Gale Warning 665, NWS Anchorage, AK

794 
FZAK61 PAFC 061210
OFFAER

Offshore Waters Forecast
National Weather Service Anchorage AK
310 AM AKST Fri Dec 6 2019

Offshore waters forecast for the Gulf of Alaska West of 144W

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.

PKZ399-070300-
310 AM AKST Fri Dec 6 2019
.SYNOPSIS FOR THE WESTERN GULF OF ALASKA...

A front over the western Gulf reaches the central Gulf Fri night.
A 989 mb North Pacific low reaches the central Gulf by Sat night.

$$

PKZ351-070300-
Gulf of Alaska Offshore North of 57N and West of 144W-
310 AM AKST Fri Dec 6 2019

.TODAY...SE wind 10 to 20 kt. Seas 4 to 7 ft.
.TONIGHT...S wind 10 to 25 kt. Seas 8 ft. Rain.
.SAT...S wind 15 to 30 kt. Seas 9 to 14 ft.
.SAT NIGHT...SE wind 15 to 30 kt. Seas 12 to 15 ft.
.SUN THROUGH MON...SE wind 25 to 40 kt. Seas 15 to 23 ft.
.TUE...SE wind 15 to 30 kt. Seas 13 to 19 ft.

$$

PKZ352-070300-
Gulf of Alaska Offshore South of 57N North of 55N and West of
144W-
310 AM AKST Fri Dec 6 2019

...GALE WARNING SATURDAY...

.TODAY...S wind 10 to 25 kt. Seas 9 ft.
.TONIGHT...S wind 15 to 30 kt. Seas 9 to 14 ft.
.SAT...S wind 25 to 40 kt. Seas 10 to 17 ft.
.SAT NIGHT...SE wind 15 to 30 kt. Seas 12 to 17 ft.
.SUN THROUGH MON...S wind 25 to 40 kt. Seas 15 to 23 ft.
.TUE...E wind 20 to 30 kt. Seas 14 to 19 ft.

$$

572 
FZAK61 PAFC 070034
OFFAER

Offshore Waters Forecast
National Weather Service Anchorage AK
334 PM AKST Fri Dec 6 2019

Offshore waters forecast for the Gulf of Alaska West of 144W

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.

PKZ399-071330-
334 PM AKST Fri Dec 6 2019
.SYNOPSIS FOR THE WESTERN GULF OF ALASKA...

A front tracks across the Gulf for Sat morning. A 989 mb North 
Pacific low moves along the trailing front to 59N 150W at 982 mb 
then inland for Sun morning. A 972 mb North Pacific low moves 
along the front to 50N 154W at 959 mb by Sun night.

$$

PKZ351-071330-
Gulf of Alaska Offshore North of 57N and West of 144W-
334 PM AKST Fri Dec 6 2019

.TONIGHT...SE wind up to 20 kt increasing to 15 to 25 kt after
midnight. Seas 8 ft. Rain.
.SAT...S wind 20 to 30 kt. Seas 8 to 13 ft. Rain.
.SAT NIGHT...S wind 30 kt. Seas 12 to 18 ft.
.SUN...SE wind 20 to 35 kt. Seas 10 to 18 ft.
.SUN NIGHT...SE wind 30 to 45 kt. Seas 16 to 24 ft.
.MON...SE wind 30 to 45 kt. Seas 19 to 28 ft.
.TUE THROUGH WED...E wind 15 to 30 kt. Seas 13 to 21 ft.

$$

PKZ352-071330-
Gulf of Alaska Offshore South of 57N North of 55N and West of
144W-
334 PM AKST Fri Dec 6 2019

.TONIGHT...S wind 15 to 30 kt. Seas 9 to 14 ft.
.SAT...S wind 15 to 30 kt. Seas 9 to 16 ft. Rain.
.SAT NIGHT...S wind 20 to 30 kt. Seas 14 to 20 ft.
.SUN...SE wind 30 to 45 kt. Seas 11 to 18 ft.
.SUN NIGHT...SE wind 35 to 45 kt. Seas 16 to 28 ft.
.MON THROUGH WED...SE wind 25 to 40 kt. Seas 14 to 26 ft.

$$

Southcentral and Southwest Alaska Forecast Discussion
National Weather Service Anchorage AK
400 AM AKST Thu Dec 5 2019

.ANALYSIS AND UPPER LEVELS...

An upper level shortwave ridge is in place over Southcentral. This
has led to the development of patchy fog in places. Meanwhile, a
weak low spins over the Gulf allowing offshore flow to continue
along the northern Gulf coast. Out west, a large low centered
over the northern Bering is lifting a front over Southwest Alaska,
bringing continued snow and blowing snow to areas along the
Southwest coast. Upstream of this low, an upper level ridge is in
place over the western Aleutians.

&&

.MODEL DISCUSSION...

