Gale Warning 682, NWS Anchorage, AK

900 
FZAK62 PAFC 240038
OFFALU

Offshore Waters Forecast
National Weather Service Anchorage AK
338 PM AKST Wed Nov 23 2022

Offshore Waters Forecast for the Bering Sea

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.

PKZ499-241415-
338 PM AKST Wed Nov 23 2022
.SYNOPSIS FOR CENTRAL BERING SEA...

A 989 mb North Kamchatka low moves to 65N 163W at 1004 mb by Fri 
afternoon. Its front enters Western Alaska for Thu afternoon. 
Several strong lows track across South of the Aleutians through 
Fri afternoon. High pressure moves over the Central Aleutians and 
Bering by Fri afternoon.

$$

PKZ411-241415-
Bering Sea Offshore West of 180 and East of the International
Dateline-
338 PM AKST Wed Nov 23 2022

.TONIGHT...W wind 15 to 30 kt. Seas 11 to 17 ft.
.THU...W wind 15 to 30 kt. Seas 10 to 16 ft.
.THU NIGHT...W wind 10 to 25 kt. Seas 10 to 13 ft.
.FRI...SW wind up to 20 kt. Seas 9 to 12 ft.
.FRI NIGHT...SE wind 15 to 30 kt. Seas 9 ft.
.SAT...E wind 20 to 35 kt. Seas 10 to 18 ft.
.SUN THROUGH MON...S wind 10 to 25 kt. Seas 9 to 14 ft.

$$

PKZ412-241415-
Bering Sea Offshore 171W to 180 and North of 56N-
338 PM AKST Wed Nov 23 2022

.TONIGHT...W wind 20 to 30 kt. Seas 11 to 15 ft.
.THU...W wind 20 to 30 kt. Seas 12 to 16 ft.
.THU NIGHT...W wind 20 to 30 kt. Seas 12 to 16 ft.
.FRI...W wind 15 to 30 kt. Seas 11 to 16 ft.
.FRI NIGHT...S wind up to 20 kt. Seas 7 to 12 ft.
.SAT...E wind 15 to 30 kt. Seas 9 to 17 ft.
.SUN...SE wind 10 to 25 kt. Seas 10 to 17 ft.
.MON...S wind 10 to 20 kt. Seas 6 to 10 ft.

$$

PKZ413-241415-
Bering Sea Offshore 171W to 180 and South of 56N-
338 PM AKST Wed Nov 23 2022

.TONIGHT...W wind 15 to 30 kt. Seas 11 to 17 ft. Widespread rain
showers.
.THU...W wind 10 to 20 kt. Seas 10 to 13 ft.
.THU NIGHT...W wind 10 to 20 kt. Seas 8 to 12 ft.
.FRI...NW wind up to 20 kt. Seas 8 to 12 ft.
.FRI NIGHT...E wind 15 to 30 kt. Seas 7 to 10 ft.
.SAT...E wind 20 to 35 kt. Seas 9 to 17 ft.
.SUN THROUGH MON...S wind 10 to 20 kt. Seas 6 to 11 ft.

$$

PKZ414-241415-
Bering Sea Offshore East of 171W-
338 PM AKST Wed Nov 23 2022

.TONIGHT...SW wind 15 to 30 kt. Seas 8 to 13 ft. Rain showers.
.THU...W wind 10 to 20 kt. Seas 9 to 13 ft.
.THU NIGHT...W wind 15 to 25 kt. Seas 9 to 12 ft.
.FRI...W wind 15 to 30 kt. Seas 10 to 14 ft.
.FRI NIGHT...NW wind 10 to 25 kt. Seas 8 to 13 ft.
.SAT...E wind 15 to 30 kt. Seas 5 to 10 ft.
.SUN THROUGH MON...S wind 10 to 25 kt. Seas 6 to 11 ft.

$$

Southcentral and Southwest Alaska Forecast Discussion
National Weather Service Anchorage AK
436 PM AKST Tue Nov 22 2022

.ANALYSIS AND UPPER LEVELS...

A strong negatively tilted short-wave trough along the Southwest
Alaska coast and down across the Alaska Peninsula is progressing
north and east toward interior Southwest Alaska and Southcentral
Alaska. However, an upper level low center has closed off over
the Kuskokwim Delta and is deepening and enlarging as it moves
down the trough axis, causing the forward motion of the trough
itself to slow. Still, the approach of the trough and associated
low level cold air advection is leading to steady snow from
interior Bristol Bay into the Kuskokwim Valley and western
Alaska Range. Steady precipitation is also developing out ahead
of this across the Kenai Peninsula. Precipitation was largely in
the form of rain/freezing rain this morning, but is transitioning
to snow as colder air filters across Cook Inlet and the Kenai
Peninsula. Out ahead of this, a weak short-wave is lifting
onshore of the north Gulf coast with a weak surface low in
western Prince William Sound. As seen in radar imagery, the
atmosphere is more unstable in the Prince William Sound with
showers pushing onshore. The approach of the stronger trough is
pulling some of these showers northwestward toward the eastern
Kenai Peninsula.

