Small Craft Advisory 235, NWS Anchorage, AK

116 
FZAK51 PAFC 201155
CWFAER

Coastal Waters Forecast
National Weather Service Anchorage Alaska
355 AM AKDT Sat Mar 20 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.

PKZ197-210045-
355 AM AKDT Sat Mar 20 2021
.SYNOPSIS FOR THE NORTH GULF COAST+KODIAK ISLAND WATERS+
COOK INLET...

A front over the western Gulf moves to the eastern Gulf by Sun
morning. A 992 mb low forms 25 nm S of Kodiak City midday Sat 
then moves into the eastern Gulf by late Sat night. Weak troughing 
persists over the northern Gulf through late Sun night.

$$

PKZ119-210045-
Cape Suckling to Cape Cleare-
355 AM AKDT Sat Mar 20 2021

...GALE WARNING THROUGH TONIGHT...

.TODAY...E wind 20 kt increasing to 35 kt in the afternoon. 
Seas 5 ft building to 9 ft in the afternoon. Freezing spray 
in the morning. Snow.
.TONIGHT...E wind 35 kt becoming N 25 kt after midnight. 
Seas 12 ft. Snow and rain.
.SUN...NW wind 20 kt. Seas 9 ft.
.SUN NIGHT...NW wind 20 kt. Seas 9 ft.
.MON...E wind 20 kt. Seas 7 ft.
.TUE...N wind 25 kt. Seas 10 ft.
.WED...W wind 30 kt. Seas 11 ft.

$$

PKZ120-210045-
Cape Cleare to Gore Point-
355 AM AKDT Sat Mar 20 2021

...GALE WARNING THROUGH TONIGHT...

.TODAY...NE wind increasing to 40 kt. Seas 7 ft building to 11 ft 
in the afternoon. Freezing spray in the morning. Snow.
.TONIGHT...NE wind 35 kt becoming N 25 kt after midnight. 
Seas 13 ft. Snow and rain.
.SUN...NW wind 25 kt. Seas 9 ft.
.SUN NIGHT...N wind 20 kt. Seas 7 ft.
.MON...NE wind 25 kt. Seas 6 ft.
.TUE...NW wind 30 kt. Seas 11 ft.
.WED...W wind 35 kt. Seas 11 ft.

$$

PKZ121-210045-
Resurrection Bay-
355 AM AKDT Sat Mar 20 2021

...SMALL CRAFT ADVISORY SUNDAY...

.TODAY...N wind 10 kt. Seas 2 ft.
.TONIGHT...N wind increasing to 20 kt. Seas building to 4 ft. 
Freezing spray.
.SUN...N wind 25 kt. Seas 5 ft. Freezing spray.
.SUN NIGHT THROUGH TUE...N wind 15 kt. Seas 3 ft.
.WED...N wind 10 kt. Seas 2 ft.

$$

PKZ125-210045-
Prince William Sound-
355 AM AKDT Sat Mar 20 2021

.TODAY...NE wind increasing to 20 kt. Seas building to 4 ft. 
Freezing spray in the morning.
.TONIGHT...NE wind 20 kt. Seas 4 ft. Freezing spray after midnight.
.SUN...NW wind 20 kt. Seas 4 ft. Freezing spray in the morning.
.SUN NIGHT THROUGH TUE...N wind 15 kt. Seas 3 ft.
.WED...N wind 10 kt. Seas 2 ft.

$$

PKZ126-210045-
Port Valdez-
355 AM AKDT Sat Mar 20 2021

.TODAY...E wind 15 kt diminishing to 10 kt in the afternoon. 
Seas 3 ft. Freezing spray in the morning.
.TONIGHT...Variable wind less than 10 kt becoming E 10 kt after
midnight. Seas 2 ft.
.SUN...E wind 15 kt becoming NE 10 kt in the afternoon. Seas 3 ft.
Freezing spray in the morning.
.SUN NIGHT...NE wind 10 kt. Seas 2 ft.
.MON THROUGH WED...E wind 15 kt. Seas 3 ft.

$$

PKZ127-210045-
Valdez Narrows-
355 AM AKDT Sat Mar 20 2021

...SMALL CRAFT ADVISORY THROUGH SUNDAY...

