Storm Warning 120, NWS Anchorage, AK

742 
FZAK52 PAFC 042320
CWFALU

COASTAL WATERS FORECAST
NATIONAL WEATHER SERVICE ANCHORAGE ALASKA
320 PM AKDT TUE OCT 4 2016

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.

PKZ199-051230-
320 PM AKDT TUE OCT 4 2016
.SYNOPSIS FOR SOUTHWEST ALASKA+BRISTOL BAY+THE ALASKA
PENINSULA WATERS AND THE ALEUTIAN ISLANDS...
A 971 MB LOW 300 NM SOUTHWEST OF SHEMYA MOVES TO 190 NM SOUTHEAST
OF SHEMYA WED AFTERNOON AND MAINTAINS STRENGTH...THEN TO 300 NM
NORTHEAST OF SHEMYA AT 981 MB BY THU AFTERNOON. A 955 MB NORTH
PACIFIC LOW MOVES TO 360 NM SOUTHWEST OF SHEMYA THU AFTERNOON.

$$

PKZ150-051230-
SOUTH OF THE AK PENINSULA SITKINAK TO CASTLE CAPE-
320 PM AKDT TUE OCT 4 2016

.TONIGHT...SW WIND 15 KT. SEAS 4 FT.
.WED...S WIND 15 KT. SEAS 3 FT.
.WED NIGHT...SE WIND 15 KT. SEAS 6 FT.
.THU...E WIND 20 KT. SEAS 7 FT.
.THU NIGHT...E WIND 25 KT. SEAS 8 FT.
.FRI...SE WIND 30 KT. SEAS 11 FT.
.SAT...SE WIND 35 KT. SEAS 17 FT.
.SUN...E WIND 20 KT. SEAS 13 FT.

$$

PKZ155-051230-
SOUTH OF THE AK PENINSULA CASTLE CAPE TO CAPE SARICHEF-
320 PM AKDT TUE OCT 4 2016

...GALE WARNING WEDNESDAY NIGHT...

.TONIGHT...S WIND 20 KT. SEAS 5 FT.
.WED...SE WIND 25 KT EXCEPT SE 15 KT FROM THE SHUMAGIN ISLANDS E.
SEAS 7 FT.
.WED NIGHT...SE WIND 35 KT EXCEPT SE 25 KT FROM THE SHUMAGIN
ISLANDS E. SEAS 11 FT.
.THU...SE WIND 35 KT. SEAS 15 FT.
.THU NIGHT...SE WIND 30 KT. SEAS 14 FT.
.FRI...SE WIND 30 KT. SEAS 14 FT.
.SAT...SE WIND 35 KT. SEAS 15 FT.
.SUN...SE WIND 15 KT. SEAS 12 FT.

$$

PKZ160-051230-
BRISTOL BAY-
320 PM AKDT TUE OCT 4 2016

.TONIGHT...VARIABLE WIND 10 KT. SEAS 3 FT.
.WED...SE WIND 20 KT. SEAS 3 FT.
.WED NIGHT...SE WIND 20 KT. SEAS 4 FT.
.THU AND THU NIGHT...SE WIND 25 KT. SEAS 6 FT.
.FRI THROUGH SAT...SE WIND 35 KT. SEAS 10 FT.
.SUN...E WIND 25 KT. SEAS 6 FT.

$$

PKZ165-051230-
PORT HEIDEN TO CAPE SARICHEF-
320 PM AKDT TUE OCT 4 2016

...GALE WARNING WEDNESDAY NIGHT...

.TONIGHT...S WIND 25 KT EXCEPT S 15 KT FROM PORT MOLLER E. SEAS
6 FT.
.WED...SE WIND 30 KT. SEAS 8 FT.
.WED NIGHT...SE WIND 30 KT INCREASING TO 40 KT AFTER MIDNIGHT.
FROM PORT MOLLER E...SE WIND 30 KT. SEAS 9 FT.
.THU...SE WIND 40 KT. SEAS 9 FT.
.THU NIGHT...SE WIND 35 KT. SEAS 8 FT.
.FRI THROUGH SAT...SE WIND 35 KT. SEAS 11 FT.
.SUN...SE WIND 20 KT. SEAS 12 FT.

$$

PKZ170-051230-
CAPE SARICHEF TO NIKOLSKI BERING SIDE-
320 PM AKDT TUE OCT 4 2016

...GALE WARNING WEDNESDAY AND WEDNESDAY NIGHT...