Models are in generally good agreement through Friday afternoon.
Solutions indicate that an upper level Bering low will move
eastward by Friday night, though there are vast differences in
the track the low takes and where it is centered over the eastern
Bering by Friday night. Models also indicate that the upper level
ridge currently over Southcentral becomes more amplified as it
moves eastward over the Alcan border by Saturday afternoon, which
would potentially yield a more active pattern over Southcentral
as any developing North Pacific lows would be steered over the
southern Mainland. Overall, confidence in the forecast beyond 48
hours is below average given model inconsistencies.

&&

.AVIATION...
PANC...Conditions are once again favorable for fog/stratus. Light
overrunning snow will develop late today. Expect MVFR conditions
by the evening.

&&

.SHORT TERM FORECAST SOUTHCENTRAL ALASKA (Days 1 and 2)...
Fog over the Anchorage area should dissipate around noon as higher
clouds begin to move over the area, but the timing on this is
difficult to determine and it could clear earlier or linger into
the afternoon. Westerly flow aloft will continue over the area
into Friday afternoon. This will bring a weather front that is
currently over southwest Alaska into Southcentral tonight. This
system will be weakening as it moves across tonight into Friday
morning. Some accumulating snow is possible from the Kenai
Peninsula northward through Anchorage and the Matanuska and
Susitna Valleys, but amounts are expected to be fairly light.
Southerly flow aloft will begin to develop over the area on Friday
night, signaling the onset of a warming trend.

&&

.SHORT TERM FORECAST SOUTHWEST ALASKA (Days 1 and 2)...
Blowing snow conditions continue for southwest Alaska as a front
is pushing through. The worst conditions are along the coast where
visibilities are dropping below one mile at times. The front will
weaken through the day as it moves farther inland. A second front
will move into the area Friday and will be warm enough to bring
some rain to the coastline around Bristol Bay. Other areas around
southwest Alaska will stay primarily as snow. Similarly to the
first front, there looks to be enough wind with the second front
to bring back blowing snow to the area into Friday night.

&&

.SHORT TERM FORECAST BERING SEA/ALEUTIANS (Days 1 and 2)...
The front over the eastern Bering will keep pushing east and move
onshore today. Behind the first front a new low has spun up near
the central Aleutians. This low is bringing another front into the
area from the south. It looks to make it to the Pribilof Islands
and Alaska Peninsula by this evening and is pulling up enough warm
air to bring mostly rain to the area. Cold air will move in
behind the front transitioning rain back to snow from west to east
across the Aleutians/Bering through Friday.

&&

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

The Gulf of Alaska remains quiet until early next week, when
southerly flow and low pressure is expected to bring in gale force
winds on Monday. Confidence is moderate in this occurring. With
southerly flow we will definitely have elevated winds and waves,
but to what degree is a bit of a question. Gale force looks to be
a reasonable solution for now.

In the Bering, low pressure will be present in multiple areas. Two
lows will be present over the weekend, one in the western Bering
and the other over the Central Aleutians. Both are forecast as
gale force for now. Models are quite erratic and consistency is
poor both over time and between different models. We are confident
in low pressure producing elevated winds and waves, but exactly
where it will be windy and how strong those winds (some models
think storm force) could be is a big question. We are not
confident in the specifics. So we will need to hone this in the
next couple of days.

&&

.LONG TERM FORECAST (Days 3 through 7: Saturday through Wednesday)...

Long term analysis still points to southerly flow and considerable
warming over the weekend for Southcentral AK. These conditions
look to persist into early next week. The high amplitude ridge
responsible for this looks to form rapidly Saturday along the
ALCAN border and push all the way into the Arctic. We can also
expect low pressure embedded in this flow to bring precipitation
to coastal areas and elevate winds. However, model guidance is
continuing to be inconsistent over Southcentral, so details will
have to come in time. However, we are confident in a big warm up
- threatening our snow pack - for Southcentral this weekend.

Out west, broad low pressure is expected to be present over the
entire area. An entrenched long wave trough will have several low
pressure systems of varying intensity spin through for the
duration of the forecast period. Right now, the forecast starts
with two low pressure systems (called a double barrel low) with
one low in the western Bering and the other over the Central
Aleutians. Models are quite erratic in the long term so the
solution for low pressure will evolve, but there is enough
agreement in models to go with this for now over the weekend. Low
placement will likely change as guidance does and it should be
noted that by early next week multiple lows will be rotating in
the long wave trough and right now it's not clear where they will
be. So stay tuned...

&&

.AFC WATCHES/WARNINGS/ADVISORIES...
PUBLIC...Winter Weather Advisory...155 161.
MARINE...Gales...160, 180, 181, 185, 411, 412, 413.
FIRE WEATHER...NONE.

&&

SYNOPSIS AND MODEL DISCUSSION...KO
SOUTHCENTRAL ALASKA...BL
SOUTHWEST ALASKA/BERING SEA/ALEUTIANS...DK
MARINE/LONG TERM...BB