Storm Warning 88, NWS Anchorage, AK

118 
FZAK51 PAFC 172342
CWFAER

Coastal Waters Forecast
National Weather Service Anchorage Alaska
342 PM AKDT Thu Sep 17 2020

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.

PKZ197-181300-
342 PM AKDT Thu Sep 17 2020
.SYNOPSIS FOR THE NORTH GULF COAST+KODIAK ISLAND WATERS+
COOK INLET...

A front moves across the Gulf by Fri night. A 1003 mb low 70 nm
South of Unimak Island Fri afternoon moves to 265 nm South of
Middleton Island for Sat afternoon. Its front moves across the 
Gulf through Sat afternoon.

$$

PKZ119-181300-
Cape Suckling to Cape Cleare-
342 PM AKDT Thu Sep 17 2020

...SMALL CRAFT ADVISORY THROUGH FRIDAY NIGHT...

.TONIGHT...S wind 25 kt. Seas 12 ft. Rain showers.
.FRI...SW wind 20 kt. Seas 11 ft.
.FRI NIGHT...SW wind 15 kt. Seas 8 ft.
.SAT...S wind 15 kt. Seas 6 ft.
.SAT NIGHT...E wind 25 kt. Seas 5 ft.
.SUN...E wind 25 kt. Seas 6 ft.
.MON...SE wind 30 kt. Seas 11 ft.
.TUE...E wind 35 kt. Seas 16 ft.

$$

PKZ120-181300-
Cape Cleare to Gore Point-
342 PM AKDT Thu Sep 17 2020

...SMALL CRAFT ADVISORY THROUGH FRIDAY NIGHT...

.TONIGHT...S wind 30 kt. Seas 13 ft.
.FRI...SW wind 25 kt. Seas 12 ft.
.FRI NIGHT...SW wind 20 kt. Seas 8 ft.
.SAT...Variable wind 10 kt. Seas 5 ft.
.SAT NIGHT...NE wind 15 kt. Seas 5 ft.
.SUN...NE wind 20 kt. Seas 6 ft.
.MON...E wind 25 kt. Seas 11 ft.
.TUE...E wind 35 kt. Seas 15 ft.

$$

PKZ121-181300-
Resurrection Bay-
342 PM AKDT Thu Sep 17 2020

...SMALL CRAFT ADVISORY TONIGHT...

.TONIGHT...S wind 25 kt. Seas 5 ft. Widespread rain showers.
.FRI...S wind 15 kt diminishing to 10 kt in the afternoon. Seas
3 ft.
.FRI NIGHT...S wind 10 kt. Seas 2 ft.
.SAT...Variable wind less than 10 kt. Seas 2 ft.
.SAT NIGHT...Variable wind less than 10 kt. Seas 2 ft.
.SUN...N wind 10 kt. Seas 2 ft.
.MON THROUGH TUE...N wind 15 kt. Seas 3 ft.

$$

PKZ125-181300-
Prince William Sound-
342 PM AKDT Thu Sep 17 2020

...SMALL CRAFT ADVISORY TONIGHT...

.TONIGHT...SE wind 25 kt. Seas 4 ft building to 6 ft after
midnight. Widespread rain showers.
.FRI...S wind 20 kt. Seas 4 ft.
.FRI NIGHT...S wind 15 kt. Seas 3 ft. Rain showers.
.SAT...SE wind 15 kt. Seas 2 ft.
.SAT NIGHT...E wind 15 kt. Seas 3 ft.
.SUN...NE wind 10 kt. Seas 2 ft.
.MON...E wind 20 kt. Seas 4 ft.
.TUE...E wind 25 kt. Seas 4 ft.

$$

PKZ126-181300-
Port Valdez-
342 PM AKDT Thu Sep 17 2020

.TONIGHT...Variable wind less than 10 kt. Seas 2 ft. Widespread
rain showers.
.FRI...Variable wind less than 10 kt. Seas 2 ft. Widespread rain
showers.
.FRI NIGHT...Variable wind less than 10 kt. Seas 2 ft. Widespread
rain showers.
.SAT AND SAT NIGHT...Variable wind less than 10 kt. Seas 2 ft.
.SUN...Variable wind less than 10 kt. Seas 2 ft.
.MON THROUGH TUE...E wind 10 kt. Seas 2 ft.

