Small Craft Advisory 426, NWS Anchorage, AK

545 
FZAK51 PAFC 281117
CWFAER

Coastal Waters Forecast
National Weather Service Anchorage Alaska
317 AM AKDT Fri May 28 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.

PKZ197-290000-
317 AM AKDT Fri May 28 2021
.SYNOPSIS FOR THE NORTH GULF COAST+KODIAK ISLAND WATERS+
COOK INLET...

A front moves across the Gulf through Sat morning. A second 
front merges with the first front over the Western Gulf by Sat 
afternoon and remains along the Gulf coast through Sun morning.

$$

PKZ119-290000-
Cape Suckling to Cape Cleare-
317 AM AKDT Fri May 28 2021

...GALE WARNING SATURDAY...

.TODAY...S wind 15 kt, becoming SE 25 kt near the coast 
in the afternoon. Seas 5 ft. Rain.
.TONIGHT...SE wind 15 kt, except 30 kt near the coast. Seas 8 ft. 
Rain.
.SAT...SE wind 30 kt increasing to 40 kt in the afternoon. 
Seas 12 ft. Rain.
.SAT NIGHT...SE wind 45 kt. Seas 15 ft.
.SUN...E wind 30 kt. Seas 12 ft.
.MON...SE wind 20 kt. Seas 9 ft.
.TUE...SE wind 15 kt. Seas 9 ft.

$$

PKZ120-290000-
Cape Cleare to Gore Point-
317 AM AKDT Fri May 28 2021

...SMALL CRAFT ADVISORY SATURDAY...

.TODAY...Variable wind 10 kt becoming NE 20 kt 
in the afternoon. Seas 4 ft. Rain.
.TONIGHT...NE wind 20 kt. Seas 5 ft. Rain.
.SAT...NE wind 25 kt. Seas 8 ft. Rain.
.SAT NIGHT...E wind 20 kt. Seas 11 ft.
.SUN...E wind 25 kt. Seas 11 ft.
.MON...E wind 25 kt. Seas 8 ft.
.TUE...SE wind 15 kt. Seas 8 ft.

$$

PKZ121-290000-
Resurrection Bay-
317 AM AKDT Fri May 28 2021

.TODAY...Variable wind less than 10 kt. Seas 2 ft. Rain.
.TONIGHT AND SAT...Variable wind less than 10 kt. Seas 2 ft. Rain.
.SAT NIGHT...Variable wind 10 kt. Seas 2 ft.
.SUN THROUGH MON...N wind 10 kt. Seas 2 ft.
.TUE...S wind 15 kt. Seas 3 ft.

$$

PKZ125-290000-
Prince William Sound-
317 AM AKDT Fri May 28 2021

...SMALL CRAFT ADVISORY SATURDAY...

.TODAY...E wind 15 kt. Seas 3 ft. Rain.
.TONIGHT...E wind 20 kt. Seas 4 ft. Rain.
.SAT...E wind 30 kt. Seas 7 ft. Rain.
.SAT NIGHT...E wind 35 kt. Seas 9 ft.
.SUN...NE wind 15 kt. Seas 3 ft.
.MON THROUGH TUE...E wind 15 kt. Seas 3 ft.

$$

PKZ126-290000-
Port Valdez-
317 AM AKDT Fri May 28 2021

.TODAY...Variable wind less than 10 kt. Seas 2 ft. Rain.
.TONIGHT THROUGH TUE...Variable wind less than 10 kt. 
Seas 2 ft. Rain.

$$

PKZ127-290000-
Valdez Narrows-
317 AM AKDT Fri May 28 2021

.TODAY...NE wind 15 kt. Seas 2 ft. Rain.
.TONIGHT...NE wind 20 kt. Seas 3 ft. Rain.
.SAT...NE wind 15 kt. Seas 3 ft. Rain.
.SAT NIGHT...N wind 15 kt. Seas 2 ft.
.SUN THROUGH TUE...Variable wind 15 kt. Seas 3 ft.

$$

PKZ128-290000-
Valdez Arm-
317 AM AKDT Fri May 28 2021

.TODAY...NE wind 15 kt. Seas 3 ft. Rain.
.TONIGHT...NE wind 15 kt. Seas 3 ft. Rain.
.SAT...NE wind 20 kt. Seas 4 ft. Rain.
.SAT NIGHT...NE wind 15 kt. Seas 3 ft.
.SUN THROUGH TUE...Variable wind 10 kt. Seas 2 ft.