.TODAY...NE wind 25 kt. Seas 3 ft. Freezing spray.
.TONIGHT...NE wind 30 kt. Seas 3 ft. Freezing spray.
.SUN...NE wind 30 kt diminishing to 20 kt in the afternoon. 
Seas 3 ft. Freezing spray.
.SUN NIGHT THROUGH WED...NE wind 25 kt. Seas 3 ft.

$$

PKZ128-210045-
Valdez Arm-
355 AM AKDT Sat Mar 20 2021

...SMALL CRAFT ADVISORY TONIGHT AND SUNDAY...

.TODAY...NE wind 20 kt. Seas 4 ft. Freezing spray.
.TONIGHT...NE wind 25 kt. Seas 5 ft. Freezing spray.
.SUN...NE wind 25 kt diminishing to 15 kt in the afternoon. 
Seas 5 ft. Freezing spray.
.SUN NIGHT AND MON...NE wind 25 kt. Seas 5 ft.
.TUE THROUGH WED...NE wind 20 kt. Seas 4 ft.

$$

PKZ129-210045-
Passage Canal-
355 AM AKDT Sat Mar 20 2021

.TODAY...E wind 10 kt. Seas 2 ft. Snow.
.TONIGHT...Variable wind 10 kt becoming W 20 kt after midnight. 
Gusts to 30 kt near Whittier after midnight. Seas 2 ft. 
Freezing spray after midnight.
.SUN...W wind 20 kt. Gusts to 30 kt near Whittier. Seas 2 ft. 
Freezing spray.
.SUN NIGHT...W wind 15 kt. Seas 2 ft.
.MON...W wind 10 kt. Seas 2 ft.
.TUE...W wind 15 kt. Seas 2 ft.
.WED...Variable wind 10 kt. Seas 2 ft.

$$

PKZ130-210045-
West of Barren Islands including Kamishak Bay-
355 AM AKDT Sat Mar 20 2021

...GALE WARNING THROUGH TONIGHT...

.TODAY...NE wind 45 kt. Seas 17 ft. Freezing spray in the morning. 
Snow.
.TONIGHT...NE wind 40 kt diminishing to 25 kt after midnight. 
Seas 15 ft subsiding to 8 ft after midnight. Freezing spray.
.SUN...NE wind 15 kt. Seas 4 ft.
.SUN NIGHT...NE wind 25 kt. Seas 6 ft.
.MON...NE wind 25 kt. Seas 7 ft.
.TUE...NW wind 30 kt. Seas 9 ft.
.WED...SW wind 25 kt. Seas 6 ft.

$$

PKZ131-210045-
Barren Islands East-
355 AM AKDT Sat Mar 20 2021

...GALE WARNING THROUGH TONIGHT...

.TODAY...E wind 45 kt. Seas 13 ft. Snow and rain.
.TONIGHT...NE wind 40 kt becoming N 25 kt after midnight. 
Seas 13 ft.
.SUN...W wind 25 kt. Seas 10 ft.
.SUN NIGHT...NW wind 20 kt. Seas 7 ft.
.MON...NE wind 25 kt. Seas 7 ft.
.TUE...NW wind 30 kt. Seas 11 ft.
.WED...W wind 30 kt. Seas 10 ft.

$$

PKZ132-210045-
Marmot Island to Sitkinak-
355 AM AKDT Sat Mar 20 2021

...GALE WARNING TONIGHT...

.TODAY...S wind 20 kt becoming SW 30 kt in the afternoon. 
Seas 10 ft. Rain.
.TONIGHT...W wind 35 kt, except N 30 kt N of Dangerous Cape. 
Seas 12 ft.
.SUN...W wind 20 kt. Seas 11 ft.
.SUN NIGHT...SW wind 15 kt. Seas 8 ft.
.MON...NE wind 25 kt. Seas 8 ft.
.TUE...NW wind 30 kt. Seas 10 ft.
.WED...W wind 35 kt. Seas 10 ft.

$$

PKZ136-210045-
Chiniak Bay-
355 AM AKDT Sat Mar 20 2021

...SMALL CRAFT ADVISORY TONIGHT...

