Small Craft Advisory 973, NWS Anchorage, AK

887 
FZAK51 PAFC 200001
CWFAER

Coastal Waters Forecast
National Weather Service Anchorage Alaska
301 PM AKST Tue Dec 19 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.

PKZ197-201300-
301 PM AKST Tue Dec 19 2017
.SYNOPSIS FOR THE NORTH GULF COAST+KODIAK ISLAND WATERS+
COOK INLET...
A front in the western Gulf will weaken as it moves to the eastern
Gulf tonight. A second front will move into the southwestern Gulf
Thu morning.

$$

PKZ119-201300-
Cape Suckling to Cape Cleare-
301 PM AKST Tue Dec 19 2017

...SMALL CRAFT ADVISORY THROUGH WEDNESDAY...

.TONIGHT...S wind 25 kt becoming W after midnight. 
Seas 10 ft. Rain.
.WED...W wind 25 kt. Seas 9 ft.
.WED NIGHT...NW wind 15 kt. Seas 6 ft.
.THU...E wind 25 kt. Seas 5 ft.
.THU NIGHT...E wind 35 kt. Seas 13 ft.
.FRI THROUGH SAT...SE wind 50 kt. Seas 27 ft.
.SUN...SE wind 25 kt. Seas 21 ft.

$$

PKZ120-201300-
Cape Cleare to Gore Point-
301 PM AKST Tue Dec 19 2017

...SMALL CRAFT ADVISORY TONIGHT...

.TONIGHT...W wind 25 kt. Seas 10 ft.
.WED...W wind 20 kt. Seas 7 ft.
.WED NIGHT...Variable wind 10 kt becoming NE 15 kt 
after midnight. Seas 5 ft.
.THU...E wind 30 kt. Seas 7 ft.
.THU NIGHT...E wind 40 kt. Seas 18 ft.
.FRI THROUGH SAT...SE wind 45 kt. Seas 29 ft.
.SUN...S wind 20 kt. Seas 18 ft.

$$

PKZ121-201300-
Resurrection Bay-
301 PM AKST Tue Dec 19 2017

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

$$

PKZ125-201300-
Prince William Sound-
301 PM AKST Tue Dec 19 2017

...SMALL CRAFT ADVISORY TONIGHT...

.TONIGHT...E wind 25 kt shifting to W 25 kt by midnight. 
Seas 5 ft.
.WED...W wind 20 kt in the morning becoming variable less 
than 10 kt. Seas 4 ft subsiding.
.WED NIGHT...Variable wind less than 10 kt becoming N 10 kt 
after midnight. Seas 2 ft.
.THU...NE wind 15 kt. Seas 3 ft.
.THU NIGHT...E wind 20 kt. Seas 4 ft.
.FRI THROUGH SAT...E wind 40 kt. Seas 10 ft.
.SUN...SE wind 15 kt. Seas 3 ft.

$$

PKZ126-201300-
Port Valdez-
301 PM AKST Tue Dec 19 2017

.TONIGHT...E wind less than 10 kt becoming SW 10 kt by midnight. 
Seas 2 ft. Snow.
.WED...Variable wind less than 10 kt. Seas 2 ft.
.WED NIGHT...NE wind 10 kt. Seas 2 ft.
.THU...Variable wind less than 10 kt. Seas 2 ft.
.THU NIGHT...NE wind 10 kt. Seas 2 ft.
.FRI THROUGH SUN...E wind 10 kt. Seas 2 ft.

$$

PKZ127-201300-
Valdez Narrows-
301 PM AKST Tue Dec 19 2017

.TONIGHT...NE wind 20 kt becoming S 15 kt late this evening. 
Seas 3 ft. Snow and rain.
.WED...NE wind 10 kt becoming N 15 kt in the afternoon. Seas 2 ft.
.WED NIGHT...NE wind 20 kt. Seas 3 ft. Freezing spray.
.THU...NE wind 20 kt. Seas 3 ft.
.THU NIGHT THROUGH SAT...NE wind 25 kt. Seas 3 ft.
.SUN...NE wind 20 kt. Seas 3 ft.

$$

PKZ128-201300-
Valdez Arm-
301 PM AKST Tue Dec 19 2017

.TONIGHT...E wind 20 kt becoming SW 20 kt by late evening. 
Seas 4 ft. Rain and snow.
.WED...N wind 10 kt. Seas 2 ft.
.WED NIGHT THROUGH THU NIGHT...NE wind 15 kt. Seas 3 ft.
.FRI...NE wind 20 kt. Seas 4 ft.
.SAT...NE wind 25 kt. Seas 5 ft.
.SUN...NE wind 15 kt. Seas 3 ft.

