Small Craft Advisory 604, NWS Anchorage, AK

204 
FZAK51 PAFC 062352
CWFAER

Coastal Waters Forecast
National Weather Service Anchorage Alaska
352 PM AKDT Mon Aug 6 2018

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.

PKZ197-071245-
352 PM AKDT Mon Aug 6 2018
.SYNOPSIS FOR THE NORTH GULF COAST+KODIAK ISLAND WATERS+
COOK INLET...
A front extends across the Northern Gulf and moves into the
Eastern Gulf by Wed afternoon. A 1009 mb low 65 nm Southwest of
Cordova moves to 60 nm South of Cordova at 1000 mb for Wed 
afternoon.

$$

PKZ119-071245-
Cape Suckling to Cape Cleare-
352 PM AKDT Mon Aug 6 2018

.TONIGHT...SW wind 15 kt. Seas 6 ft.
.TUE...SW wind 20 kt. Seas 6 ft. Rain.
.TUE NIGHT...Variable wind 10 kt. Seas 6 ft.
.WED...Variable wind 10 kt. Seas 5 ft.
.WED NIGHT...Variable wind 10 kt. Seas 4 ft.
.THU THROUGH SAT...Variable wind 10 kt. Seas 5 ft.

$$

PKZ120-071245-
Cape Cleare to Gore Point-
352 PM AKDT Mon Aug 6 2018

.TONIGHT...SW wind 20 kt. Seas 6 ft.
.TUE...W wind 15 kt. Seas 5 ft.
.TUE NIGHT...W wind 20 kt. Seas 5 ft.
.WED AND WED NIGHT...Variable wind 10 kt. Seas 4 ft.
.THU THROUGH FRI...Variable wind 10 kt. Seas 5 ft.
.SAT...S wind 15 kt. Seas 6 ft.

$$

PKZ121-071245-
Resurrection Bay-
352 PM AKDT Mon Aug 6 2018

.TONIGHT...Variable wind 10 kt. Seas 2 ft.
.TUE...Variable wind less than 10 kt becoming N 10 kt in the
afternoon. Seas 2 ft. Rain.
.TUE NIGHT...N wind 10 kt increasing to 15 kt after midnight. Seas
3 ft.
.WED...N wind 15 kt. Seas 3 ft.
.WED NIGHT...Variable wind less than 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.
.SAT...S wind 10 kt. Seas 2 ft.

$$

PKZ125-071245-
Prince William Sound-
352 PM AKDT Mon Aug 6 2018

.TONIGHT...E wind 10 kt after midnight. Seas 2 ft.
.TUE...E wind 10 kt. Seas 2 ft. Rain.
.TUE NIGHT...Variable wind less than 10 kt. Seas 2 ft.
.WED...Variable wind less than 10 kt. Seas 2 ft.
.WED NIGHT...N wind 10 kt. Seas 2 ft.
.THU THROUGH SAT...Variable wind less than 10 kt. Seas 2 ft.

$$

PKZ126-071245-
Port Valdez-
352 PM AKDT Mon Aug 6 2018

.TONIGHT...Variable wind less than 10 kt. Seas 2 ft. Rain.
.TUE...Variable wind less than 10 kt. Seas 2 ft. Rain.
.TUE NIGHT...Variable wind less than 10 kt. Seas 2 ft. Rain.
.WED AND WED NIGHT...NE wind 10 kt. Seas 2 ft.
.THU...Variable wind less than 10 kt. Seas 2 ft.
.FRI THROUGH SAT...Variable wind 10 kt. Seas 2 ft.

$$

PKZ127-071245-
Valdez Narrows-
352 PM AKDT Mon Aug 6 2018

.TONIGHT...NE wind 10 kt. Seas 2 ft. Rain.
.TUE...NE wind 10 kt. Seas 2 ft. Rain.
.TUE NIGHT...NE wind 10 kt. Seas 2 ft. Rain.
.WED...NE wind 15 kt. Seas 3 ft.
.WED NIGHT...N wind 10 kt. Seas 2 ft.
.THU...SW wind 10 kt. Seas 2 ft.
.FRI...Variable wind 10 kt. Seas 2 ft.
.SAT...SW wind 10 kt. Seas 2 ft.

