Gale Warning 285, NWS Anchorage, AK

034 
FZAK61 PAFC 082330
OFFAER

Offshore Waters Forecast
National Weather Service Anchorage AK
330 PM AKDT Sat Apr 8 2023

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.

PKZ399-091245-
330 PM AKDT Sat Apr 8 2023
.SYNOPSIS FOR THE WESTERN GULF OF ALASKA...
A 972 mb low at 53N 140W tracks to 56N 142W at 977 mb Sun morning. 
The low moves to 58N 148W at 987 mb Mon morning. Its front spreads 
over the Gulf and north Gulf coast through Mon morning.

$$

PKZ351-091245-
Gulf of Alaska Offshore North of 57N and West of 144W-
330 PM AKDT Sat Apr 8 2023

...GALE WARNING SUNDAY...

.TODAY...NE wind 10 to 20 kt becoming N 15 to 30 kt in the
afternoon. Seas 6 to 11 ft.
.TONIGHT...NW wind 15 to 30 kt. Seas 9 to 14 ft.
.SUN...W wind 20 to 35 kt. Seas 10 to 17 ft.
.SUN NIGHT...W wind 25 to 40 kt. Seas 10 to 17 ft.
.MON...SE wind 15 to 30 kt. Seas 7 to 12 ft.
.TUE THROUGH WED...W wind 20 to 30 kt. Seas 4 to 9 ft.

$$

PKZ352-091245-
Gulf of Alaska Offshore South of 57N North of 55N and West of
144W-
330 PM AKDT Sat Apr 8 2023

...GALE WARNING SUNDAY...

.TODAY...N wind 20 to 30 kt. Seas 8 to 13 ft.
.TONIGHT...NW wind 20 to 30 kt. Seas 11 to 16 ft.
.SUN...NW wind 25 to 35 kt. Seas 16 ft. Freezing spray W of 150W.
.SUN NIGHT...W wind 20 to 35 kt. Seas 14 to 18 ft.
.MON...NW wind 20 to 35 kt. Seas 9 to 14 ft.
.TUE THROUGH WED...W wind 15 to 30 kt. Seas 8 ft.

$$

220 
FZAK61 PAFC 091204
OFFAER

Offshore Waters Forecast
National Weather Service Anchorage AK
404 AM AKDT Sun Apr 9 2023

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.

PKZ399-100115-
404 AM AKDT Sun Apr 9 2023
.SYNOPSIS FOR THE WESTERN GULF OF ALASKA...

$$

PKZ351-100115-
Gulf of Alaska Offshore North of 57N and West of 144W-
404 AM AKDT Sun Apr 9 2023

...GALE WARNING THROUGH MONDAY...

.TODAY...NW wind 20 to 35 kt. Seas 10 to 17 ft. Freezing spray.
.TONIGHT...W wind 20 to 35 kt. Seas 10 to 18 ft. Freezing spray.
.MON...NW wind 20 to 35 kt diminishing to 20 kt in the
afternoon W of 147 W...S wind 15 to 25 kt becoming E up to 20 kt in
the afternoon E of 147 W. Seas 8 to 16 ft.
.MON NIGHT...SE wind up to 15 kt. Seas 5 to 9 ft.
.TUE...SW wind 10 to 25 kt. Seas 3 to 6 ft.
.WED THROUGH THU...W wind 10 to 25 kt. Seas 4 to 7 ft.

$$

PKZ352-100115-
Gulf of Alaska Offshore South of 57N North of 55N and West of
144W-
404 AM AKDT Sun Apr 9 2023

...GALE WARNING THROUGH MONDAY...

.TODAY...NW wind 25 to 35 kt. Seas 17 ft. Freezing spray.
.TONIGHT...W wind 20 to 35 kt. Seas 16 ft. Freezing spray.
.MON...W wind 20 to 35 kt. Seas 9 to 17 ft.
.MON NIGHT...W wind up to 20 kt. Seas 7 to 12 ft.
.TUE...SW wind 10 to 25 kt. Seas 4 to 7 ft.
.WED THROUGH THU...W wind 15 to 25 kt. Seas 7 ft.

$$

359 
FZAK61 PAFC 092250
OFFAER

Offshore Waters Forecast
National Weather Service Anchorage AK
250 PM AKDT Sun Apr 9 2023

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.

