Gale Warning 759, NWS Anchorage, AK

664 
FZAK62 PAFC 311247
OFFALU

Offshore Waters Forecast
National Weather Service Anchorage AK
347 AM AKST Mon Dec 31 2018

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.

PKZ499-010230-
347 AM AKST Mon Dec 31 2018
.SYNOPSIS FOR CENTRAL BERING SEA...

A 962 mb low at 60N 163W moves into interior Alaska and 
dissipates Tue night. A 962 mb low near 51N 176W Mon morning and 
a 976 mb low near 53N 160W merge to form a 958 mb low at 59N 158W 
Tue morning.

$$

PKZ411-010230-
Bering Sea Offshore West of 180 and East of the International
Dateline-
347 AM AKST Mon Dec 31 2018

.TODAY...N wind 25 kt. Seas 10 to 16 ft. Freezing spray.
.TONIGHT...NW wind 10 to 20 kt. Seas 7 to 12 ft. Freezing spray.
.TUE...W wind 10 to 15 kt. Seas 4 to 8 ft.
.TUE NIGHT...W wind up to 20 kt. Seas 4 to 7 ft.
.WED...W wind 10 to 25 kt. Seas 4 to 8 ft.
.THU THROUGH FRI...E wind up to 20 kt. Seas 5 to 9 ft.

$$

PKZ412-010230-
Bering Sea Offshore 171W to 180 and North of 56N-
347 AM AKST Mon Dec 31 2018

.TODAY...N wind 10 to 25 kt. Seas 9 to 14 ft. Freezing spray. Snow
showers.
.TONIGHT...N wind 15 to 30 kt. Seas 8 to 11 ft. Freezing spray.
.TUE...NW wind 15 to 30 kt. Seas 7 to 12 ft. Freezing spray.
.TUE NIGHT...W wind up to 20 kt. Seas 4 to 9 ft.
.WED...SW wind 15 to 30 kt. Seas 5 to 8 ft.
.THU...E wind up to 15 kt. Seas 5 to 8 ft.
.FRI...E wind 20 kt. Seas 6 ft.

$$

PKZ413-010230-
Bering Sea Offshore 171W to 180 and South of 56N-
347 AM AKST Mon Dec 31 2018

...GALE WARNING THROUGH TUESDAY...

.TODAY...N wind 20 to 35 kt. Seas 10 to 16 ft. Rain showers.
.TONIGHT...NW wind 25 to 40 kt. Seas 10 to 16 ft. Freezing spray.
Snow showers.
.TUE...W wind 20 to 35 kt diminishing to 10 to 25 kt in the
afternoon. Seas 8 to 13 ft. Freezing spray.
.TUE NIGHT...SW wind up to 20 kt. Seas 4 to 9 ft.
.WED...SW wind 10 to 25 kt. Seas 7 ft.
.THU THROUGH FRI...NE wind up to 20 kt. Seas 7 ft.

$$

PKZ414-010230-
Bering Sea Offshore East of 171W-
347 AM AKST Mon Dec 31 2018

...GALE WARNING TUESDAY...

.TODAY...S wind 10 to 25 kt. Seas 7 to 11 ft.
.TONIGHT...E wind 10 to 20 kt. Seas 6 to 11 ft.
.TUE...NW wind 20 to 35 kt. Seas 8 to 13 ft.
.TUE NIGHT...W wind 15 to 30 kt. Seas 9 to 14 ft.
.WED...SW wind up to 20 kt. Seas 6 to 11 ft.
.THU...SE wind up to 15 kt. Seas 4 to 9 ft.
.FRI...NE wind 20 kt. Seas 5 ft.

$$

Southcentral and Southwest Alaska Forecast Discussion
National Weather Service Anchorage AK
555 AM AKST Sun Dec 30 2018

.ANALYSIS AND UPPER LEVELS...