$$

PKZ128-071245-
Valdez Arm-
352 PM AKDT Mon Aug 6 2018

.TONIGHT...Variable wind less than 10 kt becoming NE 10 kt after
midnight. Seas 2 ft. Rain.
.TUE...NE wind 10 kt in the morning becoming variable less than
10 kt. Seas 2 ft. Rain.
.TUE NIGHT...Variable wind less than 10 kt becoming NE wind 10 kt
after midnight. Seas 2 ft. Rain.
.WED AND WED NIGHT...NE wind 15 kt. Seas 3 ft.
.THU...Variable wind less than 10 kt. Seas 2 ft.
.FRI THROUGH SAT...Variable wind 10 kt. Seas 2 ft.

$$

PKZ129-071245-
Passage Canal-
352 PM AKDT Mon Aug 6 2018

.TONIGHT...Variable wind less than 10 kt. Seas 2 ft. Rain.
.TUE...Variable wind less than 10 kt becoming Variable wind 10 kt
in the afternoon. Seas 2 ft. Rain.
.TUE NIGHT...W wind 10 kt. Seas 2 ft.
.WED...W wind 10 kt. Seas 2 ft.
.WED NIGHT...Variable wind less than 10 kt. Seas 2 ft.
.THU THROUGH FRI...Variable wind less than 10 kt. Seas 2 ft.
.SAT...E wind 10 kt. Seas 2 ft.

$$

PKZ130-071245-
West of Barren Islands including Kamishak Bay-
352 PM AKDT Mon Aug 6 2018

...SMALL CRAFT ADVISORY TUESDAY AND TUESDAY NIGHT...

.TONIGHT...SW wind 20 kt. Seas 5 ft.
.TUE...W wind 30 kt. Seas 8 ft.
.TUE NIGHT...W wind 25 kt. Seas 8 ft.
.WED AND WED NIGHT...NW wind 25 kt. Seas 7 ft.
.THU...W wind 20 kt. Seas 5 ft.
.FRI...Variable wind 10 kt. Seas 3 ft.
.SAT...Variable wind 10 kt. Seas 3 ft.

$$

PKZ131-071245-
Barren Islands East-
352 PM AKDT Mon Aug 6 2018

...SMALL CRAFT ADVISORY TUESDAY AND TUESDAY NIGHT...

.TONIGHT...SW wind 20 kt. Seas 6 ft.
.TUE...W wind 15 kt increasing to 30 kt in the afternoon. Seas 6 ft.
.TUE NIGHT...W wind 30 kt. Seas 9 ft.
.WED AND WED NIGHT...NW wind 25 kt. Seas 9 ft.
.THU...W wind 20 kt. Seas 7 ft.
.FRI...Variable wind 10 kt. Seas 6 ft.
.SAT...S wind 15 kt. Seas 6 ft.

$$

PKZ132-071245-
Marmot Island to Sitkinak-
352 PM AKDT Mon Aug 6 2018

...SMALL CRAFT ADVISORY THROUGH TUESDAY NIGHT...

.TONIGHT...SW wind 25 kt. Seas 6 ft. Rain.
.TUE...W wind 25 kt. Seas 6 ft.
.TUE NIGHT...W wind 30 kt except W 20 kt N of Dangerous Cape. Seas 7 ft.
.WED...W wind 25 kt. Seas 6 ft.
.WED NIGHT...NW wind 20 kt. Seas 6 ft.
.THU...W wind 20 kt. Seas 6 ft.
.FRI THROUGH SAT...SW wind 15 kt. Seas 7 ft.

$$

PKZ136-071245-
Chiniak Bay-
352 PM AKDT Mon Aug 6 2018

.TONIGHT...SW wind 10 kt in the evening becoming variable less than 
10 kt. Seas 2 ft.
.TUE...W wind 10 kt. Seas 2 ft.
.TUE NIGHT...W wind 10 kt. Seas 2 ft.
.WED AND WED NIGHT...NW wind 15 kt. Seas 2 ft.
.THU...W wind 15 kt. Seas 2 ft.
.FRI...Variable wind less than 10 kt. Seas 2 ft.
.SAT...SW wind 10 kt. Seas 1 ft.