Meanwhile, to the west of the Southwest Alaska trough axis,
Arctic air continues to advect southward across the eastern
Bering Sea and Alaska Peninsula. This is leading to strong gusty
northerly winds and snow showers. A strong amplifying ridge is
building upstream over the western Bering/Aleutians in response
to a deep low tracking along the Kamchatka Peninsula. A weak
short- wave and surface low is diving down the front of this
ridge toward the eastern Aleutians, with a small area of
enhanced winds and precipitation.

Lastly, a large deep low over the northeast Pacific is lifting
northward out ahead of the Southwest Alaska trough and toward
the eastern Gulf. Expect interaction of the two troughs to lead
to a new surface low, which will be the key weather feature for
Southcentral and the Gulf Wednesday-Thursday.

&&

.MODEL DISCUSSION...

Models continue to struggle with details of precipitation over
Southcentral through Wednesday morning. In particular, there are
stark differences in depiction of the northern edge of
precipitation, which will be right near Anchorage. Some models
bring showers from Prince William Sound to the Anchorage area as
early as this afternoon and continue precipitation through
tonight. Other areas much drier, with the bulk of precipitation
remaining over the Kenai Peninsula. With a negatively tilted
trough upstream, this is generally a favorable pattern to bring
some precipitation to Anchorage, so are leaning toward the wetter
models. Precipitation type also remains a challenge through
tonight, though weak cold air advection will favor a continued
trend toward snow as the predominant precipitation type.

Model guidance is also struggling with the track of a deep low
into the Gulf Wednesday and especially with its exit eastward on
Thursday. Other than winds/waves over the Gulf, the main impact
for Southcentral will be the deformation band of precipitation
north of the low center. This will definitely impact the
Cordova/Valdez/Copper River Basin areas, but there is a large
spread in how far west this band will rotate - which depends
heavily on the low track across the Gulf. With a very progressive
upper level flow setting up, prefer the solutions which kick the
low eastward quicker and keep the band of snow over Prince William
Sound and away from the Kenai Peninsula on Thursday.

Finally, there had been absolutely huge model spread with
interaction of a Bering trough and a system crossing the north
Pacific on Thursday. While there are still some key model
differences, both deterministic and ensemble guidance have
trended toward a similar idea of a fast moving low along the
Aleutians/Alaska Peninsula Thursday moving into the Gulf on
Friday. The 12Z NAM is an outlier with maintaining a weaker low
and farther south track. Will introduce to the forecast the idea
of a deeper low in the Gulf on Friday, supported by the
GFS/EC/Canadian solutions.

&&

.AVIATION...
PANC...There is a lot of uncertainty in the precipitation forecast
for the terminal this afternoon through tonight. Overall, it does
look favorable for periods of showers, but it is very difficult
to nail down timing. The taf forecast tries to highlight the most
likely windows for showers and the resultant impact to
ceiling/vis. As is the nature of convective precipitation, there
likely will be a lot of short duration variability in both
ceiling/vis. The atmosphere remains right on the edge of
rain/snow, but expect very gradual cooling with increasing
confidence that any precipitation that does fall will become all
snow by sometime this evening. Assuming it does fall as snow,
there will be periods of MVFR, with a chance of brief periods of
IFR if heavier showers move through. Conditions will quickly
improve Wednesday morning as northerly flow develops in response
to a deep low tracking into the Gulf from the Pacific.

&&

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

An upper level low dives south across the Alaska Peninsula
tonight, bringing cooler temperatures and increased snow chances
through tomorrow morning. Cold air has been a bit slower to move
east across Kenai Peninsula and Anchorage than expected, so we're
seeing rain and a bit of a delay in the transition to snow.
However, as temperatures cool into tonight and showers move west
from Prince William Sound and the Northern Gulf, we'll likely see
accumulating snow for the Western Kenai Peninsula and perhaps for
Anchorage. There's still uncertainty given the hit-or-miss nature
of these showers and models' struggle to represent them. For now,
it looks like Western Kenai Peninsula could receive up to about 3
inches of snow. With models coming into better agreement that
showers will barely reach South Anchorage, it seems likely that
snow amounts (if any were to occur) would likely remain an inch or
lower.