$$

PKZ127-181300-
Valdez Narrows-
342 PM AKDT Thu Sep 17 2020

.TONIGHT...NE wind 15 kt. Seas 3 ft. Widespread rain showers.
.FRI...SW wind 10 kt. Seas 2 ft. Widespread rain showers.
.FRI NIGHT...SW wind 10 kt in the evening becoming variable less
than 10 kt. Seas 2 ft. Widespread rain showers.
.SAT AND SAT NIGHT...Variable wind less than 10 kt. Seas 2 ft.
.SUN THROUGH MON...N wind 10 kt. Seas 2 ft.
.TUE...N wind 15 kt. Seas 3 ft.

$$

PKZ128-181300-
Valdez Arm-
342 PM AKDT Thu Sep 17 2020

.TONIGHT...SE wind 25 kt. Seas 4 ft. Higher winds and seas near 
Bligh Reef. Widespread rain showers.
.FRI...S wind 20 kt. Seas 4 ft. Widespread rain showers.
.FRI NIGHT...SE wind 20 kt. Higher winds and seas near Bligh
Reef. Seas 3 ft. Widespread rain showers.
.SAT...Variable wind 10 kt. Seas 2 ft.
.SAT NIGHT...NE wind 10 kt. Seas 2 ft.
.SUN...NE wind 10 kt. Seas 2 ft.
.MON THROUGH TUE...NE wind 15 kt. Seas 3 ft.

$$

PKZ129-181300-
Passage Canal-
342 PM AKDT Thu Sep 17 2020

.TONIGHT...E wind increasing to 20 kt. Seas 3 ft. Widespread rain 
showers.
.FRI...E wind 15 kt in the morning becoming variable less than
10 kt. Seas 2 ft.
.FRI NIGHT...Variable wind less than 10 kt. Seas 2 ft. Rain
showers.
.SAT AND SAT NIGHT...Variable wind less than 10 kt. Seas 2 ft.
.SUN...Variable wind less than 10 kt. Seas 2 ft.
.MON THROUGH TUE...E wind 15 kt. Seas 2 ft.

$$

PKZ130-181300-
West of Barren Islands including Kamishak Bay-
342 PM AKDT Thu Sep 17 2020

...GALE WARNING TONIGHT...

.TONIGHT...S wind 35 kt. Seas 13 ft.
.FRI...SW wind 20 kt. Seas 6 ft.
.FRI NIGHT...SW wind 15 kt. Seas 5 ft.
.SAT AND SAT NIGHT...Variable wind 10 kt. Seas 3 ft.
.SUN...NW wind 25 kt. Seas 7 ft.
.MON THROUGH TUE...NE wind 30 kt. Seas 12 ft.

$$

PKZ131-181300-
Barren Islands East-
342 PM AKDT Thu Sep 17 2020

...SMALL CRAFT ADVISORY THROUGH FRIDAY NIGHT...

.TONIGHT...SW wind 30 kt. Seas 14 ft.
.FRI...SW wind 25 kt. Seas 12 ft.
.FRI NIGHT...SW wind 20 kt. Seas 8 ft.
.SAT...Variable wind 10 kt. Seas 5 ft.
.SAT NIGHT...N wind 15 kt. Seas 6 ft.
.SUN...NW wind 25 kt. Seas 7 ft.
.MON...E wind 30 kt. Seas 11 ft.
.TUE...E wind 35 kt. Seas 14 ft.

$$

PKZ132-181300-
Marmot Island to Sitkinak-
342 PM AKDT Thu Sep 17 2020

...SMALL CRAFT ADVISORY THROUGH FRIDAY...

