Gale Warning 788, NWS Anchorage, AK

976 
FZAK62 PAFC 271256
OFFALU

OFFSHORE WATERS FORECAST
NATIONAL WEATHER SERVICE ANCHORAGE AK
356 AM AKST TUE DEC 27 2016

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.

PKZ499-280145-
356 AM AKST TUE DEC 27 2016
.SYNOPSIS FOR CENTRAL BERING SEA...
A 985 MB LOW NEAR 57N 164W MOVES OVER THE ALASKA PENINSULA THIS
AFTERNOON. A FRONT IN THE WESTERN ALEUTIANS MOVES INTO THE
CENTRAL BERING LATE TONIGHT AND EASTERN BERING THROUGH WED NIGHT.
THE ASSOCIATED 991 MB NORTH PACIFIC LOW MOVES TO 54N 168E AT 970
MB TONIGHT...THEN MOVES INLAND OVER EASTERN RUSSIAN WED EVENING AT
945 MB. 

BOGOSLOF VOLCANO LOCATED NEAR 53.9N 168.0W REMAINS ACTIVE.

$$

PKZ411-280145-
BERING SEA OFFSHORE WEST OF 180 AND EAST OF THE INTERNATIONAL
DATELINE-
356 AM AKST TUE DEC 27 2016

...STORM WARNING WEDNESDAY...

.TODAY...NW WIND 10 TO 25 KT BECOMING S 20 TO 35 KT IN THE
AFTERNOON. SEAS 8 TO 15 FT.
.TONIGHT...S WIND 30 TO 45 KT. SEAS 9 TO 17 FT BUILDING TO 15 TO
23 FT AFTER MIDNIGHT. RAIN AND SNOW.
.WED...S WIND 35 TO 50 KT. SEAS 17 TO 32 FT BUILDING TO 27 TO 35
FT IN THE AFTERNOON. RAIN.
.WED NIGHT...SW WIND 30 TO 40 KT. SEAS 22 TO 32 FT.
.THU...SW WIND 30 TO 45 KT. SEAS 20 TO 29 FT.
.FRI...S WIND 30 TO 45 KT. SEAS 20 TO 30 FT.
.SAT...SW WIND UP TO 20 KT. SEAS 10 TO 18 FT.

$$

PKZ412-280145-
BERING SEA OFFSHORE 171W TO 180 AND NORTH OF 56N-
356 AM AKST TUE DEC 27 2016

...GALE WARNING TONIGHT AND WEDNESDAY...

.TODAY...N WIND 15 TO 25 KT BECOMING NW IN THE AFTERNOON. SEAS 8
TO 17 FT.
.TONIGHT...S WIND 10 TO 25 KT BECOMING SE 20 TO 35 KT AFTER
MIDNIGHT. SEAS 7 TO 11 FT.
.WED...S WIND 30 TO 45 KT. SEAS 10 TO 18 FT BUILDING TO 15 TO 30
FT IN THE AFTERNOON. RAIN.
.WED NIGHT...SW WIND 30 TO 45 KT. SEAS 24 TO 33 FT.
.THU...W WIND 25 TO 40 KT. SEAS 22 TO 29 FT.
.FRI...S WIND 30 TO 40 KT. SEAS 19 TO 28 FT.
.SAT...SE WIND 20 TO 35 KT. SEAS 12 TO 20 FT.

$$

PKZ413-280145-
BERING SEA OFFSHORE 171W TO 180 AND SOUTH OF 56N-
356 AM AKST TUE DEC 27 2016

...STORM WARNING WEDNESDAY...

.TODAY...NW WIND 20 TO 35 KT BECOMING W 10 TO 25 KT IN THE
AFTERNOON. SEAS 11 TO 19 FT.
.TONIGHT...SW WIND 25 TO 40 KT. SEAS 11 TO 19 FT. RAIN WITH SNOW.
.WED...SW WIND 35 TO 50 KT. SEAS 13 TO 27 FT BUILDING TO 19 TO 33
FT IN THE AFTERNOON. RAIN.
.WED NIGHT...SW WIND 35 TO 50 KT. SEAS 22 TO 34 FT.
.THU...W WIND 25 TO 40 KT. SEAS 17 TO 27 FT.
.FRI THROUGH SAT...S WIND 20 TO 35 KT. SEAS 12 TO 20 FT.

$$

PKZ414-280145-
BERING SEA OFFSHORE EAST OF 171W-
356 AM AKST TUE DEC 27 2016

...GALE WARNING WEDNESDAY...

