Gale Warning 20, NWS Anchorage, AK

261 
FZAK62 PAFC 221211
OFFALU

Offshore Waters Forecast
National Weather Service Anchorage AK
311 AM AKST Wed Jan 22 2020

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.

PKZ499-230145-
311 AM AKST Wed Jan 22 2020
.SYNOPSIS FOR CENTRAL BERING SEA...

A 960 mb low at 45N 170E moves to 46N 178E at 970 mb Wed night.
The low then moves to 51N 176E at 970 mb Thu night.

$$

PKZ411-230145-
Bering Sea Offshore West of 180 and East of the International
Dateline-
311 AM AKST Wed Jan 22 2020

...GALE WARNING TONIGHT AND THURSDAY...

.TODAY...SE wind 10 to 20 kt increasing to 15 to 30 kt in the
afternoon. Seas 5 to 10 ft.
.TONIGHT...E wind 20 to 35 kt. Seas 9 to 17 ft. Snow.
.THU...E wind 30 to 45 kt. Seas 16 to 24 ft. Snow.
.THU NIGHT...E wind 35 to 50 kt. Seas 21 to 32 ft.
.FRI THROUGH SAT...E wind 30 to 45 kt. Seas 19 to 33 ft.
.SUN...E wind 35 kt. Seas 14 to 19 ft.

$$

PKZ412-230145-
Bering Sea Offshore 171W to 180 and North of 56N-
311 AM AKST Wed Jan 22 2020

...GALE WARNING THURSDAY...

.TODAY...S wind 10 to 15 kt. Seas 6 ft. Freezing spray.
.TONIGHT...E wind 15 to 30 kt. Seas 4 to 9 ft. Freezing spray.
.THU...E wind 25 to 40 kt. Seas 8 to 16 ft. Freezing spray.
.THU NIGHT...E wind 30 to 45 kt. Seas 13 to 21 ft.
.FRI THROUGH SAT...E wind 30 to 45 kt. Seas 15 to 23 ft.
.SUN...NE wind 35 kt. Seas 10 to 16 ft.

$$

PKZ413-230145-
Bering Sea Offshore 171W to 180 and South of 56N-
311 AM AKST Wed Jan 22 2020

...GALE WARNING TONIGHT AND THURSDAY...

.TODAY...E wind 10 to 20 kt increasing to 15 to 30 kt in the
afternoon. Seas 6 ft.
.TONIGHT...E wind 20 to 35 kt increasing to 30 to 40 kt after
midnight. Seas 8 to 13 ft.
.THU...E wind 35 to 45 kt. Seas 13 to 21 ft.
.THU NIGHT...E wind 40 to 50 kt. Seas 16 to 28 ft.
.FRI THROUGH SAT...E wind 30 to 45 kt. Seas 14 to 27 ft.
.SUN...E wind 35 kt. Seas 14 ft.

$$

PKZ414-230145-
Bering Sea Offshore East of 171W-
311 AM AKST Wed Jan 22 2020

.TODAY...NE wind 10 to 15 kt. Seas 3 to 6 ft.
.TONIGHT...E wind up to 20 kt increasing to 15 to 30 kt after
midnight. Seas 3 to 7 ft. Freezing spray.
.THU...NE wind 15 to 30 kt. Seas 3 to 8 ft. Freezing spray.
.THU NIGHT...NE wind 20 to 35 kt. Seas 6 to 11 ft.
.FRI THROUGH SUN...NE wind 25 to 35 kt. Seas 8 to 13 ft.

$$

212 
FZAK62 PAFC 230010
OFFALU

Offshore Waters Forecast
National Weather Service Anchorage AK
310 PM AKST Wed Jan 22 2020

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.

PKZ499-231415-
310 PM AKST Wed Jan 22 2020
.SYNOPSIS FOR CENTRAL BERING SEA...

A 964 mb low at 46N 174E moves to 50N 175E at 968 mb by Thu 
afternoon. This low then moves to 50N 174E at 968 mb Fri 
afternoon. High pressure builds over the eastern Bering through
Fri afternoon.

$$

PKZ411-231415-
Bering Sea Offshore West of 180 and East of the International
Dateline-
310 PM AKST Wed Jan 22 2020

...GALE WARNING THROUGH THURSDAY NIGHT...