.TONIGHT...SW wind 30 kt. Seas 14 ft.
.FRI...SW wind 25 kt. Seas 11 ft.
.FRI NIGHT...SW wind 20 kt. Seas 7 ft.
.SAT...E wind 20 kt. Seas 6 ft.
.SAT NIGHT...NW wind 25 kt. Seas 7 ft.
.SUN...SW wind 20 kt. Seas 7 ft.
.MON...E wind 20 kt. Seas 10 ft.
.TUE...NE wind 25 kt. Seas 11 ft.

$$

PKZ136-181300-
Chiniak Bay-
342 PM AKDT Thu Sep 17 2020

...SMALL CRAFT ADVISORY TONIGHT...

.TONIGHT...SW wind 25 kt diminishing to 15 kt after midnight. Seas 4
ft.
.FRI...SW wind 15 kt. Seas 2 ft.
.FRI NIGHT...SW wind 15 kt becoming S 10 kt after midnight. Seas
2 ft.
.SAT...E wind 10 kt. Seas 3 ft.
.SAT NIGHT...NW wind 10 kt. Seas 2 ft.
.SUN...S wind 15 kt. Seas 3 ft.
.MON...E wind 20 kt. Seas 5 ft.
.TUE...NE wind 25 kt. Seas 7 ft.

$$

PKZ137-181300-
Marmot Bay-
342 PM AKDT Thu Sep 17 2020

.TONIGHT...SW wind 20 kt. Seas 4 ft.
.FRI...SW wind 15 kt. Seas 3 ft.
.FRI NIGHT...SW wind 10 kt. Seas 3 ft.
.SAT...Variable wind less than 10 kt. Seas 3 ft.
.SAT NIGHT...NW wind 10 kt. Seas 2 ft.
.SUN...SW wind 15 kt. Seas 4 ft.
.MON...E wind 20 kt. Seas 6 ft.
.TUE...NE wind 25 kt. Seas 10 ft.

$$

PKZ138-181300-
Shelikof Strait-
342 PM AKDT Thu Sep 17 2020

...GALE WARNING TONIGHT...

.TONIGHT...SW wind 40 kt. Seas 15 ft.
.FRI...SW wind 30 kt. Seas 9 ft.
.FRI NIGHT...SW wind 25 kt becoming variable 10 kt after midnight. 
Seas 6 ft subsiding to 3 ft after midnight.
.SAT...NE wind 15 kt. Seas 3 ft.
.SAT NIGHT...NW wind 15 kt. Seas 2 ft.
.SUN...SW wind 20 kt. Seas 5 ft.
.MON...NE wind 25 kt. Seas 9 ft.
.TUE...NE wind 30 kt. Seas 10 ft.

$$

PKZ139-181300-
Cook Inlet Kalgin Island to Point Bede-
342 PM AKDT Thu Sep 17 2020

...GALE WARNING TONIGHT...

.TONIGHT...S wind 35 kt. Seas 12 ft.
.FRI...SW wind 30 kt. Seas 9 ft.
.FRI NIGHT...SW wind 25 kt diminishing to 15 kt after midnight.
Seas 6 ft subsiding to 4 ft after midnight.
.SAT...SW wind 15 kt. Seas 3 ft.
.SAT NIGHT...SW wind 10 kt. Seas 2 ft.
.SUN...NE wind 15 kt. Seas 4 ft.
.MON THROUGH TUE...NE wind 25 kt. Seas 8 ft.

$$

PKZ140-181300-
Cook Inlet North of Kalgin Island-
342 PM AKDT Thu Sep 17 2020

...SMALL CRAFT ADVISORY THROUGH FRIDAY NIGHT...

.TONIGHT...S wind 30 kt. Seas 11 ft.
.FRI...S wind 30 kt. Seas 11 ft.
.FRI NIGHT...SW wind 30 kt diminishing to 20 kt after midnight. Seas
8 ft.
.SAT...S wind 15 kt. Seas 3 ft.
.SAT NIGHT...S wind 10 kt. Seas 2 ft.
.SUN...E wind 10 kt. Seas 3 ft.
.MON THROUGH TUE...N wind 20 kt. Seas 5 ft.

$$

PKZ141-181300-
Kachemak Bay-
342 PM AKDT Thu Sep 17 2020

...SMALL CRAFT ADVISORY TONIGHT...

