Small Craft Advisory 520, NWS Anchorage, AK

407 
FZAK52 PAFC 092313
CWFALU

Coastal Waters Forecast
National Weather Service Anchorage Alaska
313 PM AKDT Sun Jul 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.

PKZ199-101145-
313 PM AKDT Sun Jul 9 2017
.SYNOPSIS FOR SOUTHWEST ALASKA+BRISTOL BAY+THE ALASKA
PENINSULA WATERS AND THE ALEUTIAN ISLANDS...
A 1002 mb low 110 nm north of Dutch Harbor will weaken and cross 
into the Gulf of Alaska Mon morning. A series of fronts will move
over the western Bering Mon and Tue as a 994 mb low moves to 220 
nm southwest of Shemya by Tue afternoon.

$$

PKZ150-101145-
South of the AK Peninsula Sitkinak to Castle Cape-
313 PM AKDT Sun Jul 9 2017

.TONIGHT...S wind 20 kt. Seas 6 ft. Rain.
.MON...SW wind 15 kt. Seas 7 ft. Rain.
.MON NIGHT...N wind 20 kt. Seas 6 ft.
.TUE AND TUE NIGHT...NW wind 20 kt. Seas 6 ft.
.WED...NW wind 20 kt. Seas 5 ft.
.THU...W wind 15 kt. Seas 4 ft.
.FRI...Variable wind 10 kt. Seas 4 ft.

$$

PKZ155-101145-
South of the AK Peninsula Castle Cape to Cape Sarichef-
313 PM AKDT Sun Jul 9 2017

...SMALL CRAFT ADVISORY THROUGH MONDAY...

.TONIGHT...SE wind 20 kt becoming SW wind 15 kt after midnight. Seas
9 ft. Patchy fog. Rain showers.
.MON...SW wind 20 kt becoming NE 15 kt in the afternoon. Seas 8 ft. 
Patchy fog.
.MON NIGHT...NW wind 20 kt. Seas 7 ft. Patchy fog.
.TUE AND TUE NIGHT...W wind 15 kt. Seas 5 ft.
.WED THROUGH FRI...W wind 15 kt. Seas 5 ft.

$$

PKZ160-101145-
Bristol Bay-
313 PM AKDT Sun Jul 9 2017

.TONIGHT...SE wind 20 kt. Seas 3 ft. Rain.
.MON...E wind 20 kt diminishing to 10 kt in the afternoon. Seas
3 ft.
.MON NIGHT...W wind 10 kt increasing to 15 kt after midnight. Seas
2 ft.
.TUE...W wind 15 kt. Seas 3 ft.
.TUE NIGHT...W wind 20 kt. Seas 4 ft.
.WED THROUGH FRI...W wind 15 kt. Seas 4 ft.

$$

PKZ165-101145-
Port Heiden to Cape Sarichef-
313 PM AKDT Sun Jul 9 2017

.TONIGHT...S wind 15 kt. Seas 4 ft. Patchy fog. Rain showers.
.MON...NW wind 15 kt. Seas 4 ft. Patchy fog.
.MON NIGHT...W wind 15 kt. Seas 3 ft. Patchy fog.
.TUE AND TUE NIGHT...W wind 15 kt. Seas 3 ft.
.WED...W wind 15 kt. Seas 3 ft.
.THU THROUGH FRI...Variable wind 10 kt. Seas 3 ft.

$$

PKZ170-101145-
Cape Sarichef to Nikolski Bering Side-
313 PM AKDT Sun Jul 9 2017

.TONIGHT...W wind 20 kt. Seas 5 ft. Patchy fog.
.MON...W wind 15 kt. Seas 4 ft. Patchy fog.
.MON NIGHT...W wind 15 kt. Seas 3 ft. Patchy fog.
.TUE...Variable wind 10 kt. Seas 2 ft.
.TUE NIGHT...SE wind 20 kt. Seas 3 ft.
.WED...S wind 20 kt. Seas 4 ft.
.THU...S wind 15 kt. Seas 4 ft.
.FRI...Variable wind 10 kt. Seas 3 ft.

