Gale Warning 740, NWS Anchorage, AK

462 
FZAK52 PAFC 190036
CWFALU

Coastal Waters Forecast
National Weather Service Anchorage Alaska
336 PM AKST Mon Dec 18 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.

PKZ199-191300-
336 PM AKST Mon Dec 18 2017
.SYNOPSIS FOR SOUTHWEST ALASKA+BRISTOL BAY+THE ALASKA
PENINSULA WATERS AND THE ALEUTIAN ISLANDS...

A 946 mb low at 59N 172E sweeps into the Chukchi Sea for Wed 
morning. The associated front moves into Mainland Alaska Tue morning.
A pair of North Pacific lows merge near 53N 179E at 984 mb Wed 
morning and shifts to 60N 176W at 969 mb Wed afternoon. Its 
associated front moves to the Central Aleutians by Wed afternoon.

$$

PKZ150-191300-
South of the AK Peninsula Sitkinak to Castle Cape-
336 PM AKST Mon Dec 18 2017

...GALE WARNING TONIGHT AND TUESDAY...

.TONIGHT...S wind 35 kt. Seas 14 ft.
.TUE...SW wind 35 kt diminishing to 25 kt in the afternoon. Seas 15 ft.
.TUE NIGHT...SW wind 20 kt. Seas 14 ft.
.WED...SW wind 15 kt. Seas 10 ft.
.WED NIGHT...SE wind 30 kt. Seas 10 ft.
.THU...E wind 45 kt. Seas 29 ft.
.FRI...SE wind 40 kt. Seas 29 ft.
.SAT...SE wind 25 kt. Seas 21 ft.

$$

PKZ155-191300-
South of the AK Peninsula Castle Cape to Cape Sarichef-
336 PM AKST Mon Dec 18 2017

...GALE WARNING TONIGHT...

.TONIGHT...S wind 40 kt. Seas 23 ft. From the Shumagin Islands E,
seas 13 ft building to 18 ft after midnight. Rain showers.
.TUE...SW wind 30 kt. Seas 20 ft.
.TUE NIGHT...SW wind 25 kt. Seas 15 ft.
.WED...S wind 25 kt. Seas 12 ft.
.WED NIGHT...SE wind 30 kt. Seas 12 ft.
.THU...E wind 45 kt. Seas 26 ft.
.FRI...SE wind 30 kt. Seas 26 ft.
.SAT...SE wind 20 kt. Seas 17 ft.

$$

PKZ160-191300-
Bristol Bay-
336 PM AKST Mon Dec 18 2017

...GALE WARNING TONIGHT...

.TONIGHT...S wind 35 kt. Seas 11 ft. Rain showers.
.TUE...SW wind 30 kt. Seas 10 ft.
.TUE NIGHT...SW wind 30 kt. Seas 11 ft.
.WED...S wind 25 kt. Seas 9 ft.
.WED NIGHT...SE wind 35 kt. Seas 8 ft.
.THU...E wind 50 kt. Seas 12 ft.
.FRI...E wind 40 kt. Seas 12 ft.
.SAT...E wind 25 kt. Seas 7 ft.

$$

PKZ165-191300-
Port Heiden to Cape Sarichef-
336 PM AKST Mon Dec 18 2017

...GALE WARNING THROUGH TUESDAY...

.TONIGHT...S wind 40 kt diminishing to 30 kt after midnight. Seas 20
ft subsiding to 15 ft after midnight. Rain showers.
.TUE...SW wind 35 kt. Seas 19 ft.
.TUE NIGHT...SW wind 30 kt. Seas 18 ft.
.WED AND WED NIGHT...SE wind 35 kt. Seas 15 ft.
.THU THROUGH FRI...SE wind 40 kt. Seas 13 ft.
.SAT...E wind 20 kt. Seas 10 ft.

$$

PKZ170-191300-
Cape Sarichef to Nikolski Bering Side-
336 PM AKST Mon Dec 18 2017

...GALE WARNING THROUGH TUESDAY NIGHT...

