Gale Warning 667, NWS Anchorage, AK

500 
FZAK61 PAFC 080049
OFFAER

Offshore Waters Forecast
National Weather Service Anchorage AK
349 PM AKST Sat Dec 7 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.

PKZ399-081345-
349 PM AKST Sat Dec 7 2019
.SYNOPSIS FOR THE WESTERN GULF OF ALASKA...

A 978 mb low at 58N 153W moves inland Tonight. A 968 mb North 
Pacific low moves along the front into the Eastern Bering Sea
through Mon afternoon. Its front pushes to the North Gulf Coast
and Central Gulf by Mon afternoon.

$$

PKZ351-081345-
Gulf of Alaska Offshore North of 57N and West of 144W-
349 PM AKST Sat Dec 7 2019

...GALE WARNING THROUGH SUNDAY NIGHT...

.TONIGHT...S wind 25 to 35 kt becoming SW 15 to 30 kt after
midnight. Seas 14 to 22 ft.
.SUN...SE wind up to 20 kt becoming E 25 to 40 kt in the
afternoon. Seas 13 to 16 ft.
.SUN NIGHT...SE wind 30 to 45 kt. Seas 13 to 27 ft. Rain.
.MON...SE wind 30 to 45 kt. Seas 21 to 28 ft.
.MON NIGHT...S wind 15 to 30 kt. Seas 15 to 26 ft.
.TUE...SE wind 20 to 35 kt. Seas 12 to 19 ft.
.WED...E wind 30 kt. Seas 18 to 23 ft.
.THU...S wind 15 to 25 kt. Seas 13 to 18 ft.

$$

PKZ352-081345-
Gulf of Alaska Offshore South of 57N North of 55N and West of
144W-
349 PM AKST Sat Dec 7 2019

...STORM WARNING SUNDAY NIGHT...

.TONIGHT...SW wind 20 to 35 kt becoming S up to 20 kt after
midnight. Seas 15 to 22 ft.
.SUN...E wind 15 to 30 kt becoming SE 30 to 45 kt in the
afternoon. Seas 13 to 19 ft. Rain.
.SUN NIGHT...SE wind 35 to 50 kt. Seas 16 to 28 ft building to 23
to 27 ft after midnight. Rain.
.MON...S wind 30 to 45 kt. Seas 19 to 28 ft.
.MON NIGHT...S wind 15 to 30 kt. Seas 15 to 21 ft.
.TUE THROUGH THU...SW wind 20 to 35 kt. Seas 14 to 22 ft.

$$

233 
FZAK61 PAFC 081217
OFFAER

Offshore Waters Forecast
National Weather Service Anchorage AK
317 AM AKST Sun Dec 8 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.

PKZ399-090300-
317 AM AKST Sun Dec 8 2019
.SYNOPSIS FOR THE WESTERN GULF OF ALASKA...

A 977 mb North Pacific low moves to 55N 157W at 960 mb Sun night
and then moves into the Bering. Its storm force front reaches the
central Gulf Mon morning and moves to the eastern Gulf by Mon
night.

$$

PKZ351-090300-
Gulf of Alaska Offshore North of 57N and West of 144W-
317 AM AKST Sun Dec 8 2019

...GALE WARNING THROUGH MONDAY...

.TODAY...SE wind up to 20 kt becoming E 25 to 40 kt in the
afternoon. Seas 14 ft. Rain.
.TONIGHT...SE wind 30 to 45 kt. Seas 15 to 23 ft. Rain.
.MON...SE wind 30 to 45 kt. Seas 23 to 28 ft. Rain.
.MON NIGHT...S wind 25 to 40 kt. Seas 16 to 27 ft.
.TUE THROUGH WED...E wind 20 to 35 kt. Seas 15 to 23 ft.
.THU...SE wind up to 20 kt. Seas 13 to 17 ft.

$$

PKZ352-090300-
Gulf of Alaska Offshore South of 57N North of 55N and West of
144W-
317 AM AKST Sun Dec 8 2019

...STORM WARNING TONIGHT...

.TODAY...E wind 15 to 30 kt becoming SE 30 to 45 kt in the
afternoon. Seas 13 to 17 ft. Rain.
.TONIGHT...SE wind 35 to 50 kt. Seas 16 to 25 ft building to 22 to
26 ft after midnight. Rain.
.MON...S wind 30 to 45 kt becoming SW 10 to 20 kt in the
afternoon. Seas 19 to 26 ft. Rain.
.MON NIGHT...S wind 10 to 25 kt. Seas 16 to 19 ft.
.TUE THROUGH WED...E wind 20 to 35 kt. Seas 14 to 22 ft.
.THU...SW wind 10 to 25 kt. Seas 14 to 20 ft.

$$

190 
FZAK61 PAFC 090040
OFFAER

Offshore Waters Forecast
National Weather Service Anchorage AK
340 PM AKST Sun Dec 8 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.