.TONIGHT...S WIND 30 KT. SEAS 9 FT.
.WED...SE WIND 35 KT INCREASING TO 45 KT IN THE AFTERNOON. SEAS
13 FT.
.WED NIGHT...SE WIND 45 KT. SEAS 15 FT. RAIN.
.THU...SE WIND 45 KT. SEAS 14 FT.
.THU NIGHT...SE WIND 35 KT. SEAS 11 FT.
.FRI...SE WIND 35 KT. SEAS 11 FT.
.SAT...S WIND 25 KT. SEAS 12 FT.
.SUN...S WIND 15 KT. SEAS 15 FT.

$$

PKZ171-051230-
UNALASKA BAY-
320 PM AKDT TUE OCT 4 2016

...GALE WARNING WEDNESDAY AND WEDNESDAY NIGHT...

.TONIGHT...SE WIND 20 KT. SEAS 3 FT.
.WED...SE WIND 25 KT INCREASING TO 35 KT IN THE AFTERNOON. SEAS
5 FT.
.WED NIGHT...SE WIND 35 KT. SEAS 5 FT. RAIN.
.THU...SE WIND 40 KT. SEAS 6 FT.
.THU NIGHT...SE WIND 30 KT. SEAS 4 FT.
.FRI...S WIND 25 KT. SEAS 3 FT.
.SAT...S WIND 15 KT. SEAS 2 FT.
.SUN...S WIND 10 KT. SEAS 2 FT.

$$

PKZ172-051230-
CAPE SARICHEF TO NIKOLSKI PACIFIC SIDE-
320 PM AKDT TUE OCT 4 2016

...GALE WARNING WEDNESDAY AND WEDNESDAY NIGHT...

.TONIGHT...S WIND 25 KT. SEAS 8 FT.
.WED...SE WIND 30 KT INCREASING TO 40 KT IN THE AFTERNOON. SEAS
14 FT.
.WED NIGHT...SE WIND 45 KT. SEAS 21 FT. RAIN.
.THU...SE WIND 45 KT. SEAS 21 FT.
.THU NIGHT...SE WIND 30 KT. SEAS 17 FT.
.FRI...S WIND 30 KT. SEAS 15 FT.
.SAT...S WIND 25 KT. SEAS 17 FT.
.SUN...SW WIND 15 KT. SEAS 17 FT.

$$

PKZ173-051230-
NIKOLSKI TO SEGUAM ISLAND BERING SIDE-
320 PM AKDT TUE OCT 4 2016

...STORM WARNING WEDNESDAY...

.TONIGHT...S WIND 25 KT INCREASING TO 35 KT AFTER MIDNIGHT. SEAS
12 FT.
.WED...SE WIND 55 KT. SEAS 21 FT. RAIN.
.WED NIGHT...SE WIND 45 KT DIMINISHING TO 35 KT AFTER MIDNIGHT.
SEAS 20 FT SUBSIDING TO 15 FT AFTER MIDNIGHT. RAIN.
.THU...SE WIND 30 KT. SEAS 12 FT.
.THU NIGHT...S WIND 25 KT. SEAS 9 FT.
.FRI...S WIND 35 KT. SEAS 13 FT.
.SAT...S WIND 30 KT. SEAS 17 FT.
.SUN...SW WIND 20 KT. SEAS 19 FT.

$$

PKZ174-051230-
NIKOLSKI TO SEGUAM ISLAND PACIFIC SIDE-
320 PM AKDT TUE OCT 4 2016

...STORM WARNING WEDNESDAY...

.TONIGHT...S WIND 25 KT INCREASING TO 35 KT AFTER MIDNIGHT. SEAS
13 FT.
.WED...SE WIND 50 KT. SEAS 23 FT. RAIN.
.WED NIGHT...S WIND 45 KT DIMINISHING TO 35 KT AFTER MIDNIGHT.
SEAS 23 FT. RAIN.
.THU AND THU NIGHT...S WIND 25 KT. SEAS 18 FT.
.FRI...S WIND 35 KT. SEAS 24 FT.
.SAT...SW WIND 30 KT. SEAS 22 FT.
.SUN...SW WIND 20 KT. SEAS 24 FT.

$$

PKZ175-051230-
SEGUAM ISLAND TO ADAK BERING SIDE-
320 PM AKDT TUE OCT 4 2016

...STORM WARNING WEDNESDAY...