.TONIGHT...SW wind 40 kt. Seas 19 ft.
.TUE...SW wind 35 kt. Seas 22 ft.
.TUE NIGHT...S wind 35 kt. Seas 21 ft.
.WED...S wind 45 kt. Seas 19 ft.
.WED NIGHT...SE wind 35 kt. Seas 18 ft.
.THU...E wind 35 kt. Seas 13 ft.
.FRI THROUGH SAT...NW wind 20 kt. Seas 15 ft.

$$

PKZ171-191300-
Unalaska Bay-
336 PM AKST Mon Dec 18 2017

...GALE WARNING TONIGHT...

.TONIGHT...SW wind 35 kt diminishing to 25 kt after midnight. Seas 4
ft. Rain showers.
.TUE...SW wind 25 kt. Seas 4 ft.
.TUE NIGHT...S wind 20 kt. Seas 2 ft.
.WED AND WED NIGHT...SE wind 30 kt. Seas 5 ft.
.THU...E wind 30 kt. Seas 5 ft.
.FRI THROUGH SAT...NW wind 10 kt. Seas 3 ft.

$$

PKZ172-191300-
Cape Sarichef to Nikolski Pacific Side-
336 PM AKST Mon Dec 18 2017

...GALE WARNING TONIGHT...

.TONIGHT...SW wind 45 kt diminishing to 30 kt after midnight. Seas
27 ft. Rain.
.TUE...SW wind 30 kt. Seas 20 ft.
.TUE NIGHT...SW wind 25 kt. Seas 16 ft.
.WED...S wind 35 kt. Seas 14 ft.
.WED NIGHT...SE wind 30 kt. Seas 18 ft.
.THU...E wind 30 kt. Seas 18 ft.
.FRI...NW wind 25 kt. Seas 18 ft.
.SAT...NW wind 20 kt. Seas 12 ft.

$$

PKZ173-191300-
Nikloski to Seguam Island Bering Side-
336 PM AKST Mon Dec 18 2017

...GALE WARNING THROUGH TUESDAY NIGHT...

.TONIGHT...SW wind 40 kt. Seas 22 ft.
.TUE...SW wind 40 kt diminishing to 30 kt in the afternoon. Seas
24 ft.
.TUE NIGHT...SW wind 30 kt becoming S 40 kt after midnight. Seas
21 ft.
.WED...S wind 50 kt. Seas 23 ft.
.WED NIGHT...SE wind 35 kt. Seas 20 ft.
.THU...W wind 35 kt. Seas 15 ft.
.FRI...NW wind 25 kt. Seas 17 ft.
.SAT...NW wind 20 kt. Seas 14 ft.

$$

PKZ174-191300-
Nikolski to Seguam Island Pacific Side-
336 PM AKST Mon Dec 18 2017

...GALE WARNING TONIGHT AND TUESDAY NIGHT...

.TONIGHT...SW wind 35 kt. Seas 25 ft.
.TUE...SW wind 30 kt. Seas 21 ft.
.TUE NIGHT...SW wind 25 kt becoming S 35 kt after midnight. Seas
18 ft.
.WED...S wind 45 kt. Seas 23 ft.
.WED NIGHT...SE wind 35 kt. Seas 24 ft.
.THU...NW wind 35 kt. Seas 19 ft.
.FRI...NW wind 30 kt. Seas 19 ft.
.SAT...NW wind 20 kt. Seas 15 ft.

$$

PKZ175-191300-
Seguam Island to Adak Bering Side-
336 PM AKST Mon Dec 18 2017

...STORM WARNING TUESDAY NIGHT...

.TONIGHT...SW wind 30 kt increasing to 40 kt after midnight. Seas 25
ft.
.TUE...W wind 40 kt. Seas 25 ft.
.TUE NIGHT...SW wind 45 kt becoming S 55 kt after midnight. Seas
21 ft.
.WED...SW wind 60 kt. Seas 24 ft.
.WED NIGHT...NW wind 35 kt. Seas 15 ft.
.THU...NW wind 35 kt. Seas 15 ft.
.FRI...NW wind 25 kt. Seas 16 ft.
.SAT...NW wind 15 kt. Seas 14 ft.

$$

PKZ176-191300-
Seguam Island to Adak Pacific Side-
336 PM AKST Mon Dec 18 2017

...STORM WARNING TUESDAY NIGHT...