$$

PKZ137-071245-
Marmot Bay-
352 PM AKDT Mon Aug 6 2018

.TONIGHT...W wind 20 kt becoming SW 10 kt after midnight. Seas 3 ft.
.TUE...W wind 10 kt increasing to 15 kt in the afternoon. Seas 3 ft.
.TUE NIGHT...W wind 20 kt. Seas 3 ft.
.WED AND WED NIGHT...NW wind 15 kt. Seas 3 ft.
.THU...W wind 15 kt. Seas 2 ft.
.FRI...Variable wind less than 10 kt. Seas 2 ft.
.SAT...S wind 10 kt. Seas 2 ft.

$$

PKZ138-071245-
Shelikof Strait-
352 PM AKDT Mon Aug 6 2018

...SMALL CRAFT ADVISORY THROUGH TUESDAY NIGHT...

.TONIGHT...SW wind 25 kt. Seas 8 ft.
.TUE...W wind 25 kt. Seas 7 ft.
.TUE NIGHT...W wind 25 kt. Seas 7 ft.
.WED AND WED NIGHT...NW wind 20 kt. Seas 5 ft.
.THU...W wind 15 kt. Seas 3 ft.
.FRI...Variable wind 10 kt. Seas 3 ft.
.SAT...S wind 15 kt. Seas 3 ft.

$$

PKZ139-071245-
Cook Inlet Kalgin Island to Point Bede-
352 PM AKDT Mon Aug 6 2018

...SMALL CRAFT ADVISORY TONIGHT...

.TONIGHT...SW wind 25 kt. Seas 7 ft.
.TUE...SW wind 15 kt becoming W 10 kt in the afternoon. Seas 4 ft
subsiding to 2 ft in the afternoon.
.TUE NIGHT...SW wind 15 kt becoming NW 10 kt after midnight. Seas
2 ft.
.WED AND WED NIGHT...NW wind 10 kt. Seas 3 ft.
.THU...W wind 10 kt. Seas 2 ft.
.FRI...SW wind 10 kt. Seas 2 ft.
.SAT...S wind 10 kt. Seas 2 ft.

$$

PKZ140-071245-
Cook Inlet North of Kalgin Island-
352 PM AKDT Mon Aug 6 2018

.TONIGHT...S wind 20 kt. Seas 6 ft.
.TUE...S wind 10 kt in the morning becoming variable less than
10 kt. Seas subsiding to 2 ft.
.TUE NIGHT...Variable wind less than 10 kt becoming NW 10 kt after
midnight. Seas 2 ft.
.WED...Variable wind less than 10 kt. Seas 2 ft.
.WED NIGHT...NW wind 10 kt. Seas 2 ft.
.THU...W wind 10 kt. Seas 2 ft.
.FRI...SW wind 10 kt. Seas 2 ft.
.SAT...S wind 10 kt. Seas 2 ft.

$$

PKZ141-071245-
Kachemak Bay-
352 PM AKDT Mon Aug 6 2018

.TONIGHT...SW wind 20 kt diminishing to 10 kt by midnight. Seas 6 ft
subsiding to 2 ft. 
.TUE...Variable wind 10 kt becoming SW 15 kt in the afternoon. Seas
building to 4 ft. 
.TUE NIGHT...W wind 10 kt becoming N after midnight. Seas 2 ft.
.WED AND WED NIGHT...NW wind 10 kt. Seas 2 ft.
.THU...NW wind 10 kt. Seas 2 ft.
.FRI...Variable wind less than 10 kt. Seas 2 ft.
.SAT...S wind 10 kt. Seas 2 ft.

$$

750 
FZAK51 PAFC 071150
CWFAER

Coastal Waters Forecast
National Weather Service Anchorage Alaska
350 AM AKDT Tue Aug 7 2018

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.

