Gale Warning 249, NWS Anchorage, AK

840 
FZAK52 PAFC 122322
CWFALU

Coastal Waters Forecast
National Weather Service Anchorage Alaska
322 PM AKDT Mon Mar 12 2018

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.

PKZ199-131215-
322 PM AKDT Mon Mar 12 2018
.SYNOPSIS FOR SOUTHWEST ALASKA+BRISTOL BAY+THE ALASKA
PENINSULA WATERS AND THE ALEUTIAN ISLANDS...
A 994 mb low 230 nm southwest of St. Paul will move over Bristol 
Bay at 1004 mb Tue night then track inland Wed morning. A 1001 mb 
Kamchatka low will move to the western Bering at 1001 mb Tue 
afternoon, then move to the northern Bering Wed morning. A North 
Pacific front will move over the central Aleutians Wed morning. 
A second front will approach the western Aleutians Wed afternoon.

$$

PKZ150-131215-
South of the AK Peninsula Sitkinak to Castle Cape-
322 PM AKDT Mon Mar 12 2018

...SMALL CRAFT ADVISORY THROUGH TUESDAY NIGHT...

.TONIGHT...NW wind 15 kt. Seas 8 ft.
.TUE...Variable wind 10 kt. Seas 8 ft.
.TUE NIGHT...W wind 15 kt. Seas 8 ft.
.WED...W wind 15 kt. Seas 8 ft.
.WED NIGHT...S wind 20 kt. Seas 7 ft.
.THU...S wind 30 kt. Seas 12 ft.
.FRI...SW wind 25 kt. Seas 12 ft.
.SAT...W wind 20 kt. Seas 15 ft.

$$

PKZ155-131215-
South of the AK Peninsula Castle Cape to Cape Sarichef-
322 PM AKDT Mon Mar 12 2018

...SMALL CRAFT ADVISORY THROUGH TUESDAY NIGHT...

.TONIGHT...S wind 20 kt except W 15 kt from the Shumagin Islands
E. Seas 8 ft.
.TUE...SW wind 20 kt except S 15 kt from the Shumagin Islands E.
Seas 8 ft.
.TUE NIGHT...W wind 15 kt. Seas 9 ft.
.WED...E wind 20 kt. Seas 8 ft.
.WED NIGHT...S wind 25 kt. Seas 11 ft.
.THU...S wind 30 kt. Seas 16 ft.
.FRI THROUGH SAT...W wind 20 kt. Seas 16 ft.

$$

PKZ160-131215-
Bristol Bay-
322 PM AKDT Mon Mar 12 2018

.TONIGHT...W wind 15 kt becoming S after midnight. Seas in 
ice free waters 6 ft.
.TUE...SE wind 10 kt increasing to 15 kt in the afternoon. 
Seas in ice free waters 4 ft.
.TUE NIGHT...S wind 20 kt. Seas in ice free waters 6 ft.
.WED...NW wind 15 kt. Seas in ice free waters 5 ft.
.WED NIGHT...E wind 20 kt. Seas in ice free waters 4 ft.
.THU...E wind 20 kt. Seas in ice free waters 4 ft.
.FRI...SW wind 15 kt. Seas in ice free waters 3 ft.
.SAT...W wind 10 kt. Seas in ice free waters 4 ft.

$$

PKZ165-131215-
Port Heiden to Cape Sarichef-
322 PM AKDT Mon Mar 12 2018

...SMALL CRAFT ADVISORY TONIGHT...

.TONIGHT...S wind 15 kt. Seas 10 ft.
.TUE...SW wind 20 kt. Seas 6 ft.
.TUE NIGHT...W wind 20 kt. Seas 7 ft.
.WED AND WED NIGHT...E wind 20 kt. Seas 5 ft.
.THU...SE wind 20 kt. Seas 5 ft.
.FRI THROUGH SAT...SW wind 15 kt. Seas 9 ft.

$$

PKZ170-131215-
Cape Sarichef to Nikolski Bering Side-
322 PM AKDT Mon Mar 12 2018

...SMALL CRAFT ADVISORY TONIGHT...

