Heavy Freezing Spray Warning 38, NWS Anchorage, AK

851 
FZAK62 PAFC 161243
OFFALU

Offshore Waters Forecast
National Weather Service Anchorage AK
343 AM AKST Tue Feb 16 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.

PKZ499-170215-
343 AM AKST Tue Feb 16 2021
.SYNOPSIS FOR CENTRAL BERING SEA...

A 980 mb low at 54N 173W moves to 53N 166W at 992 mb Wed morning,
then moves to 53N 160W at 997 mb as it weakens Wed afternoon. A 
second 997 mb low near 54N 160W Tue morning moves to 58N 162W at 
992 mb by Wed morning, then moves inland over Southwest Alaska by
Thurs morning. Another North Pacific low extends a front into the
Western Aleutians by Thurs morning.

$$

PKZ411-170215-
Bering Sea Offshore West of 180 and East of the International
Dateline-
343 AM AKST Tue Feb 16 2021

.TODAY...NE wind 15 to 30 kt. Seas 9 to 13 ft. Freezing spray.
.TONIGHT...NE wind 10 to 25 kt. Seas 9 to 12 ft. Freezing spray.
.WED...E wind 10 to 15 kt. Seas 9 ft. Freezing spray.
.WED NIGHT...SE wind 10 to 25 kt. Seas 6 to 11 ft.
.THU...S wind 30 to 45 kt. Seas 9 to 14 ft.
.FRI THROUGH SAT...SE wind 10 to 25 kt. Seas 10 to 18 ft.

$$

PKZ412-170215-
Bering Sea Offshore 171W to 180 and North of 56N-
343 AM AKST Tue Feb 16 2021

...GALE WARNING TODAY...
...HEAVY FREEZING SPRAY WARNING TONIGHT...

.TODAY...NE wind 20 to 35 kt. Seas 10 to 14 ft. Rain showers.
.TONIGHT...NE wind 15 to 30 kt. Seas 8 to 12 ft. Heavy freezing 
spray.
.WED...N wind 10 to 20 kt. Seas 8 ft. Freezing spray.
.WED NIGHT...N wind up to 15 kt. Seas 3 to 6 ft.
.THU...E wind 25 to 40 kt. Seas 7 to 12 ft.
.FRI...E wind 25 to 40 kt. Seas 11 to 19 ft.
.SAT...NE wind 10 to 20 kt. Seas 10 to 14 ft.

$$

PKZ413-170215-
Bering Sea Offshore 171W to 180 and South of 56N-
343 AM AKST Tue Feb 16 2021

...GALE WARNING TODAY...

.TODAY...N wind 20 to 35 kt. Seas 8 to 13 ft.
.TONIGHT...N wind 10 to 25 kt. Seas 7 to 12 ft.
.WED...NW wind 10 to 20 kt. Seas 8 ft.
.WED NIGHT...W wind up to 15 kt. Seas 6 ft.
.THU...SE wind 25 to 40 kt. Seas 6 to 11 ft.
.FRI...SW wind 15 to 30 kt. Seas 10 to 18 ft.
.SAT...E wind up to 15 kt. Seas 9 to 14 ft.

$$

PKZ414-170215-
Bering Sea Offshore East of 171W-
343 AM AKST Tue Feb 16 2021

...HEAVY FREEZING SPRAY WARNING TONIGHT AND WEDNESDAY...

.TODAY...E wind 10 to 20 kt. Seas 7 ft.
.TONIGHT...NE wind 10 to 20 kt. Seas 3 to 6 ft. Heavy freezing
spray.
.WED...N wind 15 kt. Seas 4 ft. Heavy freezing spray.
.WED NIGHT...NW wind 20 kt. Seas 4 ft.
.THU...N wind 25 to 40 kt. Seas 4 to 9 ft.
.FRI...E wind 25 to 40 kt. Seas 8 to 13 ft.
.SAT...NE wind 10 to 25 kt. Seas 8 to 13 ft.

$$

414 
FZAK62 PAFC 170036
OFFALU

Offshore Waters Forecast
National Weather Service Anchorage AK
336 PM AKST Tue Feb 16 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.

PKZ499-171415-
336 PM AKST Tue Feb 16 2021
.SYNOPSIS FOR CENTRAL BERING SEA...

A 988 mb low near 53N 171W moves to 58N 161W at 997 mb Wed
evening and then moves inland while dissipating. A front
associated with a North Pacific low moves into the Western 
Aleutians Wed evening and continues moving across the Bering 
through Thu afternoon.

$$

PKZ411-171415-
Bering Sea Offshore West of 180 and East of the International
Dateline-
336 PM AKST Tue Feb 16 2021

.TONIGHT...NE wind 10 to 25 kt. Seas 9 to 12 ft. Freezing spray.
.WED...E wind 10 to 15 kt. Seas 9 ft. Freezing spray.
.WED NIGHT...E wind 10 to 25 kt. Seas 5 to 10 ft.
.THU...SE wind 25 to 40 kt. Seas 8 to 13 ft.
.THU NIGHT...S wind 25 to 40 kt. Seas 12 to 16 ft.
.FRI THROUGH SUN...E wind 10 to 25 kt. Seas 10 to 18 ft.