.TONIGHT...E wind 20 to 35 kt. Seas 9 to 17 ft.
.THU...E wind 30 to 45 kt. Seas 15 to 23 ft. Widespread rain
showers.
.THU NIGHT...E wind 45 kt. Seas 21 to 32 ft. Widespread snow and
rain showers.
.FRI...E wind 35 to 50 kt. Seas 24 to 33 ft.
.FRI NIGHT...E wind 30 to 45 kt. Seas 20 to 31 ft.
.SAT...E wind 30 to 45 kt. Seas 18 to 28 ft.
.SUN THROUGH MON...E wind 35 kt. Seas 12 to 19 ft.

$$

PKZ412-231415-
Bering Sea Offshore 171W to 180 and North of 56N-
310 PM AKST Wed Jan 22 2020

...GALE WARNING THURSDAY AND THURSDAY NIGHT...
...HEAVY FREEZING SPRAY WARNING THURSDAY NIGHT...

.TONIGHT...E wind 15 to 30 kt. Seas 4 to 9 ft. Freezing spray.
.THU...E wind 25 to 40 kt. Seas 8 to 16 ft. Freezing spray.
.THU NIGHT...E wind 30 to 45 kt. Seas 14 to 22 ft. Heavy freezing 
spray E of 174W.
.FRI...E wind 30 to 45 kt. Seas 16 to 24 ft.
.FRI NIGHT...E wind 30 to 45 kt. Seas 15 to 23 ft.
.SAT THROUGH SUN...NE wind 30 to 40 kt. Seas 12 to 20 ft.
.MON...NE wind 30 kt. Seas 9 to 12 ft.

$$

PKZ413-231415-
Bering Sea Offshore 171W to 180 and South of 56N-
310 PM AKST Wed Jan 22 2020

...STORM WARNING THURSDAY NIGHT...

.TONIGHT...E wind 25 to 40 kt. Seas 8 to 13 ft.
.THU...E wind 30 to 45 kt. Seas 13 to 21 ft.
.THU NIGHT...E wind 40 to 50 kt. Seas 16 to 28 ft. Rain.
.FRI...E wind 30 to 45 kt. Seas 16 to 28 ft.
.FRI NIGHT...E wind 30 to 45 kt. Seas 15 to 23 ft.
.SAT THROUGH MON...NE wind 25 to 40 kt. Seas 14 to 22 ft.

$$

PKZ414-231415-
Bering Sea Offshore East of 171W-
310 PM AKST Wed Jan 22 2020

...GALE WARNING THURSDAY NIGHT...
...HEAVY FREEZING SPRAY WARNING THURSDAY NIGHT...

.TONIGHT...N wind up to 15 kt becoming NE 10 to 25 kt after
midnight. Seas 4 ft. Freezing spray.
.THU...NE wind 15 to 30 kt. Seas 4 to 8 ft. Freezing spray.
.THU NIGHT...NE wind 20 to 35 kt. Seas 6 to 11 ft. Heavy freezing
spray.
.FRI...NE wind 25 to 35 kt. Seas 7 to 12 ft.
.FRI NIGHT...NE wind 20 to 30 kt. Seas 7 to 12 ft.
.SAT THROUGH MON...N wind 20 to 30 kt. Seas 8 to 13 ft.

$$

812 
FZAK62 PAFC 231237
OFFALU

Offshore Waters Forecast
National Weather Service Anchorage AK
337 AM AKST Thu Jan 23 2020

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.

PKZ499-240200-
337 AM AKST Thu Jan 23 2020
.SYNOPSIS FOR CENTRAL BERING SEA...

A 969 mb low at 46N 178E Thu morning moves to 50N 174E Fri 
morning at 965 mb, then moves to 54N 168E Sat morning at 970 mb. 
A front moves into the western Aleutians near Shemya and the Rat 
Islands by Friday morning, then moves the western Bering to near 
Atka Sat morning.

$$

PKZ411-240200-
Bering Sea Offshore West of 180 and East of the International
Dateline-
337 AM AKST Thu Jan 23 2020

...STORM WARNING TONIGHT...

.TODAY...E wind 30 to 45 kt. Seas 14 to 26 ft. Snow showers.
.TONIGHT...E wind 35 to 50 kt. Seas 21 to 33 ft. Snow and rain
showers.
.FRI...E wind 30 to 45 kt. Seas 24 to 33 ft. Snow and rain showers.
.FRI NIGHT...E wind 35 to 45 kt. Seas 20 to 31 ft.
.SAT THROUGH MON...NE wind 30 to 45 kt. Seas 15 to 28 ft.

$$

PKZ412-240200-
Bering Sea Offshore 171W to 180 and North of 56N-
337 AM AKST Thu Jan 23 2020

...GALE WARNING THROUGH FRIDAY...