.TONIGHT...S wind 20 kt. Seas 9 ft. Rain and snow.
.TUE...SW wind 20 kt. Seas 7 ft.
.TUE NIGHT...N wind 15 kt. Seas 6 ft.
.WED...E wind 25 kt. Seas 5 ft.
.WED NIGHT...NE wind 20 kt. Seas 7 ft.
.THU...NW wind 25 kt. Seas 9 ft.
.FRI THROUGH SAT...SW wind 20 kt. Seas 16 ft.

$$

PKZ171-131215-
Unalaska Bay-
322 PM AKDT Mon Mar 12 2018

.TONIGHT...S wind 15 kt. Seas 2 ft. Rain.
.TUE...SW wind 15 kt. Seas 3 ft.
.TUE NIGHT...N wind 10 kt. Seas 3 ft.
.WED...E wind 15 kt. Seas 2 ft.
.WED NIGHT...E wind 10 kt. Seas 3 ft.
.THU...W wind 15 kt. Seas 5 ft.
.FRI THROUGH SAT...SW wind 15 kt. Seas 2 ft.

$$

PKZ172-131215-
Cape Sarichef to Nikolski Pacific Side-
322 PM AKDT Mon Mar 12 2018

...SMALL CRAFT ADVISORY THROUGH TUESDAY NIGHT...

.TONIGHT...SW wind 25 kt. Seas 11 ft. Rain.
.TUE...SW wind 20 kt. Seas 11 ft.
.TUE NIGHT...NE wind 15 kt. Seas 10 ft.
.WED AND WED NIGHT...SE wind 25 kt. Seas 11 ft.
.THU THROUGH FRI...SW wind 25 kt. Seas 18 ft.
.SAT...SW wind 20 kt. Seas 18 ft.

$$

PKZ173-131215-
Nikloski to Seguam Island Bering Side-
322 PM AKDT Mon Mar 12 2018

...SMALL CRAFT ADVISORY THROUGH TUESDAY...

.TONIGHT...SW wind 25 kt. Seas 9 ft.
.TUE...NW wind 20 kt. Seas 8 ft.
.TUE NIGHT...NE wind 15 kt. Seas 6 ft.
.WED...NE wind 25 kt. Seas 7 ft.
.WED NIGHT...N wind 30 kt. Seas 10 ft.
.THU...NW wind 30 kt. Seas 10 ft.
.FRI...SW wind 25 kt. Seas 15 ft.
.SAT...SW wind 20 kt. Seas 14 ft.

$$

PKZ174-131215-
Nikolski to Seguam Island Pacific Side-
322 PM AKDT Mon Mar 12 2018

...SMALL CRAFT ADVISORY THROUGH TUESDAY NIGHT...

.TONIGHT...SW wind 30 kt. Seas 14 ft.
.TUE...W wind 20 kt. Seas 13 ft.
.TUE NIGHT...NE wind 15 kt. Seas 9 ft.
.WED...E wind 25 kt. Seas 8 ft.
.WED NIGHT...N wind 30 kt. Seas 12 ft.
.THU...W wind 30 kt. Seas 15 ft.
.FRI...SW wind 25 kt. Seas 20 ft.
.SAT...SW wind 20 kt. Seas 17 ft.

$$

PKZ175-131215-
Seguam Island to Adak Bering Side-
322 PM AKDT Mon Mar 12 2018

...SMALL CRAFT ADVISORY TONIGHT...

.TONIGHT...W wind 20 kt. Seas 8 ft.
.TUE...NW wind 15 kt. Seas 7 ft.
.TUE NIGHT...N wind 15 kt. Seas 4 ft.
.WED...N wind 25 kt. Seas 8 ft.
.WED NIGHT...N wind 30 kt. Seas 8 ft.
.THU...SE wind 20 kt. Seas 7 ft.
.FRI THROUGH SAT...SW wind 25 kt. Seas 14 ft.

$$

PKZ176-131215-
Seguam Island to Adak Pacific Side-
322 PM AKDT Mon Mar 12 2018

...SMALL CRAFT ADVISORY THROUGH TUESDAY NIGHT...