.TONIGHT...SW wind 30 kt. Seas 3 ft building to 8 ft after
midnight. Rain showers.
.FRI...SW wind 20 kt. Seas 6 ft.
.FRI NIGHT...SW wind 15 kt. Seas 2 ft building to 4 ft after
midnight.
.SAT...S wind 10 kt. Seas 2 ft.
.SAT NIGHT...Variable wind less than 10 kt. Seas 2 ft.
.SUN...SE wind 15 kt. Seas 2 ft.
.MON...NE wind 20 kt. Seas 4 ft.
.TUE...NE wind 25 kt. Seas 5 ft.

$$

Southcentral and Southwest Alaska Forecast Discussion
National Weather Service Anchorage AK
459 AM AKDT Thu Sep 17 2020

.ANALYSIS AND UPPER LEVELS...

A deep low has now made its way from the North Pacific across the
Alaska Peninsula and into Bristol Bay. A tap of Pacific moisture
that extends nearly to Hawaii is feeding into the low. This
moisture feed is boosting pockets of moderate rainfall extending
along the low's front, or roughly between the Y-K Delta and the
Prince William Sound. A dry slot curling into the low behind the
front is helping to clear out the rain rather abruptly for the
time being between Sand Point and King Salmon, but the break may
be short lived as moisture wraps into the head of the occlusion
just west of the surface low. Gale force winds are being generated
in spots between Sand Point and Kodiak Island where the low level
winds are mostly aligned with the storm's current heading. Knik
and Turnagain winds are gradually picking up as well, but they are
currently being driven down the Cook Inlet by the appreciable
north to south pressure gradient in place ahead of the approaching
system.

&&

.MODEL DISCUSSION...

Models are now in very good agreement with the track and strength
of the low as it merges with another weak low over the Bering
Strait and tracks inland just east of the Bering Coast. The
confidence in expected wind and precipitation impacts across the
region has greatly improved now that the system is ongoing. Still,
timing out precipitation end time and potential fog development
behind the front's passage could be tricky for Friday to Saturday
due to a nearly saturated air mass that may very well linger in
place without any obvious clearing mechanism behind the low.
Otherwise, synoptic agreement remains quite good for the current
model cycle through Saturday, and the forecast confidence remains
high through this period.

&&

.AVIATION...

PANC...Mainly VFR conditions are expected through most of the TAF
forecast period. However, periods of rain with low clouds may dip
ceilings below the 5000' threshold to MVFR and perhaps briefly
IFR/LIFR at times through Friday morning. A front will move
through Thursday afternoon with LLWS of 20 kts persisting until
the front moves through. Gusty Turnagain winds from the Southeast
should begin to move in behind the front and continue well into
Friday morning.

&&

.SHORT TERM FORECAST SOUTHCENTRAL ALASKA (Days 1 through 3: Today
through Saturday Night)...

A strong low moving north across Southwest Alaska today has a
leading front moving across Southcentral. The front is causing the
ongoing rain over nearly all of Southcentral except Kodiak Island.
Peak wind gusts as of this writing include 60 mph in Portage, 47
mph at McHugh Creek, and 35 mph both on the Hillside and up in the
Mat Valley. As the front lifts north today, strong winds will
persist along the Hillside, Turnagain Arm and Portage Valley. More
details on that are in the recently issued Special Weather
Statement. The winds will diminish this evening, though gusty
winds will also move into the Bowl and Palmer/Wasilla as well.
This is due to the front lifting northward, causing a southerly
push up Cook Inlet that will drive the Turnagain Arm and Knik
River Valley winds northward into the aforementioned populated
areas. The south to southwesterly winds will remain gusty through
the day on Friday as well in the Susitna Valley, Anchorage, and
along the Cook Inlet.

Heavy rain is also ongoing across many areas of Southcentral this
morning. As expected Seward has the greatest precipitation totals
so far, picking up nearly 0.7 inches of rain since yesterday
afternoon. The heavy rain will cause higher river levels in the
Seward area, and in the headwaters of the Yentna and Skwentna
Rivers in the Susitna Valley. More details on that are also in
the Special Weather Statement. The heavy rain will persist into
this afternoon in the aforementioned areas, then will gradually
diminish. The front is causing the heavy rain, but following
frontal passage, southwesterly onshore flow will allow upslope to
keep the rain going along the coastal Chugach mountains into
Saturday, though it is not expected to be particularly heavy by
then.