.TODAY...SE wind 10 kt becoming NE 15 kt in the afternoon. 
Seas 4 ft. Rain.
.TONIGHT...N wind 25 kt becoming NW 15 kt after midnight. 
Seas 5 ft subsiding to 2 ft after midnight. Rain and snow.
.SUN...W wind 10 kt. Seas 2 ft.
.SUN NIGHT...N wind 10 kt. Seas 3 ft.
.MON...NE wind 20 kt. Seas 4 ft.
.TUE...NW wind 20 kt. Seas 3 ft.
.WED...SW wind 20 kt. Seas 3 ft.

$$

PKZ137-210045-
Marmot Bay-
355 AM AKDT Sat Mar 20 2021

...SMALL CRAFT ADVISORY THROUGH TONIGHT...

.TODAY...E wind 25 kt. Seas 10 ft. Rain and snow.
.TONIGHT...NE wind 25 kt becoming NW 15 kt after midnight. 
Seas 8 ft subsiding to 2 ft after midnight. Snow and rain.
.SUN...W wind 10 kt increasing to 15 kt in the afternoon. 
Seas 2 ft.
.SUN NIGHT...NW wind 10 kt. Seas 3 ft.
.MON...NE wind 20 kt. Seas 6 ft.
.TUE...NW wind 20 kt. Seas 4 ft.
.WED...SW wind 20 kt. Seas 4 ft.

$$

PKZ138-210045-
Shelikof Strait-
355 AM AKDT Sat Mar 20 2021

...GALE WARNING TODAY...

.TODAY...NE wind 35 kt. Seas 12 ft. Freezing spray in the 
morning. Snow changing to rain.
.TONIGHT...N wind 30 kt becoming variable 15 kt after midnight. 
Seas 11 ft subsiding to 5 ft after midnight.
.SUN...SW wind 20 kt. Seas 5 ft.
.SUN NIGHT...N wind 15 kt. Seas 3 ft.
.MON...N wind 20 kt. Seas 6 ft.
.TUE...W wind 25 kt. Seas 5 ft.
.WED...SW wind 25 kt. Seas 6 ft.

$$

PKZ139-210045-
Cook Inlet Kalgin Island to Point Bede-
355 AM AKDT Sat Mar 20 2021

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

.TODAY...NE wind 40 kt. Seas in ice free waters 13 ft. Heavy freezing
spray in the morning. Snow.
.TONIGHT...N wind 40 kt becoming NE 25 kt after midnight. Seas in
ice free waters 12 ft subsiding to 7 ft after midnight. Heavy
freezing spray.
.SUN...NE wind 15 kt. Seas in ice free waters 3 ft. Freezing spray.
.SUN NIGHT AND MON...N wind 25 kt. Seas in ice free waters 6 ft.
.TUE...NW wind 20 kt. Seas in ice free waters 4 ft.
.WED...SW wind 20 kt. Seas in ice free waters 4 ft.

$$

PKZ140-210045-
Cook Inlet North of Kalgin Island-
355 AM AKDT Sat Mar 20 2021

...BRISK WIND ADVISORY THROUGH TONIGHT...

.TODAY...NE wind 25 kt. 
.TONIGHT...N wind 25 kt becoming NE 15 kt after midnight.
.SUN...Variable wind less than 10 kt becoming NE 10 kt 
in the afternoon.
.SUN NIGHT...NE wind 10 kt.
.MON...N wind 15 kt.
.TUE...W wind 10 kt.
.WED...S wind 15 kt.

$$

PKZ141-210045-
Kachemak Bay-
355 AM AKDT Sat Mar 20 2021

.TODAY...NE wind 20 kt. Seas 3 ft. Freezing spray.
.TONIGHT...N wind 20 kt becoming NE 10 kt after midnight. 
Seas 2 ft. Freezing spray in the evening.
.SUN...NE wind 10 kt in the morning becoming variable 
less than 10 kt. Seas 2 ft.
.SUN NIGHT...NE wind 10 kt. Seas 2 ft.
.MON...N wind 10 kt. Seas 2 ft.
.TUE...NW wind 15 kt. Seas 4 ft.
.WED...SW wind 15 kt. Seas 4 ft.

$$

Southcentral and Southwest Alaska Forecast Discussion
National Weather Service Anchorage AK
527 AM AKDT Fri Mar 19 2021

.ANALYSIS AND UPPER LEVELS...