A long wave ridge encompasses much of the Bering Sea. A deep,
closed low anchors this trough and sits right over the western
Aleutians. It is this low that is providing the activity for
powerful series of lows we will be experiencing the next few days.
Meanwhile, a long wave ridge sits over the ALCAN border, with our
forecast area sandwiched between the two, providing strong
southwesterly flow on the active side of the ridge. This is also
setting up our active weather pattern.

This active weather pattern is producing snow and strong winds in
southwest Alaska, to include hurricane force wind gusts for some
areas later today. It is also producing high winds in southcentral
Alaska, with strong winds coming down the Turnagain and Knik Arms.
Areas like Turnagain Pass and Portage are also due to receive
heavy snow. Quite the dose of active weather which has kept all of
us busy tonight.

&&

.MODEL DISCUSSION...

Model guidance continues to be poor. They are difficult enough to
work with that they are not of much use past 48hrs. Therefore, we
have been concentrating on the rapidly changing weather in the
first 48hrs. They have finally come together enough to identify
weather and subsequent impacts with the current low moving through
our area and the next strong low moving through tonight into
Monday. Past that, models indicate another strong low coming
Tuesday, but there is so little agreement between them that we
need more confidence in guidance before we make a call for
Tuesday.

&&

.AVIATION...
PANC...The main impact to the airport during the TAF period will
be gusty winds and windshear. Strong southeasterly winds will exit
the Turnagain arm this morning and mainly stay elevated, producing
wind shear for most of the TAF period. Wind gusts will also be
present at the airfield, though the most windy conditions will
stay over the Turnagain Arm and bend south over Cook Inlet.

&&

.SHORT TERM FORECAST SOUTHCENTRAL ALASKA (Days 1 and 2/Today
through Monday night)...

A strong front pushing into the western Gulf this morning combined
with an upper level short-wave lifting northward across Southwest
Alaska will help spread precipitation across much of Southcentral
early this morning. Temperatures are cold enough to initially
support snow everywhere except Kodiak Island where rain will fall.
As the front continues across the Gulf and toward Southcentral,
low level southeast flow will rapidly strengthen. This will open a
downslope hole by mid to late morning across the western Kenai
Peninsula, Anchorage, the Matanuska Valley, and the eastern
Susitna Valley - bringing an end to snowfall. These winds will
also help coastal locations warm up, with temperatures near sea
level steadily rising through the day and snow changing to rain.
Prior to that happening, expect a period of blizzard conditions
through Portage Valley and eastern Turnagain Arm along with
Turnagain Pass. While temperatures low down warm up, it will
remain cold enough to stay all snow through Turnagain Pass, so
expect snow and blowing snow to persist.

Meanwhile, cyclogenesis is ongoing this morning south of the
eastern Aleutians and Alaska Peninsula. This rapidly deepening
low will track to Southwest Alaska tonight, sending an even
stronger front across the Gulf and Southcentral tonight through
Monday morning. The big story for The Gulf of Alaska and
Southcentral will be widespread strong winds and warming
temperatures, with most of the region expected to be well above
freezing by Monday morning. As is typical, some of the strongest
winds will occur along Turnagain Arm and higher elevations of
Anchorage. The warm advection with the first front is not very
strong, so one key to this wind event is the absence of a strong
temperature inversion in Anchorage and vicinity. Forecast soundings
indicate a nearly isothermal profile in the low levels. Thus,
expect the high winds up on the mountains to stay there or even
escape upward. Lower elevations will still see some locally strong
and gusty winds, but this does NOT have the makings of a damaging
wind event.

While the population centers will remain mostly dry due to the
strong downslope flow tonight through early Monday, the coastal
zones (namely the eastern Kenai Peninsula and Prince William
Sounds region) can expect heavy precipitation. Turnagain Pass can
expect snow to intensify this evening and continue through the
overnight hours. Have issued a Winter Storm Warning to cover both
the blizzard conditions today and the heavy snow tonight. Also
issued a Winter Storm Warning for heavy snow for Thompson Pass.
Precipitation type in valdez is a tough call in these situations.
If the precipitation is heavy enough, they may stay all or mostly
snow tonight as warmer air arrives. Thus, have upped snow amounts
there.