By Saturday, the upper level low over interior Alaska will
gradually drag a trough across Southcentral. This will lead to
widespread shower activity, especially over the mountains Saturday
afternoon during peak heating. However, even lower elevation areas
can't rule out a few showers. A colder air mass will move into
Southcentral Saturday night, which depending on the timing of a
strong upper level trough crossing southcentral, could be the next
chance for termination dust to occur on the Talkeetna and Chugach
Mountains.

&&

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

A 982 mb low pressure system is currently spinning just north of
Nelson Lagoon. This low is currently in the process of occluding
(when a cold front overtakes the warm front) this morning. As the
low occludes it will slow down as it continues moving to the west
and northwest. Areas across the Yukon-Kuskokwim Delta will be
raining a good portion of the day as this region will be in the
deformation band of the storm (where the precipitation pivots)
keeping the rain over one area for a longer time period especially
between Bethel and Hooper Bay. A band of rain will continue to
affect portions of the Middle Kuskokwim Valley this morning before
a dry slot moves into the region late morning into early
afternoon as the front continues northward. This dry slot is
currently bringing dry and relatively clear sky to King Salmon
south to Egegik early this morning. However, this will change
later on this morning around 9-11 am as the backside of the system
brings lower ceilings and rain showers to the region for the
remainder of the day. On and off rain showers will then be the
main theme for the forecast package as different pieces of upper
level energy rotate through the area.

Winds will also be breezy to windy today across Southwest Alaska
and the AKPEN due to the tight pressure gradient created with this
storm system. Winds will be strongest today as the system will be
in its mature stage. Winds slowly begin to subside Friday as the
system moves inland and weakens and the pressure gradient over the
area lessens.

Another fast moving system is expected to bring a quick period of
rain to the AKPEN north to around King Salmon Friday afternoon
through Saturday afternoon before quickly moving east into the
western Gulf of Alaska.

&&

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

A 982 mb low pressure system across the eastern Bering Sea is
creating a tight pressure gradient with higher pressure off to the
southwest across the North Pacific. This is creating breezy
conditions mainly with a northerly to northwesterly wind
component.

A fast-moving system is expected to quickly skirt across the
southern Bering and much of the Aleutian Chain beginning this
afternoon and continuing through Friday evening before moving
eastward into the Gulf of Alaska. This will bring a quick burst of
rain to much of the Chain with small craft advisory winds to the
southern marine zones south of the Chain.

The next system will begin to move into the western Aleutian Chain
and western Bering Friday evening. A 120-140kt jet is expected to
be racing across the North Pacific Friday evening along a
baroclinic zone with cold air at 850 mb to the north of -4 to -6
Celsius and 8-10 degrees Celsius along and south of the jet
stream. This will result in rapid cyclogenesis Friday night into
Saturday as the low moves into the Bering. At this time, this is
expected to be a gale force low with storm force gusts though a
storm force low with sustained storm force winds isn't off the
table at this time. This was held off on for now as the GFS
solution was the outlier and the strongest model as of now. This
system will also tap moisture from the tropics and bring a fairly
decent rain to much of the Chain Friday night through Saturday.

&&

.MARINE (Days 3 through 5: Saturday through Monday)...

By Saturday, a strong low pushes into the Bering Sea, bringing
gale force winds to the coastal areas of the Western/Central
Aleutian Chain and small craft elsewhere. Models are in
disagreement on the exact strength and location of this low,
but do agree on the general track as it travels eastward toward
Southwest Alaska. The Canadian tracks slightly more northeast
toward Chignik, whereas the GFS and EC are more in agreement
tracking it more toward Dutch Harbor. It looks like it then
travels to the Gulf by Monday, but there is uncertainty on both
the specific track and the strength of the winds over the Gulf.

&&

.LONG TERM FORECAST (Days 4 through 7: Sunday through Wednesday)...

