100-
Valdez Narrows-
340 AM AKDT Mon Aug 14 2017

.TODAY...Variable wind less than 10 kt becoming SW 15 kt in the
afternoon. Seas 3 ft. Patchy fog.
.TONIGHT...SW wind 15 kt becoming N 10 kt after midnight. Seas 3 ft.
.TUE...SW wind 10 kt. Seas 2 ft.
.TUE NIGHT...N wind 10 kt. Seas 2 ft.
.WED...SW wind 10 kt. Seas 2 ft.
.THU...SW wind 10 kt. Seas 2 ft.
.FRI...Variable wind 10 kt. Seas 2 ft.

$$

PKZ128-150100-
Valdez Arm-
340 AM AKDT Mon Aug 14 2017

.TODAY...Variable wind less than 10 kt. Seas 2 ft. Patchy fog.
.TONIGHT...Variable wind less than 10 kt. Seas 2 ft.
.TUE...Variable wind less than 10 kt. Seas 2 ft.
.TUE NIGHT...Variable wind less than 10 kt. Seas 2 ft.
.WED THROUGH THU...NE wind 10 kt. Seas 2 ft.
.FRI...Variable wind 10 kt. Seas 2 ft.

$$

PKZ129-150100-
Passage Canal-
340 AM AKDT Mon Aug 14 2017

.TODAY...Variable wind less than 10 kt. Seas 2 ft. Patchy fog.
.TONIGHT...Variable wind less than 10 kt. Seas 2 ft.
.TUE...Variable wind less than 10 kt. Seas 2 ft.
.TUE NIGHT...E wind 10 kt. Seas 2 ft.
.WED THROUGH THU...E wind 10 kt. Seas 2 ft.
.FRI...Variable wind less than 10 kt. Seas 2 ft.

$$

PKZ130-150100-
West of Barren Islands including Kamishak Bay-
340 AM AKDT Mon Aug 14 2017

.TODAY...SW wind 15 kt. Seas 3 ft.
.TONIGHT...SE wind 15 kt. Seas 4 ft.
.TUE...Variable wind 10 kt. Seas 2 ft.
.TUE NIGHT...SE wind 15 kt. Seas 4 ft.
.WED...SW wind 15 kt. Seas 3 ft.
.THU...Variable wind 10 kt. Seas 3 ft.
.FRI...W wind 15 kt. Seas 3 ft.

$$

PKZ131-150100-
Barren Islands East-
340 AM AKDT Mon Aug 14 2017

.TODAY...SW wind 15 kt. Seas 6 ft.
.TONIGHT...Variable wind 10 kt. Seas 4 ft.
.TUE...Variable wind 10 kt. Seas 4 ft.
.TUE NIGHT...S wind 15 kt. Seas 7 ft.
.WED THROUGH THU...SW wind 15 kt. Seas 7 ft.
.FRI...W wind 15 kt. Seas 7 ft.

$$

PKZ132-150100-
Marmot Island to Sitkinak-
340 AM AKDT Mon Aug 14 2017

...SMALL CRAFT ADVISORY TUESDAY...

.TODAY...SW wind 15 kt. Seas 6 ft.
.TONIGHT...SE wind 15 kt. Seas 6 ft.
.TUE...Variable wind 10 kt. Seas 8 ft.
.TUE NIGHT...SW wind 20 kt. Seas 9 ft.
.WED...SW wind 20 kt. Seas 7 ft.
.THU THROUGH FRI...W wind 20 kt. Seas 11 ft.

$$

PKZ136-150100-
Chiniak Bay-
340 AM AKDT Mon Aug 14 2017

.TODAY...Variable wind less than 10 kt. Seas 3 ft.
.TONIGHT...Variable wind less than 10 kt. Seas 3 ft.
.TUE...Variable wind less than 10 kt. Seas 3 ft.
.TUE NIGHT...S wind 10 kt. Seas 3 ft.
.WED THROUGH FRI...W wind 10 kt. Seas 2 ft.