.TONIGHT...SW wind 25 kt. Seas 15 ft.
.TUE...NW wind 20 kt in the morning becoming variable 10 kt. 
Seas 12 ft.
.TUE NIGHT...Variable wind 10 kt becoming N 20 kt after 
midnight. Seas 8 ft.
.WED AND WED NIGHT...N wind 30 kt. Seas 10 ft.
.THU...SW wind 25 kt. Seas 14 ft.
.FRI...SW wind 25 kt. Seas 22 ft.
.SAT...SW wind 25 kt. Seas 15 ft.

$$

PKZ177-131215-
Adak to Kiska-
322 PM AKDT Mon Mar 12 2018

...SMALL CRAFT ADVISORY THROUGH TUESDAY NIGHT...

.TONIGHT...N wind 20 kt. Seas 13 ft.
.TUE...W wind 20 kt. Seas 10 ft.
.TUE NIGHT...NW wind 20 kt. Seas 8 ft.
.WED...N wind 20 kt. Seas 7 ft.
.WED NIGHT...SE wind 25 kt. Seas 8 ft.
.THU THROUGH FRI...SW wind 25 kt. Seas 20 ft.
.SAT...SW wind 30 kt. Seas 20 ft.

$$

PKZ178-131215-
Kiska to Attu-
322 PM AKDT Mon Mar 12 2018

...SMALL CRAFT ADVISORY THROUGH TUESDAY NIGHT...

.TONIGHT...NW wind 20 kt becoming W 30 kt after midnight. 
Seas 10 ft.
.TUE...W wind 25 kt. Seas 10 ft.
.TUE NIGHT...W wind 15 kt. Seas 8 ft.
.WED...S wind 25 kt. Seas 6 ft.
.WED NIGHT...SE wind 30 kt. Seas 14 ft.
.THU THROUGH SAT...SW wind 30 kt. Seas 24 ft.

$$

PKZ179-131215-
Pribilof Islands Near Shore Waters-
322 PM AKDT Mon Mar 12 2018

...SMALL CRAFT ADVISORY TONIGHT...

.TONIGHT...Variable wind 10 kt. Seas 8 ft.
.TUE...NW wind 20 kt. Seas 7 ft. Snow.
.TUE NIGHT...NW wind 20 kt in the evening becoming variable 10 kt.
Seas 7 ft.
.WED...NE wind 15 kt. Seas 6 ft.
.WED NIGHT...NE wind 25 kt. Seas 7 ft.
.THU...NE wind 25 kt. Seas 12 ft.
.FRI...SE wind 15 kt. Seas 12 ft.
.SAT...S wind 15 kt. Seas 12 ft.

$$

PKZ180-131215-
Kuskokwim Delta and Etolin Strait-
322 PM AKDT Mon Mar 12 2018

.TONIGHT...N wind 10 kt. Seas in ice free waters 7 ft.
.TUE...SE wind 15 kt. Seas in ice free waters 5 ft.
.TUE NIGHT...NW wind 15 kt. Seas in ice free waters 6 ft. 
Freezing spray.
.WED...NE wind 15 kt. Seas in ice free waters 5 ft.
.WED NIGHT...NE wind 20 kt. Seas in ice free waters 4 ft.
.THU...NE wind 30 kt. Seas in ice free waters 7 ft.
.FRI...E wind 20 kt. Seas in ice free waters 6 ft.
.SAT...E wind 10 kt. Seas in ice free waters 8 ft.

$$

PKZ181-131215-
North and West of Nunivak Island-
322 PM AKDT Mon Mar 12 2018

...HEAVY FREEZING SPRAY WARNING TONIGHT AND TUESDAY NIGHT...