.TONIGHT...SW wind 35 kt. Seas 24 ft.
.TUE...W wind 30 kt. Seas 23 ft.
.TUE NIGHT...SW wind 35 kt becoming S 55 kt after midnight. Seas
17 ft building to 23 ft after midnight.
.WED...S wind 55 kt. Seas 30 ft.
.WED NIGHT...NW wind 35 kt. Seas 26 ft.
.THU...NW wind 35 kt. Seas 20 ft.
.FRI...NW wind 30 kt. Seas 18 ft.
.SAT...NW wind 15 kt. Seas 16 ft.

$$

PKZ177-191300-
Adak to Kiska-
336 PM AKST Mon Dec 18 2017

...STORM WARNING TUESDAY NIGHT...

.TONIGHT...SW wind 45 kt. Seas 28 ft.
.TUE...SW wind 45 kt. Seas 25 ft.
.TUE NIGHT...S wind 50 kt increasing to 60 kt after midnight. Seas
29 ft. Rain showers.
.WED...W wind 55 kt. Seas 28 ft.
.WED NIGHT...W wind 30 kt. Seas 18 ft.
.THU...NW wind 45 kt. Seas 20 ft.
.FRI...W wind 25 kt. Seas 13 ft.
.SAT...NW wind 20 kt. Seas 16 ft.

$$

PKZ178-191300-
Kiska to Attu-
336 PM AKST Mon Dec 18 2017

...STORM WARNING TUESDAY AND TUESDAY NIGHT...

.TONIGHT...W wind 45 kt. Seas 31 ft.
.TUE...SW wind 35 kt increasing to 50 kt in the afternoon. Seas
26 ft.  and rain showers.
.TUE NIGHT...W wind 50 kt becoming NW 30 kt after midnight. Seas
26 ft subsiding to 20 ft after midnight. Rain showers.
.WED...W wind 40 kt. Seas 18 ft.
.WED NIGHT...W wind 45 kt. Seas 22 ft.
.THU...W wind 45 kt. Seas 20 ft.
.FRI THROUGH SAT...NW wind 20 kt. Seas 15 ft.

$$

PKZ179-191300-
Pribilof Islands Near Shore Waters-
336 PM AKST Mon Dec 18 2017

...GALE WARNING THROUGH TUESDAY NIGHT...

.TONIGHT...SW wind 30 kt increasing to 40 kt after midnight. Seas
23 ft.
.TUE...SW wind 40 kt. Seas 25 ft.
.TUE NIGHT...SW wind 30 kt becoming S 45 kt after midnight. Seas
24 ft.
.WED...S wind 55 kt. Seas 29 ft.
.WED NIGHT...S wind 45 kt. Seas 27 ft.
.THU...SE wind 30 kt. Seas 19 ft.
.FRI...W wind 15 kt. Seas 14 ft.
.SAT...Variable wind 10 kt. Seas 13 ft.

$$

PKZ180-191300-
Kuskokwim Delta and Etolin Strait-
336 PM AKST Mon Dec 18 2017

...GALE WARNING THROUGH TUESDAY NIGHT...

.TONIGHT...S wind 40 kt. Seas 18 ft. Rain.
.TUE...SW wind 35 kt. Seas 16 ft.
.TUE NIGHT...SW wind 30 kt increasing to 40 kt after midnight.
Seas 17 ft.
.WED AND WED NIGHT...S wind 45 kt. Seas 18 ft.
.THU...SE wind 45 kt. Seas 17 ft.
.FRI...SE wind 40 kt. Seas 17 ft.
.SAT...E wind 20 kt. Seas 10 ft.

$$

PKZ181-191300-
North and West of Nunivak Island-
336 PM AKST Mon Dec 18 2017

...GALE WARNING TUESDAY AND TUESDAY NIGHT...