A surface low and associated Gulf moisture continue to depart the
area this morning, but are still likely producing snow along the
Edgerton Highway through McCarthy. Elsewhere, skies have cleared
out entirely for all areas from Glennallen west up to the Alaska
Range. Skies are mainly clear across Southwest Alaska, but that
will rapidly change as the next storm system approaches today.
That storm system is a nicely wound up low over the open waters of
the Bering well west of the Pribilofs. It is drawing warmer air
northward, with rain occurring as far north as St. George. This
storm system is keeping nearly the entire Bering under a dense
overcast.

In the upper levels a trough is over eastern Alaska, with axis
along the Yukon border. A 90 knot jet streak is rounding the base
of the trough over Southwest Alaska. A stronger jet streak is
aimed at the Eastern Aleutians, with a larger longwave trough with
embedded upper level lows over the far western Bering. The pattern
continues to favor well below average temperatures across
Southcentral and most of Southwest Alaska as well.

&&

.MODEL DISCUSSION...

The models remain in excellent agreement on the large scale
pattern across southern Alaska. The main area of contention
continues to be run-to-run changes among nearly all the models on
the track of a low that hasn't even formed yet on how close to
Kodiak it will track. The trend has certainly been north with the
track center, which makes the low far less impactful compared to
where it was in the guidance 24 to 48 hours ago. More on that
below. Other than also assessing the impacts of the same front
reaching Southwest Alaska later today, also discussed below most
everything else is very high confidence.

&&

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

&&

.SHORT TERM FORECAST SOUTHCENTRAL ALASKA (Days 1 through 3/Today
through Sunday night)...

Cold and dry conditions will prevail across most of Southcentral
over the next few days. The only storm to speak of will pass to
the south across the Gulf tonight through Saturday night. This
will bring some high clouds northward into Southcentral Saturday
afternoon through Saturday night. Otherwise, expect mostly clear
skies with abundant sunshine today and Sunday. Strong gap winds
along the coast will slowly diminish today through tonight as
offshore flow weakens and a short-wave ridge approaches.

There have been some changes made to the forecast for Kodiak and
the Gulf waters, as it now looks like the frontal system moving in
from the Bering Sea will track a bit farther north, with a triple
point low now expected to track across Kodiak Island (instead of
passing to the south). As a result, now expect above freezing air
to make it as far north as Kodiak City on Saturday, causing snow
to mix with or change to rain. Even with this, still expect snow
and blowing snow out ahead of the warm front tonight through
Saturday morning. Snow could be briefly heavy at times, especially
along the northern and eastern sides of Kodiak Island due to
upslope flow from an easterly wind. Then expect little snow
accumulation during the day on Saturday as surface temperatures
rise above freezing for most of the island. There could be some
additional light snow accumulation Saturday evening as the triple
point low exits eastward across the Gulf and temperatures cool
back below freezing.

With the farther north progression of this system, some light snow
will attempt to spread northward to the Kenai Peninsula. However,
the cold, dry airmass in place will largely lead to sublimation of
the snow before it reaches the surface. There could be some very
light snow along the immediate coastline and coastal mountains.