.TONIGHT...E wind 15 kt. Seas in ice free waters 5 ft. 
Heavy freezing spray.
.TUE...Variable wind 10 kt. Seas in ice free waters 4 ft.
.TUE NIGHT...N wind 15 kt. Seas in ice free waters 6 ft. 
Heavy freezing spray.
.WED...Variable wind 10 kt. Seas in ice free waters 4 ft.
.WED NIGHT...E wind 15 kt. Seas in ice free waters 4 ft.
.THU THROUGH FRI...NE wind 25 kt. Seas in ice free waters 8 ft.
.SAT...E wind 20 kt. Seas in ice free waters 8 ft.

$$

PKZ185-131215-
Saint Matthew Island Waters-
322 PM AKDT Mon Mar 12 2018

...SMALL CRAFT ADVISORY TONIGHT...

.TONIGHT...E wind 20 kt. Seas 9 ft. Freezing spray.
.TUE...E of Saint Matthew Island, variable wind 10 kt becoming 
N 20 kt in the afternoon. W of Saint Matthew Island, W wind 20 kt. 
Seas 7 ft. Freezing spray.
.TUE NIGHT...W wind 20 kt. Seas 7 ft. Freezing spray.
.WED...S wind 20 kt. Seas 8 ft.
.WED NIGHT...S wind 15 kt. Seas 7 ft.
.THU...E wind 25 kt. Seas 12 ft.
.FRI THROUGH SAT...E wind 30 kt. Seas 16 ft.

$$

Southcentral and Southwest Alaska Forecast Discussion
National Weather Service Anchorage AK
456 PM AKDT Sun Mar 11 2018

.ANALYSIS AND UPPER LEVELS...
Snow from a low moving northward across the Gulf has developed
along the North Gulf Coast from Cordova to Valdez, and is beginning
to spread further westward toward the Kenai Peninsula. This low
is also bringing a brief round of gusty outflow winds to areas
such as Resurrection Bay and Passage Canal, but these should all
diminish this evening as the low makes landfall. Just to the west
of this low, a narrow area of high pressure has allowed for the
development of widespread stratus and some patchy fog over much of
the Southwest Mainland, which is beginning to break up as a gale
force front over the Eastern Bering begins to make landfall. This
front will be the focus for snow and blowing snow that will spread
into the Southwest this afternoon and evening. This front has
pushed through the Aleutians and AKpen today, bringing rain and
snow (which has been heavy at times) along with gusty southerly
winds. Behind the front, strong cold air advection can be seen
moving from the Western Bering into the Central Bering with broad
northwesterly flow.

&&

.MODEL DISCUSSION...
Now that the models have come into better agreement with the track
of the low into Prince William Sound this evening, confidence has
begun to increase that much of the Anchorage Bowl and Matanuska
Valley (especially as you move further east) will see a brief
period of light snowfall late this afternoon/early this evening.
Afterwards the models are in very good synoptic agreement through
Monday, and have improved significantly in the track of the next
trough crossing the Gulf late Monday-Tuesday, and as a result
confidence is increasing that another round of rain and snow will
spread back into the North Gulf Coast and Copper River Basin.
Confidence is much lower however over Southcentral as differences
begin to arise in how quickly a front over the Southwest Mainland
will lift northward into the interior, and how far west this will
allow the precip to reach. Overnight the models were in good
agreement that precip would struggle to reach any further west
than Whittier, but the daytime runs today are beginning to trend
slightly further west.

&&

.AVIATION...
PANC...Potential for MVFR snow will be the primary concern this
afternoon/evening as snowfall moves into the area from the east.
The terminal will likely be on the very western edge of this
snowfall, so at this point it appears that the greatest impact
of the MVFR conditions will be for operations to the east of the
airport.