$$

PKZ412-171415-
Bering Sea Offshore 171W to 180 and North of 56N-
336 PM AKST Tue Feb 16 2021

.TONIGHT...NE wind 15 to 30 kt. Seas 8 to 12 ft. Freezing spray.
.WED...N wind 10 to 20 kt. Seas 8 ft. Freezing spray.
.WED NIGHT...N wind 10 to 15 kt. Seas 5 ft.
.THU...E wind 15 to 30 kt. Seas 4 to 9 ft.
.THU NIGHT...E wind 25 to 40 kt. Seas 8 to 13 ft.
.FRI...E wind 25 to 40 kt. Seas 11 to 19 ft.
.SAT THROUGH SUN...NE wind 10 to 20 kt. Seas 8 to 13 ft.

$$

PKZ413-171415-
Bering Sea Offshore 171W to 180 and South of 56N-
336 PM AKST Tue Feb 16 2021

.TONIGHT...N wind 10 to 25 kt. Seas 7 to 12 ft.
.WED...NW wind 10 to 20 kt. Seas 8 ft.
.WED NIGHT...W wind 10 to 15 kt. Seas 6 ft.
.THU...SE wind 25 to 40 kt. Seas 5 to 10 ft.
.THU NIGHT...S wind 25 to 40 kt. Seas 7 to 12 ft.
.FRI...W wind up to 20 kt. Seas 9 to 14 ft.
.SAT THROUGH SUN...SE wind up to 15 kt. Seas 8 to 13 ft.

$$

PKZ414-171415-
Bering Sea Offshore East of 171W-
336 PM AKST Tue Feb 16 2021

.TONIGHT...NE wind 10 to 15 kt. Seas 5 ft.
.WED...N wind 15 kt becoming up to 20 kt in the afternoon. Seas
4 ft.
.WED NIGHT...NW wind 10 to 20 kt. Seas 3 to 6 ft. Freezing spray.
.THU...NW wind up to 20 kt. Seas 4 ft.
.THU NIGHT...E wind 15 to 30 kt. Seas 4 to 9 ft.
.FRI...E wind 15 to 30 kt. Seas 5 to 10 ft.
.SAT...NE wind 10 to 25 kt. Seas 8 to 13 ft.
.SUN...NW wind up to 20 kt. Seas 6 to 9 ft.

$$

Southcentral and Southwest Alaska Forecast Discussion
National Weather Service Anchorage AK
417 AM AKST Mon Feb 15 2021

.ANALYSIS AND UPPER LEVELS...

A broad, vertically stacked low continues to spin in place over
the central Bering with the low center positioned just east of
Adak. A frontal boundary associated with this low is visible on
satellite imagery and extends along the Southwest coast, over the
Alaska Peninsula, and into the western Gulf. Meanwhile an upper
level ridge over the Alaska-Yukon border has kept conditions clear
and dry over the Copper River Basin and eastern Southcentral.
Farther west, higher clouds have begun to develop over the Susitna
Valley and are gradually spreading toward the southeast and
filling in over Southcentral this morning.

&&

.MODEL DISCUSSION...

Model solutions remain in great synoptic agreement through the
short term. The main forecast challenge continues to be
precipitation amounts across Southcentral as the front extending
across the Gulf lifts inland through Tuesday. Model solutions are
also struggling to resolve the next low arriving over Southcentral
Tuesday into Wednesday. While there is good agreement with an
upper level trough over the Alaska Peninsula progressing eastward
Wednesday morning, at the surface, models disagree on the strength
of a surface low forming in the vicinity of Kodiak Island and the
timing in which the associated front moves inland over
Southcentral.

&&

.AVIATION...

PANC...VFR conditions and light winds will persist. A front
lifting inland tonight will reduce conditions to MVFR during the
overnight hours into Tuesday morning with light snow expected.

&&

.SHORT TERM FORECAST SOUTHCENTRAL ALASKA (Days 1 through 3: Today
through Wednesday Night)...

A frontal boundary draped over the northern half of Kodiak Island
this morning will slowly lift northward today as an upper-level
shortwave moves from the western Gulf to the northern Gulf. A
steady, light rain this morning over portions of Kodiak Island
will transition to scattered showers as the front and upper-level
wave move north. Farther north, light snow will develop across the
southern Kenai Peninsula later this morning and spread into Prince
William Sound, the Anchorage Bowl, and Mat-Su Valleys tonight.
Light snow showers will persist through Tuesday as the surface
front stalls and weakens along the coast and a series of upper-
level shortwaves lift north across the region. A general 1 to 3
inches is still expected with this system; however, a persistent
moist, southwesterly flow and colder air working in aloft may
favor localized higher amounts in upslope areas such as the
Anchorage Hillside and along the Parks Highway from Willow to
Talkeetna. Snowfall amounts of 6 to 8 inches are not out of the
question for Hatcher Pass, given the favored southwesterly flow.