.TONIGHT...S WIND 35 KT BECOMING SE 45 KT AFTER MIDNIGHT. SEAS
14 FT. RAIN.
.WED...SE WIND 50 KT. SEAS 17 FT. RAIN.
.WED NIGHT...SE WIND 25 KT. SEAS 11 FT.
.THU...S WIND 25 KT. SEAS 9 FT.
.THU NIGHT...S WIND 35 KT. SEAS 10 FT.
.FRI...S WIND 40 KT. SEAS 17 FT.
.SAT...SW WIND 35 KT. SEAS 21 FT.
.SUN...SW WIND 25 KT. SEAS 17 FT.

$$

PKZ176-051230-
SEGUAM ISLAND TO ADAK PACIFIC SIDE-
320 PM AKDT TUE OCT 4 2016

...STORM WARNING THROUGH WEDNESDAY...

.TONIGHT...S WIND 35 KT INCREASING TO 50 KT AFTER MIDNIGHT. SEAS
14 FT BUILDING TO 20 FT AFTER MIDNIGHT. RAIN.
.WED...S WIND 50 KT DIMINISHING TO 40 KT IN THE AFTERNOON. SEAS
21 FT. RAIN.
.WED NIGHT...S WIND 30 KT. SEAS 17 FT.
.THU...SW WIND 30 KT. SEAS 18 FT.
.THU NIGHT...SW WIND 35 KT. SEAS 17 FT.
.FRI...SW WIND 45 KT. SEAS 30 FT.
.SAT...SW WIND 35 KT. SEAS 23 FT.
.SUN...SW WIND 25 KT. SEAS 22 FT.

$$

PKZ177-051230-
ADAK TO KISKA-
320 PM AKDT TUE OCT 4 2016

...GALE WARNING TONIGHT AND WEDNESDAY NIGHT...

.TONIGHT...S WIND 45 KT. SEAS 17 FT BERING SIDE...21 FT PACIFIC SIDE.
WIDESPREAD RAIN SHOWERS AND ISOLATED THUNDERSTORMS.
.WED...S WIND 30 KT. SEAS 17 FT. RAIN SHOWERS.
.WED NIGHT...SW WIND 25 KT BECOMING W 35 KT AFTER MIDNIGHT. SEAS
11 FT BERING SIDE...18 FT PACIFIC SIDE.
.THU...W WIND 30 KT. SEAS 17 FT.
.THU NIGHT...S WIND 45 KT. SEAS 17 FT.
.FRI...SW WIND 50 KT. SEAS 33 FT.
.SAT...W WIND 40 KT. SEAS 25 FT.
.SUN...SW WIND 25 KT. SEAS 18 FT.

$$

PKZ178-051230-
KISKA TO ATTU-
320 PM AKDT TUE OCT 4 2016

...GALE WARNING THROUGH WEDNESDAY NIGHT...

.TONIGHT...E WIND 40 KT. SEAS 16 FT. WIDESPREAD RAIN SHOWERS AND
ISOLATED THUNDERSTORMS.
.WED...SE WIND 15 KT BECOMING N IN THE AFTERNOON. FROM SHEMYA
W...N WIND 40 KT. SEAS 15 FT. RAIN SHOWERS.
.WED NIGHT...NW WIND 35 KT. SEAS 16 FT.
.THU...W WIND 30 KT. SEAS 14 FT.
.THU NIGHT...E WIND 30 KT. SEAS 22 FT.
.FRI THROUGH SAT...W WIND 40 KT. SEAS 24 FT.
.SUN...W WIND 30 KT. SEAS 17 FT.

$$

PKZ179-051230-
PRIBILOF ISLANDS NEAR SHORE WATERS-
320 PM AKDT TUE OCT 4 2016

...GALE WARNING WEDNESDAY AND WEDNESDAY NIGHT...

.TONIGHT...S WIND 25 KT. SEAS 11 FT. RAIN.
.WED...SE WIND 40 KT. SEAS 16 FT.
.WED NIGHT...SE WIND 35 KT INCREASING TO 45 KT IN THE AFTERNOON.
SEAS 21 FT. RAIN.
.THU...SE WIND 45 KT. SEAS 20 FT.
.THU NIGHT...SE WIND 35 KT. SEAS 17 FT.
.FRI THROUGH SAT...SE WIND 30 KT. SEAS 16 FT.
.SUN...SE WIND 20 KT. SEAS 15 FT.

$$

PKZ180-051230-
KUSKOKWIM DELTA AND ETOLIN STRAIT-
320 PM AKDT TUE OCT 4 2016

...GALE WARNING WEDNESDAY NIGHT...

