Heavy Freezing Spray Warning 5, NWS Anchorage, AK

594 
FZAK62 PAFC 142358
OFFALU

Offshore Waters Forecast
National Weather Service Anchorage AK
258 PM AKST Thu Jan 14 2021

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.

PKZ499-151415-
258 PM AKST Thu Jan 14 2021
.SYNOPSIS FOR CENTRAL BERING SEA...

A low over the Western Gulf moves into Bristol Bay at 985 mb Fri 
morning and moves inland over the Kuskokwim Delta Fri Evening. A 
small 1000 mb low at 55N 171E moves to 58N 179E at 995 mb Fri 
morning before dissipating Fri evening. Another low in the 
Western Gulf moves to 56N 157W by Sat evening.

$$

PKZ411-151415-
Bering Sea Offshore West of 180 and East of the International
Dateline-
258 PM AKST Thu Jan 14 2021

.TONIGHT...S to W wind 10 to 20 kt. Seas 4 to 8 ft. Freezing spray.
.FRI...NW wind 10 to 25 kt. Seas 5 to 8 ft. Freezing spray.
.FRI NIGHT...NW wind 10 to 25 kt. Seas 4 to 8 ft. Freezing spray.
.SAT...NW wind 10 to 25 kt. Seas 5 to 10 ft.
.SAT NIGHT...W wind 10 to 25 kt. Seas 6 to 10 ft.
.SUN...SE wind 25 to 40 kt. Seas 7 to 12 ft.
.MON...SW wind 15 to 30 kt. Seas 11 to 17 ft.
.TUE...S wind 15 to 30 kt. Seas 15 to 22 ft.

$$

PKZ412-151415-
Bering Sea Offshore 171W to 180 and North of 56N-
258 PM AKST Thu Jan 14 2021

.TONIGHT...NW wind 10 to 25 kt. Seas 4 to 9 ft. Freezing spray.
.FRI...NW wind 15 to 30 kt. Seas 5 to 10 ft. Freezing spray.
.FRI NIGHT...NW wind 15 to 30 kt. Seas 6 to 12 ft. Freezing spray.
.SAT...NW wind 20 to 30 kt. Seas 9 to 14 ft.
.SAT NIGHT...NW wind 20 to 30 kt. Seas 9 to 12 ft.
.SUN...NW wind 15 to 30 kt. Seas 7 to 12 ft.
.MON...SE wind 20 to 35 kt. Seas 8 to 13 ft.
.TUE...S wind 20 to 30 kt. Seas 15 to 18 ft.

$$

PKZ413-151415-
Bering Sea Offshore 171W to 180 and South of 56N-
258 PM AKST Thu Jan 14 2021

.TONIGHT...N wind 10 to 25 kt. Seas 5 to 9 ft. Freezing spray.
.FRI...NW wind 15 to 30 kt. Seas 7 to 12 ft. Freezing spray.
.FRI NIGHT...NW wind 20 to 30 kt. Seas 7 to 12 ft. Freezing spray.
.SAT...NW wind 20 to 35 kt. Seas 9 to 16 ft.
.SAT NIGHT...NW wind 20 to 35 kt. Seas 9 to 17 ft.
.SUN THROUGH MON...SW wind 20 to 35 kt. Seas 8 to 13 ft.
.TUE...S wind 30 kt. Seas 14 to 19 ft.

$$

PKZ414-151415-
Bering Sea Offshore East of 171W-
258 PM AKST Thu Jan 14 2021

.TONIGHT...N wind 15 to 25 kt. Seas 5 to 8 ft. Freezing spray.
.FRI...N wind 15 to 30 kt. Seas 5 to 10 ft. Freezing spray. Snow
showers.
.FRI NIGHT...N wind 15 to 30 kt. Seas 6 to 11 ft. Freezing spray.
.SAT...N wind 20 to 35 kt. Seas 7 to 12 ft.
.SAT NIGHT...NW wind 30 to 40 kt. Seas 9 to 16 ft.
.SUN...NW wind 25 to 40 kt. Seas 8 to 16 ft.
.MON...S wind 15 to 30 kt. Seas 8 to 16 ft.
.TUE...SW wind 15 to 25 kt. Seas 11 to 15 ft.