PKZ197-080045-
350 AM AKDT Tue Aug 7 2018
.SYNOPSIS FOR THE NORTH GULF COAST+KODIAK ISLAND WATERS+
COOK INLET...
A trough of low pressure in the northern Gulf moves over Middleton
Island to form a 1001 mb low Wed night.

$$

PKZ119-080045-
Cape Suckling to Cape Cleare-
350 AM AKDT Tue Aug 7 2018

.TODAY...SW wind 20 kt. Seas 6 ft. Patchy Fog.
.TONIGHT...Variable wind 10 kt. Seas 5 ft.
.WED...Variable wind 10 kt. Seas 5 ft.
.WED NIGHT...N wind 15 kt. Seas 4 ft.
.THU...Variable wind 10 kt. Seas 4 ft.
.FRI THROUGH SAT...S wind 20 kt. Seas 6 ft.

$$

PKZ120-080045-
Cape Cleare to Gore Point-
350 AM AKDT Tue Aug 7 2018

.TODAY...W wind 15 kt. Seas 5 ft. Patchy Fog.
.TONIGHT...W wind 20 kt. Seas 6 ft.
.WED...Variable wind 10 kt. Seas 5 ft.
.WED NIGHT...Variable wind 10 kt. Seas 4 ft.
.THU...W wind 15 kt. Seas 4 ft.
.FRI...S wind 20 kt. Seas 5 ft.
.SAT...W wind 15 kt. Seas 5 ft.

$$

PKZ121-080045-
Resurrection Bay-
350 AM AKDT Tue Aug 7 2018

.TODAY...Variable wind less than 10 kt becoming N 10 kt in the
afternoon. Seas 2 ft. Rain. Patchy Fog.
.TONIGHT...N wind 10 kt increasing to 15 kt after midnight. Seas
3 ft.
.WED...N wind 15 kt diminishing to 10 kt in the afternoon. Seas
3 ft.
.WED NIGHT...N wind 15 kt. Seas 3 ft.
.THU...N wind 15 kt. Seas 3 ft.
.FRI THROUGH SAT...S wind 10 kt. Seas 2 ft.

$$

PKZ125-080045-
Prince William Sound-
350 AM AKDT Tue Aug 7 2018

.TODAY...E wind 15 kt. Seas 3 ft.
.TONIGHT...Variable wind less than 10 kt. Seas 2 ft.
.WED...Variable wind less than 10 kt. Seas 2 ft. Rain.
.WED NIGHT...Variable wind less than 10 kt. Seas 2 ft.
.THU...Variable wind less than 10 kt. Seas 2 ft.
.FRI THROUGH SAT...E wind 15 kt. Seas 2 ft.

$$

PKZ126-080045-
Port Valdez-
350 AM AKDT Tue Aug 7 2018

.TODAY...Variable wind 10 kt in the morning becoming variable less
than 10 kt. Seas 2 ft. Rain.
.TONIGHT...Variable wind 10 kt. Seas 2 ft. Rain.
.WED...Variable wind less than 10 kt becoming NE 10 kt in the
afternoon. Seas 2 ft. Rain.
.WED NIGHT...NE wind 15 kt. Seas 3 ft.
.THU...NE wind 15 kt. Seas 3 ft.
.FRI THROUGH SAT...Variable wind 10 kt. Seas 2 ft.

$$

PKZ127-080045-
Valdez Narrows-
350 AM AKDT Tue Aug 7 2018

.TODAY...NE wind 10 kt. Seas 2 ft. Rain.
.TONIGHT...NE wind 10 kt. Seas 2 ft. Rain.
.WED...NE wind 15 kt. Seas 3 ft. Rain.
.WED NIGHT...NE wind 20 kt. Seas 3 ft.
.THU...NE wind 15 kt. Seas 3 ft.
.FRI THROUGH SAT...NE wind 10 kt. Seas 2 ft.

$$

PKZ128-080045-
Valdez Arm-
350 AM AKDT Tue Aug 7 2018

.TODAY...NE wind 10 kt. Seas 2 ft. Rain.
.TONIGHT...Variable wind less than 10 kt becoming NE wind 10 kt
after midnight. Seas 2 ft. Rain.
.WED...NE wind 10 kt. Seas 2 ft. Rain.
.WED NIGHT...NE wind 15 kt. Seas 3 ft.
.THU THROUGH SAT...NE wind 10 kt. Seas 2 ft.

$$

PKZ129-080045-
Passage Canal-
350 AM AKDT Tue Aug 7 2018

.TODAY...Variable wind less than 10 kt becoming Variable wind 10
kt in the afternoon. Seas 2 ft. Widespread rain showers.
.TONIGHT...W wind 10 kt. Seas 2 ft.
.WED...W wind 10 kt. Seas 2 ft.
.WED NIGHT...Variable wind less than 10 kt. Seas 2 ft.
.THU...Variable wind less than 10 kt. Seas 2 ft.
.FRI THROUGH SAT...E wind 10 kt. Seas 2 ft.

$$

PKZ130-080045-
West of Barren Islands including Kamishak Bay-
350 AM AKDT Tue Aug 7 2018

...SMALL CRAFT ADVISORY THROUGH WEDNESDAY...