A strong low pushes into the Bering Sea on Sunday. Widespread
rainfall and gale force winds along the Aleutian Chain are
expected in association with this low. A low amplitude ridge out
ahead of the low moves over the Southwest region at this same
time, providing somewhat drier conditions, although the
possibility of rain can't be ruled out completely. This ridge
moves with the low and will be over Southcentral by Monday. By
Tuesday, the low will travel into the Southern Gulf, with the
heaviest rainfall confined to Kodiak Island and the Coastal areas.
Gale force winds are also possible for the Southcentral Coast and
Northern Gulf.

&&

.AFC WATCHES/WARNINGS/ADVISORIES...
PUBLIC...NONE.
MARINE...Gale Warning 119 125 130 131 132 138 139 150 155 160
165 180.
FIRE WEATHER...NONE.

&&

SYNOPSIS AND MODEL DISCUSSION...AS
SOUTHCENTRAL ALASKA...JPW
SOUTHWEST ALASKA/BERING SEA/ALEUTIANS...MV
MARINE/LONG TERM...KM

SPECIAL WEATHER STATEMENT
National Weather Service ANCHORAGE AK
426 AM AKDT Thu Sep 17 2020

AKZ101-180030-
Anchorage-
Including the cities of Anchorage, Eagle River, Indian,
and Eklutna
426 AM AKDT Thu Sep 17 2020

...STRONG WINDS OCCURRING ALONG TURNAGAIN ARM AND HIGHER
ELEVATIONS TODAY...

...GUSTY WINDS ACROSS THE REMAINDER OF THE ANCHORAGE AREA AND
MATANUSKA VALLEY TODAY...

The third strong wind event of the Fall season is bringing
another round of strong winds to Anchorage and the Matanuska
Valley today.

Turnagain Arm and higher elevations of Anchorage (including the
Upper Hillside)...

East to southeast winds are increasing, with peak wind gusts to
60 to 70 mph expected today. Gusts of 45 to 60 mph will then
persist tonight before diminishing on Friday.

Remainder of the Anchorage area...

The Eagle River Valley and areas close to the mountains could
see southeast wind gusts to 30 mph this morning. The southeast
winds will become more widespread and stronger across all of
Anchorage Thursday afternoon, with gusts as high as 50 mph near
the mountains (including East Anchorage and Eagle River) and gusts
to 35 mph in the Anchorage Bowl. Winds will diminish Thursday
evening, but remain gusty through Thursday night.

Matanuska Valley...East winds will increase this morning and peak
during the day today, with gusts of 25 to 40 mph. The strongest
winds will occur along the Knik River Valley on into Wasilla.
Winds will gradually diminish Thursday night.

Precautions should be taken today to secure loose objects. The
winds will also have the potential to bring down branches from
trees.

AKZ125-145-180030-
Western Prince William Sound-Susitna Valley-
Including the cities of Whittier, Seward, Girdwood, Moose Pass,
Talkeetna, Willow, and Cantwell
426 AM AKDT Thu Sep 17 2020

...HEAVY RAIN WILL LEAD TO ELEVATED RIVER LEVELS IN THE SEWARD
AREA TODAY AND THE WESTERN SUSITNA VALLEY ON FRIDAY...

...STRONG WINDS OCCURRING THROUGH PORTAGE VALLEY TODAY...

A strong front moving across Southcentral today will produce
periods of heavy rain in Seward and surrounding mountains as well
as across the western Susitna Valley and bordering areas of the
Alaska Range.

For Seward...
The heaviest rain will continue through midday today, with a
total of 2 to 2.5 inches of rain expected through this afternoon.
Additional rainfall of around half in inch is likely tonight.
This will lead to elevated water levels in the Resurrection River
and other area rivers and streams.

For Portage Valley...
Strong wind gusts to 55 mph have been reported in Portage already
this morning. Gusts to 65 mph are possible this morning, gradually
diminishing to 35 to 50 mph this afternoon.

Western Susitna Valley...
The heaviest rain fall through this afternoon, with around 1 inch
of rain expected in the valley and 2 inches in the headwaters of
the Yentna and Skwentna Rivers. This will lead to elevated river
levels beginning tonight into Friday, as these rivers are slower
to respond to the rainfall.