$$

PKZ171-101145-
Unalaska Bay-
313 PM AKDT Sun Jul 9 2017

.TONIGHT...W wind 15 kt. Seas 2 ft. Patchy fog.
.MON...W wind 15 kt diminishing to 10 kt in the afternoon. Seas
2 ft. Patchy fog.
.MON NIGHT...W wind 10 kt in the evening becoming variable less
than 10 kt. Seas 2 ft. Patchy fog.
.TUE...Variable wind less than 10 kt. Seas 1 foot.
.TUE NIGHT...SE wind 10 kt. Seas 1 foot.
.WED THROUGH THU...S wind 10 kt. Seas 2 ft.
.FRI...Variable wind less than 10 kt. Seas 1 foot.

$$

PKZ172-101145-
Cape Sarichef to Nikolski Pacific Side-
313 PM AKDT Sun Jul 9 2017

...SMALL CRAFT ADVISORY THROUGH MONDAY...

.TONIGHT...W wind 25 kt. Seas 10 ft. Patchy fog.
.MON...W wind 20 kt. Seas 8 ft. Patchy fog.
.MON NIGHT...W wind 15 kt. Seas 6 ft. Patchy fog.
.TUE...Variable wind 10 kt. Seas 4 ft.
.TUE NIGHT...S wind 15 kt. Seas 4 ft.
.WED THROUGH THU...SW wind 15 kt. Seas 6 ft.
.FRI...Variable wind 10 kt. Seas 5 ft.

$$

PKZ173-101145-
Nikloski to Seguam Island Bering Side-
313 PM AKDT Sun Jul 9 2017

.TONIGHT...W wind 20 kt. Seas 6 ft. Areas of fog.
.MON...W wind 15 kt. Seas 4 ft. Areas of fog.
.MON NIGHT...SW wind 10 kt. Seas 3 ft. Areas of fog.
.TUE...S wind 20 kt. Seas 4 ft.
.TUE NIGHT...SE wind 25 kt. Seas 6 ft.
.WED...S wind 25 kt. Seas 6 ft.
.THU...S wind 15 kt. Seas 5 ft.
.FRI...Variable wind 10 kt. Seas 4 ft.

$$

PKZ174-101145-
Nikolski to Seguam Island Pacific Side-
313 PM AKDT Sun Jul 9 2017

...SMALL CRAFT ADVISORY TONIGHT...

.TONIGHT...W wind 20 kt. Seas 8 ft. Areas of fog.
.MON...W wind 15 kt. Seas 6 ft. Areas of fog.
.MON NIGHT...SW wind 10 kt. Seas 5 ft. Areas of fog.
.TUE...S wind 25 kt. Seas 5 ft.
.TUE NIGHT...S wind 20 kt. Seas 7 ft.
.WED...S wind 20 kt. Seas 8 ft.
.THU...S wind 15 kt. Seas 7 ft.
.FRI...Variable wind 10 kt. Seas 6 ft.

$$

PKZ175-101145-
Seguam Island to Adak Bering Side-
313 PM AKDT Sun Jul 9 2017

.TONIGHT...W wind 15 kt. Seas 4 ft. Areas of fog.
.MON...SW wind 15 kt. Seas 3 ft. Areas of fog.
.MON NIGHT...S wind 20 kt. Seas 3 ft. Areas of fog.
.TUE...SE wind 30 kt. Seas 6 ft.
.TUE NIGHT...SE wind 25 kt. Seas 6 ft.
.WED...S wind 25 kt. Seas 6 ft.
.THU THROUGH FRI...SW wind 15 kt. Seas 4 ft.