As the storm system exits to the north Monday gusty southerly
winds will be felt just about everywhere. Winds will gradually
diminish through the day allowing temperatures to begin to fall.
Yet another strong storm is on the way for Monday night and
Tuesday, though the track of this storm is very much in question.
The latest models take it on a similar track to the first storm,
so we could see similar impacts as with the first storm.

&&

.SHORT TERM FORECAST SOUTHWEST ALASKA (Days 1 and 2: Today and
Monday)...

Minuscule changes were needed to the first few hours of this
morning's forecast as the blizzard conditions occurred as
expected west of Dillingham and are in the process of ending from
south to north along the coast of the Kuskokwim Delta. A short
break in the weather is expected behind the front, as temperatures
continue to warm area-wide as winds turn to an onshore direction.
The break may even include a time with clear skies as well due to
the sinking motion of the atmosphere behind the front. The break
will be short-lived however, as the next in a series of lows
gathers strength this morning well south of the Aleutians. This
next low will rapidly intensify as it approaches the Alaska
Peninsula this afternoon, then tracks straight north across
Bristol Bay and up along the Kuskokwim Delta coast from Cape
Newenham north through Bethel. Along this track, precipitation
will begin this afternoon across much of Bristol Bay and especially
the Kuskokwim Mountains. As the low approaches, strong southeast
winds are expected through the Kamishak Gap, including Iliamna.
Gusts in Iliamna and points north and west may approach 70 mph. As
the front currently tracking across the area scours out the cold
air over Southwest Alaska from south to north, additional warm air
with the low will mean much of the lower elevations of Bristol
Bay gets plain rain as the low tracks inland. The one exception
may be west of Bethel in the Kuskokwim Delta, which is expected to
be the only area of land in Southwest Alaska that will be west of
the expected track of the center of the low. As the low
approaches, northeast offshore winds will kick up across the
Kuskokwim Delta and with that being a cold direction, the
precipitation may stay all snow, and as such, another period of
blowing snow with reduced visibilities is possible across that
area. The remnants of the strong low that crossed the Pribilofs
overnight last night will still be out across the Bering, so as
this new low approaches, the pressure gradient that leads to
strong winds and blizzard conditions will not be nearly as strong
across the Kuskokwim Delta, and as such, blizzard conditions are
not expected at this time.

In the wake of the low, however, things wind-wise will be very
different than up north across the Kuskokwim Delta. Here there
will be a very intense pressure gradient. The first area to be
impacted by the very strong winds will be along the Alaska
Peninsula this evening. 55 to 70 mph winds with gusts to 80 mph
are possible along the Shumagin Islands and Sand Point, where a
High Wind Warning has been issued. Any channeling of west winds
through the Alaska Peninsula may help increase gusts in places
like Cold Bay, and especially near the King Cove airport. As the
center of the low moves into the Western Capes and Kuskokwim Bay
in the late evening, those same southwest winds are expected to
impact the Bristol Bay waters, and up along the coast from Pilot
Point north with 55 to 70 mph winds with gusts to 80 mph. The
southwest winds may be locally channeled up Kvichak Bay and the
Kvichak River, so places like Naknek and Levelock are also
expected to see warning level winds. The winds and the overall
weather quiet down briefly once again during the day on Monday,
but the models are coming into better agreement of yet another
strong low tracking south to north somewhere near the Bristol Bay
region just in time for Monday night, bringing yet another round
of precipitation and strong winds to the area. Phew!