$$

PKZ129-201300-
Passage Canal-
301 PM AKST Tue Dec 19 2017

.TONIGHT...Variable wind 10 kt becoming W 15 kt during the evening. 
Gusts to 25 kt near Whittier. Seas 2 ft.
.WED...W wind 10 kt. Gusts to 20 kt near Whittier in the morning. 
Seas 2 ft.
.WED NIGHT...Variable wind less than 10 kt. Seas 2 ft.
.THU...E wind 10 kt. Seas 2 ft.
.THU NIGHT...E wind 15 kt. Seas 2 ft.
.FRI...E wind 25 kt. Seas 4 ft.
.SAT...E wind 30 kt. Seas 5 ft.
.SUN...E wind 10 kt. Seas 2 ft.

$$

PKZ130-201300-
West of Barren Islands including Kamishak Bay-
301 PM AKST Tue Dec 19 2017

.TONIGHT...SW wind 20 kt. Seas 6 ft.
.WED...SW wind 20 kt. Seas 5 ft.
.WED NIGHT...E wind 20 kt. Seas 6 ft.
.THU...E wind 40 kt. Seas 16 ft.
.THU NIGHT...E wind 50 kt. Seas 24 ft.
.FRI...E wind 50 kt. Seas 24 ft.
.SAT...SE wind 45 kt. Seas 20 ft.
.SUN...SW wind 20 kt. Seas 6 ft.

$$

PKZ131-201300-
Barren Islands East-
301 PM AKST Tue Dec 19 2017

...SMALL CRAFT ADVISORY TONIGHT...

.TONIGHT...SW wind 25 kt. Seas 9 ft.
.WED...W wind 20 kt. Seas 7 ft.
.WED NIGHT...Variable wind 10 kt becoming E 20 kt 
after midnight. Seas 5 ft.
.THU...E wind 40 kt. Seas 10 ft.
.THU NIGHT...E wind 50 kt. Seas 24 ft.
.FRI...E wind 50 kt. Seas 28 ft.
.SAT...SE wind 45 kt. Seas 28 ft.
.SUN...SW wind 20 kt. Seas 15 ft.

$$

PKZ132-201300-
Marmot Island to Sitkinak-
301 PM AKST Tue Dec 19 2017

...SMALL CRAFT ADVISORY THROUGH WEDNESDAY NIGHT...

.TONIGHT...W wind 20 kt. Seas 11 ft.
.WED...W wind 15 kt. Seas 8 ft.
.WED NIGHT...SE wind 20 kt becoming E 30 kt after midnight. 
Seas 8 ft.
.THU...E wind 50 kt. Seas 17 ft.
.THU NIGHT...SE wind 50 kt. Seas 30 ft.
.FRI...SE wind 45 kt. Seas 28 ft.
.SAT...S wind 35 kt. Seas 23 ft.
.SUN...SW wind 20 kt. Seas 15 ft.

$$

PKZ136-201300-
Chiniak Bay-
301 PM AKST Tue Dec 19 2017

.TONIGHT...SW wind 15 kt diminishing to 10 kt after midnight. 
Seas 2 ft.
.WED...SW wind 10 kt in the morning becoming variable less 
than 10 kt. Seas 2 ft.
.WED NIGHT...Variable wind less than 10 kt becoming SE 20 kt 
after midnight. Seas 2 ft building to 4 ft after midnight.
.THU...E wind 40 kt. Seas 14 ft.
.THU NIGHT...SE wind 45 kt. Seas 18 ft.
.FRI...SE wind 40 kt. Seas 16 ft.
.SAT...SE wind 25 kt. Seas 10 ft.
.SUN...SW wind 15 kt. Seas 2 ft.

$$

PKZ137-201300-
Marmot Bay-
301 PM AKST Tue Dec 19 2017

.TONIGHT...W wind 15 kt. Seas 3 ft.
.WED...SW wind 10 kt. Seas 2 ft.
.WED NIGHT...Variable wind less than 10 kt becoming SE 20 kt 
after midnight. Seas building to 4 ft.
.THU AND THU NIGHT...E wind 40 kt. Seas 17 ft.
.FRI...SE wind 35 kt. Seas 16 ft.
.SAT...SE wind 25 kt. Seas 10 ft.
.SUN...SW wind 15 kt. Seas 3 ft.

$$

PKZ138-201300-
Shelikof Strait-
301 PM AKST Tue Dec 19 2017

...SMALL CRAFT ADVISORY TONIGHT...