.TODAY...E wind 25 to 40 kt. Seas 8 to 16 ft. Freezing spray.
.TONIGHT...E wind 30 to 45 kt. Seas 14 to 22 ft. Freezing spray.
.FRI...E wind 30 to 45 kt. Seas 16 to 24 ft. Freezing spray.
.FRI NIGHT...E wind 30 to 40 kt. Seas 15 to 23 ft.
.SAT THROUGH MON...NE wind 30 to 40 kt. Seas 12 to 20 ft.

$$

PKZ413-240200-
Bering Sea Offshore 171W to 180 and South of 56N-
337 AM AKST Thu Jan 23 2020

...STORM WARNING TONIGHT...

.TODAY...E wind 30 to 45 kt. Seas 14 to 22 ft.
.TONIGHT...E wind 35 to 50 kt. Seas 16 to 29 ft.
.FRI...E wind 30 to 45 kt. Seas 15 to 27 ft. Rain showers and snow
showers.
.FRI NIGHT...E wind 30 to 40 kt. Seas 14 to 22 ft.
.SAT THROUGH MON...NE wind 25 to 40 kt. Seas 14 to 22 ft.

$$

PKZ414-240200-
Bering Sea Offshore East of 171W-
337 AM AKST Thu Jan 23 2020

...GALE WARNING TONIGHT...
...HEAVY FREEZING SPRAY WARNING THROUGH FRIDAY...

.TODAY...NE wind 15 to 30 kt. Seas 4 to 8 ft. Heavy freezing spray.
.TONIGHT...NE wind 20 to 35 kt. Seas 6 to 11 ft. Heavy freezing
spray.
.FRI...NE wind 30 kt. Seas 7 to 12 ft. Heavy freezing spray.
.FRI NIGHT...NE wind 20 to 30 kt. Seas 7 to 12 ft.
.SAT THROUGH MON...N wind 20 to 30 kt. Seas 8 to 13 ft.

$$

Southcentral and Southwest Alaska Forecast Discussion
National Weather Service Anchorage AK
357 AM AKST Tue Jan 21 2020

.ANALYSIS AND UPPER LEVELS...

A mainly zonal flow aloft extends from the Bering into southwest
Alaska this morning, turning more southwesterly for Southcentral.
Closer to the surface, infra-red satellite imagery shows a low
moving ashore across eastern Prince William Sound, with a pair of
meso (small scale) lows near the southern tip of Kodiak Island, and
also near Saint Matthew Island. Showery type precipitation is seen
in various data sets with all of these features, with the nighttime
microphysics imagery showing low stratus and/or fog hanging just
west of Anchorage in the Cook Inlet, and also across portions of the
Copper Basin and Bristol Bay regions.

&&

.MODEL DISCUSSION...

The models remain in good agreement through Friday evening,
before some differences begin to show up. Even then, they remain
in fairly decent agreement aloft with the overall theme of the
synoptic features. The main differences lie with regard to where
the center of a very deep mid-level low sets up. This occurs as
high amplitude negatively tilted ridging develops from the tip of
the Alaska Peninsula to the Pribilof islands. A disturbance riding
the top of the ridge dives into south central or southwest Alaska,
allowing for a 490-492 dm low to develop, as very cold air dives
south.

Initially, all models agree on this developing just south of
Seward. As the pattern amplifies due to shortwave energy diving
into the base of the trough on Monday, the low repositions to
either Shelikof Straight (European), central Bristol Bay (GFS), or
north of King Salmon (Canadian Global). This dictates who gets the
coldest of the air as 850 mb temps are projected to be around -26
deg. C. These are similar values, with a similar setup, to what
was seen across southwest Alaska around New Year's Eve, when wind
chills pushed or exceeded -40 deg. F. This is also a pattern where
several rounds of cyclogenesis (low pressure development) would
occur in the Gulf of Alaska, probably just south of Prince William
Sound. Should this occur, snowfall potential would increase for
Southcentral.

&&

.AVIATION...

PANC...Stratus clouds seen on satellite imagery, likely around
1500 feet, continues to lurk just west of the airfield. Model
guidance has been split on whether this will make it into the
terminal. For now, plan to cover this with a tempo group and see
how things unfold. Light winds will prevail through the period.

&&

.SHORT TERM FORECAST SOUTHCENTRAL ALASKA (Days 1 and 2)...
An upper level short wave trough will slide across Southcentral
from southwest to northeast today. Some showers and considerable
clouds will linger over the area. Tonight through Wednesday night
a long wave trough will slowly dig into southern Alaska. This will
bring increasing offshore winds and usher in a drier air mass.
Some showers could still occur in the Copper River Basin and along
the coast from Prince William Sound eastward. Temperatures should
also start to cool on Wednesday and Wednesday night as the long wave
trough slowly slides east into Southcentral.

