Small Craft Advisory 315, NWS Anchorage, AK

Issued

Apr 17, 2021, 3:13 PM AKDT (23:13 UTC)

Expired

Apr 18, 2021, 3:45 AM AKDT

In force

13 hr

Issued by

NWS Anchorage, AK

568 
FZAK51 PAFC 172313
CWFAER

Coastal Waters Forecast
National Weather Service Anchorage Alaska
313 PM AKDT Sat Apr 17 2021

Coastal Waters Forecast for the Northern Gulf of Alaska Coast
up to 100 nm out including Kodiak Island and Cook Inlet.

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.

PKZ197-181145-
313 PM AKDT Sat Apr 17 2021
.SYNOPSIS FOR THE NORTH GULF COAST+KODIAK ISLAND WATERS+
COOK INLET...

A front over the western Gulf of Alaska extends to the eastern 
Bering on Sun morning. Its trailing trough crosses Kodiak Island 
by Mon morning.

$$

PKZ119-181145-
Cape Suckling to Cape Cleare-
313 PM AKDT Sat Apr 17 2021

...SMALL CRAFT ADVISORY SUNDAY AND SUNDAY NIGHT...

.TONIGHT...NE wind 20 kt. Seas 5 ft.
.SUN...E wind 25 kt. Seas 6 ft.
.SUN NIGHT...NE wind 25 kt. Seas 6 ft.
.MON...E wind 25 kt. Seas 6 ft.
.MON NIGHT...SE wind 15 kt. Seas 8 ft.
.TUE...W wind 15 kt. Seas 8 ft.
.WED THROUGH THU...Variable wind 10 kt. Seas 7 ft.

$$

PKZ120-181145-
Cape Cleare to Gore Point-
313 PM AKDT Sat Apr 17 2021

...SMALL CRAFT ADVISORY THROUGH SUNDAY NIGHT...

.TONIGHT...NE wind 15 kt increasing to 25 kt after midnight. Seas
6 ft.
.SUN...NE wind 30 kt. Seas 9 ft.
.SUN NIGHT...NE wind 30 kt. Seas 9 ft.
.MON...NE wind 25 kt. Seas 8 ft.
.MON NIGHT...E wind 20 kt. Seas 9 ft.
.TUE...Variable wind 10 kt. Seas 8 ft.
.WED THROUGH THU...Variable wind 10 kt. Seas 7 ft.

$$

PKZ121-181145-
Resurrection Bay-
313 PM AKDT Sat Apr 17 2021

.TONIGHT...N wind 10 kt. Seas 2 ft.
.SUN...Variable wind 10 kt. Seas 2 ft.
.SUN NIGHT...N wind 10 kt. Seas 2 ft.
.MON AND MON NIGHT...N wind 10 kt. Seas 2 ft.
.TUE...N wind 10 kt. Seas 2 ft.
.WED...Variable wind 10 kt. Seas 2 ft.
.THU...N wind 10 kt. Seas 2 ft.

$$

PKZ125-181145-
Prince William Sound-
313 PM AKDT Sat Apr 17 2021

.TONIGHT...N wind 10 kt. Seas 2 ft.
.SUN...N wind 10 kt. Seas 2 ft.
.SUN NIGHT...N wind 10 kt. Seas 2 ft.
.MON AND MON NIGHT...NE wind 10 kt. Seas 2 ft.
.TUE...NW wind 10 kt. Seas 2 ft.
.WED THROUGH THU...N wind 10 kt. Seas 2 ft.

$$

PKZ126-181145-
Port Valdez-
313 PM AKDT Sat Apr 17 2021

.TONIGHT...E wind 15 kt. Seas 3 ft.
.SUN...E wind 10 kt. Seas 2 ft.
.SUN NIGHT...E wind 10 kt. Seas 2 ft.
.MON...E wind 10 kt. Seas 2 ft.
.MON NIGHT...Variable wind less than 10 kt. Seas 2 ft.
.TUE THROUGH THU...E wind 10 kt. Seas 2 ft.

$$

PKZ127-181145-
Valdez Narrows-
313 PM AKDT Sat Apr 17 2021

...SMALL CRAFT ADVISORY TONIGHT...