&&

.SHORT TERM FORECAST SOUTHCENTRAL ALASKA (Days 1 and 2)...
The low moving rapidly into Prince William Sound will continue
to produce snow across the North Gulf Coast tonight, with snow
eventually spreading as far west as Anchorage and the Mat Valley
through late evening before the low dissipates. Accumulations
should remain minimal for most areas, although several inches will
be possible in the Valdez area. Precipitation should continue to
fall as mostly rain towards Cordova where surface temperatures are
a bit warmer. A rather quiet day is on tap for Monday, with a
just a few showers lingering along the Gulf Coast in the wake of
this system. A somewhat complex scenario then looks to take shape
Monday night into Tuesday as a weak upper level trough and a
dissipating front approach the Cook Inlet region from the
southwest while another stronger front moves into the Gulf from
the southeast. This stronger front will spread snow back into
Prince William Sound and the Copper River Basin, with rain once
again mixing in closer to sea level. Meanwhile, the passage of the
upper trough looks to be mostly dry for Cook Inlet and the Mat-Su.
The primary forecast question then becomes the extent to which
the eastward moving trough impedes the westward progress of the
more robust precipitation associated with the front over the Gulf.
Trending towards keeping Anchorage and surrounding areas dry
through Tuesday for now, but there is lower confidence in the
forecast moving into the end of the short term.

&&

.SHORT TERM FORECAST SOUTHWEST ALASKA (Days 1 and 2)...
Snow will spread over the mainland from the coast this evening.
While the the system is weakening as it moves ashore, winds will
remain just strong enough for blowing snow and reduced visibility
along the coast, where an advisory for blowing snow has been
issued through early Sunday morning. The front slowly falls apart
as it moves inland, lingering light snow through late Monday for
Bristol Bay and the Kuskokwim Valley.

Another system is in the progressive flow as a trough from east
Asia impinges on the frontal boundary draped over the Bering Sea.
The interaction will develop another compact quick moving system
that will move ashore the mainland late Tuesday, with another
round of snow.

&&

.SHORT TERM FORECAST BERING SEA/ALEUTIANS (Days 1 and 2)...
The warm front currently over the Alaska Peninsula will continue
to moves eastward, ushering in a short period of showery northwest
flow for the Bering Sea. However, another small and compact system
will move from the Adak/Atka area late tonight toward the mainland
with another shot of snow for the Pribilof Islands. Winds should
remain below gale-force, but not far off.

&&

.LONG TERM FORECAST (Days 3 through 7)...
The long term forecast begins Wednesday with a broad upper level
trough extending down from Northeastern Russia across the Bering
Sea. Short-waves rotating around the base of the trough will spin
up several systems through the end of the week and into next
weekend, continuing the active pattern seen recently across the
region. At the surface, a short-wave trough will push east across
mainland Alaska Wednesday, bringing accumulating snowfall to the
southwest mainland before crossing the Alaska Range and weakening
some as it makes its way into Southcentral, where the prospect of
accumulating snowfall is less certain. On Thursday, a stronger
upper level trough digs down across the Western Aleutians which
looks to spawn the development of a surface low south of the
Central Aleutian chain. The models begin to heavily diverge at
this point with the Euro/Canadian models keeping the low embedded
within the main SW'ly jet, bringing the system, and a decent
amount of precipitation and warmer air, NE across the AKPEN and
into southcentral by Friday. The GFS cuts the low off from the
SW'ly jet by the time it reaches the Aleutians and retrogrades the
system back into the Bering Sea on Friday. Obviously, these two
solutions will have wildly differing impacts of the sensible
weather seen on the ground, especially over Southcentral.

The deterministic models have been struggling lately with the
progressive pattern, and the predictability of individual systems
has been around 120 hrs or less due to poor upstream initialization.
Therefore, the long range forecast has trended more toward the
ensemble means past day 5, which have been more consistent with
the Euro model.

&&

.AFC WATCHES/WARNINGS/ADVISORIES...
PUBLIC...Winter Weather Advisory 155 161.
MARINE...Gale Warning 180 185.
         Heavy Freezing Spray 180 181.

&&

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