&&

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

Kicking off the forecast across the Bering is another series of
lows that continue to rotate around the basin keeping the area
very active. A strong low over the western Aleutians is slowly
drifting eastward along the chain, and will keep winds well into
gale force on both sides of the low across that area. The low that
tracked past the Pribilofs this morning will continue to move
northward into the Bering Strait by this evening and dissipate.
Finally, a third low developing well south of the Aleutians is on
its way to the Alaska Peninsula this afternoon then into Southwest
Alaska by tonight. As this third low moves over the Peninsula late
this afternoon, behind it, very strong southwest winds will
develop, impacting primarily the Pacific side of the Peninsula and
the Shumagin Islands with hurricane force wind gusts as it moves
through. Thus, a High Wind Warning is in effect for the Alaska
Peninsula through midnight tonight. Make no mistake, the winds
will also be strong on the Bering side as well once the low
passes, but the Pacific side will have some channeling between
the low tracking north and the peninsula, which will enhance the
winds there, while the same effect diminishes the winds on the
Bering side a bit. Rain associated with the low falling in the
strong winds will make for sideways rain at times.

Even after this low moves into Southwest Alaska tonight, the
Bering will still be left with the western Aleutians low, which
will track near or over Adak tonight. As it once was, this low
will be the dominant weather feature in the Bering for a time, but
slow weakening and slow movement will also make the low a
relatively benign feature compared with the stronger lows moving
across Bristol Bay and the Alaska Peninsula further east. Yet
another of those lows may impact Bristol Bay again Monday night,
as the western Aleutians low tracks about halfway between the
Pribilofs and Unalaska Monday night. Model disagreement rapidly
increases after that regarding the fate of the low. Where there is
much better agreement in the meantime is that the western
Aleutians low will bring a reinforcing shot of cold air streaming
southward out of Russia into the western Bering, which will expand
following behind the low, so by Monday, much of the western Bering
and Aleutians will return to a cooler, snow-showery weather
regime, which will persist into midweek.

&&

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

The run to run consistency with the global models continues to be
atrocious. Generally speaking, anticipate a wet pattern for this
forecast period for the southern tier of Alaska with the
possibility of a rain/snow/freezing rain mix for Southwest Alaska.
The forecast period commences Tuesday January 1st with a broad
trough over NE Russia, the Bering and Aleutians with southwest
flow aloft over most of mainland Alaska. There is a high amplitude
positive tilt ridge from the Eastern Pacific to British
Columbia/Alberta. Meanwhile at the surface at 12z Tuesday, both
the GFS and the ECMWF have a potent low north of the chain, the
GFS places the low NW of St Paul and the ECMWF places the low on
top of the Pribilof Islands with a trough axis extending out of
it. However, the axis/orientation of the trough is completely
different between the GFS and the ECMWF. But the real eye sore is
near the AKPEN/Kodiak and over the Gulf Of Alaska where the GFS
has a bombed-out low and the ECMWF basically has a very weak low.
This GFS cyclone looks a bit aggressive, but maybe three days
from now we will all be singing the praises of the GFS solution
that locked onto bombed-out low before any of the other guidance.
The lack of consensus is echoed at 500 mb at 12z Tuesday, which
compounds with time. The timing of the precipitation shield and
the gale/storm or even hurricane force winds are dependent on the
placement of the lows that develop and on the track of the low.
There was a hefty amount of blending and hedging this forecast
period as a result of the models poor performance record. Stay
tuned for more details with these potential winter weather storms.
Many of the important decisions being made with these storms is
occurring one or two days out because the models have not been
doing well this winter.

&&

.AFC WATCHES/WARNINGS/ADVISORIES...
PUBLIC...High Wind Warning: 101 161 181.
 		 Blizzard Warning: 155.
 		 Winter Storm Warning: 125 131.

MARINE...Hurricane Force Wind: 150 155 160.
 		 Heavy Freezing Spray: 185.
 		 Storm: 119 130 131 132 138 139 140 141 165 180 185.
 		 Gale: 120 125 128 129 136 137 172 174 175 176 177 178 179
		       181 351 352 411 412 414.

&&

SYNOPSIS AND MODEL DISCUSSION...BB
SOUTHCENTRAL ALASKA...SEB
SOUTHWEST ALASKA/BERING SEA/ALEUTIANS...JPW
LONG TERM...PJS