$$

PKZ129-290000-
Passage Canal-
317 AM AKDT Fri May 28 2021

.TODAY...E wind 10 kt. Seas 2 ft. Rain.
.TONIGHT...NE wind 10 kt increasing to 15 kt after midnight. 
Seas 2 ft. Rain.
.SAT...E wind 20 kt. Seas 3 ft. Rain.
.SAT NIGHT...E wind 25 kt. Seas 4 ft.
.SUN...E wind 10 kt. Seas 2 ft.
.MON THROUGH TUE...Variable wind less than 10 kt. Seas 2 ft.

$$

PKZ130-290000-
West of Barren Islands including Kamishak Bay-
317 AM AKDT Fri May 28 2021

...SMALL CRAFT ADVISORY TODAY AND SATURDAY...

.TODAY...SE wind 25 kt becoming NE 20 kt in the afternoon. 
Seas 8 ft.
.TONIGHT...NE wind 20 kt. Seas 6 ft.
.SAT...NE wind 30 kt. Seas 11 ft. Rain.
.SAT NIGHT...NE wind 30 kt. Seas 11 ft.
.SUN...NE wind 25 kt. Seas 8 ft.
.MON...E wind 20 kt. Seas 7 ft.
.TUE...E wind 15 kt. Seas 4 ft.

$$

PKZ131-290000-
Barren Islands East-
317 AM AKDT Fri May 28 2021

...SMALL CRAFT ADVISORY THROUGH SATURDAY...

.TODAY...S wind 15 kt, except E wind increasing to 25 kt 
near the Barren Islands. Seas 4 ft, building to 8 ft near 
the Barren Islands.
.TONIGHT...E wind 15 kt, except E 25 kt near the Barren Islands. 
Seas 5 ft, except 8 ft near the Barren Islands. Rain.
.SAT...SE wind 20 kt. Near the Barren Islands, E wind 30 kt
diminishing to 20 kt in the afternoon. Seas 8 ft. Rain.
.SAT NIGHT...SE wind 20 kt. Seas 9 ft.
.SUN...E wind 30 kt. Seas 10 ft.
.MON...E wind 25 kt. Seas 8 ft.
.TUE...SE wind 15 kt. Seas 8 ft.

$$

PKZ132-290000-
Marmot Island to Sitkinak-
317 AM AKDT Fri May 28 2021

.TODAY...SE wind 15 kt. Seas 5 ft.
.TONIGHT...E wind 20 kt. Seas 5 ft.
.SAT...S wind 20 kt. Seas 7 ft.
.SAT NIGHT...S wind 20 kt. Seas 8 ft.
.SUN THROUGH MON...SE wind 20 kt. Seas 8 ft.
.TUE...S wind 15 kt. Seas 7 ft.

$$

PKZ136-290000-
Chiniak Bay-
317 AM AKDT Fri May 28 2021

.TODAY...Variable wind less than 10 kt becoming SE 10 kt 
in the afternoon. Seas 2 ft.
.TONIGHT...E wind 10 kt. Seas 3 ft. Rain.
.SAT...SE wind 10 kt becoming S 15 kt in the afternoon. 
Seas 3 ft. Rain.
.SAT NIGHT...S wind 20 kt. Seas 3 ft.
.SUN THROUGH MON...E wind 15 kt. Seas 4 ft.
.TUE...S wind 10 kt. Seas 3 ft.

$$

PKZ137-290000-
Marmot Bay-
317 AM AKDT Fri May 28 2021

.TODAY...Variable wind less than 10 kt becoming E 10 kt 
in the afternoon. Seas 3 ft.
.TONIGHT...E wind 15 kt. Seas 4 ft. Rain.
.SAT...E wind 15 kt diminishing to 10 kt in the afternoon. 
Seas 4 ft.
.SAT NIGHT...Variable wind 15 kt. Seas 3 ft.
.SUN THROUGH MON...E wind 15 kt. Seas 4 ft.
.TUE...SE wind 10 kt. Seas 3 ft.

$$

PKZ138-290000-
Shelikof Strait-
317 AM AKDT Fri May 28 2021

...SMALL CRAFT ADVISORY TONIGHT AND SATURDAY...

.TODAY...SW wind 15 kt becoming NE 20 kt in the afternoon. 
Seas 4 ft.
.TONIGHT...NE wind 30 kt. Seas 9 ft. Rain.
.SAT...NE wind 30 kt becoming variable 15 kt in the afternoon. 
Seas 10 ft subsiding to 5 ft in the afternoon. Rain.
.SAT NIGHT...SW wind 15 kt. Seas 4 ft.
.SUN THROUGH MON...NE wind 20 kt. Seas 6 ft.
.TUE...SE wind 15 kt. Seas 3 ft.

$$

PKZ139-290000-
Cook Inlet Kalgin Island to Point Bede-
317 AM AKDT Fri May 28 2021

...SMALL CRAFT ADVISORY TODAY AND SATURDAY...