&&

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

Snow showers continue to linger across the Kuskokwim Delta area
this morning. While showers will eventually taper off, lingering
moisture in the area will keep low level stratus and patchy fog
around through Tuesday morning. By midweek, a broad upper level
trough arrives over Southwest. This will initiate a plunge in
temperatures across Southwest for the rest of the week as the
trough deepens and pulls down plenty of cold Arctic air from the
northwest. With a building ridge in place over the eastern Bering
Wednesday night into early Thursday, northerly winds are expected
to increase (especially along the coast and usual gaps and passes
along the southern Alaska Peninsula) through Thursday night. This
translates into a generally clear, but cold end to the work week
for southwest Alaska.

&&

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

An unstable airmass over the Bering continues to allow for showery
conditions this morning. Scattered snow showers are expected to
continue over most of the northern Bering through early Wednesday.
The next storm arrives over the western Aleutians Wednesday
morning, bringing southeasterly gales. Snow will start initially
with a quick change to rain as warmer air moves in. As the low
lifts northward, the front spreads across the Bering through
Thursday. Expect high end gale force winds with this next system.
Storm force gusts are possible and will likely be concentrated
over the western Bering. This low will eventually move northward
as a blocking ridge remains in place over the eastern Bering
through the end of the week.

&&

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

Gulf of Alaska:

A low over the eastern Gulf Thursday will turn westward and move
to near Middleton Island by Friday morning. The low will stall out
and remain nearly stationary through Saturday morning, then
dissipate or get absorbed into a new low moving into the eastern
Gulf Saturday evening. This will keep gales ongoing continuously
across the Barren Islands and through bays and passes southwest
of Kodiak Island through Friday. The gales may weaken to small
craft winds on Saturday, depending on where the low is at that
point and where the next low moves into the eastern Gulf.
Significant forecast uncertainty persists on Saturday.

Bering Sea and Aleutians:

A strong and nearly stationary low centered south of the western
Aleutians will keep widespread gales with occasional embedded
storms ongoing across the central and western Bering through
Friday. Seas of 20 to 35 ft are expected over a large area of the
central and western Bering and Aleutians through Friday night. By
Saturday the low will move to near Kamchatka, which will result
in gradually diminishing winds over the western Bering on
Saturday. Strengthening high pressure over the eastern Bering will
cause gale force offshore winds to develop Friday night through
Saturday from the Southwest Alaska coast. The gales will extend
south through the bays and passes of the Alaska Peninsula and
eastern Aleutians by Saturday evening.

&&

.LONG TERM FORECAST (Days 3 through 7: Thursday through Monday)...

The stagnant weather pattern intensifying on Thursday will persist
through the weekend, and potentially last even longer. A strong
and nearly stationary low centered south of the western Aleutians
will keep gale force winds and rain ongoing across the central and
western Aleutians through at least Friday night. On Saturday, the
low moves off to the Kamchatka Peninsula, but another North
Pacific low may move in to the same area to replace the old one
into Monday. There is significant model uncertainty about where
the new low tracks, however.

Meanwhile, across the eastern Bering and mainland Alaska, high
pressure will strengthen with time through at least Saturday.
After that there is some model disagreement as to how quickly the
high pressure moves westward into the Bering. The GFS is much
faster moving the high westward than the foreign models. Either
way, the high will support increasingly cold air flooding
southward on strong winds across Southwest Alaska, the eastern
Bering, and the gaps and passes of Southcentral from Saturday
through Monday. This will be a favorable pattern for another round
of wind chill hazards in these same areas.

Across the Gulf, the weather will remain unsettled as a low over
the eastern Gulf on Thursday moves to near Middleton Island on
Friday morning, then parks itself there and spins moisture, very
likely in the form of snow given the cold air around, into
coastal areas. Since the low will be relatively weak and hardly
moving, any snow that falls is not expected to become heavy, but
it looks to persist in some areas through Saturday. There is
considerable uncertainty on who gets what amount of snow and when,
so stay tuned for future forecast updates. By Monday, with the
high gradually drifting west over the Bering, the storm track may
begin to shift westward along with it into the Gulf and
Southcentral, which, if it occurs, would bring back more
seasonably cold temperatures, and much greater threats for snow
into Southcentral.

&&

.AFC WATCHES/WARNINGS/ADVISORIES...
PUBLIC...NONE.
MARINE...Heavy Freezing Spray Warning 160 185
         Gale Warning 176 177 178
FIRE WEATHER...NONE.

&&

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