.TONIGHT...SW wind 25 kt. Seas 8 ft.
.WED...SW wind 20 kt diminishing to 10 kt in the afternoon. 
Seas 5 ft subsiding to 3 ft in the afternoon.
.WED NIGHT...Variable wind 10 kt becoming E 20 kt 
after midnight. Seas 4 ft.
.THU...E wind 40 kt. Seas 10 ft.
.THU NIGHT...E wind 45 kt. Seas 12 ft.
.FRI...E wind 40 kt. Seas 10 ft.
.SAT...SE wind 30 kt. Seas 7 ft.
.SUN...Variable wind 10 kt. Seas 3 ft.

$$

PKZ139-201300-
Cook Inlet Kalgin Island to Point Bede-
301 PM AKST Tue Dec 19 2017

...SMALL CRAFT ADVISORY THROUGH WEDNESDAY...

.TONIGHT...SW wind 25 kt. Seas 8 ft.
.WED...SW wind 25 kt diminishing to 15 kt in the afternoon. 
Seas 8 ft subsiding to 4 ft in the afternoon.
.WED NIGHT...W wind 10 kt becoming NE 20 kt after midnight. 
Seas 2 ft building to 4 ft after midnight.
.THU...NE wind 30 kt. Seas 9 ft.
.THU NIGHT...NE wind 35 kt. Seas 10 ft.
.FRI THROUGH SAT...E wind 35 kt. Seas 12 ft.
.SUN...S wind 15 kt. Seas 3 ft.

$$

PKZ140-201300-
Cook Inlet North of Kalgin Island-
301 PM AKST Tue Dec 19 2017

...SMALL CRAFT ADVISORY THROUGH WEDNESDAY...

.TONIGHT...SW wind 15 kt increasing to 25 kt after midnight. 
Seas 3 ft building to 7 ft after midnight. 
.WED...SW wind 25 kt becoming W 15 kt in the afternoon. 
Seas 7 ft subsiding to 3 ft in the afternoon.
.WED NIGHT...NE wind 10 kt increasing to 15 kt after midnight.
Seas 3 ft. Patchy freezing fog.
.THU...NE wind 20 kt. Seas 5 ft.
.THU NIGHT...NE wind 25 kt. Seas 7 ft.
.FRI...NE wind 30 kt. Seas 9 ft.
.SAT...NE wind 25 kt. Seas 8 ft.
.SUN...E wind 10 kt. Seas 2 ft.

$$

PKZ141-201300-
Kachemak Bay-
301 PM AKST Tue Dec 19 2017

.TONIGHT...W wind 20 kt. Seas 6 ft.
.WED...SW wind 15 kt. Seas 4 ft.
.WED NIGHT...Variable wind less than 10 kt becoming E 10 kt 
after midnight. Seas 2 ft.
.THU...E wind 25 kt. Seas 4 ft.
.THU NIGHT...E wind 40 kt. Seas 5 ft.
.FRI...E wind 40 kt. Seas 5 ft.
.SAT...SE wind 35 kt. Seas 5 ft.
.SUN...S wind 10 kt. Seas 2 ft.

$$

Southcentral and Southwest Alaska Forecast Discussion
National Weather Service Anchorage AK
541 AM AKST Tue Dec 19 2017

.ANALYSIS AND UPPER LEVELS...
Looking at water vapor satellite this morning, it's pretty clear
what the main focus for the coming days will be. A beauty of a low
pressure system is occluded in the northwest Bering Sea. The front
associated with it stretches from the Chukchi Sea southward
through western Alaska and down into the sub-tropics. The sub-
tropical connection is bringing precipitable water values around
.7 inches, good for 200% of normal for this time of year. Behind
the front, open-celled cumulus show up water vapor, showing
instability extends quite high in the atmospheric column and
indicative of strong cold advection.

The front itself brought gale-force winds to the southwest
mainland overnight and a slow transition from snow to rain in most
places. For Southcentral Alaska, the front is beginning to push
into our area this morning.

&&

.MODEL DISCUSSION...
The general synoptics are well agreed upon among the models as far
as frontal progression and timing. The differences come with small
details such as amount of Turnagain Arm wind and downslope drying,
and low-level temperatures, all making for a very challenging
forecast around the Cook Inlet region.

&&

.AVIATION...
PANC...Uncertainty today revolves around precipitation type.
Confidence is higher that the airport will see Turnagain Arm wind.
The question is how high do surface temperatures spike when the
winds come in? The depth of warm air should be fairly shallow, so
mixed precipitation is expected at this time. Once winds begin to
change from southeast to southwest in the afternoon, precipitation
intensity could change rain back to snow as the cold air is
arriving behind the front.