.TODAY...W wind 20 kt increasing to 30 kt in the afternoon. Seas 8 
ft.
.TONIGHT...W wind 25 kt. Seas 8 ft.
.WED...W wind 25 kt. Seas 7 ft.
.WED NIGHT...W wind 35 kt. Seas 9 ft.
.THU...W wind 30 kt. Seas 8 ft.
.FRI...SE wind 25 kt. Seas 5 ft.
.SAT...SW wind 15 kt. Seas 3 ft.

$$

PKZ131-080045-
Barren Islands East-
350 AM AKDT Tue Aug 7 2018

...SMALL CRAFT ADVISORY THROUGH WEDNESDAY...

.TODAY...W wind 15 kt increasing to 30 kt in the afternoon. Seas
6 ft.
.TONIGHT...W wind 30 kt. Seas 8 ft.
.WED...NW wind 25 kt. Seas 7 ft.
.WED NIGHT...NW wind 30 kt. Seas 7 ft.
.THU...W wind 30 kt. Seas 7 ft.
.FRI...S wind 20 kt. Seas 6 ft.
.SAT...SW wind 20 kt. Seas 6 ft.

$$

PKZ132-080045-
Marmot Island to Sitkinak-
350 AM AKDT Tue Aug 7 2018

...SMALL CRAFT ADVISORY THROUGH WEDNESDAY...

.TODAY...W wind 25 kt. Seas 7 ft.
.TONIGHT...W wind 30 kt except W 20 kt N of Dangerous Cape. Seas
8 ft.
.WED...W wind 25 kt. Seas 7 ft.
.WED NIGHT...NW wind 25 kt. Seas 7 ft.
.THU...W wind 25 kt. Seas 6 ft.
.FRI...SW wind 25 kt. Seas 8 ft.
.SAT...SW wind 20 kt. Seas 8 ft.

$$

PKZ136-080045-
Chiniak Bay-
350 AM AKDT Tue Aug 7 2018

.TODAY...W wind 10 kt. Seas 2 ft.
.TONIGHT...W wind 10 kt. Seas 2 ft.
.WED...W wind 15 kt. Seas 2 ft.
.WED NIGHT...NW wind 20 kt. Seas 3 ft.
.THU...W wind 20 kt. Seas 2 ft.
.FRI THROUGH SAT...SW wind 10 kt. Seas 2 ft.

$$

PKZ137-080045-
Marmot Bay-
350 AM AKDT Tue Aug 7 2018

.TODAY...W wind 10 kt increasing to 15 kt in the afternoon. Seas
3 ft.
.TONIGHT...W wind 20 kt. Seas 3 ft.
.WED...NW wind 20 kt. Seas 3 ft.
.WED NIGHT...NW wind 20 kt. Seas 3 ft.
.THU...W wind 15 kt. Seas 3 ft.
.FRI THROUGH SAT...SW wind 10 kt. Seas 3 ft.

$$

PKZ138-080045-
Shelikof Strait-
350 AM AKDT Tue Aug 7 2018

...SMALL CRAFT ADVISORY THROUGH TONIGHT...

.TODAY...W wind 25 kt. Seas 5 ft.
.TONIGHT...W wind 25 kt. Seas 6 ft.
.WED...W wind 20 kt. Seas 4 ft.
.WED NIGHT...NW wind 25 kt. Seas 6 ft.
.THU...W wind 20 kt. Seas 4 ft.
.FRI...Variable wind 10 kt. Seas 2 ft.
.SAT...SW wind 15 kt. Seas 3 ft.

$$

PKZ139-080045-
Cook Inlet Kalgin Island to Point Bede-
350 AM AKDT Tue Aug 7 2018