.TONIGHT...SW wind 30 kt. Seas 16 ft. Rain showers.
.TUE...SW wind 40 kt. Seas 19 ft.
.TUE NIGHT...SW wind 35 kt becoming S 45 kt after midnight. Seas
18 ft.
.WED...S wind 50 kt. Seas 23 ft.
.WED NIGHT...S wind 55 kt. Seas 24 ft.
.THU THROUGH FRI...SE wind 35 kt. Seas 17 ft.
.SAT...SE wind 20 kt. Seas 10 ft.

$$

PKZ185-191300-
Saint Matthew Island Waters-
336 PM AKST Mon Dec 18 2017

...GALE WARNING THROUGH TUESDAY NIGHT...

.TONIGHT...S wind 35 kt E of Saint Matthew Island...S 45 kt W of
Saint Matthew Island. Seas 31 ft.
.TUE...SW wind 40 kt E of Saint Matthew Island... SW 45 kt W of
Saint Matthew Island. Seas 32 ft.
.TUE NIGHT...S wind 45 kt. Seas 27 ft subsiding to 21 ft after
midnight.
.WED AND WED NIGHT...SW wind 55 kt. Seas 27 ft.
.THU...E wind 30 kt. Seas 16 ft.
.FRI...E wind 25 kt. Seas 15 ft.
.SAT...NE wind 15 kt. Seas 13 ft.

$$

Southcentral and Southwest Alaska Forecast Discussion
National Weather Service Anchorage AK
434 PM AKST Sun Dec 17 2017

.ANALYSIS AND UPPER LEVELS...

A weakening positive tilt trough over Southern Alaska is shifting
east this afternoon. Embedded within the larger trough are
numerous smaller scale and weak disturbances, one along the North
Gulf Coast and another moving across the Kuskokwim Delta. An
unstable environment remains over the Gulf of Alaska and along the
immediate coast where snow showers are ongoing. There is a weak
surface trough axis along the North Gulf Coast, otherwise, the
gradient over Southcentral is rather weak. Out west, ridging
building into the Bering is keeping a tight northwest flow
gradient over the Southwest coastline. This is ahead of a
developing bomb cyclone over the far western Bering Sea as a
potential vorticity anomaly is in the process of intersecting a
modest warm front. Himawari satellite imagery is already showing
the classic signs of a powerful low, including a developing
emerging cloud head out of the left exit of the upper jet.

&&

.MODEL DISCUSSION...

The numerical models are in unusually good agreement with the
details of a powerful bomb cyclone over the western Bering
Sea...and the associated front which will cross the Bering Sea and
move inland Monday and Tuesday. The biggest discrepancy in the
models is how much inland precipitation will fall across parts of
Southcentral owing to a low level cross-barrier flow component
which will act to diminish precip values for some locations.
Places like Anchorage, the Copper Basin, and parts of the northern
Kenai Peninsula will likely see some impact of cross-barrier flow
and possibly even some low level warming which may result in mixed
precip on the onset of the event (a mix of rain and snow).

&&

.AVIATION...
PANC...Fog is likely to redevelop during the overnight as mid
level clouds clear out and the low level flow remains weak. This
will likely bring in IFR to LIFR CIGS and VSBYS which will last
through the morning. However, confidence is only moderate since
the coverage of fog is not expected to be widespread.

&&

.SHORT TERM FORECAST SOUTHCENTRAL ALASKA (Days 1 and 2)...
A weak surface low currently located in the Gulf of Alaska will
slowly weaken tonight while moving off to the east, bringing an
end to the scattered snow showers along the coast by the early
morning hours. A transient ridge will quickly build in behind the
departing low tomorrow morning. Weak flow with clearing skies and
abundant low level moisture will allow areas of dense fog to
reform tonight for locations along the Cook Inlet and Knik Arm.
Besides the fog, skies will be mostly sunny and temperatures will
be noticeably colder compared to the first half of the month.