&&

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

There is warmer air moving into Southcentral Alaska with the
southwest flow aloft and fairly deep moisture with the front
approaching from the west.
The most challenging portion of the forecast is in the northern
Cook Inlet region including the Anchorage and Matanuska Valley
areas today with precipitation type being the most difficult part.
The issue all resolves around the Turnagain Arm and Knik River
wind. With gusty southeast winds expected across the Anchorage
area and Matanuska Valley, it will likely delay the precipitation
in the morning which is why there is just a chance of snow. These
Southeast winds typically either downslope out these areas with
little to no precipitation, or enough warm air spills into the
area to cause rain or freezing rain and it is possible for there
to be a little freezing rain this morning. There is a good chance
that this afternoon will see some precipitation with a rain and
snow mix. Late this afternoon into early evening the southeast
winds will shift to the south- southwest and this is when there
will likely be a burst of snow that could give and inch or two
accumulation. The timing of this will probably be around the
afternoon rush hour commute. The southerly winds will also be a
little gusty (though not as strong as the southeast winds during
most of the day) which could reduce visibilities at times during
the late afternoon to early evening.

The Susitna Valley remains under a Winter Storm Warning due to
snow with 6 to 12 inches expected across most of the valley.
Higher amounts closer to 16 inches may occur north of Talkeetna as
one gets into the passes of the Alaska Range.

&&

.SHORT TERM FORECAST SOUTHWEST ALASKA (Days 1 through 3)...
Conditions should begin to improve with diminishing winds and
precipitation from west to east this morning as the front
continues to dissipate. Cold air advection riding along the back
edge of the front should allow for rain to transition to snow for
a few hours in most areas before ending, leaving generally light
accumulations of around an inch or so. This will be the beginning
of a broad area of cold air advection that will move through the
region into mid week as the Bering low continues to lift towards
the Bering Strait. The low position will remain well north and
west of the area however, so any snow showers that do pass through
shouldn't be more than isolated-scattered in coverage with
minimal accumulations expected. Starting Thursday, a North Pacific
low approaching from the south will bring a return to above
freezing temperatures to much of the region for the end of the
work week, along with strong easterly winds along the
Aleutian/Alaskan Ranges. These strong easterly winds will
limit most if not all of the precipitation in the downslope prone
areas of Eastern Bristol Bay, while Western Bristol Bay and the
Kuskokwim Delta should expect to see rain/snow with gusty easterly
winds into Friday.

&&

.SHORT TERM FORECAST BERING SEA/ALEUTIANS (Days 1 through 3)...
A very active weather pattern continues over the region as the
departing gale force low over the Northern Bering will quickly be
replaced by a solid storm force low by this evening. For today,
the departing Northern Bering low will bring a broad area of
westerly gales and snow showers to most of the Bering Sea, along
with a the possibility of a few lightning strikes over the
Southern Bering. Attention then quickly shifts to the incoming
low to the Western Aleutians which will bring a broad area of
southerly storm force winds stretching from the Central Aleutians
northward into the Pribilof Islands for Wednesday. This front also
has the potential to produce near warning level (75 mph) gusts to
the Adak area late tonight-early Wednesday, however at this point
conditions are not expected be long lived or widespread enough
for a warning. Strong warm air advection will accompany this front
however, which should cause all precipitation to fall as rain as
well as keep the much stronger winds aloft from mixing down to the
surface. Yet another storm force North Pacific low will then take
a much more northerly track towards the AKpen on Thursday,
focusing the most active weather to east of the Pribilofs into
Friday.

&&

.LONG TERM FORECAST (Wednesday through Saturday)...

By Wednesday, the mainland will be experiencing a brief break in
the weather as the North Pacific Ridge builds in, while yet
another storm force low moves into the Bering Sea. Temperatures
over the mainland will cool off, as colder air moves in aloft and
clearing will allow the air mass to cool overnight. Meanwhile, in
the Bering, the storm force low will bring another slug of warm
air aloft and precipitation will be mixed.

After this quick break, the ridge will settle in, forcing the jet
stream southward. The next low pressure systems we see will
approach the state from the south beginning Thursday afternoon,
which will provide a connection to some very moist air from
further south. Models continue to bring two lows across the
Alaska Peninsula, focusing the brunt of the weather first on
Kodiak, then on the southern Kenai Peninsula. There has been some
variation in the model runs on whether the heaviest precipitation
will fall in Kodiak, or later on the coastal Kenai, or even as far
east as Yakutat. Right now the thinking focuses the heaviest rain
on Kodiak for next weekend, but we'll continue to watch these
systems carefully, keeping concerns for holiday travelers in mind.
&&

.AFC WATCHES/WARNINGS/ADVISORIES...
PUBLIC...Winter Storm Warning 145.
MARINE...Storm 175 176 177 178 179 181 185.
         Gale 165 170 174 180.

&&

SYNOPSIS AND MODEL DISCUSSION...MTL
SOUTHCENTRAL ALASKA...EZ
SOUTHWEST ALASKA/BERING SEA/ALEUTIANS...DEK
LONG TERM...LF