.TODAY...SW wind 15 kt. Seas 4 ft subsiding to 2 ft in the
afternoon.
.TONIGHT...SW wind 15 kt becoming NW 10 kt after midnight. Seas
3 ft.
.WED...N wind 10 kt. Seas 2 ft.
.WED NIGHT...NW wind 10 kt. Seas 2 ft.
.THU...SW wind 10 kt. Seas 2 ft.
.FRI THROUGH SAT...SW wind 10 kt. Seas 3 ft.

$$

PKZ140-080045-
Cook Inlet North of Kalgin Island-
350 AM AKDT Tue Aug 7 2018

.TODAY...S wind 10 kt in the morning becoming variable less than
10 kt. Seas 2 ft.
.TONIGHT...Variable wind less than 10 kt becoming NW 10 kt after
midnight. Seas 1 ft.
.WED...Variable wind less than 10 kt. Seas 1 ft.
.WED NIGHT...NW wind 15 kt. Seas 2 ft.
.THU...W wind 10 kt. Seas 2 ft.
.FRI...Variable wind less than 10 kt. Seas 2 ft.
.SAT...S wind 10 kt. Seas 3 ft.

$$

PKZ141-080045-
Kachemak Bay-
350 AM AKDT Tue Aug 7 2018

.TODAY...SW wind 15 kt. Seas 6 ft.
.TONIGHT...W wind 15 kt becoming N 10 kt after midnight. Seas 4 ft
subsiding to 2 ft after midnight.
.WED...N wind 10 kt. Seas 2 ft.
.WED NIGHT...NW wind 10 kt. Seas 2 ft.
.THU...NW wind 10 kt. Seas 2 ft.
.FRI...SE wind 10 kt. Seas 2 ft.
.SAT...SW wind 10 kt. Seas 2 ft.

$$

Southcentral and Southwest Alaska Forecast Discussion
National Weather Service Anchorage AK
509 PM AKDT Sun Aug 5 2018

.ANALYSIS AND UPPER LEVELS...
An atmospheric river rain event is underway as a strong jet stream
at all levels of the atmosphere transports very warm and moist
tropical air from the northwest Pacific across the southern and
eastern Bering Sea to Mainland Alaska. 12Z soundings from the
southern half of Alaska show TPW (Total Precipitable Water) values
of around 1.25" while the satellite-based Blended TPW product
shows widespread values of 1.5" or higher over the Bering Sea
and Aleutian Islands. Also of note this morning, southwest
downslope winds in Dutch Harbor on top of the already balmy air
mass have quickly warmed the temperature at the airport to 72
degrees (with a dewpoint of 64 degrees). This is actually pretty
typical for Dutch Harbor in August, which is it's warmest month.
With all of this warm and moist air across the region, both fog
and rain are prevalent. It doesn't take much upward vertical
motion to produce rain, and where winds run into the terrain,
heavy rain develops.

As far as specific features, a series of upper level short-waves
are spread out along the jet stream, bringing rounds of rain from
the western Aleutians to the Pribilof Islands to Southwest and
Southcentral Alaska. The bulk of rain is currently falling over
northern areas of Southwest and Southcentral, though the nose of
the upper level ridge (along the Alaska Peninsula and western
Gulf) is being pushed south and eastward, allowing rain to
gradually spread farther south. Lastly, the strong jet stream
combined with tight pressure gradients is producing gusty south to
southwest winds across much of Alaska. Oftentimes, the presence
of wind results in higher clouds and good visibility. That is
certainly not the case in this type of environment, with some
areas of Bristol Bay reporting fog with winds of 15 to 20 mph and
widespread low clouds being observed across the Bering
Sea/Aleutians and on into Southwest Alaska.

&&

.MODEL DISCUSSION...
Models are in good agreement and consistent with primary features
early on, but differences develop on Monday which will affect the
forecast moving forward. Most solutions are now resolving two
specific upper vort-maxes crossing Southcentral Monday afternoon
and evening. As a result, there has been a trend toward wetter
conditions and less of a break between upper waves.