PKZ399-091315-
340 PM AKST Sun Dec 8 2019
.SYNOPSIS FOR THE WESTERN GULF OF ALASKA...

A front across the western Gulf Sun afternoon will move over the
AKPEN Sun night. A second front will move northward across the
Gulf from Mon morning through Tue morning. 

$$

PKZ351-091315-
Gulf of Alaska Offshore North of 57N and West of 144W-
340 PM AKST Sun Dec 8 2019

...STORM WARNING THROUGH MONDAY...

.TONIGHT...SE wind 35 to 50 kt. Seas 17 to 32 ft. Rain.
.MON...SE wind 35 to 50 kt. Seas 21 to 33 ft. Rain.
.MON NIGHT...S wind 25 to 40 kt diminishing to 15 to 30 kt after
midnight. Seas 15 to 25 ft.
.TUE...SE wind 15 to 30 kt. Seas 11 to 15 ft.
.TUE NIGHT...E wind 25 to 40 kt. Seas 15 to 23 ft.
.WED...E wind 25 to 40 kt. Seas 17 to 23 ft.
.THU THROUGH FRI...S wind 10 to 25 kt. Seas 10 to 17 ft.

$$

PKZ352-091315-
Gulf of Alaska Offshore South of 57N North of 55N and West of
144W-
340 PM AKST Sun Dec 8 2019

...STORM WARNING TONIGHT...

.TONIGHT...SE wind 35 to 50 kt. Seas 20 to 33 ft. Rain.
.MON...S wind 30 to 45 kt becoming SW 15 to 25 kt in the
afternoon. Seas 20 to 29 ft. Rain.
.MON NIGHT...S wind 15 to 25 kt. Seas 17 ft.
.TUE...E wind 25 to 40 kt. Seas 13 to 16 ft.
.TUE NIGHT...E wind 25 to 40 kt. Seas 17 to 25 ft.
.WED THROUGH THU...SW wind 15 to 30 kt. Seas 14 to 22 ft.
.FRI...SW wind 15 to 25 kt. Seas 11 to 15 ft.

$$

Southcentral and Southwest Alaska Forecast Discussion
National Weather Service Anchorage AK
530 PM AKST Fri Dec 6 2019

.ANALYSIS AND UPPER LEVELS...

The first in a series of warm fronts is pressing in along the West
Coast of AK. This will start the shift across much of the
southern half of AK to a warmer and much wetter pattern. First,
the weak shortwave that clipped through Southcentral AK last night
is moving off through the Copper River Basin today. In general,
it dropped anywhere from a trace to 1 inch of fresh snow. Out
west, radar and satellite are showing the incoming snow well. Snow
and blowing snow is already reducing visibilities a s low as one
quarter mile across parts of the YK Delta. A Winter Weather
Advisory is in place to address the snow and blowing snow out
there. Meanwhile, there are signs of the warm air coming as
observations across the Bristol Bay area are showing temperatures
already into the upper 30s.

An impressive jet is helping to amplify this pattern. From west to east,
we can see the 300mb (30,000’) jet moving under the Western
Aleutians at 195 kts. This is helping to support the broad, cold
trough over the Bering Sea. Further east, we can start to see
signs of the jet strengthening over the North Pacific as
transverse banding is very evident on satellite. This jet is
currently around 115 kts. It is ushering much warmer air towards
the southern mainland and will serve to creating a strong area of
low pressure near Bristol Bay as we head into the overnight-Sat.

&&

.MODEL DISCUSSION...

Models have come into significantly better agreement in handling the
various surface low pressure centers over the next couple of
days. Generally, the American models have performed slightly
better to this point. However, there are still key differences in
the lows’ tracks and timing that will be key factors in the
sensible weather through Tue. The depth and track of the low
across Bristol Bay and the Western Capes tonight is much more
certain. The remaining area of uncertainty surrounds how much of a
coastal erosion/high surf impact this could be. Variables such as
sea ice and duration of the fetch will make this a challenging
forecast. Then for the next system moving towards Southcentral on
Sat afternoon, the NAM has recently come in much stronger and
further east. We have opted for a middle ground solution with that
feature. Then finally, the 3rd system late Sun into Mon is the
strongest. It will approach from the N Pacific into the Gulf of
AK. This is a common source region for high model uncertainty.

&&

.AVIATION...
PANC...VFR conditions should persist through the TAF period. Wind shear
will become a concern by early Sat morning. Down-inlet north
winds will hold at the surface, while southeast flow increases
aloft in response to the approaching front.