.TODAY...S wind 25 kt diminishing to 15 kt during the morning, 
then shifting to NE 20 kt in the afternoon. Seas 8 ft subsiding 
to 4 ft by afternoon.
.TONIGHT...N wind 20 kt. Seas 5 ft.
.SAT...NE wind 30 kt. Seas 10 ft. Rain.
.SAT NIGHT...N wind 30 kt. Seas 10 ft.
.SUN...NE wind 25 kt. Seas 7 ft.
.MON...NE wind 15 kt. Seas 4 ft.
.TUE...S wind 10 kt. Seas 2 ft.

$$

PKZ140-290000-
Cook Inlet North of Kalgin Island-
317 AM AKDT Fri May 28 2021

...SMALL CRAFT ADVISORY SATURDAY...

.TODAY...Variable wind 10 kt becoming NE 15 kt in the afternoon. 
Seas 3 ft.
.TONIGHT...NE wind 15 kt. Seas 3 ft.
.SAT...NE wind 25 kt. Seas 7 ft. Rain.
.SAT NIGHT...NE wind 25 kt. Seas 7 ft.
.SUN...NE wind 20 kt. Seas 5 ft.
.MON...NE wind 15 kt. Seas 4 ft.
.TUE...S wind 10 kt. Seas 2 ft.

$$

PKZ141-290000-
Kachemak Bay-
317 AM AKDT Fri May 28 2021

.TODAY...Variable wind less than 10 kt becoming W 10 kt 
in the afternoon. Seas 2 ft.
.TONIGHT...Variable wind less than 10 kt. Seas 2 ft. Rain.
.SAT...N wind 10 kt. Seas 2 ft. Rain.
.SAT NIGHT...NE wind 10 kt. Seas 2 ft.
.SUN THROUGH MON...NE wind 15 kt. Seas 3 ft.
.TUE...Variable wind 10 kt. Seas 2 ft.

$$

Southcentral and Southwest Alaska Forecast Discussion
National Weather Service Anchorage AK
456 AM AKDT Thu May 27 2021

.ANALYSIS AND UPPER LEVELS...

A relatively strong vertically stacked low remains nearly
stationary in the western Bering. As such, moderate rain and gusty
winds are currently observed over the western Aleutians. Weaker
flow over the remainder of the Bering/Aleutians is leading to the
usual low stratus, with benign surface conditions. An upper low
centered north of the Canadian Arctic is bringing more widespread
cloud cover across the mainland as shortwave troughs embedded
within in its flow propagate from north to south.

&&

.MODEL DISCUSSION...

Models remain in good synoptic agreement showing a cooler, wet
pattern into the long weekend with the aforementioned upper low
moving southward. Specific precipitation timing and amounts remain
the greatest challenge, though confidence is moderate to high in
the short term.

&&

.AVIATION...

PANC...VFR conditions will persist. Gusty southerly winds will
steadily increase through the day, potentially gusting up to 30
kts by this evening, before diminishing Friday morning.

&&

.SHORT TERM FORECAST SOUTHCENTRAL ALASKA (Days 1 through 3: Today
through Saturday night)...

A major change in weather is on the way for the next few days,
bringing a swift end to the warm and dry conditions of the past
several days. A potent upper level low and trough centered over
the Canadian Arctic this morning will dig southward across
northeast Alaska today, then head southwestward across the
Interior to Southwest Alaska tonight through Friday before
ending up in the Bering Sea on Saturday. The track of the
low is favorable for widespread rain over Southcentral, as
short-waves continuously round the low center and move into
Southcentral, producing a prolonged period of strong upward
vertical motion over a deep layer. Airmass instability in place
today will also contribute to upward motion and abundant rainfall.

The initial short-waves ahead of the low center will cross the
Alaska Range and head across the Copper River Basin today. Thus,
expect showers to develop this morning and become more widespread
as we head through the day. As the trough then begins to dig
southwestward tonight, showers will spread southward toward the
coast. By Friday morning, expect widespread rain across most of
Southcentral. High temperatures on Friday will top out in the
mid 40s to mid 50s, some 15 to 25 degrees cooler than early
this week.