PKZ399-101345-
250 PM AKDT Sun Apr 9 2023
.SYNOPSIS FOR THE WESTERN GULF OF ALASKA...

A 980 mb low near 60N 146W moves to 59N 149W at 991 mb by Mon 
morning. It tracks to 57N 146W at 1005 mb by Mon afternoon, then 
dissipates by Tue morning. A 1006 mb low develops at 56N 156W Tue 
morning, then moves to 57N 152W at 1008 mb by Tue afternoon.

$$

PKZ351-101345-
Gulf of Alaska Offshore North of 57N and West of 144W-
250 PM AKDT Sun Apr 9 2023

...GALE WARNING THROUGH MONDAY...

.TONIGHT...W wind 20 to 35 kt. Seas 10 to 17 ft. Freezing spray.
.MON...S wind 20 to 35 kt becoming E 10 to 25 kt in the afternoon.
Seas 8 to 16 ft. Freezing spray in the morning.
.MON NIGHT...SE wind 10 to 15 kt. Seas 5 to 9 ft.
.TUE...S wind up to 20 kt. Seas 5 ft.
.TUE NIGHT...SW wind 10 to 25 kt. Seas 3 to 6 ft.
.WED THROUGH FRI...NE wind 10 to 25 kt. Seas 4 to 7 ft.

$$

PKZ352-101345-
Gulf of Alaska Offshore South of 57N North of 55N and West of
144W-
250 PM AKDT Sun Apr 9 2023

...GALE WARNING THROUGH MONDAY...

.TONIGHT...W wind 20 to 35 kt. Seas 15 ft. Freezing spray.
.MON...W wind 20 to 35 kt. Seas 10 to 16 ft. Freezing spray in the morning.
.MON NIGHT...NW wind 10 to 25 kt becoming W up to 15 kt after
midnight. Seas 6 to 11 ft.
.TUE...S wind 10 to 25 kt. Seas 4 to 7 ft.
.TUE NIGHT...W wind 15 to 25 kt. Seas 4 to 7 ft.
.WED THROUGH FRI...N wind 15 to 25 kt. Seas 6 to 9 ft.

$$

145 
FZAK61 PAFC 101141
OFFAER

Offshore Waters Forecast
National Weather Service Anchorage AK
341 AM AKDT Mon Apr 10 2023

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.

PKZ399-110030-
341 AM AKDT Mon Apr 10 2023
.SYNOPSIS FOR THE WESTERN GULF OF ALASKA...
A 990 mb low near 59N 148W moves to 57N 147W Mon evening and 
dissipates. A 1006 mb low develops at 56N 156W Tue morning and then 
moves to 58N 145W at 1005 mb Wed morning.

$$

PKZ351-110030-
Gulf of Alaska Offshore North of 57N and West of 144W-
341 AM AKDT Mon Apr 10 2023

.TODAY...W wind 15 to 30 kt becoming SE 10 to 25 kt in the
afternoon. Seas 9 to 14 ft.
.TONIGHT...S wind 10 to 20 kt. Seas 5 to 9 ft.
.TUE...S wind 10 to 20 kt. Seas 5 ft. Rain.
.TUE NIGHT...SW wind 10 to 25 kt. Seas 3 to 7 ft.
.WED...W wind 15 to 25 kt. Seas 7 ft.
.THU THROUGH FRI...E wind 15 to 30 kt. Seas 5 to 9 ft.

$$

PKZ352-110030-
Gulf of Alaska Offshore South of 57N North of 55N and West of
144W-
341 AM AKDT Mon Apr 10 2023

.TODAY...W wind 15 to 30 kt. Seas 10 to 15 ft.
.TONIGHT...W wind 10 to 25 kt. Seas 7 to 12 ft.
.TUE...S wind 10 to 25 kt. Seas 6 ft.
.TUE NIGHT...W wind 15 to 25 kt. Seas 5 to 8 ft.
.WED...W wind 25 kt. Seas 8 ft.
.THU THROUGH FRI...N wind 10 to 25 kt. Seas 8 ft.

$$

Southcentral and Southwest Alaska Forecast Discussion
National Weather Service Anchorage AK
440 PM AKDT Fri Apr 7 2023

.ANALYSIS AND UPPER LEVELS...