Inconsistency continues Monday night through Tuesday with handling
of a more significant upper level short-wave. The latest trend is
toward a flatter and faster moving wave as it crosses the Aleutians
and southeastern Bering Sea, with amplification not occurring
until it reaches Bristol Bay and on into the Gulf and Southcentral.
The past couple days this looked like it could produce widespread
heavy rain across most of Southcentral. Based on the model runs,
it might not be that widespread. The NAM is a clear outlier on the
12Z runs, with amplification not occurring until it is in the
Gulf and the bulk of rain heading toward eastern Prince William
Sound and the Copper River Basin. Will stick closer to the other
solutions which amplify the wave sooner and still bring rain into
the Cook Inlet/Susitna Valley corridor. In any case, short-waves
rotating down from the northwest behind this wave should bring
additional rain to Anchorage and the Mat-Su (though not necessarily
a widespread heavy rain event). Will continue to closely monitor
future model runs as this last wave may be key to whether flooding
is experienced along Mat-Su rivers and streams.

&&

.HYDROLOGY...
Have issued a fairly broad Flood Watch for the Susitna River Basin
(all rivers and streams which flow into the Susitna River). Based
on the latest QPF forecast, the Yentna and Maclaren Rivers have
the highest likelihood of rising out of their banks. However, with
the uncertainty in rainfall amounts Monday night and Tuesday (as
per the model discussion above), it seems prudent to include all
the rivers which do have potential for flooding if the heavier
rain scenario works out. This includes Skwentna River, Montana
Creek, Willow Creek, and the Little Susitna River. The threat for
flooding will extend through at least Wednesday, especially for
the larger rivers, which are slower to rise in response to heavy
rainfall.

&&

.AVIATION...
PANC...The high confidence aspect of the TAF is winds, which will
remain gusty out of the south to south-southeast. The strongest
period of winds looks to be from 03Z and 09Z as a short-wave
crosses the Alaska Range from the west, leading to a strengthening
lee side trough in Cook Inlet. This in turn will lead to strong
up Inlet flow and stronger winds coming out of Turnagain Arm.
Expect ceilings to gradually lower during this period as the low
level winds shift from a southerly direction more toward
southwesterly.

The biggest challenge is ceiling and visibility, which will
largely depend on the intensity of precipitation. With upslope
flow, the heaviest rain will be along the Chugach, though there
may be a period of heavier precip over the terminal as well. In
any case, don't think the conditions should get any worse than
MVFR at the terminal, though there could be IFR clouds to the east
along the mountains.

&&

.SHORT TERM FORECAST SOUTHCENTRAL ALASKA (Days 1 and 2)...
A wet and cool pattern is anticipated tonight, tomorrow and
Tuesday. Energy is going to enter the region from the west and is
embedded in zonal flow which means its going to be fast moving.
However, regardless of which model you look at, the impulses of
energy are lined up from the Alaska Range to the Kamchatka
Peninsula. All of the associate moisture is destined for Southcentral
or the northern Gulf of Alaska over the next 72 hrs. The
watersheds draining from the Alaska Range and Talkeetna Mountains
are being actively monitored for flooding. Climatologically,
August is the wettest month of the year for Anchorage and Palmer.
However, sampling from the latest satellite imagery indicates that
portions of this water vapor plume are above 200 percent of
normal.

&&

.SHORT TERM FORECAST SOUTHWEST ALASKA (Days 1 through 3)...

A low-amplitude trough encompassing the entirety of the central
and northern Bering will continue to eject a series of quick-
moving shortwaves toward the Southwest through Tuesday. The first
such wave has already pushed through the region, with only areas
of upslope rain persisting across the Alaska Range. The second is
currently situated over the Y-K Delta and will bring another
round of rain and gusty southwesterly winds to the area through
the overnight hours. Another shortwave will move through Monday
night, bringing rain primarily to the Bristol Bay region. The
broader trough then begins to slide east, moving over the western
coast by Tuesday morning and into the interior by Tuesday evening.
Additional shortwaves embedded in the main cyclonic flow will
keep the weather unsettled; however as the winds shift to the
northwest and colder air begins to advect into the region,
precipitation will begin to diminish in coverage and become more
showery in nature.

&&

.SHORT TERM FORECAST BERING SEA/ALEUTIANS (Days 1 through 3)...

