Small Craft Advisory 577, NWS Anchorage, AK

Southcentral and Southwest Alaska Forecast Discussion
National Weather Service Anchorage AK
624 PM AKDT Sun Jul 12 2026

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

Today marks the beginning of a prolonged wet and rainy pattern
for Southcentral, with expanding showers across Southcentral and a
slow-moving front into Prince William Sound. Anchorage, situated
under the axis of the trough stretching from Prince William Sound
to the Susitna Valley, has received several periods of moderate
rainfall today. Bands of rain showers will move through the
region the remainder of today into tonight, with precipitation
filling in over typical down-slope areas given the weak forcing.
Coastal ridging and strengthening easterly flow aloft will result
in relatively lower moisture for areas west of the Chugach,
limiting overall rain totals for Anchorage, but not to the extent
seen with previous systems. Meanwhile, the Copper River Basin
remains forecast to see relatively drier conditions with the best
chances for rain expected over the mountains.

Confidence has grown with regards to the expected pattern settling
over Southcentral Monday into Tuesday with regards to gusty winds
near Anchorage. Near Anchorage, there is increased potential for
strong winds to develop out of the Turnagain Arm Tuesday morning.
Strong and gusty winds will be possible through the Arm, and
depending on how these winds move over Cook Inlet, may span into
the southern reach of Anchorage, including the Hillside, Rabbit
Creek, and Potter Valley. Areas slightly further inland such as
Bear Valley into Glen Alps will see some gusty winds, but likely
less impactful than areas close to the Arm. This will also bring
another wet low pressure system over Kodiak Island early next
week. Uncertainty remains with the progression and speed of this
system, but forecast models show a faster moving trough
overspreading Kodiak Island Monday afternoon, amplifying over
Southcentral Tuesday morning. Rain chances will temporarily
diminish on Monday with the exception of the Gulf coast and
coastal mountains. Then rain chances return in earnest on Tuesday
as upper level diffluence overspreads the region.

-CL/BL

&&

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

Rain continues across Southwest Alaska this afternoon as a potent
shortwave embedded within the large upper level trough over the
eastern Bering exits the region north into the Interior. Rainfall
across Southwest should become increasingly more showery this
afternoon through the overnight hours as the better upper- level
support and moisture shifts north. Meanwhile, a weaker wave and
surface low drops south across the western Bering, bringing a
chance for rain through this evening to the Pribilof Islands.

The 500 mb pattern becomes increasingly amplified through Monday
as focus shifts towards a closed upper low/trough complex lifting
northeast around the ridge in the North Pacific. This will set the
stage for a North Pacific low to move towards the Central and
Eastern Aleutians before continuing its track across the
southeastern Bering towards the Southwest mainland. The moisture-
rich fetch of warm air from the Pacific and more rainfall will
overspread the Aleutian Chain by late tonight and spread across
the Alaska Peninsula and Southwest Alaska through Tuesday, with
most locations seeing between 0.5 to 1 inch of rain through
Tuesday. As the low progresses east, small-craft southwesterly
winds and increasing wave heights can be expected for the coastal
zones on the Pacific side of the eastern Aleutians and AKPen
beginning tomorrow, and for Bristol Bay on Tuesday. Additionally,
this system will bring a renewed possibility of marine lightning
and isolated thunderstorms. At this time, the greatest potential
for marine lightning continues to be Monday morning for the
coastal zones south of Adak/Atka. As this system continues east,
an isolated thunderstorm in the coastal zones south of the Alaska
Peninsula through early Tuesday morning also cannot be ruled out,
but confidence remains low for this area.

Looking ahead to Wednesday, the pattern continues as the upper
trough remains in place over western Alaska and the Bering Sea. By
Wednesday morning, the next deepening shortwave trough digs
across the Bering, bringing yet another round of rain to the
Aleutians and eventually to Southwest Alaska by midweek.

-JH

&&

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

A longwave trough remains in place over the Mainland through the
end of this week. Multiple waves of moisture moving through
Southwest and Southcentral Alaska will provide periods of light
to moderate rainfall during this time. Utilizing an ensemble mean
forecast model approach mitigates the outlier differences while
keeping this long range forecast trend.

Southcentral: Waves of moisture move through the Gulf bringing
periods of locally moderate rainfall to Prince William Sound,
Kodiak Island and Eastern Kenai Peninsula through Saturday.
Persistent southerly to southwesterly flow will provide the
conditions for stronger waves of moisture to track inland to the
Copper River Basin, Anchorage Bowl and Mat-Su Valleys. This flow
will also result in seasonally cooler pattern from increased
cloud cover and cooler temperatures.

Southwest: With the trough firmly in place, multiple low pressure
systems will move through the Bering Sea. Periods of light to
moderate rain are expected from the Aleutians to the Alaska
Peninsula through Friday. These conditions reach the Mainland by
Saturday keeping the pattern of seasonally cool temperatures and
cloud cover through this upcoming weekend.

-Johnston

&&

.AVIATION...

PANC...

Periods of rain with VFR to MVFR conditions will prevail through
Monday morning with a few breaks in the rainfall possible late
this evening. A second round of heavier rain, along with IFR
ceilings, is possible early Monday morning between 12z and 18z.
Southeast winds with gusts around 20 to 25 knots are likely late
this evening before weakening early Monday morning.

&&