Heavy Freezing Spray Warning 77, NWS Anchorage, AK

122 
FZAK52 PAFC 221220
CWFALU

Coastal Waters Forecast
National Weather Service Anchorage Alaska
320 AM AKST Mon Feb 22 2021

Coastal Waters Forecast for Southwest Alaska+Bristol Bay+The
Alaska Peninsula Waters and the Aleutian Islands up to 100 nm out.

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.

PKZ199-230100-
320 AM AKST Mon Feb 22 2021
.SYNOPSIS FOR SOUTHWEST ALASKA+BRISTOL BAY+THE ALASKA
PENINSULA WATERS AND THE ALEUTIAN ISLANDS...

There is a 983 mb low 200 nm South of Attu Island Mon morning 
that moves to 120 nm West of St Paul Island at 990 mb Tue 
afternoon. Its front sweeps the Aleutians and moves into Western 
Alaska. A 976 mb low and front approach the Western Aleutians Tue
afternoon.

$$

PKZ150-230100-
South of the AK Peninsula Sitkinak to Castle Cape-
320 AM AKST Mon Feb 22 2021

...SMALL CRAFT ADVISORY THROUGH TUESDAY...

.TODAY...W wind 30 kt. Seas 15 ft. Freezing spray.
.TONIGHT...SW wind 25 kt. Seas 12 ft.
.TUE...S wind 25 kt. Seas 10 ft.
.TUE NIGHT...SE wind 20 kt. Seas 9 ft.
.WED...W wind 35 kt. Seas 14 ft.
.THU...SW wind 30 kt. Seas 14 ft.
.FRI...S wind 25 kt. Seas 14 ft.

$$

PKZ155-230100-
South of the AK Peninsula Castle Cape to Cape Sarichef-
320 AM AKST Mon Feb 22 2021

...SMALL CRAFT ADVISORY THROUGH TUESDAY...

.TODAY...SW wind 25 kt. Seas 14 ft. Freezing spray. Snow.
.TONIGHT...S wind 30 kt. Seas 13 ft.
.TUE...S wind 25 kt. Seas 12 ft.
.TUE NIGHT...SW wind 30 kt. Seas 11 ft.
.WED...SW wind 35 kt. Seas 15 ft.
.THU THROUGH FRI...S wind 25 kt. Seas 14 ft.

$$

PKZ160-230100-
Bristol Bay-
320 AM AKST Mon Feb 22 2021

...HEAVY FREEZING SPRAY WARNING THROUGH TUESDAY...
...SMALL CRAFT ADVISORY THROUGH TONIGHT...

.TODAY...NW wind 25 kt becoming N 15 kt in the afternoon. Seas in
ice free waters 6 ft. Heavy freezing spray.
.TONIGHT...E wind 15 kt increasing to 25 kt after midnight. Seas in 
ice free waters 4 ft. Heavy freezing spray. Snow.
.TUE...SE wind 20 kt. Seas in ice free waters 5 ft. Heavy freezing
spray. Snow.
.TUE NIGHT...SE wind 20 kt. Seas in ice free waters 5 ft.
.WED THROUGH THU...SW wind 30 kt. Seas in ice free waters 8 ft.
.FRI...S wind 20 kt. Seas in ice free waters 5 ft.

$$

PKZ165-230100-
Port Heiden to Cape Sarichef-
320 AM AKST Mon Feb 22 2021

...HEAVY FREEZING SPRAY WARNING TODAY...
...SMALL CRAFT ADVISORY TONIGHT AND TUESDAY...

.TODAY...NW wind 20 kt becoming E in the afternoon. Seas 6 ft.
Heavy freezing spray. Snow.
.TONIGHT...S wind 30 kt. Seas 7 ft.
.TUE...S wind 30 kt. Seas 7 ft. Rain showers.
.TUE NIGHT...S wind 25 kt. Seas 7 ft.
.WED...SW wind 35 kt. Seas 13 ft.
.THU...S wind 25 kt. Seas 13 ft.
.FRI...S wind 25 kt. Seas 8 ft.

$$

PKZ170-230100-
Cape Sarichef to Nikolski Bering Side-
320 AM AKST Mon Feb 22 2021

...SMALL CRAFT ADVISORY THROUGH TUESDAY...