&&

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

Mostly clear conditions will continue through the morning under an
upper level ridge. Cloud cover will increase this afternoon ahead
of a front. Snow will move onshore over Bristol Bay this evening.
Blowing snow reducing visibilities to one half mile or less is
likely along the immediate coastline west of Dillingham. The
heaviest snowfall will occur this evening through early Saturday
morning. Snow-to-liquid ratios will be somewhat tricky to
determine. The snow growth layer in centered around 650 mb where
temperatures are near -15C. However, strongest negative omega
values (which would indicate rising motion) are seen well below
this layer, closer to the surface. A 900 mb low level jet will
accompany the front, leading to flakes being reduced in size as
they descend. As such, this may slightly inhibit higher snowfall
totals, however a general 4 to 8 inches remains likely in
Dillingham and surrounding areas. Lesser amounts will occur over
the Kuskokwim Delta. Moderate snow will taper to snow showers by
Saturday afternoon and move slightly farther inland. A weak upper
trough will lead to widespread snow showers on Sunday, with only
minimal accumulations and calm winds.

&&

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

A front continues to track across the Pribilofs and eastern
Aleutians. Snow will change to rain this morning over the
Pribilofs. All rain will persist across the Aleutians in a long
southwest fetch. Cold air will build behind the front by Saturday.
An upper low will lead to a weak surface disturbance and rain/snow
showers will continue across the Chain. These will slightly taper
off by Sunday, although snow showers will continue over the
Pribilofs and Bering side of the Aleutians as a cold, northerly
flow develops.

&&

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

Gulf: A weak trough sets up across the northern Gulf through Tue.
Forecast guidance agrees. Widespread small craft winds and waves
behind the low diminish Mon. Seas to 12 feet over the southern
Gulf, subsiding. A new low and front moves to the central Gulf
for Tue. Small craft winds spread from the Shumagin Islands to the
Barren Islands and into the Gulf for Tue.

Bering: A low and front move into Western Alaska for Sun. High
pressure slides across the Bering through Tue. Forecast guidance
agrees. Upper level features bring widespread northwesterly small
craft winds and waves over the Bering through Mon. These combine
with a low and front passing south of the Aleutians Mon and Tue
to bring gale force winds over the Aleutians through Tue. A new
low and front move into the western Bering by Tue. Widespread
high end southerly gale force winds extend into the central
Bering for Tue. Seas building to 22 feet spread into the central
Bering by Tue.

&&

.LONG TERM FORECAST (Days 4 through 7)...

The long term forecast begins late Sunday with an upper-level
ridge extending from Pribilofs to the North Slope. This feature is
bookended by two upper-level lows, one over the Al-Can boarder
and the other over the Gulf of Anadyr. This is resulting in an
omega block type pattern for the northern half of the state, while
a more zonal flow dominates across the Aleutians and Gulf. The
Gulf of Anadyr low slides to the northeast on Monday, bringing
snow to the western coast. The track of this low not only allows
the upper-level ridge to retreat, but also begins the transition
to a more zonal pattern from the Bering east across the state by
mid-week. This pattern shift will bring a strong low into the
western Bering with a front moving quickly east across the Bering,
reaching the western coast by late Tuesday. As the front moves
onshore and weakens, a second shortwave will move from the North
Pacific northeast toward Southwest Alaska. This feature looks to
deepen a secondary low as it tracks into the Y-K Delta Wednesday.
Its associated front moves over Southcentral with a triple-point
low likely spinning up in the northern Gulf. The uncertainty for
Southcentral will be how much warmer air moves in along with the
southwesterly flow ahead of the developing Gulf low. This current
set up could bring a brief period of warmer temps and mixed
precipitation across the Kenai Peninsula and Anchorage Bowl
before the Gulf low deepens, moves east, and wraps colder air
back over the Southern Mainland.

&&

.AFC WATCHES/WARNINGS/ADVISORIES...
PUBLIC...Winter Weather Advisory: 161.
MARINE...Gale: 119 120 130 131 138 139 180-185 351 411 412 414.
Heavy Freezing Spray: 121 129 130 139 160 165 180 185.

&&

SYNOPSIS AND MODEL DISCUSSION...JPW
SOUTHCENTRAL ALASKA...SEB
SOUTHWEST ALASKA/BERING SEA/ALEUTIANS...AP
MARINE/LONG TERM...KZ/MF