.TONIGHT...SE WIND 25 KT. SEAS 7 FT.
.WED...SE WIND 30 KT. SEAS 8 FT.
.WED NIGHT...SE WIND 35 KT. SEAS 10 FT.
.THU AND THU NIGHT...SE WIND 35 KT. SEAS 11 FT.
.FRI THROUGH SAT...SE WIND 40 KT. SEAS 14 FT.
.SUN...E WIND 25 KT. SEAS 8 FT.

$$

PKZ181-051230-
NORTH AND WEST OF NUNIVAK ISLAND-
320 PM AKDT TUE OCT 4 2016

...GALE WARNING WEDNESDAY NIGHT...

.TONIGHT...SE WIND 30 KT. SEAS 11 FT. RAIN.
.WED...SE WIND 30 KT. SEAS 11 FT.
.WED NIGHT...SE WIND INCREASING TO 40 KT. SEAS 16 FT.
.THU AND THU NIGHT...SE WIND 40 KT. SEAS 16 FT.
.FRI THROUGH SAT...SE WIND 40 KT. SEAS 15 FT.
.SUN...SE WIND 25 KT. SEAS 11 FT.

$$

PKZ185-051230-
SAINT MATTHEW ISLAND WATERS-
320 PM AKDT TUE OCT 4 2016

...GALE WARNING WEDNESDAY AND WEDNESDAY NIGHT...

.TONIGHT...SE WIND 30 KT. SEAS 13 FT. RAIN.
.WED...SE WIND 30 KT INCREASING TO 40 KT IN THE AFTERNOON. SEAS
16 FT. RAIN.
.WED NIGHT...SE WIND 45 KT. SEAS 22 FT. RAIN.
.THU AND THU NIGHT...SE WIND 40 KT. SEAS 19 FT.
.FRI THROUGH SAT...SE WIND 35 KT. SEAS 18 FT.
.SUN...SE WIND 30 KT. SEAS 14 FT.

$$

Southcentral and Southwest Alaska Forecast Discussion
National Weather Service Anchorage AK
416 AM AKDT TUE OCT 4 2016

.ANALYSIS AND UPPER LEVELS...

Water vapor satellite imagery this morning depicts a rather quiet
weather pattern for mainland Alaska as high pressure aloft begins
to take over the synoptic pattern. Farther west, a gale-force low
is moving across the western Bering Sea with another amplifying
shortwave trough south of Kamchatka. These lows are forming as the
base of a parent low over Eastern Siberia where the strongest
thermal gradient exists. Closer to Alaska, water vapor imagery
depicts an elongating and shearing-out upper trough stretching
from the west coast to Cook Inlet. Finally, a weak upper low is
centered over the southern ALCAN border. In conjunction with a low
moving toward Haida Gwaii, this is supporting a weak offshore
pressure gradient along the North Gulf coast. Inland gradients are
rather weak, so once again, some areas of local low stratus and
fog have already developed this morning across Southcentral and
Southwest. With time, a series of gale to storm force lows over
the Bering will help amplify the mainland ridge as we head into
the weekend.

&&

.MODEL DISCUSSION...

The models are in superb agreement with no impactful
discrepancies. They are also tightly clustered with the strength
and track of the post-tropical remnants of former Super Typhoon
Chaba as it enters the western Bering Thursday night and Friday.
The models continue to remain in strong agreement with a low-end
storm force low moving into the Bering Sea Wednesday and Thursday.
Forecast confidence is extremely high.

&&

.AVIATION...
PANC...Cigs should largely remain VFR, but will be highly
dependent on mid-level cloud coverage. Any degree of clearing of
the mid-level deck through late morning will initiate radiational
cooling that will allow for at least patchy fog to develop given
continued moist lower levels of the atmosphere. Clearing commences
this evening/tonight, but with low-level moisture remaining and
weak winds patchy fog or low stratus will be possible, though this
is low confidence at this time.