.TODAY...SE wind 30 kt. Seas 10 ft. Rain and snow.
.TONIGHT...S wind 30 kt diminishing to 20 kt after midnight. 
Seas 10 ft.
.TUE...S wind 25 kt. Seas 7 ft. Rain.
.TUE NIGHT...SW wind 30 kt. Seas 11 ft.
.WED...SW wind 35 kt. Seas 13 ft.
.THU...S wind 25 kt. Seas 12 ft.
.FRI...S wind 30 kt. Seas 13 ft.

$$

PKZ171-230100-
Unalaska Bay-
320 AM AKST Mon Feb 22 2021

.TODAY...S wind increasing to 20 kt. Seas 3 ft. Rain and snow.
.TONIGHT...S wind 20 kt. Seas 2 ft. Rain.
.TUE...S wind 20 kt. Seas 3 ft. Rain.
.TUE NIGHT...SW wind 30 kt. Seas 4 ft.
.WED...SW wind 25 kt. Seas 4 ft.
.THU...S wind 25 kt. Seas 4 ft.
.FRI...S wind 20 kt. Seas 3 ft.

$$

PKZ172-230100-
Cape Sarichef to Nikolski Pacific Side-
320 AM AKST Mon Feb 22 2021

...SMALL CRAFT ADVISORY THROUGH TUESDAY...

.TODAY...S wind 30 kt. Seas 15 ft.
.TONIGHT...S wind 30 kt. Seas 16 ft. Rain.
.TUE...S wind 30 kt. Seas 14 ft. Rain.
.TUE NIGHT...SW wind 30 kt. Seas 16 ft.
.WED...SW wind 35 kt. Seas 16 ft.
.THU...S wind 25 kt. Seas 14 ft.
.FRI...S wind 30 kt. Seas 15 ft.

$$

PKZ173-230100-
Nikolski to Seguam Island Bering Side-
320 AM AKST Mon Feb 22 2021

...GALE WARNING TODAY...

.TODAY...S wind 35 kt diminishing to 25 kt in the afternoon. 
Seas 13 ft. Rain.
.TONIGHT...S wind 25 kt. Seas 10 ft.
.TUE...SW wind 30 kt. Seas 10 ft.
.TUE NIGHT...SW wind 30 kt. Seas 11 ft.
.WED...SW wind 35 kt. Seas 12 ft.
.THU...S wind 25 kt. Seas 13 ft.
.FRI...SW wind 30 kt. Seas 22 ft.

$$

PKZ174-230100-
Nikolski to Seguam Island Pacific Side-
320 AM AKST Mon Feb 22 2021

...GALE WARNING TODAY...

.TODAY...S wind 35 kt diminishing to 25 kt in the afternoon. 
Seas 17 ft. Rain.
.TONIGHT...S wind 25 kt. Seas 15 ft.
.TUE...SW wind 30 kt. Seas 17 ft.
.TUE NIGHT...SW wind 35 kt. Seas 19 ft.
.WED...SW wind 35 kt. Seas 16 ft.
.THU THROUGH FRI...SW wind 30 kt. Seas 19 ft.

$$

PKZ175-230100-
Seguam Island to Adak Bering Side-
320 AM AKST Mon Feb 22 2021

...SMALL CRAFT ADVISORY THROUGH TUESDAY...

.TODAY...SW wind 25 kt. Seas 7 ft. Rain.
.TONIGHT...S wind 30 kt. Seas 9 ft. Widespread snow and rain
showers.
.TUE...SW wind 30 kt. Seas 9 ft. Snow showers.
.TUE NIGHT...SW wind 30 kt. Seas 9 ft.
.WED...SW wind 35 kt. Seas 14 ft.
.THU...S wind 30 kt. Seas 11 ft.
.FRI...SW wind 30 kt. Seas 21 ft.

$$

PKZ176-230100-
Seguam Island to Adak Pacific Side-
320 AM AKST Mon Feb 22 2021

...GALE WARNING TODAY AND TUESDAY...