$$

PKZ137-150100-
Marmot Bay-
340 AM AKDT Mon Aug 14 2017

.TODAY...SW wind 10 kt in the morning becoming variable less than
10 kt. Seas 3 ft.
.TONIGHT...Variable wind less than 10 kt. Seas 3 ft.
.TUE...Variable wind less than 10 kt. Seas 3 ft.
.TUE NIGHT...Variable wind less than 10 kt. Seas 3 ft.
.WED...Variable wind less than 10 kt. Seas 2 ft.
.THU THROUGH FRI...W wind 10 kt. Seas 2 ft.

$$

PKZ138-150100-
Shelikof Strait-
340 AM AKDT Mon Aug 14 2017

.TODAY...SW wind 20 kt. Seas 7 ft.
.TONIGHT...NE wind 15 kt. Seas 4 ft.
.TUE...Variable wind 10 kt. Seas 2 ft.
.TUE NIGHT...SW wind 15 kt. Seas 4 ft.
.WED THROUGH FRI...W wind 15 kt. Seas 4 ft.

$$

PKZ139-150100-
Cook Inlet Kalgin island to Point Bede-
340 AM AKDT Mon Aug 14 2017

.TODAY...S wind 15 kt. Seas 4 ft. Patchy fog.
.TONIGHT...S wind diminishing to 10 kt after midnight. Seas subsiding
to 2 ft.
.TUE...Variable wind less than 10 kt becoming SW 10 kt in the
afternoon. Seas 2 ft.
.TUE NIGHT...S wind 10 kt. Seas 4 ft.
.WED...S wind 10 kt. Seas 3 ft.
.THU...Variable wind less than 10 kt. Seas 2 ft.
.FRI...SW wind 10 kt. Seas 2 ft.

$$

PKZ140-150100-
Cook Inlet North of Kalgin Island-
340 AM AKDT Mon Aug 14 2017

.TODAY...SE wind 10 kt. Seas 3 ft. Patchy fog.
.TONIGHT...S wind 10 kt. Seas 3 ft.
.TUE...Variable wind less than 10 kt becoming SW 10 kt in the
afternoon. Seas 2 ft.
.TUE NIGHT...S wind 15 kt. Seas 4 ft.
.WED...S wind 10 kt. Seas 2 ft.
.THU...Variable wind less than 10 kt. Seas 2 ft.
.FRI...SW wind 10 kt. Seas 2 ft.

$$

PKZ141-150100-
Kachemak Bay-
340 AM AKDT Mon Aug 14 2017

.TODAY...S wind 10 kt becoming SW 15 kt in the afternoon. Seas 2
ft building to 4 ft in the afternoon.
.TONIGHT...SW wind 15 kt in the evening becoming variable less
than 10 kt. Seas 4 ft subsiding to 2 ft after midnight.
.TUE...Variable wind less than 10 kt becoming SW 10 kt in the
afternoon. Seas 2 ft.
.TUE NIGHT...S wind 10 kt. Seas 2 ft.
.WED...S wind 10 kt. Seas 2 ft.
.THU...Variable wind less than 10 kt. Seas 2 ft.
.FRI...W wind 10 kt. Seas 2 ft.

$$

Southcentral and Southwest Alaska Forecast Discussion
National Weather Service Anchorage AK
422 AM AKDT Sun Aug 13 2017

.ANALYSIS AND UPPER LEVELS...

A rather deep potential vorticity anomaly associated with the
arctic stream is moving through Southcentral this morning. This
upper trough is about -2.5 standard deviations below normal for
this time of year, so this is rather impressive for late
summer/early fall. Towards the Alaska Panhandle, there is a
separate shortwave trough moving east, however, some of the
moisture from this low is streaming northward and is responsible
for some of the locally heavy rainfall across Southcentral. To the
southwest, there is a subtropical jet stream and associated upper
low meandering over the North Pacific near 45N 180 (south of the
Rat Islands in the Aleutian Chain). Confluent flow underneath the
aforementioned potential vorticity anomaly is keeping the deep
layer subtropical moisture associated with this system well to the
south of the Gulf of Alaska.