.TONIGHT...NE wind 25 kt. Seas 3 ft.
.SUN...NE wind 20 kt. Seas 3 ft.
.SUN NIGHT...NE wind 20 kt. Seas 3 ft.
.MON...NE wind 20 kt. Seas 3 ft.
.MON NIGHT...NE wind 10 kt. Seas 2 ft.
.TUE THROUGH WED...NE wind 15 kt. Seas 3 ft.
.THU...NE wind 10 kt. Seas 2 ft.

$$

PKZ128-181145-
Valdez Arm-
313 PM AKDT Sat Apr 17 2021

.TONIGHT...NE wind 15 kt. Seas 3 ft.
.SUN...NE wind 15 kt. Seas 3 ft.
.SUN NIGHT...NE wind 10 kt increasing to 15 kt after midnight.
Seas 3 ft.
.MON...NE wind 15 kt. Seas 3 ft.
.MON NIGHT...NE wind 10 kt. Seas 2 ft.
.TUE THROUGH THU...N wind 10 kt. Seas 2 ft.

$$

PKZ129-181145-
Passage Canal-
313 PM AKDT Sat Apr 17 2021

.TONIGHT...Variable wind less than 10 kt. Seas 2 ft.
.SUN...E wind 10 kt. Seas 2 ft.
.SUN NIGHT...E wind 10 kt. Seas 2 ft.
.MON...E wind 10 kt. Seas 2 ft.
.MON NIGHT...Variable wind less than 10 kt. Seas 2 ft.
.TUE...W wind 10 kt. Seas 2 ft.
.WED...E wind 10 kt. Seas 2 ft.
.THU...W wind 10 kt. Seas 2 ft.

$$

PKZ130-181145-
West of Barren Islands including Kamishak Bay-
313 PM AKDT Sat Apr 17 2021

...SMALL CRAFT ADVISORY SUNDAY AND SUNDAY NIGHT...

.TONIGHT...N wind 20 kt. Seas 5 ft.
.SUN...NE wind 25 kt. Seas 7 ft.
.SUN NIGHT...NE wind 25 kt. Seas 8 ft.
.MON AND MON NIGHT...E wind 25 kt. Seas 6 ft.
.TUE...E wind 20 kt. Seas 5 ft.
.WED...Variable wind 10 kt. Seas 3 ft.
.THU...Variable wind 10 kt. Seas 3 ft.

$$

PKZ131-181145-
Barren Islands East-
313 PM AKDT Sat Apr 17 2021

...SMALL CRAFT ADVISORY THROUGH SUNDAY NIGHT...

.TONIGHT...Variable wind 10 kt becoming NE 25 kt after midnight.
Seas 6 ft.
.SUN...NE wind 30 kt. Seas 9 ft.
.SUN NIGHT...NE wind 30 kt. Seas 10 ft.
.MON...E wind 30 kt. Seas 8 ft.
.MON NIGHT...E wind 25 kt. Seas 10 ft.
.TUE THROUGH WED...E wind 15 kt. Seas 9 ft.
.THU...Variable wind 10 kt. Seas 7 ft.

$$

PKZ132-181145-
Marmot Island to Sitkinak-
313 PM AKDT Sat Apr 17 2021

...GALE WARNING SUNDAY AND SUNDAY NIGHT...

.TONIGHT...NE wind 25 kt. Seas 7 ft.
.SUN...NE wind 25 kt increasing to 35 kt in the afternoon. Seas
9 ft.
.SUN NIGHT...NE wind 35 kt. Seas 11 ft.
.MON...E wind 25 kt. Seas 12 ft.
.MON NIGHT...SE wind 20 kt. Seas 12 ft.
.TUE THROUGH WED...E wind 25 kt. Seas 10 ft.
.THU...NE wind 15 kt. Seas 8 ft.

$$

PKZ136-181145-
Chiniak Bay-
313 PM AKDT Sat Apr 17 2021

...SMALL CRAFT ADVISORY SUNDAY NIGHT...

.TONIGHT...N wind 10 kt increasing to 15 kt after midnight. Seas
3 ft.
.SUN...NE wind 20 kt. Seas 4 ft.
.SUN NIGHT...NE wind 25 kt. Seas 7 ft. Rain.
.MON...NE wind 20 kt. Seas 6 ft.
.MON NIGHT...SE wind 15 kt. Seas 4 ft.
.TUE THROUGH THU...NE wind 10 kt. Seas 3 ft.

$$

PKZ137-181145-
Marmot Bay-
313 PM AKDT Sat Apr 17 2021

...SMALL CRAFT ADVISORY SUNDAY NIGHT...