.TODAY...SW wind 35 kt diminishing to 25 kt in the afternoon. 
Seas 16 ft.
.TONIGHT...S wind 30 kt. Seas 17 ft.
.TUE...SW wind 35 kt. Seas 20 ft.
.TUE NIGHT...SW wind 35 kt. Seas 19 ft.
.WED...SW wind 35 kt. Seas 15 ft.
.THU...S wind 30 kt. Seas 20 ft.
.FRI...SW wind 30 kt. Seas 18 ft.

$$

PKZ177-230100-
Adak to Kiska-
320 AM AKST Mon Feb 22 2021

...SMALL CRAFT ADVISORY THROUGH TUESDAY...

.TODAY...S wind 30 kt. Seas 14 ft.
.TONIGHT...S wind 30 kt. Seas 12 ft Bering side...20 ft Pacific 
side. Widespread snow showers.
.TUE...W wind 30 kt. Seas 11 ft Bering side...19 ft Pacific side.
.TUE NIGHT...S wind 35 kt. Seas 14 ft.
.WED...SW wind 35 kt. Seas 18 ft.
.THU...S wind 30 kt. Seas 17 ft.
.FRI...SW wind 30 kt. Seas 18 ft.

$$

PKZ178-230100-
Kiska to Attu-
320 AM AKST Mon Feb 22 2021

...SMALL CRAFT ADVISORY THROUGH TUESDAY...

.TODAY...S wind 25 kt. Seas 16 ft.
.TONIGHT...NW wind 25 kt. Seas 17 ft.
.TUE...NW wind 25 kt diminishing to 15 kt in the afternoon. 
Seas 13 ft.
.TUE NIGHT...E wind 30 kt. Seas 12 ft.
.WED...S wind 35 kt. Seas 21 ft.
.THU...S wind 30 kt. Seas 21 ft.
.FRI...W wind 30 kt. Seas 17 ft.

$$

PKZ179-230100-
Pribilof Islands Near Shore Waters-
320 AM AKST Mon Feb 22 2021

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

.TODAY...E wind 30 kt increasing to 40 kt in the afternoon. 
Seas7 ft building to 11 ft in the afternoon. Heavy freezing 
spray in the morning. Snow with rain.
.TONIGHT...SW wind 25 kt becoming S 15 kt after midnight. 
Seas 10 ft.
.TUE...SE wind 20 kt. Seas 8 ft. Snow showers and rain showers.
.TUE NIGHT...SW wind 20 kt. Seas 9 ft.
.WED...SW wind 30 kt. Seas 14 ft.
.THU THROUGH FRI...S wind 25 kt. Seas 14 ft.

$$

PKZ180-230100-
Kuskokwim Delta and Etolin Strait-
320 AM AKST Mon Feb 22 2021

...GALE WARNING TONIGHT...
...HEAVY FREEZING SPRAY WARNING THROUGH TONIGHT...

.TODAY...NW wind 20 kt becoming E in the afternoon. Seas in ice
free waters 4 ft. Heavy freezing spray.
.TONIGHT...E wind 25 kt increasing to 35 kt after midnight. 
Seas in ice free waters 6 ft. Heavy freezing spray. Snow.
.TUE...S wind 25 kt. Seas in ice free waters 7 ft. Rain.
.TUE NIGHT...S wind 25 kt. Seas in ice free waters 7 ft.
.WED...SW wind 25 kt. Seas in ice free waters 9 ft.
.THU...S wind 25 kt. Seas in ice free waters 9 ft.
.FRI...SE wind 20 kt. Seas in ice free waters 7 ft.

$$

PKZ181-230100-
North and West of Nunivak Island-
320 AM AKST Mon Feb 22 2021

...BRISK WIND ADVISORY TONIGHT...

.TODAY...Variable wind 10 kt becoming E 20 kt in the afternoon.
.TONIGHT...E wind increasing to 30 kt. Snow.
.TUE...SE wind 20 kt.
.TUE NIGHT...NE wind 25 kt.
.WED...N wind 25 kt.
.THU THROUGH FRI...E wind 20 kt.

$$

PKZ185-230100-
Saint Matthew Island Waters-
320 AM AKST Mon Feb 22 2021

...GALE WARNING TONIGHT...
...HEAVY FREEZING SPRAY WARNING THROUGH TUESDAY...