A large upper-level centered over Kotzebue this afternoon
continues to be the dominant weather feature across the state.
This is the feature responsible for the polar airmass in place
over much of state with temperatures remaining well below normal
for this time of year.

Two shortwaves moving from the Bering southward over the
Aleutians are acting to reinforce the cold air advection over the
Aleutian and Pribilof Islands. A compact surface low just west of
Saint George Island is producing and area of snow and easterly
winds for the Pribilofs this afternoon. Snow is also falling from
Unalaska to Cold Bay due to the unstable airmass in the wake of a
second surface low now south of Unimak Island.

To the east, a weak wave lifting to the Southcentral coast,
coupled with a light easterly flow aloft, is producing a few
scattered showers around Prince William Sound and over the coastal
mountains. Elsewhere across Southcentral, it is generally clear
and cold with scattered high clouds.

&&

.MODEL DISCUSSION...

Models have shifted in their solutions with respect to the
interaction between a shortwave diving south from the polar low
and a second wave lifting north-northwest from the eastern Gulf of
Alaska. Guidance is shifting the trough over the eastern Gulf
farther to the east and keeping the best vorticity advection east
of Prince William Sound with minimal interaction with the digging
wave to the west as it strengthens and becomes negatively titled.

At the surface, this translates to a more elongated inverted
trough just clipping the eastern Kenai Peninsula before sliding
southwest toward the Barren Islands. The result is twofold. First,
the farther east solution delays the onset of the steadier snow
for the Kenai Peninsula, Anchorage Bowl, and Matanuska Valley by
as much as six hours, with the 12z and 18z NAM and 18z hi-res
models the slowest. The best lift and instability along the
trough is also farther east over western Prince William Sound.
This solution could potentially lower expected snow amounts for
areas west of the Chugach and Kenai Mountains.

While the most recent NAM and hi-res model runs are indicating
this eastward shift, the GEM and EC continue to be a bit faster
and farther west, a good middle ground to the 12z GFS, which has
become the outlier with more west solution and the only model now
spinning up a consolidated low over the north-central Gulf by
Sunday afternoon.

Given this slower, more eastward trend, pinning down snow amounts
has gotten a little more challenging, especially with less
confidence in the overall forecast. Still, there is the potential
for several inches of snow with this system due to models still
keying in on decent moisture advection, cold air advection over
the interior, and a north to northeasterly flow ahead of the
trough over the Anchorage Bowl and Kenai Peninsula.

&&

.AVIATION...
PANC...VFR conditions and light northerly winds are expected to
persist through the TAF period. Ceilings lowering to around 5,000
ft are possible for Saturday morning.

&&

.SHORT TERM FORECAST SOUTHCENTRAL ALASKA (Days 1 through 3:
Tonight through Monday morning)...

An unsettled weather pattern remains forecast across Southcentral
over the weekend into next week. A polar low located over the
Seward Peninsula will help to push an unseasonably colder air mass
into Southcentral from the Western Alaska Range Saturday into
Sunday. On the leading edge of the colder air mass a shortwave
trough will move across the Alaska Peninsula and begin to interact
with a secondary area of low pressure located over the eastern
Gulf of Alaska late Saturday. This latter low is expected to be
drawn northwestward along the Gulf coast through Sunday morning,
eventually stalling just south of the Kenai Peninsula Sunday
night. Whew! Ultimately, this should result in increasing snow
chances from Whittier, westward, into the Anchorage Bowl Saturday
night through Sunday night. General forecast amounts of 2 to 4
inches of snow are expected from Anchorage, northward into the
Mat-Su, with the higher amounts, potentially greater than 4
inches, confined to east Anchorage into the Upper Hillside and
into Eagle River. Higher snow amounts are forecast across Western
Prince William Sound into the eastern Turnagain Arm, where upslope
flow could lend itself to convective snow showers. Thus, amounts
could range anywhere from 6 to 10 inches over a 30 hour period
from Whittier to Girdwood. While this doesn't necessarily meet
advisory or winter storm warning criteria, travel conditions will
be poor with periods of heavy wet snow likely. Further south and
along the Seward Highway, general snow amounts of 2 to 4 inches
will be possible with snow totals tapering off with westward
extent into Soldotna.