.TONIGHT...Variable wind less than 10 kt becoming N 10 kt after
midnight. Seas 3 ft.
.SUN...NE wind 20 kt. Seas 6 ft.
.SUN NIGHT...NE wind 25 kt. Seas 7 ft.
.MON...E wind 20 kt. Seas 7 ft.
.MON NIGHT...E wind 20 kt. Seas 4 ft.
.TUE THROUGH THU...NE wind 10 kt. Seas 3 ft.

$$

PKZ138-181145-
Shelikof Strait-
313 PM AKDT Sat Apr 17 2021

...GALE WARNING SUNDAY AND SUNDAY NIGHT...

.TONIGHT...NE wind 25 kt. Seas 9 ft.
.SUN...NE wind 35 kt. Seas 13 ft.
.SUN NIGHT...NE wind 40 kt. Seas 16 ft.
.MON...NE wind 35 kt. Seas 13 ft.
.MON NIGHT...E wind 30 kt. Seas 8 ft.
.TUE THROUGH WED...NE wind 20 kt. Seas 5 ft.
.THU...NE wind 15 kt. Seas 4 ft.

$$

PKZ139-181145-
Cook Inlet Kalgin Island to Point Bede-
313 PM AKDT Sat Apr 17 2021

...SMALL CRAFT ADVISORY SUNDAY AND SUNDAY NIGHT...

.TONIGHT...N wind 20 kt. Seas 6 ft.
.SUN...N wind 25 kt. Seas 7 ft.
.SUN NIGHT...N wind 25 kt. Seas 7 ft.
.MON...N wind 25 kt. Seas 7 ft.
.MON NIGHT...N wind 10 kt. Seas 3 ft.
.TUE...SW wind 10 kt. Seas 3 ft.
.WED...N wind 10 kt. Seas 3 ft.
.THU...Variable wind less than 10 kt. Seas 2 ft.

$$

PKZ140-181145-
Cook Inlet North of Kalgin Island-
313 PM AKDT Sat Apr 17 2021

.TONIGHT...N wind 10 kt increasing to 15 kt after midnight. Seas
3 ft.
.SUN...NE wind 20 kt. Seas 4 ft.
.SUN NIGHT...NE wind 20 kt. Seas 4 ft.
.MON...NE wind 15 kt. Seas 4 ft.
.MON NIGHT...N wind 10 kt. Seas 3 ft.
.TUE...SW wind 10 kt. Seas 3 ft.
.WED THROUGH THU...N wind 10 kt. Seas 3 ft.

$$

PKZ141-181145-
Kachemak Bay-
313 PM AKDT Sat Apr 17 2021

.TONIGHT...Variable wind less than 10 kt. Seas 2 ft.
.SUN...N wind 10 kt. Seas 2 ft.
.SUN NIGHT...NE wind 10 kt. Seas 2 ft.
.MON AND MON NIGHT...E wind 10 kt. Seas 2 ft.
.TUE THROUGH THU...Variable wind less than 10 kt. Seas 2 ft.

$$

NWS Anchorage, AK wrote its last area forecast discussion before this small craft advisory went out at Apr 17, 4:01 AM AKDT, 11 hours 12 minutes earlier.

Southcentral and Southwest Alaska Forecast Discussion
National Weather Service Anchorage AK
401 AM AKDT Sat Apr 17 2021

.ANALYSIS AND UPPER LEVELS...A Rex Block pattern is dominating the
area with an upper level high pressure over the interior of Alaska
with a ridge extending into the Bering and another ridge over
western Canada. Low pressure is south of the Gulf and AKPEN.
Satellite is showing clear skies throughout Southcentral and most
of Southwest Alaska with clouds over Kodiak Island and out across
the Bering and Aleutians. Radar is clear with no echoes to speak
of due to dry air while temperatures are in the 20s and 30s across
Southcentral and Southwest with coastal areas hanging near 40.
Temperatures across the Aleutians are in the 30s with upper 30s to
near 40 across the central and western Aleutians. No fog showing
up on current observations but most of the Aleutians and Pribilofs
are observing low stratus clouds.