$$

Southcentral and Southwest Alaska Forecast Discussion
National Weather Service Anchorage AK
520 PM AKST Wed Jan 13 2021

.ANALYSIS AND UPPER LEVELS...
Southern mainland Alaska is under south-southeast flow aloft
today with an upper level wave bringing some snow showers to
parts of Southwest and Southcentral Alaska. There is a break to
the south of this wave but the next system can be seen
prominently on satellite in the north Pacific and heading toward
Alaska. This low has an unusual number of upper level disturbances
visible in it on satellite. The main center is seen in the lower
convective clouds, but the main lifting in conjunction with the
jet stream to the low's east. There are at least three strong
perturbations along the front north and west of this low center
which indicates that it is already a complex low as the models
have been indicating.

&&

.MODEL DISCUSSION...
Models remain in good synoptic agreement with the main issue still
being the development and behavior of the smaller lows in the
center of the complex low that will reach the Gulf Thursday.
Models are still detecting a Polar low in the western Bering Sea
Thursday into Friday but are all keeping it over Bering Sea far
away from land.

&&

.AVIATION...
PANC...VFR conditions and light winds will persist. There is a
chance for some low level wind shear to develop on Thursday, but
it is not a sure thing.

&&

.SHORT TERM FORECAST SOUTHCENTRAL ALASKA (Days 1 through
3/Wednesday through Friday)...

The persistent low near Kodiak Island has now finally lifted north
and mostly dissipated with a coastal ridge building into the
northern Gulf just ahead of the next major system of interest in
the Northeast Pacific. Aside from lingering snow showers drifting
north near the Gulf coast within increasingly southerly flow, a
relative calm before the storm has set in for Southcentral this
evening with mainly light winds and breaks in the cloud cover
notable on satellite imagery.

Conditions will take a rapid turn for the worse on Thu as a
complex low with multiple embedded centers enters the Gulf with a
strong associated front and barrier jet reaching the Gulf Coast by
Thu evening. Storm force winds with hurricane force gusts are
expected ahead of the front as it works its way north until it
moves inland Thu evening. There should be more than enough cool
air in the low levels for precipitation with the low's approach
over land to start out as all snow, and this will combine with
strong and gusty winds to produce significant visibility
reductions with blowing snow through areas around Turnagain
Pass/Portage Valley and through Thompson Pass from Thu morning
through early Fri morning.

A Blizzard Warning has been issued for Thompson Pass for
blowing and falling snow with visibilities down to 1/4 mile and
around 5-10 inches of new snowfall from 9 AM Thu to 6 AM Fri. Gap
winds through the pass prior to the frontal passage could peak
with gusts as high as 55 mph before rapidly diminishing early Fri
morning. A Winter Weather Advisory has also been issued for
Turnagain Pass and Portage Valley from 6 AM to 6 PM on Thu for
blowing and falling snow resulting in hazardous travel conditions
and visibilities as low 1/2 mile at times. Winds will advect
warmer air into the valleys by Thu afternoon, potentially
switching snow over to rain at the lowest elevations. However,
heavy snow will continue throughout the day at higher elevations
and through Turnagain Pass where up to 15 inches of snow is
possible through Thu night. Winds even in the lower elevations in
the area could occasionally gust as high as 45 mph before quickly
diminishing early Fri morning.

The active weather will continue Fri into Sat with another strong
low moving into the Western Gulf by Fri evening. Similar impacts,
especially stronger winds, will be possible with this next
system, but not necessarily for the exact same areas with models
indicating a low track much farther west up the AKPEN possible.
Continue to monitor the forecast for further updates on this next
impactful storm going into the early weekend.

&&

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

Snow showers continue to linger around Southwest Alaska this
evening associated with a weakening low over Bristol Bay, which
should allow for drying conditions overnight into Thursday
morning. The chance for showers returns Thursday afternoon as a
front from a North Pacific low extends into southern Bristol Bay
and the Alaska Peninsula. This system will bring breezy
conditions, as well as a mix of rain and snow to some places with
temperatures at or slightly above the freezing mark.