It should be noted that forecast uncertainty has increased with
the afternoon forecast package. The timing of the Gulf low moving
south of the Kenai Peninsula and moisture pivoting from Prince
William Sound down across the Peninsula is noticeably different
amongst each forecast model. The GFS continues to be the fastest
solution with the higher amounts of snow. Meanwhile, the NAM
continues to be the slower and further east solution. Falling
somewhere in the middle are the Canadian and ECMWF forecast
models. In a surprise move, afternoon hi-res guidance has trended
closer to the NAM. As a result, the timing of expected snow has
shifted from a Saturday night/Sunday morning event, to more of a
Sunday event instead. This also poses additional uncertainties
with daytime heating potentially reducing accumulations on the
ground.

A temporary reprieve in precipitation may develop by early Monday
before yet another low pressure system brings renewed snow
chances into Southcentral early next week.

&&

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

A deep upper-level low centered over Kotzebue Sound will remain
nearly stationary through the weekend, keeping a cold air mass and
weak high pressure near the surface in place across Southwest
Alaska. Light, northwesterly flow will draw cold Arctic air across
the region, allowing temperatures to cool to near or below zero
for most locations under mostly clear skies. Some portions of the
Lower Kuskokwim Valley are poised to see another night of low
temperatures 20 to 30 below zero. Near the surface, Northwesterly
winds increase this evening to 10 to 20 mph and will remain
persistent through much of the weekend. The dense, cold air
streaming across the Alaska Peninsula will lead to stronger winds
and higher gusts there, especially through bays and passes. The
coldest conditions are expected Saturday night, when the coldest
portion of the air mass surges south from the Bering Strait.
Temperatures then gradually warm for Sunday as a weak passing
trough allows warmer air from the Bering Sea to nudge northward,
though the area will remain mostly dry. Then, the axis of the
surface ridge pushes east over Southwest Alaska, allowing winds to
diminish to light and variable for Sunday night into Monday.

&&

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

Northwesterly winds and snow showers will continue across the
central and eastern Bering Sea/Aleutians through tonight as a weak
trough extends off a low in the North Pacific. The trough exits
southward tonight, allowing winds and snow showers to diminish
somewhat. This will be hampered, however, by weak meso-lows
developing over the northern Bering and crossing the Pribilof
Islands to the eastern Aleutians and Alaska Peninsula through
Saturday night. This will lead to intermittent periods of heavier
snow showers and gusty winds. Meanwhile, gusty cold winds filter
through the eastern Aleutians and Alaska Peninsula through the
weekend. A warm front pushes from the western Aleutians tonight,
where it will bring a mix of rain and snow, to the Pribilof
Islands by Sunday night, where it is likely to have weakened to
only produce light snow. A large Kamchatka low also pushes its
cold front to the western Aleutians/Bering on Sunday. The front
traverses eastward across the Bering through Monday, bringing
mostly rain to the Aleutian Chain.

&&

.LONG TERM FORECAST (Days 4 through 7: Tuesday through
Friday)...

Overall synoptic flow appears to be in relatively good agreement
for the long term. A ridge that builds across the southern Alaska
on Tuesday will be flatted by a well established polar low as it
moves through the mainland. This will pave the way for embedded
troughs to travel a more southerly track across the Gulf of
Alaska. The polar low appears to become less blocked toward the
end of the week. There is a high probability for the odds to favor
colder than normal temperatures across southern Alaska. Northerly
and offshore flow is possible as the low nudges southward and the
cold airmass points toward Southwest. Winds with cold air
advection for the last half of the week could lead to accelerated
outflow winds for the Alaska Peninsula and as far west as the
Pribilofs and the eastern Aleutians. The exact location and timing
of the polar low movement, along with interacting troughs from
the west, increases forecast uncertainty. However, the prevailing
pattern appears to be unsettled however, but the bulk of the
moisture plumes is nudging further east toward Southeast Alaska.

&&

SYNOPSIS AND MODEL DISCUSSION...TM
SOUTHCENTRAL ALASKA...BL
SOUTHWEST ALASKA/BERING SEA/ALEUTIANS...CQ
LONG TERM...VR