&&
.SHORT TERM FORECAST SOUTHCENTRAL ALASKA (Days 1 and 2)...

A large stream of subtropical moisture will begin to move into
the area this evening associated with strong southerly flow, east
of a low tracking across the Alaska Peninsula. Brief snow and/or
freezing rain is possible over the western Kenai Peninsula,
however it will be light and quickly change to rain as the
aforementioned southerly winds will warm surface temperatures
above freezing. Winds along Turnagain Arm are expected to peak
near 60 mph Saturday morning, but are not likely to affect the
Anchorage Bowl. As flow will have an easterly component, much of
the moisture will struggle to make it to the leeward side of the
mountains. However as the low moves over Southcentral, downsloping
will cease and snow/freezing rain is possible across Anchorage
and the southern Susitna Valley late Saturday night into Sunday
morning and temperatures briefly cool below freezing.
Precipitation will gradually end through Sunday as the system
departs to the north.

&&

.SHORT TERM FORECAST SOUTHWEST ALASKA (Days 1 and 2)...
A very active weather pattern has moved into Southwest Alaska this
afternoon and evening as a strong Pacific warm front is lifting
north across Bristol Bay and into the Kusko Delta. Heavy snow and
blowing snow is impacting the Delta and will gradually turn to
rain or pockets of freezing rain in the late evening and early
overnight. Rain has already changed over along the coast of
Bristol Bay, although heavy snow will continue over higher
elevation interior mountains. Attention quickly turns to a fast
moving but strong gale force low moving north across Bristol Bay
to north of Nunivak Island overnight through Saturday. This low
will wrap up quickly and impact coastal locations with a strong
onshore S-SW wind possibly gusting as high as 45-50 knots. Cold
air wrapping around this low will likely result in a return to a
mix of rain and snow, but given the onshore flow off the warm
waters, no blowing snow is anticipated. A second area of enhanced
precipitation will develop across the Alaska Range Saturday and
Saturday night, bringing accumulating snow to that region and
locations near the Alaska Range. Yet another low barrels into the
Alaska Peninsula Sun eve, but the bulk of this system come
overnight and Monday (see extended discussion).

&&

.SHORT TERM FORECAST BERING SEA/ALEUTIANS (Days 1 and 2)...

A strong Pacific gale force warm front has reached the Southwest
coast with a secondary trailing low moving north in between
Dutch Harbor and Cold Bay, which will then quickly move into
Bristol Bay and track toward the Strait through the day Saturday.
This low will reach brief storm force over the marine waters south
of the Eastern Aleutians/AKPEN, but will likely remain a powerful
gale force low as it tracks along the coast as it moves northward.
Thereafter, a series of weaker and smaller lows will move across
the Western/Central Aleutians as broad cyclonic flow remains over
the Bering Sea. Yet another low barrels into the Alaska Peninsula
Sun eve, but the bulk of this system come overnight and Monday
(see extended discussion).

&&

.MARINE (Days 3 through 5)...
Monday there is a potent low near Bristol Bay which has the
potential to produce gale force winds and also produce light to
heavy freezing spray near Nunivak Island. A second low which will
be south of Adak also has the potential for producing small craft
to gale force winds. As time elapses, the Bristol Bay low
retrogrades towards NE Russia and the Adak low moves towards
Kodiak and phases with another low. Expect the gusty winds and
enhanced sea states to move into the Gulf Of Alaska. With this
cold pattern in place, expect the sea ice to grow for both the
Kuskokwim Delta and Bristol Bay.

&&

.LONG TERM FORECAST (Days 3 through 7)...

The vagaries of the models continue to influence the confidence
level in the long term forecast period. Looking at both
deterministic and ensemble guidance categorically the confidence
level is below average. There are a few items that can be
gleaned. Expect a highly progressive pattern with the longwave
pattern to retain residence over the Bering and the north Pacific.
There are multiple lows from Kamchatka to the southcentral Alaska
this forecast period. Although for the Bering and the NW Pacific
the placement and the intensities of the lows are not in sync.
The storm that will impact southcentral this weekend will break
the cold snap with temperatures in the Anchorage Metro Area
possibly getting back up into the 40s this Sunday. Also noteworthy
and very plausible, the GFS at this time is suggesting an
atmospheric river will move into southcentral on Monday.

&&

.AFC WATCHES/WARNINGS/ADVISORIES...
PUBLIC...WSW 155.
MARINE...Storm 155. Gales 119 125 130 139 150 160 165 170 172 177 178
                          180 181 185 414.
FIRE WEATHER...NONE.

&&

SYNOPSIS AND MODEL DISCUSSION...MO
SOUTHCENTRAL ALASKA...AP
SOUTHWEST ALASKA/BERING SEA/ALEUTIANS...JA
MARINE/LONG TERM...PS