.TODAY...E wind 30 kt. Seas in ice free waters 9 ft. 
Heavy freezing spray.
.TONIGHT...E wind 35 kt. Seas in ice free waters 12 ft. 
Heavy freezing spray. Snow.
.TUE...E wind 25 kt E of Saint Matthew Island...NE 30 kt 
W of Saint Matthew Island. Seas in ice free waters 12 ft. 
Heavy freezing spray.
.TUE NIGHT...NE wind 30 kt. Seas in ice free waters 10 ft.
.WED...NE wind 30 kt. Seas in ice free waters 9 ft.
.THU THROUGH FRI...NE wind 35 kt. Seas in ice free waters 13 ft.

$$

Southcentral and Southwest Alaska Forecast Discussion
National Weather Service Anchorage AK
515 AM AKST Sun Feb 21 2021

.ANALYSIS AND UPPER LEVELS...

The minimum temperature recorded at the National Weather Service
Office in Anchorage yesterday was -6 degrees Fahrenheit. The
brutally cold temperatures extend into Southwest Alaska and to
Thompson Pass. There is a surface low south of Cordova with an
inverted trough extending into Prince William Sound. The jet
stream is south of the Gulf of Alaska. The longwave pattern
features a broad upper trough from north of Kaktovik to the North
Pacific. The radar at Middleton Island has detected light snow
showers near the Copper River Delta this morning but the Kenai and
King Salmon radars have been pretty quiet. The latest ASCAT
(Advanced Scatterometer) imagery has detected gale force winds
near the Barren Islands and in Shelikof Straight.

&&

.MODEL DISCUSSION...

Model consensus is good with the major synoptic features through
Monday. Also the models are doing well depicting the intensity of
the arctic air impacting SW Alaska and Southcentral Alaska. There
is a new low that will impact the Aleutians late Sunday through
Tuesday and there are some minor differences with the intensity of
this new low and the thermodynamic profile.

&&

.AVIATION...

PANC...VFR conditions and light winds will persist.

&&

.SHORT TERM FORECAST SOUTHCENTRAL ALASKA (Days 1 and 2...Sun and
Mon)...
Cold and dry will be the dominate themes across much of the area
today into Mon. The Arctic airmass continues to hold court across
much of the mainland. However, temperatures are not quite as cold
this morning compared to 24 hours ago thanks to some mid- high
clouds. These clouds are generally courtesy of a low pressure
center driving quickly towards Yakutat. As the low clears the
area, these clouds should continue to dissipate and this will
allow temperatures to drop a several more degrees before the sun
comes up.

In the upper levels, the general pattern is a broad
trough over Western Alaska. On the eastern periphery of this
trough, various pieces of energy will continue to pick up moisture
over the Gulf of AK as they move quickly from west to east. Some
of this moisture will get lofted over the Copper River Basin and
fall as light snow, mainly from Glennallen east. Some of this
moisture will try to creep back as far west as Thompson Pass late
tonight into early Mon. This could result in some blowing snow
through the pass, but models continue to differ with exactly how
far west this snow can make it. On the west side of the trough,
various pieces of energy will drive cold air through the
Alaska/Aleutian Ranges. This will once again cause gusty winds
across Cook Inlet, the Barren Islands, and localized gaps such as
Seward and Whittier. As these winds increase over marine areas,
expect another round of heavy freezing spray late Sun night
through Mon.

The other area that bears watching with this set up is the
southern end of Cook Inlet. As this cold air streams from west to
east over the warmer open waters, it should be able to create some
snow bands (similar to lake effect snow). These bands are
incredibly hard to forecast as they are usually very narrow in
extent (10-20 miles). However, there is a chance they could focus
on the Kachemak Bay and Homer Bluffs area. This could lead to some
heavy snow showers, brief accumulations, and some blowing snow.
The good news is, regardless of where these bands establish, they
should be fairly short lived as a new system reorients the flow
late Mon into Tue. This system will bring another chance of
widespread snow by Tue to most of Southcentral.