&&

.MODEL DISCUSSION...Models continue to be in very good agreement
with high forecast confidence. The main forecast challenge will be
forecasting high temperatures as snow cover continues to give us
slightly lower temperatures than what guidance is suggesting.

&&

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

&&

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

A quasi-rex block pattern will persist over the state through the
weekend with an upper-level ridge remaining over the interior of
the state and an upper-level trough re-establishing itself south
of Kodiak Island. At the surface, this translates to a surface
ridge extending from the Canadian Territories west over the
interior of Alaska while a series of weak surface troughs lift
northwest from the the southern Gulf to the eastern Bering.

The increased pressure gradient across Southcentral will allow
for northerly gap winds to peak today before slowly diminishing
tonight through Sunday as the ridge begins to weaken and shift
east. This pattern will also allow for conditions to remain clear
and dry across Southcentral through the weekend with daytime highs
pushing into the 50s.

Periods of light rain and high elevation snow will continue across
Kodiak Island through the weekend as the aforementioned weak
troughs move from the southern Gulf to the AKPEN.

&&

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

Temperatures will continue to gradually increase through the rest
of the weekend as the upper level ridge persists across much of
the State. There will be a distinct difference between daytime and
nighttime temperatures as clear skies promote radiational cooling
during overnight hours. As cloud covers returns late Saturday
night, the temperature differences will begin to shrink. Daytime
temperatures will hold relatively steady and overnight
temperatures will gradually increase. As a front off a North
Pacific low pushes onto the Southern AKPen, precip is likely along
the AKPEN for areas south of King Salmon, and over the Bristol
Bay waters. Coastal Bristol Bay may see a brief period of rain
showers overnight Saturday into Sunday.

&&

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

Semisopochnoi Volcano near Adak remains active. Please see the
marine weather statement for further details.

A front moves across the western Bering today, stalling over the
central Bering by this evening. Moderate to heavy precipitation,
mostly rain, is likely along the Western Aleutians as this front
passes. Ahead of the front, along the central Bering, winds will
be primarily southerly, while behind the front, in the western
Bering, winds are mainly northerly. A secondary front off a North
Pacific low moves northwestward towards the Eastern Aleutians, and
slowly drifts towards the Pribilofs. This front is not excessively
strong, however, periods of gale force winds are expected south of
the AKPen out of Shelikof Strait as well as south of Kodiak
Island. Additionally, periods of rain (during warmer daytime
hours) and possibly a rain/snow mix (during cooler overnight
hours) are likely across the Southern AKPen and the
Central/Eastern Aleutians as the front passes.

&&

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

Bering Sea/Aleutians:

A long-wave from the western Gulf enters the Bering and Aleutians
on Monday morning, then continues west-northwest through
Wednesday. Two separate North Pacific lows will bring strong
northerly gales with higher gusts near the Bays and Passes of the
Aleutians and AKPEN during the forecast period.

Gulf of Alaska:

A stacked North Pacific low will bring long period southerly
swells and seas up to 13 ft across the Gulf Monday and Monday
night, followed by an upper ridge by Tuesday morning. Relatively
quiet conditions are expected after Monday night.

&&

.Long Term Forecast (Days 4 through 7: Tuesday through Friday)...

A "Rex Block" Pattern will persist as the North Pacific low
continues northwestward across the Bering Sea through Wednesday.
This same low will enter the Gulf of Anadyr by Wednesday night,
leading the upper high from the Arctic to shift south-
southeastward toward the central Bering. Essentially, the high
will predominate the Bering Sea from Thursday night through
Friday afternoon. As a result, anticipate a quiet forecast period
mainly after Tuesday night.

&&

.AFC WATCHES/WARNINGS/ADVISORIES...
PUBLIC...NONE.
MARINE...Gale: 132 138 150.
FIRE WEATHER...NONE.

&&

SYNOPSIS AND MODEL DISCUSSION...RC
SOUTHCENTRAL ALASKA...TM
SOUTHWEST ALASKA/BERING SEA/ALEUTIANS...KM
MARINE/LONG TERM...CB

Small Craft Advisories in Alaska, 2021Every small craft advisory in 2021

The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text.