By Wednesday, a strong surface low moves north into the Gulf of
Alaska. Considerable model disagreements remain, but there is
consensus that the central pressure for this system will drop
below 970 mb. Given the low's strength, strong and gusty outflow
winds are expected from Wednesday night through Thursday morning.
The location to watch will be Thompson Pass as we head into
Thursday morning; a snow band moving east to west around the Gulf
low could lead to blowing snow through Thompson Pass. For now, the
worst of the winds look to diminish by the time snow arrives.
Another concern will be snow amounts across the Copper River
Basin, and whether the snow band will make it far enough west to
impact Kenai Peninsula. Given model disagreements at the synoptic
scale, potential snow amounts are still being refined, and the
potential threat is still being assessed.

As we head into Friday, a North Pacific low will swing across the
Alaska Peninsula and into the Gulf of Alaska. Expect strong
outflow winds through the Western Gulf. Given the quick-moving
nature of this system, overall precipitation amounts with this
feature are not expected to be a concern.

&&

.SHORT TERM FORECAST SOUTHWEST ALASKA (Days 1 through 3: Today
through Friday afternoon)...

An upper low continues to track southward near Bristol Bay. Gusty
northwesterly surface flow on its backside is leading to bands of
snow along the coast. These will gradually taper off from north
to south overnight into Wednesday morning as the low departs.
Brief periods of blowing snow reducing visibility are also
possible. Light snow is likewise seen across interior regions
associated with a weak low currently moving over the Kenai
Peninsula. This is also expected to mostly end by Wednesday
morning. A ridge will bring clearer and drier conditions for much
of Wednesday afternoon through early Thursday morning and may lead
to morning low temperatures at or below zero over the Middle
Kuskokwim Valley.

A front will track across the Kuskokwim Delta on Thursday.
Moderate precipitation is also expected Thursday into Friday for
the Bristol Bay area north of a low. Southwesterly flow both aloft
and at the surface looks to keep the latter precipitation as a
mix or all rain until Friday morning, changing to snow as the flow
switches to northwesterly. Precipitation to the north looks to
remain all snow for the duration of the event with cooler
temperatures. Exact timing and amounts remain somewhat uncertain,
however overall confidence in this general solution is growing.

&&

.SHORT TERM FORECAST BERING SEA/ALEUTIANS (Days 1 through 3: Today
through Friday afternoon)...

Northwesterly flow will continue to bring widespread ocean-effect
snow showers to much of the Aleutians through Wednesday afternoon.
A weak ridge will lead to a brief lull Wednesday evening before a
North Pacific low begins to approach the Chain by Thursday.
Agreement is improving with regards to the low center remaining
south of the Aleutians. In any case, widespread precipitation and
gusty southerly winds will move west to east through Thursday.
Much of this is expected to remain as all rain. High pressure and
cooler temperatures will return for Friday, potentially bringing
more ocean-effect snow showers to the eastern Aleutians.

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

A progressive pattern is advertised through the long-term
forecast period. A trough will set up in the Gulf of Alaska and
shift eastward as a longwave ridge builds over Southcentral for
the weekend. Temperatures look to remain below average for
Southcentral with a shortwave tracking from the Bering Sea into
the Gulf late in the period. As a North Pacific low enters the
eastern Gulf and draws a strong surge of cold air across the
Aleutian Range, winds will intensify Friday night into Saturday
out of bays and passes along the western Gulf coast. As the low in
the Gulf exits east in tandem with the deepening trough aloft on
Saturday, cold, offshore flow will promote drier conditions across
southern mainland Alaska.

Out west, run-to-run consistency is low with a North Pacific low
tracking into the Bering Sea toward the end of the week. The
associated front with the aforementioned low is south to north
oriented which indicates the potential for a strong push of
warmer air and rain into the region. This gale force front will
reach the northern Bering and eastern Aleutians by Saturday and
Southwest Alaska early Sunday. With a strong southerly push of
warm air aloft, mixed precipitation, including freezing rain, will
be possible for portions of Southwest Alaska with this system as
it pushes ashore. The aforementioned low and its associated
trough aloft are then advertised to track over top of a strong
ridge into the Gulf for Sunday night. Models have been struggling
with the exact track of this feature, therefore, uncertainty
remains. However, with this track, Southcentral should stay cold
enough that any precipitation on Sunday would primarily remain
snow. As the aforementioned ridge tracks over Southcentral,
warmer air trapped under the ridge will make its way into
Southcentral for early next week, bringing unseasonable warmer
temperatures to the region.

&&

.AFC WATCHES/WARNINGS/ADVISORIES...
PUBLIC...NONE.
MARINE...Gale Warning 119 127 130 131 132 138 150 155 160
		 165 172 177 178 180 185 351 352 411.
FIRE WEATHER...NONE.

&&

SYNOPSIS AND MODEL DISCUSSION...SEB
SOUTHCENTRAL ALASKA...KC
SOUTHWEST ALASKA/BERING SEA/ALEUTIANS...AP
LONG TERM...NS