$$

PKZ176-101145-
Seguam Island to Adak Pacific Side-
313 PM AKDT Sun Jul 9 2017

.TONIGHT...W wind 20 kt. Seas 7 ft. Areas of fog.
.MON...SW wind 15 kt. Seas 6 ft. Areas of fog.
.MON NIGHT...S wind 20 kt. Seas 5 ft. Areas of fog.
.TUE...SE wind 30 kt. Seas 8 ft.
.TUE NIGHT...S wind 25 kt. Seas 9 ft.
.WED...S wind 25 kt. Seas 9 ft.
.THU THROUGH FRI...SW wind 15 kt. Seas 7 ft.

$$

PKZ177-101145-
Adak to Kiska-
313 PM AKDT Sun Jul 9 2017

...SMALL CRAFT ADVISORY MONDAY AND MONDAY NIGHT...

.TONIGHT...SW wind 15 kt. Seas 5 ft. Areas of fog.
.MON...S wind 25 kt. Seas 6 ft. Areas of fog.
.MON NIGHT...SE wind 30 kt. Seas 8 ft. Areas of fog.
.TUE...SE wind 30 kt. Seas 10 ft.
.TUE NIGHT...S wind 25 kt. Seas 9 ft.
.WED THROUGH FRI...S wind 20 kt. Seas 8 ft.

$$

PKZ178-101145-
Kiska to Attu-
313 PM AKDT Sun Jul 9 2017

...SMALL CRAFT ADVISORY MONDAY AND MONDAY NIGHT...

.TONIGHT...SE wind 20 kt. Seas 5 ft. Areas of fog.
.MON...SE wind 25 kt. Seas 7 ft. Areas of fog. Rain.
.MON NIGHT...SE wind 30 kt. Seas 11 ft. Areas of fog. Rain.
.TUE...SE wind 30 kt. Seas 11 ft.
.TUE NIGHT...S wind 20 kt. Seas 9 ft.
.WED...S wind 25 kt. Seas 9 ft.
.THU THROUGH FRI...S wind 20 kt. Seas 7 ft.

$$

PKZ179-101145-
Pribilof Islands Near Shore Waters-
313 PM AKDT Sun Jul 9 2017

.TONIGHT...N wind 10 kt. Seas 4 ft. Areas of fog.
.MON...NW wind 10 kt. Seas 3 ft. Areas of fog.
.MON NIGHT...W wind 10 kt. Seas 3 ft. Patchy fog.
.TUE...Variable wind 10 kt. Seas 3 ft.
.TUE NIGHT...S wind 20 kt. Seas 3 ft.
.WED...S wind 20 kt. Seas 6 ft.
.THU...S wind 15 kt. Seas 5 ft.
.FRI...Variable wind 10 kt. Seas 4 ft.

$$

PKZ180-101145-
Kuskokwim Delta and Etolin Strait-
313 PM AKDT Sun Jul 9 2017

.TONIGHT...SE wind 15 kt becoming NE after midnight. Seas 5 ft.
Patchy fog.
.MON...NW wind 10 kt. Seas 3 ft. Patchy fog.
.MON NIGHT...W wind 10 kt. Seas 3 ft. Patchy fog.
.TUE...W wind 10 kt. Seas 3 ft.
.TUE NIGHT...W wind 15 kt. Seas 2 ft.
.WED...W wind 15 kt. Seas 4 ft.
.THU THROUGH FRI...W wind 10 kt. Seas 4 ft.

$$

PKZ181-101145-
North and West of Nunivak Island-
313 PM AKDT Sun Jul 9 2017

.TONIGHT...NW wind 20 kt. Seas 5 ft. Patchy fog.
.MON...NW wind 20 kt. Seas 5 ft. Patchy fog.
.MON NIGHT...N wind 15 kt. Seas 4 ft. Patchy fog.
.TUE...Variable wind 10 kt. Seas 3 ft.
.TUE NIGHT...Variable wind 10 kt. Seas 2 ft.
.WED THROUGH THU...S wind 15 kt. Seas 5 ft.
.FRI...Variable wind 10 kt. Seas 3 ft.