&&

.SHORT TERM FORECAST SOUTHCENTRAL ALASKA (Days 1 and 2)...
A series of weak upper level short-waves will continue to drop
southward across Southcentral today, then southeastward across
the Gulf along the leading edge of a ridge building in across
the western Gulf. Clouds will begin to break up a bit during the
morning hours as cooler and drier air filters in from the north.
The airmass over the Mat-Su, Anchorage, and western Kenai Peninsula
remains saturated this morning, so as clouds begin to break up
will likely see formation of localized areas of dense fog. With
fairly weak low level flow, this may linger through mid-day. A
more significant push of cold air will advect in Tonight helping
to completely clear out skies for most of the region. This general
pattern will persist as we head through the week, so expect at
least several days of dry and clear weather. Meanwhile, a persistent
northerly flow regime with bouts of weak cold advection will
continue to produce weak outflow and gap winds along the coast.

&&

.SHORT TERM FORECAST SOUTHWEST ALASKA (Days 1 and 2)...
The Southwest Alaska region has an upper level ridge moving in
from the eastern Bering which is producing drier/stable
conditions with sunny skies today. While upstream the next
synoptic feature will be a shortwave tracking into the
Kuskokwim/Bristol Bay regions by late Tuesday evening. Therefore,
look for increased cloud cover mainly along the Kuskokwim Delta
coastline as this fast moving shortwave tracks northward into the
Bering Strait. The forecast challenge continues with the development
of patchy to dense fog amounts for the overnight/morning hours in
the region. In the Kuskokwim Delta area, Bethel looks to have
only patchy fog due to cloud cover streaming into the area from
the west. While the Bristol Bay area has patchy fog along the
Western Capes this morning. Meanwhile, thicker fog has developed
along the Alaska Peninsula this morning. The fog in these regions
will dissipate by late morning today before redeveloping
Wednesday morning.

&&

.SHORT TERM FORECAST BERING SEA/ALEUTIANS (Days 1 and 2)...
There is a 989 mb low located in the western Bering with an
associated weather front moving through the central to northern
Bering this morning. This system phases in with a storm force low
tracking near Shemya from the North Pacific Ocean side by Tuesday
evening. The associated weather front with this system tracks
through the Central Bering/Aleutians by Wednesday. This feature
will bring storm force southerly winds through the aforementioned
regions with widespread rain. By Wednesday afternoon this front
tracks into the Eastern Aleutians/Bering. Therefore, look for
gusty southerly gap winds to develop through the bays and passes
on the Bering side along the Chain. Meanwhile, on the backside of
this system the winds will shift out of the north/northwesterly
direction accompanied by a showery regime for the Western
Bering/Aleutians heading into late Wednesday evening.

&&

.LONG TERM FORECAST (Days 3 through 7)...

The most significant change to forecast grids overnight was to
strengthen winds around the remnants of Super Typhoon Chaba as it
moves into the Western Aleutians. As a result of models depicting
a stronger cyclone entering the Western Aleutians, associated
ridging downstream is also enhanced, so updates were also made
over the Gulf to strengthen surface high pressure ridging over the
central Gulf of Alaska late Friday into Saturday.

From previous discussion...

The most active weather through the end of this week will continue
to be focused around the Bering Sea and Aleutians, where a series
of at least gale force lows will quickly pass through the region.
Meanwhile over the Mainland, ridging should prevent the associated
fronts from reaching the southwest coast. The main challenge over
the past few days continues to be determining the strength and
longevity of the blocking ridge that will develop over the
mainland. The models have trended back towards stronger ridging
that would persist through the end of this week. This pattern
would keep most of the active weather that will be moving through
the Bering this week from reaching the mainland or Gulf until
this weekend. Starting Friday, there remains reasonable agreement
that the remnants of Super Typhoon Chaba will move through the
Aleutians, and likely shift the blocking ridge northward, however
the challenge remains how far. Due to this uncertainty the
forecast for this weekend heavily uses ensembles from WPC
guidance, but this will likely need to be updated as model
agreement improves.

&&

.AFC WATCHES/WARNINGS/ADVISORIES...
PUBLIC...None.
MARINE...Storms...173-177 412 413
         Gales...170-172 178 179 185 411 414.

&&

SYNOPSIS AND MODEL DISCUSSION...JA
AVIATION...CC.
SOUTHCENTRAL ALASKA...SB
SOUTHWEST ALASKA/BERING SEA/ALEUTIANS...PD
LONG TERM...CC/DEK