A new feature will then come in to play and help extend the
rainfall. A storm will move up from the Pacific toward the
Alaska Peninsula and eastern Aleutians on Friday, with its
frontal system and an upper level short-wave heading northward
to Kodiak and the Gulf. This will bring rain to Kodiak Friday
night. All of this will then head straight for Southcentral on
Saturday, once again leading to widespread rain. Strong south to
southeast flow along with a very moist atmosphere will lead to
heavy rain along the Gulf coast and Prince William Sound. Total
rainfall amounts from today through saturday night will be on the
order of one inch or more for interior Southcentral, with 2 to 4
inches likely along the coast.

Last, but not least, the airmass accompanying the upper low is
downright frigid, with 850 temperatures as low as -12 degrees
Celsius advecting into northern Alaska. The track of the low will
keep the coldest of air north of the Alaska Range. However, still
expect significant cooling of the airmass, especially across the
northern Susitna Valley and northern Copper River Basin. Snow
levels will drop to roughly 2000 to 3000 feet above sea level
tonight and persist through Friday night. This will lead to some
fresh snow on interior mountains, and possibly even some wet snow
through and near mountain passes. Specifically, the most likely
areas to see snow include Paxson on the Richardson Highway and
Eureka on the Glenn Highway.

&&

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

Warm and dry conditions are expected for most of the area today as
a ridge continues to hold over Southwest Alaska. A shortwave
trough dropping down from the interior of Alaska will kick off
a few showers over the lower Kuskokwim Valley this afternoon and
evening. On Friday this shortwave will move south and skirt north
and eastern parts of the Southwest with increasing clouds and
showers. This shortwave will begin to bring cooler temperatures to
the area on Friday as northeast low level flow develops. As we
head into Saturday the shortwave evolves into a closed upper level
low that will push towards the Kuskokwim Delta this will bring
much cooler air to the area on Saturday with highs in the 50s.
This low will interact with a front moving across the AKPEN and
will pull moisture into the Bristol Bay area with rain likely on
Saturday.

&&

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

A diminishing front lingers over the AKPEN and the eastern Bering
with a few showers but no impacts expected. This front will
dissipate later today. A gale force low will move south of the
western Aleutians today with its front pushing into the Bering and
through the Aleutians through Friday morning. The front will then
stall near Unalaska and weaken on Friday. The low will track
south of the Aleutians on Friday and move south of the area.
Another north Pacific low will move towards the central and
eastern Aleutians late Friday and Saturday this will bring winds
generally 30 knots or less to this area. The accompanying front
will spread rain and wind into the AKPEN on Saturday. Finally the
pressure gradient will tighten across most of the Bering on
Saturday in response to this low and colder air interacting with
an upper low over Southwest Alaska bringing winds 25 to 30 knots
across most of the Bering.

&&

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

There is growing confidence that a weakening low pressure system
moving south of the Aleutians will have the potential to bring
easterly gale force winds along the north gulf coast from Saturday
afternoon through Sunday morning. Elsewhere, expect winds less
than 35 kts and seas less than 20 ft over the Bering and the Gulf
for the Day 3 through 5 period.

&&

Long Term Discussion (Days 4 through 7: Sunday through Wednesday)

A broad upper level trough will extend across the Bering/Aleutians
and across Southcentral and Southwest Alaska during the extended
period. There is a high degree of confidence in this trend as good
ensemble agreement exists with respect to sea surface pressure as
the spread of ensemble members shows to remain within 0.8
standard deviations. These ensembles all show the same solution
which is the strengthening of the Aleutian Low this weekend. The
stronger Aleutian Low will support more on-shore flow across
Southcentral and Southwest Alaska. The stronger onshore flow will
allow for more cloud cover, cooler temperatures and a greater
chance of precipitation. Moreover, a series of southeasterly upper
level waves associated with the aforementioned Aleutian Low will
move over Southcentral and Southwest Alaska and increasing the
chance for precipitation during the extended period. Windward
locations (areas on the side of the mountains facing the Gulf of
Alaska) will see the highest chance for clouds and precipitation.
Leeward locations (areas on the land facing side of the mountains)
such as the Anchorage Bowl, will be the areas that will have the
least cloud cover and lowest chance of precipitation due to
downsloping.

&&

.AFC WATCHES/WARNINGS/ADVISORIES...
PUBLIC...NONE.
MARINE...NONE.
FIRE WEATHER...NONE.

&&

SYNOPSIS AND MODEL DISCUSSION...AP
SOUTHCENTRAL ALASKA...SB
SOUTHWEST ALASKA/BERING SEA/ALEUTIANS...RC
MARINE/LONG TERM...MF/ED