.TODAY...NW WIND 10 TO 25 KT INCREASING TO 20 TO 30 KT IN THE
AFTERNOON. SEAS 9 TO 15 FT.
.TONIGHT...W WIND 10 TO 25 KT. SEAS 8 TO 13 FT.
.WED...S WIND 15 TO 30 KT BECOMING SW 25 TO 35 KT IN THE
AFTERNOON. SEAS 9 TO 14 FT. RAIN WITH SNOW.
.WED NIGHT...SW WIND 25 TO 40 KT. SEAS 15 TO 23 FT.
.THU...SW WIND 30 TO 45 KT. SEAS 15 TO 28 FT.
.FRI...SW WIND 20 TO 35 KT. SEAS 12 TO 20 FT.
.SAT...SE WIND 30 TO 40 KT. SEAS 15 TO 21 FT.

$$

877 
FZAK62 PAFC 272338
OFFALU

OFFSHORE WATERS FORECAST
NATIONAL WEATHER SERVICE ANCHORAGE AK
238 PM AKST TUE DEC 27 2016

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.

PKZ499-281400-
238 PM AKST TUE DEC 27 2016
.SYNOPSIS FOR CENTRAL BERING SEA...

A 992 MB LOW NEAR 57N 159W MOVES EAST ACROSS THE ALASKA PENINSULA
THIS EVENING. A FRONT IN THE WESTERN ALEUTIANS MOVES INTO THE
CENTRAL BERING LATE TONIGHT BEFORE MOVING INTO THE EASTERN TO
NORTHERN BERING BY WED AFTERNOON. THIS FRONT MOVES INLAND ALONG
THE SOUTHWEST ALASKA COASTLINE BY WED EVENING. THE BERING/ALEUTIANS
WILL HAVE SOUTHWESTERLY FLOW THROUGH THU EVENING. THE BOGOSLOF
VOLCANO LOCATED NEAR 53.9N 168.0W REMAINS ACTIVE.

$$

PKZ411-281400-
BERING SEA OFFSHORE WEST OF 180 AND EAST OF THE INTERNATIONAL
DATELINE-
238 PM AKST TUE DEC 27 2016

...STORM WARNING WEDNESDAY...

.TONIGHT...S WIND 30 TO 45 KT. SEAS 8 TO 16 FT BUILDING TO 16 TO
24 FT AFTER MIDNIGHT. RAIN AND SNOW.
.WED...S WIND 40 TO 55 KT. SEAS 17 TO 32 FT BUILDING TO 29 TO 35
FT IN THE AFTERNOON. RAIN.
.WED NIGHT...SW WIND 30 TO 45 KT. SEAS 23 TO 33 FT. SNOW SHOWERS.
.THU...W WIND 40 KT. SEAS 24 TO 29 FT.
.THU NIGHT...SW WIND 40 TO 55 KT. SEAS 21 TO 31 FT.
.FRI...S WIND 40 TO 55 KT. SEAS 20 TO 32 FT.
.SAT...SW WIND UP TO 20 KT. SEAS 9 TO 17 FT.
.SUN...SW WIND 25 KT. SEAS 12 TO 19 FT.

$$

PKZ412-281400-
BERING SEA OFFSHORE 171W TO 180 AND NORTH OF 56N-
238 PM AKST TUE DEC 27 2016

...STORM WARNING WEDNESDAY AND WEDNESDAY NIGHT...

.TONIGHT...S WIND 10 TO 25 KT BECOMING SE 20 TO 35 KT AFTER
MIDNIGHT. SEAS 7 TO 11 FT.
.WED...S WIND 25 TO 40 KT INCREASING TO 35 TO 50 KT IN THE
AFTERNOON. SEAS 10 TO 18 FT BUILDING TO 15 TO 30 FT IN THE
AFTERNOON. RAIN.
.WED NIGHT...SW WIND 35 TO 50 KT. SEAS 23 TO 34 FT. RAIN.
.THU...SW WIND 30 TO 40 KT. SEAS 23 TO 29 FT.
.THU NIGHT...SW WIND 30 TO 45 KT. SEAS 21 TO 29 FT.
.FRI...S WIND 35 TO 50 KT. SEAS 20 TO 30 FT.
.SAT THROUGH SUN...S WIND 20 TO 35 KT. SEAS 15 TO 23 FT.

$$

PKZ413-281400-
BERING SEA OFFSHORE 171W TO 180 AND SOUTH OF 56N-
238 PM AKST TUE DEC 27 2016

...STORM WARNING WEDNESDAY AND WEDNESDAY NIGHT...