Closer to home, the heaviest band of rainfall stretches from the
northern Susitna Valley eastward toward the southern Copper
Basin/Valdez. More showery conditions have developed south of this
line as the main PV anomaly moves into Cook Inlet. Behind the low
across Southwest Alaska strong cyclonic flow exists with gale
force winds impacting much of the Southwest coastline.

&&

.MODEL DISCUSSION...
The numerical guidance is in overall good synoptic agreement with
the main weather features through Tuesday before rapidly
diverging as another arctic trough eventually phases with a weaker
trough over the Eastern Bering Sea. The main areas of concern
over the next couple of days will be the potential for fog
development Sunday night into Monday morning, especially across
Southcentral where there will be plenty of low level moisture and
clearing skies (aloft). The precipitation distribution associated
with showers across inland areas will also be a challenge given
the weak features embedded within the larger scale flow pattern.
This forecast utilized a blend of the NAM and GFS to account for
the differences. Forecast confidence is moderately high.

&&

.AVIATION...
PANC...Moderate to intense rainfall this morning will limit
VSBYs to as low as 3 to 5 SM before showers begin to diminish mid
morning. Rain showers will end by the afternoon hours. Patchy fog
may be a threat near the terminal by Monday morning as skies
begin to clear.

&&

.SHORT TERM FORECAST SOUTHCENTRAL ALASKA (Days 1 and 2)...
A large and cold upper low tracks east across Southcentral today
while a cold frontal trough moves east at the surface. Widespread
showers associated with these features will be moderate to heavy
at times this morning, but should diminish from the west through
today. The cooling temperatures aloft will increase the
instability and may give rise to isolated thunderstorms across
the Gulf and portions of the Copper River Basin through this
evening. West to southwest gale gusts over the western Gulf will
diminish tonight. Monday will bring fewer showers and some cloud
breaks, though there will likely be areas of patchy early morning
fog in many areas.

&&

.SHORT TERM FORECAST SOUTHWEST ALASKA (Days 1 and 2)...
At the onset of the forecast period...there is a closed low over
the AK Peninsula with multiple vort lobes circulating around it. The
lion's share of the precipitation has already exited the
region...however...with that cold pool aloft combined with the
impulses of shortwave energy...lingering showers are possible
today. The jet will continue to track along the coast and over
Bristol Bay...resulting in more gusty winds today but then
subsiding over night. Monday's weather will be drier.

&&

.SHORT TERM FORECAST BERING SEA/ALEUTIANS (Days 1 and 2)...
On satellite imagery there is a low south of Adak with the cloud
shield extending from Attu to the Gulf Of Alaska. Anticipating a
skosh of warm air to advect into the region contributing to the
stratus factor. There is a ridge northwest of the low which is
influencing the steering pattern...keeping the track eastward and
relatively parallel along the Aleutian Archipelago and towards the
Gulf of Alaska. The tight pressure gradient remains in place over
the Eastern Aleutians this forecast period which will result in
gusty winds. Late Sunday...a new low will close off over Nunivak
Island and will push south on Monday resulting in the next batch
of unsettled weather for the Bering.

&&

.LONG TERM FORECAST (Days 3 through 7)...
One important change in the models early next week has been a
trend towards a more progressive upper level trough over the
mainland late Sunday. As a result there is now general consensus
that weak high pressure will develop over the South Mainland Mon-
Tue between the departing low and the next low diving southward
into the Eastern Bering. This high pressure should bring a brief
break in the active weather pattern to much of Southcentral early
next week, however there is very good agreement that a series of
arctic troughs will move through the Mainland and Eastern Bering
into late next week. There are some timing/intensity issues in
the models from these trough, so forecast confidence is low on the
exact details of the long term forecast. Forecast confidence is
however good with the overall trend of continued cool, wet, and
fall-like conditions.

&&

.AFC WATCHES/WARNINGS/ADVISORIES...
PUBLIC...NONE.
MARINE...Gale 138 160.
FIRE WEATHER...NONE.

&&

SYNOPSIS AND MODEL DISCUSSION...Ahsenmacher
SOUTHCENTRAL ALASKA...RMC
SOUTHWEST ALASKA/BERING SEA/ALEUTIANS...PJS
LONG TERM...MMC