Precipitation will taper off through late Friday morning,
allowing for another dry day across Southwest Alaska before the
next system moves in late Friday afternoon into Saturday. This
second North Pacific system will bring a more organized front to
the region, with snowfall extending farther north to the Kuskokwim
Delta and Valley through Saturday. Strong winds with this system
with falling snow could lead to some blowing snow, but models are
still struggling on wind speeds over the land.

&&

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

A relatively quiet pattern is set up over the Bering and Aleutians
this afternoon, with a few snow showers across the region. By
Thursday morning, a North Pacific low lifting north into the Gulf
will allow for strong winds, including a swath of storm force
winds, to enter the waters south of the Alaska Peninsula. This
will also bring widespread showers to the AKPEN and eastern
Aleutians, which will taper off through early Friday. However,
precipitation and strong winds will return by Friday afternoon as
a second system, a bit farther west this time, enters the region.
Widespread gale force winds will accompany this low as it lifts
over the Alaska Peninsula and into Southwest Alaska by Saturday.

&&

.MARINE (Days 3 through 5 - Sat through Mon)...

Gulf of Alaska: A strong North Pacific low moves over Kodiak
Island into the Northern Alaska Peninsula for Mon. Model tracks
and development vary somewhat, but forecast confidence is good.
Widespread high end easterly gale force winds and waves move
northward over the Gulf with the front and diminish Sun. Behind
the front, widespread southwesterly small craft winds with gale
force gusts move over the Gulf and diminish Mon. A new North
Pacific low enters the Gulf. Southerly small craft with gale force
gusts over the Southeast Gulf increasing through Mon. Wave
heights peak near 23 feet over the Gulf and subside Mon.

Aleutians / Bering: As a new North Pacific low enters Southwest
Alaska, the Western Bering high pressure weakens and moves east
through Mon. Model tracks and development are close, and forecast
confidence is good. Widespread northerly small craft winds and
waves with gale force gusts moves across the Aleutians and Bering
diminishing Sun. A strong Kamchatka low and front moves east
through Mon. Widespread high end gale force winds with the front
move to the Central Aleutians and Bering by Mon. A second area of
widespread high end gale force winds accompany the low into the
Western Aleutians and Bering for Mon. Wave heights to 18 feet for
the Bering side Central-Eastern Aleutians and Alaska Peninsula
Sat-Sun, and Pacific side Western Aleutians Sun-Mon.

&&

.LONG TERM FORECAST (Days 3 through 7: Saturday through
Wednesday)...

An active pattern is expected across the AOR through the forecast
period. Generally speaking, a broad longwave trough will exist
over the Bering Sea while the North American Ridge persists over
Southeast Alaska. This pattern will allow for north Pacific storms
to travel into the southern mainland through Wednesday. With the
broad southerly flow aloft will come ample moisture and warmer
temperatures. This could lead to rain over coastal areas of the
Gulf and lee of the western Alaska Range with significant snow
accumulation for the mountains. Long term guidance is in excellent
agreement for the time period with the first broad low moving and
stalling over the AKPen this weekend. This will bring plenty of
QPF to the Gulf coast, Southwest, and the eastern Aleutians.

By Monday the upper level pattern becomes more active due to a
strong system near the Kamchatka Peninsula. At this time the low
center appears to remain over the western Bering but the storm's
front could sweep east across the Bering and into Southwest,
bringing snow and strong winds through Wednesday. Meanwhile, a
compact low from the north Pacific could move into the Prince
William Sound on Monday. Depending on the low track, this could
mean significant snow for the population centers of Southcentral.

&&

.AFC WATCHES/WARNINGS/ADVISORIES...
PUBLIC...WSW 125 and 131.
MARINE...Storms 119 120 130-132 138 139 150 351 352. Gales 127 136
137 155 160.
FIRE WEATHER...NONE.

&&

SYNOPSIS AND MODEL DISCUSSION...EZ
SOUTHCENTRAL ALASKA...AS
SOUTHWEST ALASKA/BERING SEA/ALEUTIANS...AH
MARINE/LONG TERM...MK/CJ