$$

PKZ185-101145-
Saint Matthew Island Waters-
313 PM AKDT Sun Jul 9 2017

.TONIGHT...NE wind 15 kt. Seas 6 ft. Areas of fog.
.MON...N wind 20 kt E of Saint Matthew Island...variable 10 kt W
of Saint Matthew Island. Seas 4 ft. Patchy fog.
.MON NIGHT...E wind 15 kt. Seas 4 ft. Patchy fog.
.TUE...S wind 20 kt. Seas 4 ft.
.TUE NIGHT...SE wind 25 kt. Seas 5 ft.
.WED...SE wind 25 kt. Seas 8 ft.
.THU THROUGH FRI...S wind 15 kt. Seas 7 ft.

$$

Southcentral and Southwest Alaska Forecast Discussion...UPDATED
National Weather Service Anchorage AK
906 PM AKDT Sat Jul 8 2017

Updated Long Term Discussion

.ANALYSIS AND UPPER LEVELS...
The upper levels across the state are being dominated by three
primary features. Out West, a strong upper level low is moving
Eastward along the Aleutian Chain. A nearly stationary secondary
low is churning in the Gulf of Alaska. This low has flung a few
lobes of shortwave energy that have been the spawn of precip over
the last few days. The strongest shortwave is moving across the
Alaskan and Canadian border, moving West (as we aptly call these
systems 'Easterlies') and is enhancing upward motion. The last
feature of note aloft is a ridge of high pressure that spans much
of the central interior and stretches southeast through much of
western Canada. Features at the surface are not all that different
than aloft as weakening low pressure is moving near Adak. A
weather front extends from this low to the east, near Dutch and
then south through the pacific. A weak low is evident under the
Gulf low as high pressure is being pinched off along the Gulf
coast. As the upper level easterly is tracking towards the area,
blossoming radar returns are showing across much of southcentral.
As of 2030z, rain has overspread Palmer/Wasilla and is encroaching
on Anchorage.

&&

.MODEL DISCUSSION...
Models are, and have been, in good agreement with the evolution of
this potent easterly wave. Probably the biggest disagreement they
have is on the longevity of the rain through tomorrow and into the
morning hour. Some high resolution guidance is showing a relative
sharp cutoff to the precipitation, but thoughts are that as the
models are ending rain - the upper level support has not passed.
Beyond this system - model agreement is pretty good through much
of the week, but falls apart into the weekend. We note almost
daily changes in whether south central will see ridging into next
weekend, or some weather system moving across. With no strong
longwave pattern, it makes long term forecasts lower confidence as
we head into the next week.

&&

.AVIATION...
PANC...MVFR conditions to remain as rain overspreads the terminal.
There is a chance for cigs to drop to IFR in the rain this
afternoon in the heaviest of showers. Not expecting vis to drop
below MVFR. Conditions to improve tomorrow morning as rain exits.

&&

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

The next "car" in the train of easterly waves is upon us here in
Southcentral this afternoon. A number of ingredients are in place
for Southcentral to pick up its highest rainfall totals of 2017 so
far through this evening:
1) A very moist air mass that already in place in the pre-event
atmosphere 2) An amplifying inverted trough moving westward across
the region 3) Upper level inverted ridging west of the Alaska
Range further increasing the jet stream winds 4) A branch of the
jet over western Alaska splitting from the main jet, causing
increased divergence/diffluence over the area, further adding lift
to the atmosphere 5) Strong veering wind profile on the 00Z
Anchorage sounding, which is indicative of warm air advection
favorable for lift.

The only negative influence for high rainfall totals is the fast
moving nature of the easterly wave, so all of the above
ingredients will only be in place for a 12-18 hour period. Thus, a
rapid end of the heavy precipitation from east to west will occur
overnight, though lingering showers behind the wave may add
modestly to rainfall totals into Sunday morning.