.TONIGHT...SW WIND 20 TO 35 KT INCREASING TO 30 TO 45 KT AFTER
MIDNIGHT. SEAS 11 TO 19 FT. RAIN WITH SNOW.
.WED...SW WIND 35 TO 45 KT INCREASING TO 40 TO 55 KT IN THE
AFTERNOON. SEAS 13 TO 28 FT BUILDING TO 19 TO 34 FT IN THE
AFTERNOON. RAIN.
.WED NIGHT...SW WIND 35 TO 50 KT. SEAS 22 TO 34 FT. RAIN.
.THU...W WIND 35 KT. SEAS 18 TO 26 FT.
.THU NIGHT...SW WIND 25 TO 40 KT. SEAS 16 TO 24 FT.
.FRI THROUGH SUN...S WIND 25 TO 40 KT. SEAS 13 TO 21 FT.

$$

PKZ414-281400-
BERING SEA OFFSHORE EAST OF 171W-
238 PM AKST TUE DEC 27 2016

...GALE WARNING WEDNESDAY AND WEDNESDAY NIGHT...

.TONIGHT...W WIND 15 TO 30 KT. SEAS 8 TO 13 FT.
.WED...S WIND 15 TO 30 KT BECOMING SW 25 TO 40 KT IN THE
AFTERNOON. SEAS 9 TO 14 FT. RAIN WITH SNOW.
.WED NIGHT...SW WIND 30 TO 45 KT. SEAS 13 TO 27 FT. PATCHY FOG.
.THU...SW WIND 30 TO 45 KT. SEAS 18 TO 28 FT.
.THU NIGHT...W WIND 20 TO 35 KT. SEAS 14 TO 20 FT.
.FRI...S WIND 15 TO 30 KT. SEAS 10 TO 18 FT.
.SAT THROUGH SUN...S WIND 30 TO 40 KT. SEAS 13 TO 21 FT.

$$

Southcentral and Southwest Alaska Forecast Discussion
National Weather Service Anchorage AK
535 AM AKST Mon Dec 26 2016

.ANALYSIS AND UPPER LEVELS...
Nearly the entire state is under the influence of a broad longwave
trough that is based over the Bering Sea. Within this trough, the
remnant warm occlusion from several days ago continues to fall
apart over SW AK. Several weak lows have been able to form along
this boundary. One of these is pushing some light snow through
Bethel and the Kuskokwim Delta. The other is wreaking havoc with
the aviation forecasts in Bristol Bay. Places near the low center
or just east of it continue to see a light rain and snow mix.
Places west of it have onshore flow ushering in widespread fog.
But there is some weak cold advection along the immediate coast
that is helping to break up the fog in Dillingham and King Salmon.
This cold air might be just enough to keep the surface visibility
from dropping, but low clouds should linger through the day. The
last low we will mention has formed just north of Kodiak Island
overnight. This low will fall in behind the main upper-level wave
that is moving through South Central this morning. It will
continue to keep plenty of moisture moving into the Gulf Coast and
provide some additional lift. Therefore, the snow over portions of
the Kenai Peninsula will continue through a good portion of the
day. It is estimated that Turnagain Pass accumulated roughly 2
feet of snow from the Christmas storm. Snow for today should be
much lighter in nature and should start to wind down late today as
the low tracks towards Prince William Sound.

The last feature of interest is a vorticity max breaking off from
a strong low well up into the Arctic. This piece of energy will
play a critical role in our forecast as we go through the week.
It will be a key feature for the potential for some snow across
South Central.

&&

.MODEL DISCUSSION...
Across the west, models remain in good agreement and forecast
confidence remains moderate to high. There are some strength and
placement differences associated with the surface low near the
Kamchatka Peninsula on Tue. But these differences will have little
bearing on the sensible weather associated with the system.

In the east, the higher-resolution NAM was favored due to some
minor, yet important differences among the models. Forecast
confidence is high that a low will track along the north Gulf
Coast through the early part of the week. However, forecast
confidence is low in precipitation type (rain vs snow) and how
much will fall. Models all indicate some form of a deformation
zone setting up along the Western Kenai Peninsula this morning and
then drifting east through the day. Yet even with impressive radar
returns as of 5am, we have yet to see any precipitation reach the
ground. We will keep an eye on the radar and observations to
adjust as needed.

&&

.AVIATION...
Conditions are expected to remain VFR through the day, even if
some light snow does fall. As downsloping continues to wane
tonight, it will leave the area vulnerable to some light
precipitation wrapping around the low near Prince William Sound.
Confidence is low in the timing and intensity of tonight's snow,
but if it does get going, it won't take much to drop conditions
to MVFR.