This system will gradually weaken by late Tuesday as a second,
more potent storm system moves into the western Gulf. A developing
surface low near the Barren Islands and associated front sweeping
into the northern Gulf looks to bring widespread snow to the Kenai
and Chugach Mountains beginning early Wednesday morning.
Precipitation will also likely start as snow for coastal locations
along the eastern Kenai Peninsula and Prince William Sound. There
is still some uncertainty as to how strong and how far north the
front will track. The strength and position of the front will have
influence on whether enough warm air works in and changes snow to
rain along the coast and whether there is a significant increase
in freezing levels to vary snow amounts in the higher elevations.
Gap winds will also increase ahead of the front which may cause
concern for blowing snow in Portage Valley and Turnagain Pass, at
least initially before temperatures increase. As for locations in
the lee of the Kenai and Chugach Mountains, a strong cross-
barrier flow should act to limit precipitation totals due to
downsloping conditions.

&&

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

Broad low pressure exists across much of the Southwest as a
multitude of shortwaves move across the Mainland. As a result,
much of the region will remain under widespread showers over the
next couple of days. Temperatures will be at or above freezing for
Bristol Bay and the AKPEN, and below freezing elsewhere.
Regardless, precipitation will be mostly snow across the
Southwest, will accumulations of 1-2 inches in the lower
elevations and up to 6 inches for the higher elevations. By
Wednesday, the Bering low begins weakening at a faster rate and
moves off to the east. After the low passes and dissipates, the
Southwest should see a some dry and cloudy conditions as well as
some cooler temperatures as flow transitions to northerly by late
Wednesday into Thursday.

&&

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

Broad low pressure extends across the Bering and Southwest through
mid-week as a vertically stacked low remains almost stationary
between Adak and Unalaska through Tuesday night. This systems
loses much of its jet support by late tonight and begins rapidly
weakening by Tuesday afternoon allowing its energy to be absorbed
by a secondary North Pacific low approaching the Gulf late
Wednesday. Thus, the low moves off to the east Wednesday, pulling
colder northerly air behind it and spilling into the Eastern
Aleutians and Southern AKPEN. With this, precipitation will
transition from a rain/rain-snow mix back to mostly snow for these
areas starting Wednesday night. There will be a quick break
Wednesday evening through early Thursday morning until a front
off a Kamchatka low pushes into the Western Bering. This will
bring a round of gale force winds and precipitation to the Western
Aleutians starting early Thursday morning.

&&

.MARINE (Days 3 through 5: Wednesday through Friday)...

Bering Sea: A low exits Bristol Bay for Thu. Model changes are
similar, so confidence is good. Widespread small craft winds and
waves over the central and eastern Bering diminish Thu. Wave
heights to 8 feet expected south of the ice edge. A well
developed low and front enters the Western Aleutians and Bering
and moves to the Central Aleutians and Bering by Fri. Widespread
high end gale force winds along the front through Fri. Wave
heights to 20 feet possible in the Bering, 14 feet on the Pacific
side of the Aleutians.

Gulf of Alaska: A front across the Gulf moves to the north Gulf
Coast for Fri. Model changes are similar, so confidence is good.
Widespread small craft winds and waves with areas of gale force
winds with the front will diminish late Thu, but gales will linger
away from the front over the Barren Islands, Cook Inlet and
Shelikof Strait. Wave heights with the front up to 20 feet
possible through Fri.

&&

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

A low over the eastern Bering will be the primary weather maker
across Southern Alaska to start off the long-term forecast on
Wednesday. The leading front and upper level wave will move north
out of the North Pacific and impact the north Gulf Coast. A round
of potentially heavy snow is expected along the Kenai Peninsula
and Seward Highway through the day. Already by Thursday, model
discrepancies emerge, namely how long the heaviest precipitation
persists along the coast. Some of the models try to bring some of
the moisture into the Cook Inlet region, but that too is
uncertain. Across Southwest Alaska, precipitation early on in the
day will spread northward, resulting in decreasing precipitation
rates by Wednesday night, though some light precipitation will
still be around. A front will move into the Western Aleutians
Thursday morning. The front will spread across all of the Bering
by Friday afternoon. Weak embedded lows may form along the front,
but will not significantly impact the placement of the front.

For Southcentral, the discrepancies on a late-week round of snow
are large enough that very little detail can be determined at this
point. Most of the guidance suggests snow will move in at some
point, but whether that occurs Thursday or Friday in association
with a Gulf low or if it will be entirely driven by upslope
southwesterly flow and upper level support is highly uncertain.

&&

.AFC WATCHES/WARNINGS/ADVISORIES...
PUBLIC...NONE.
MARINE...Gale: 175, 176, 177, 185, 412.
         Heavy Freezing Spray: 185
         Marine Weather Statement: 185.
FIRE WEATHER...NONE.

&&

SYNOPSIS AND MODEL DISCUSSION...KO
SOUTHCENTRAL ALASKA...TM
SOUTHWEST ALASKA/BERING SEA/ALEUTIANS...KM
MARINE/LONG TERM...MK/JW