The ridge will depart quickly to the east as the next storm system
comes barreling through the area from the west by Monday night. A
front will move into southcentral by Tuesday morning and a triple
point low is expected to form south of Homer and move north. Warm
air is expected to advect up from the south and easterly winds
will increase through Turnagain Arm and the Knik River Valley.
This will likely keep the typical downsloped areas, including the
Western Kenai Peninsula, Anchorage, and Palmer, mostly dry and
warmer through the day on Tuesday. It is not until the low passes
to the northeast late Tuesday afternoon that precipitation will
develop over these areas. Colder air filtering in from the NW will
likely change precipitation over to all snow, though total
accumulations should be no more than 1-2". In the Susitna Valley,
favorable midlevel flow from the SW will provide a good push of
moisture up the Cook Inlet brining a decent snow event to
locations along the Parks Highway, especially north of Willow,
where total snowfall is expected to be between 6-8" with localized
amounts near a foot by Tuesday night. A winter storm watch has
therefore been issued for this area. Hatcher Pass will also see
significant snowfall, with 1-1.5 ft of snow falling through the
day on Wednesday.

The low will track across the northern Gulf and Prince William
sound spreading precipitation across coastal areas by late Tuesday
morning. Precipitation should mostly be rain or mixed, though
colder air trapped in Valdez will lead to all snow, with nearly a
foot of snow expected to fall in town through Wednesday morning.

&&

.SHORT TERM FORECAST SOUTHWEST ALASKA (Days 1 and 2)...
Weak ridging has moved in over southwest Alaska and will remain
overnight bringing a possibility of fog to the area. Then on
Monday morning a front will push in from the west at first
bringing snow to southwest Alaska. This front has a long fetch of
warm air with it that will transition the snow over to rain for
areas at and near the coast. By Tuesday afternoon the front will
have pushed off to the east with cold air coming in behind it.

&&

.SHORT TERM FORECAST BERING SEA/ALEUTIANS (Days 1 and 2)...
Over the eastern Bering, high pressure is quickly tracking to the
east. Out west there is a deep low over the far western Bering
with its front draped through the western Aleutians. As the front
moves through the central Aleutians this evening it will bring
strong gusty winds reaching warning level. As it passes early
Monday morning the winds will diminish.

The front is pulling up warm air from the south causing it to
bring rain to the islands. It will track east through the area and
make it to the eastern Bering and Aleutians Monday morning. Cold
westerly flow will follow behind the front bringing snow showers
to the area. Then on Tuesday another warm system will approach the
western Aleutians from the North Pacific.

&&

.LONG TERM FORECAST (Days Tuesday through Saturday)...

The long term forecast remains on track for Tuesday, with snow
expected in the Susitna Valley and along the Chugach Range toward
Valdez. Current snow amounts look to be close to a foot north and
east of Talkeetna, which will bring some much welcome ground cover
in those areas. Details are slightly less certain through Valdez,
but right now snow amounts are expected to be very similar in this
area as well. Unfortunately for snow lovers, this will be a non-
event for Anchorage and the Kenai Peninsula, with an inch or less
expected.

After Tuesday, most of the state will experience a quick shot of
cold air (a.k.a. return to seasonable temperatures) before the
North Pacific ridge builds back in, starting Thursday. The
orientation of the ridge makes a big difference in the forecast,
but models keep trending towards a more negatively tilted ridge,
pushing low pressure systems further westward. Friday and Saturday
a new, strong system moves up from the Gulf of Alaska and has the
potential to bring an atmospheric river for the Southcentral
region. Currently, Kodiak appears to be in the crosshairs, but if
the solutions wobble again, the southern Kenai may see the brunt
of the system. Unfortunately a combination of warm southerly flow
and downsloping across the Southcentral area are currently
indicating more of a wind and rain storm, instead of an early snow
for Christmas.

&&

.AFC WATCHES/WARNINGS/ADVISORIES...
PUBLIC...WSW 145 & NPW 187.
MARINE...Storms 170 173-177 179 411-414.
         Gales 150 155 160 165 170 171 178 180 181 185.
&&

SYNOPSIS AND MODEL DISCUSSION...JA
SOUTHCENTRAL ALASKA...KVP
SOUTHWEST ALASKA/BERING SEA/ALEUTIANS...DK
LONG TERM...LF