&&

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

The steady and heavy precipitation over the eastern Kenai
Peninsula and western Prince William Sound has begun to diminish
to showers as the front falls apart and tries to push inland. Meanwhile,
the next feature taking shape in the area is a low pressure center
deepening between Kodiak Island and the Kenai Peninsula this
morning. Winds across the Kodiak area have begun to gust out of
the west, and overall flow across the region will slowly become
more offshore in nature as this low moves slowly toward Middleton
Island through tonight. The big question mark continues to be how
much precip will fall over the western Kenai Peninsula and the
Anchorage area today and tonight as the cross- barrier winds
weaken and general shower activity is allowed to spread over the
area. Things don't look too impressive at this point, but a
dusting of snow can't be ruled out in any areas. No significant
warm or cold temperature advection during the day today, so
precipitation type will continue to be a challenge along the gulf
coast locations, but the trend by this evening with any ongoing
shower activity should definitely be toward an all-snow scenario
as cold advection begins to spread in from the west.

&&

.SHORT TERM FORECAST SOUTHWEST ALASKA (Days 1 through 3)...
A broad trough currently stretches from a surface low in the
central Bering, inland across the Kuskokwim Delta and through
Southwest Alaska to another low east of the Barren Islands. With
much of Southwest Alaska in a region of relatively flat pressure
gradient and warm and moist air, fog and low clouds as well a mix
of rain and snow continue to be a forecasting challenge for
Southwest Alaska. Cooler air aloft will spread in from the
southwest during the day today associated with an upper level
trough tracking east along the Aleutians and Alaska Peninsula.
With this cooling, showers should turn to predominantly snow
this afternoon through tonight.

The pressure gradient will further flatten across Southwest Alaska
late Monday night through midday Tuesday as a weakening Bering low
tracks into southern Bristol Bay across the Alaska Peninsula.
Behind this surface low, a cold arctic trough digging south
across the Bering Strait and over the Seward Peninsula will push a
significantly colder air mass with increasing northwesterly winds
over the Kuskokwim Delta Tuesday afternoon and across the rest of
Southwest Alaska Tuesday night. This cold snap, however will be
short lived with a strong warm front reaching the Southwest Alaska
coast Wednesday afternoon and lifting inland Wednesday night.
This frontal system is warm enough that most areas along the
Kuskokwim Delta and greater Bristol Bay area will switch over to
rain quickly, however do have some concerns for precipitation
starting off as freezing rain in the sheltered inland valleys
along the Kuskokwim Valley.

&&

.SHORT TERM FORECAST BERING SEA/ALEUTIANS (Days 1 through 3)...
The broad upper level low over the Bering will shift east today
through Tuesday as a flat ridge builds in from the west across
the Aleutians. As the arctic low swings into western Alaska
Tuesday night, the ridge will continue to amplify and shift east
over the eastern Bering. A strong low will rapidly spin up over
the western Bering Tuesday night and Wednesday along a very strong
thermal gradient offshore of the Kamchatka Peninsula. This low
will send a strong warm front across the Bering Tuesday night
through Wednesday bringing widespread gales to storms and a rapid
warm up.

&&

.LONG TERM FORECAST (Days 3 through 7)...
A big pattern change with possible warmer air and rain is on the
way for much of Southern Alaska. Beginning on Tuesday night, the
upper level low pressure currently responsible for active weather
over the northern Gulf region will still be in the area, but on
it's way out to the east. Isolated to scattered showers will
linger around the Gulf, while inland areas will not see much
outside of cloud cover. Winds will remain relatively light with a
weak outflow pattern along the coast taking hold. Out west, the
instrument of pattern change will be entering the Bering. A large
deepening low pressure system will be sending a warm front from
west to east, pushing onshore the mainland Wednesday night,
starting as snow, quickly changing to rain. These events set us up
for the extended forecast.

A big pattern change is progged by the models with the
aforementioned system. It will pump up a large ridge over the
Bering Sea first, then over Southcentral Alaska. Guidance is in
agreement with this longwave feature. The uncertainty comes with
the extent of warm air involved and it's push onto the mainland.
The two camps of solutions at this point are as follows: one
bringing the warm front through southcentral AK from southwest to
northeast which would bring much warmer air and rain, and the
other, shunting the warm air just to the south in the Gulf which
would severely limit the amount of moisture available, but
precipitation would stay snow rather than rain. The high-
confidence portion of the forecast would be pattern amplification,
followed by a strong cold-front passage. Guidance all hang on to
an amplified pattern for the remainder of the forecast.

&&

.AFC WATCHES/WARNINGS/ADVISORIES...
PUBLIC...None.
MARINE...None.

&&

SYNOPSIS AND MODEL DISCUSSION...MO
SOUTHCENTRAL ALASKA...AD
SOUTHWEST ALASKA/BERING SEA/ALEUTIANS...JR
LONG TERM...JA