A storm system situated west of Adak will continue its slow
progression toward the eastern Aleutians as the ridge out ahead of
it flattens and slides east. Areas of rain and fog along portions
of the central and eastern Aleutians will shift east and diminish
as the warm front associated with this system moves across the
Alaska Peninsula and into the western Gulf. A band of gusty
southerly winds will also precede the trailing cold front as it
moves across the Aleutians, reaching the Alaska Peninsula by
Monday afternoon. A developing low in the northwest Pacific will
bring rain to the western Aleutians Tuesday as its associated
warm front lifts north. This system slides to the east by
Wednesday spreading rain and southerly winds across the central
Aleutians. High pressure to the north of the low introduce more
low status and areas of fog across the western Bering beginning
Tuesday and into the central Bering Tuesday night.

&&

.LONG TERM FORECAST (Days 3 through 7: Wednesday through Sunday)...

On Wednesday, the models are all in good agreement that the axis
of a large upper level long wave trough will be right over the
Cook Inlet region and Susitna Valley Wednesday morning. For areas
east of there, including Prince William Sound and the Copper River
Basin north into the Talkeetnas, showers that may be heavy at
times will continue into the day. For Anchorage, the Susitna
Valley, and the eastern Kenai Peninsula, much more infrequent
shower activity is expected as these areas will be right on the
edge of the steadier showers. For the western Kenai Peninsula
southward through Kodiak, much of the day will be dry as
northwesterly offshore flow kicks in. A bit better chance for
showers are expected Wednesday across Southwest Alaska since the
area will remain quite unstable. The trough closes off into an
upper level low by Thursday morning over the northeastern Gulf,
which will help to shut off the shower activity except over
eastern portions of the Copper River Basin.

Weak ridging spreads across much of Southern Alaska on Thursday,
which except for some possible showers over the Copper River
Basin, should make for a rare dry day for most of the area. This
has been generally agreed upon for a couple days now, so it seems
there is decent confidence that outdoor activities can be planned
for Thursday. There remains some disagreement on how an upper
level low diving south out of the Arctic across western Alaska
tracks. The Canadian is by far the furthest south, and as such is
the only model bringing rain to interior Southwest Alaska Thursday
evening. The next low moves into the southern Bering and Aleutians
on Thursday.

On Friday, the GFS and EC both bring the Bering low into Southwest
Alaska, making for a rainy and wet day there. Both begin to bring
the moisture and precipitation into Southcentral by Friday
evening. Thus, much of Southcentral should be dry at least for
the first half of the day, with precipitation chances increasing
as time goes on. The weekend forecast is highly uncertain at this
point. The EC brings another much stronger and longer lasting
round of rain quickly behind the first on Saturday into the first
part of Sunday, while the GFS is much slower. The GFS holds off
until Sunday for the steady rains, with showery conditions likely
in between the end of the Friday night round of rain and Sunday's
storm.

&&

.AFC WATCHES/WARNINGS/ADVISORIES...
PUBLIC...Flood Watch 141 145.
MARINE...Gale 139 140.

&&

SYNOPSIS AND MODEL DISCUSSION...SEB
SOUTHCENTRAL ALASKA...PS
SOUTHWEST ALASKA/BERING SEA/ALEUTIANS...TM
LONG TERM...JW

SPECIAL WEATHER STATEMENT
National Weather Service ANCHORAGE AK
215 AM AKDT Mon Aug 6 2018

AKZ141-061930-
Copper River Basin-
Including the cities of Glennallen, Eureka, McCarthy, Paxson,
and Slana
215 AM AKDT Mon Aug 6 2018

...RISING WATER LEVELS ALONG THE DENALI HIGHWAY TODAY...

Heavy rain across the southern part of the Alaska Range and the
northwestern Copper River Basin has led to a rise in local rivers
and streams. Between 1-2 inches of rain has already fallen in the
area since yesterday evening and up to an additional inch is
expected through this afternoon, which could cause rivers to rise
to near minor flood stage later in the day today. River gauges at
both the Susitna and Maclaren Rivers along the Denali Highway
have already reported water levels rising to at or above bankfull.

Another round of heavy rain is on tap for Tuesday. With elevated
river levels from the first round of rain, the threat of flooding
will increase.

Anyone heading into the mountains and backcountry should be
prepared for heavy rain and rapidly rising water levels on rivers
and streams. Those who live along the effected rivers and streams
should monitor the latest forecasts and information on flooding
potential at www.weather.gov/afc.