The best forcing and lift will be north of Anchorage, across the
Copper River Basin and Susitna Valley. Expected rainfall totals
will range from nearly 2 inches through the Talkeetna Mountains,
1-1.5 inches in the Mat-Su Valleys and the Alaska Range, 0.75 to
1 inch through the Anchorage Bowl, around a half inch through
Kenai, Soldotna, and Seward, and the lowest rainfall totals in the
southern Kenai near Homer, with around 0.2 inches expected.

Clouds will decrease through the day Sunday from east to west,
with many areas of Southcentral ending the day with mixed sun and
clouds. The exception will be over the eastern Copper River Basin,
as the next wave already encroaches into the area. Unlike the
current wave though, the lion's share of the energy associated
with the wave will pass north of the area, so the northern Copper
River Basin west through the far northern Susitna Valley will be
the areas most likely to pick up additional rain through Monday.

At the same time Sunday afternoon and night, a front will move
into Kodiak and stall there, making for an extended period of time
of rain, moisture, and easterly winds across the island. In
between the two systems, a squeeze play may lead to pleasant
weather from Anchorage south with a fair amount of sunshine on
Monday. Clouds increase from north to south ahead of a third wave
Monday evening, though that next wave looks to favor areas east of
Anchorage primarily.

&&

.SHORT TERM FORECAST SOUTHWEST ALASKA (Days 1 and 2)...
An upper level wave will move into the Kuskokwim Valley from the
east overnight and continue slowly westward through the day
Sunday. This wave is being forced into the ridge along the Bering
Sea coast which will force it a little farther northward but it
should still make it into the northern Kuskokwim Delta by Sunday
afternoon. It remains questionable as to whether this rain wil
make it as far south as Bethel and areas south of there will see
some sunny periods under the ridge so there will be a large
difference in weather over a small distance tomorrow with these
features.

&&

.SHORT TERM FORECAST BERING SEA/ALEUTIANS (Days 1 and 2)...
Wet and foggy. The low in the south-central Bering Sea will
continue to move slowly eastward as it is hindered by the weak ridge
over the southwest mainland. This will keep the front stalled over
the Alaska Peninsula tonight before the low scoots farther to the
south and under the ridge Monday. When this happens it will allow
a stronger ridge to build over the central Bering Sea Monday
night. There is a bit of warm air aloft with this ridge which will
keep widespread fog over the Bering Sea and Aleutians for the
next few days.

&&

.LONG TERM FORECAST (Days 3 through 7...Tue through Sun)...
Confidence is slowly increasing that the middle to end of next
week could feature some fairly potent ridging across much of the
southern half of AK. To start the period, the remnants of yet
another stacked low in the eastern Gulf of AK will be moving off
to the east into SE AK. Meanwhile, a ridge will begin to build up
from the North Pacific over Western AK while yet another cold
trough digs over the Western Bering. Tue could be another day of
afternoon-evening showers across SW AK and some rain stretching
from the Copper River Basin into the Cook Inlet as the last bit
energy wraps around the Gulf Low. But then it does look
increasingly likely that dry conditions will set-up for the back
half of the week over much of the southern mainland courtesy of
the ridge. There are some indications that this could be one of
the warmest airmasses of the year so far as well. There is still
plenty of uncertainty regarding temperatures though, especially
since they are highly dependent on how much cloud cover is in
overhead. However, for places over the Eastern Bering and the West
Coast, the ridge will likely bring widespread stratus and some fog
as per the climatological normals for July. Over the Central and
Western Bering, the cold trough will keep rain and sub-small craft
southerly winds in the forecast.

The biggest question will be how long the longwave pattern
features a dominant ridge. The GFS shows energy impinging upon it
from the west and breaking it down by next weekend. The EC shows
it holding firm a few days longer.

&&

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

&&

SYNOPSIS AND MODEL DISCUSSION...SS
SOUTHCENTRAL ALASKA...JPW
SOUTHWEST ALASKA/BERING SEA/ALEUTIANS...EZ
LONG TERM...MSO