&&

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

A broad upper level trough over Southwest Alaska will keep a cold
Arctic airmass in place. A weak surface low has generated some
light snow across the Bristol Bay region this morning that will
eventually dissipate as it moves east. Meanwhile a low over the
eastern Aleutians will move eastward today, spreading in clouds
and light snow showers across the southern Alaska Peninsula.
Conditions across the Kuskokwim Delta will remain clear and cold
overnight tonight as an upper level wave reinforces the cold
Arctic air moving in from the north. Increasing cloud cover is
expected late Monday as the next front arrives. As the front moves
inland across Southwest Monday night, snow will spread in and
winds will increase, especially along the coast. This will likely bring
snow and blowing snow conditions across the Kuskokwim Delta area.
At this time, there are some model differences regarding the
timing of this front arriving, and how far inland snow will
spread. With ample cold air in place ahead of the front, it is
likely to be all snow, however areas along the southern Alaska
Peninsula are likely to see rain or a rain/snow mix. Precipitation
is expected to last across Southwest through much of Tuesday.

&&

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

Active weather will continue across the Bering this week. A
broad upper level trough has allowed cold Arctic air to drop
southward with northerly flow across much of the Bering this
morning. A low currently centered over the central Aleutians will
track eastward today as another system arrives on its heels. A
strong upper level low arrives over the western Aleutians tonight.
At the surface, a gale force low spins up over the western Bering
and as its leading front pushes eastward, it occludes quickly.
Cold air will fill in rapidly on the backside of the low, leading
to the potential for snow and blowing snow across the western
Aleutians tonight into Monday. As the leading front reaches the
Pribilofs Monday, gusty southeasterly winds are expected. Given
the abundance of cold air in place, precipitation is expected to
fall as snow, though there may be a brief period of rain/snow mix
Monday afternoon. As the low center gradually tracks eastward
along the Chain, snow is expected across the western and central
Aleutians Monday night into Tuesday.

&&

.MARINE (Days 3 through 5: Tuesday through Thursday)...

Bering Sea: A low continues to track into the Eastern Bering by
Thu. Models agree, so confidence is good. Widespread small craft
winds and waves wrap the low through Thu. Wave heights to 21 feet
on the Pacific side, 16 feet in the Eastern Bering, subsiding
through Thu. A new low and front enters the Western Bering late
Tue and moves to the Central Bering by Thu. Widespread high end
small craft winds with areas of gale force winds wrap this low
through Thu. Wave heights to 33 feet on the Pacific side, 23 feet
on the Bering side through Thu.

Gulf of Alaska: A well developed low and front move over the Gulf
for Wed and Thu. Models vary, but confidence is good. Widespread
high end small craft winds and waves with areas of high end gale
force winds wrap the low through Thu. Wave heights building to 20
feet for Thu.

&&

.LONG TERM FORECAST (Days 4 through 7/Wednesday through Saturday)...

The long-term looks to be active, with the upper level synoptic
flow showing a more zonal pattern for our forecast area. A series
of troughs and ridges move through until a deeper longwave trough
sets up of the Bering late in the week. A ridge also sets up over
mainland AK ahead of it. Models differ on the placement and
strength of both, but all are in agreement that this general
pattern sets up.

On the surface, we start out midweek with a low somewhere in the
Eastern Bering and a low somewhere near the Southwest Gulf. Models
have a pretty big spread on where both setup, so low confidence on
the specifics of the forecast in the long-term. Moving through
the period, a series of weak lows look to exist in the Bering and
a low moves through the Gulf. The mainland looks quiet. Beyond
that, we can't discern much. Overall, moderate confidence in the
weather pattern. We know it will be active but that's about it for
now.

&&

.AFC WATCHES/WARNINGS/ADVISORIES...
PUBLIC...NONE.
MARINE...Gale 411 412 165 170 172 174 176 178 119 120 130 131 139.
Heavy Freezing Spray Warning 412 414 160 179 180 185 127 130 131
139.
FIRE WEATHER...NONE.

&&

SYNOPSIS AND MODEL DISCUSSION...PJS
SOUTHCENTRAL ALASKA...MSO
SOUTHWEST ALASKA/BERING SEA/ALEUTIANS...KO
MARINE/LONG TERM...MK/BJB

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE ANCHORAGE AK
316 PM AKST SUN FEB 21 2021

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0316 PM     SNOW             UPPER POTTER VALLEY     61.06N 149.76W
02/21/2021  M0.9 INCH        ANCHORAGE          AK   TRAINED SPOTTER

            SPOTTER REPORTED 0.9 INCHES OF SNOW.

&&

MV