Small Craft Advisory 705, NWS Anchorage, AK

Southcentral and Southwest Alaska Forecast Discussion
National Weather Service Anchorage AK
428 PM AKDT Thu Aug 27 2026

.SHORT TERM FORECAST SOUTHCENTRAL ALASKA (Days 1 through 3:
This afternoon through Sunday afternoon)...

Key Messages:

- Rain and wind from tonight through much of Friday.

- For Susitna Valley, 48-hour rain totals around 0.5 to 1.5 inches will
  allow for rises on many small streams and rivers, and localized
  ponding in low-lying or poor drainage areas.

- Winds increase through Cook Inlet tonight, with localized gusty
  southeasterly gap winds through Anchorage, Knik Valley, and
  Copper River Valley.

- From Saturday through Sunday, showers taper off and gusty
  northerly to westerly winds pick up, strongest along the coast.

Discussion:

Overall, the main weather messages remain largely unchanged since
yesterday, though there have been some changes to rain timing and
amounts, and forecast max wind gusts have increased in some
areas. Generally, much of Southcentral can expect to see
conditions similar to the winds and rain that were experienced on
Tuesday.

Clearer skies will come to an end tonight as a Bering Sea low
moves east across the region. The primary concerns will be rain
amounts in Susitna Valley and subsequent river rises, as well as
gusty winds for much of Southcentral. Widespread rain will spread
into Southcentral tonight...first into the western Susitna
Valley, but quickly pushing into the Cook Inlet, Mat-Su, Kodiak,
and Kenai Peninsula. The heaviest rainfall looks to fall tonight
before becoming more showery Friday morning. A secondary trough
and associated front will reinvigorate more robust rain showers
Friday afternoon. This system, like the previous system, is fairly
progressive and will quickly move through...helping to minimize
some of the flood concerns. However, with river levels still high
from our rain earlier this week, parts of Susitna Valley will
likely see minor impacts as the watershed absorbs this additional
rainfall.

This system will also bring another round of gusty gap flow winds
for the Turnagain Arm, Knik, and Copper Valley. Similar to the
Tuesday event, winds with gusts up to 40-50 mph are possible for
west Anchorage and the Hillside. The western Gulf will see small
craft to gales move in behind the front and the development of a
barrier jet will allow for some high end small craft to even gale
force winds along the northern Gulf coast and into Prince William
Sound. These strong winds will likely push inland some bringing
gusty winds to Cordova Friday night.

- PP/KC

&&

.SHORT TERM FORECAST SOUTHWEST ALASKA/BERING SEA/ALEUTIANS (Days
1 through 3: This afternoon through Saturday evening)...

Key Messages:

* A Wind Advisory remains in effect for the Kuskokwim Delta,
  Western Capes, and Northern Bristol Bay coast until 4PM Friday.
  South to southwest winds 25 to 35 mph with gusts up to 50 mph
  are expected.

* A High Surf Advisory remains in effect for the Kuskokwim Delta
  Coast until 4PM Friday for water levels 1 to 2 feet above the
  normal highest tide line.

* Moderate to heavy rain across Southwest Alaska through tonight,
  and tapers to showers through Friday.

Discussion:

Little change to the previous forecast package as the strong
front bringing gusty southerly to southwesterly winds and moderate
to heavy rainfall to Southwest Alaska continues through tonight
into tomorrow. The occluding front will continue to push inland
across western Alaska this evening as its deepening parent low
progresses east across the northern Bering and inland into the
Seward Peninsula. Rainfall intensity and winds are expected to
peak in strength late this afternoon into this evening, with gale-
force winds along the Kuskokwim Delta Coast and gale-force gusts
reaching as far inland as Bethel through this evening. The
corridor of gale-force winds moves southward into Bristol Bay as
well by this evening. A Wind Advisory remains in effect for the
Kuskokwim Delta Coast, Interior Kuskokwim Delta, the Western
Capes, and the Northern Bristol Bay Coast through 4 PM AKDT Friday
to address the gusty southerly to southwesterly winds.
Additionally, due to the tropical nature of the airmass
accompanying this system and strong jet dynamics, lightning that
has occurred across the Bering today is expected to become more
isolated as it spreads east across the southeastern Bering and
Bristol Bay waters through this evening.

The fetch of southwesterly winds into Kuskokwim Bay and Bristol
Bay will be quite lengthy. Wave heights in Kuskokwim Bay will
build through this afternoon with peak heights around 5 to 7 ft
near the coast with 8 to 11 ft away from the coast. Peak heights
should occur this afternoon through evening before slowly
subsiding through Friday. A High Surf Advisory remains in effect
until 4 PM AKDT Friday for the Kuskokwim Delta Coast for water
levels 1 to 2 feet above the highest tide line. There is potential
for coastal erosion due to the high surf, though the coastal
flood threat remains low (15 to 25 percent).

Heavy rain tapers to showers across the Kuskokwim Delta late this
evening into tonight as heavy rain pushes east into the Kuskokwim
Valley, Bristol Bay, and along the Western Alaska Range this
evening. The surface low tracks into Norton Sound by Friday
morning as the main upper- level trough begins to move into
Southwest from the Bering. This will keep steady rain going across
the mountain ranges aided by southwesterly upslope flow. Colder
air moves into Southwest from the Bering and creates more of a
showery regime across the rest of the area. Showers will taper off
from west to east through Saturday afternoon as the area finally
begins to see a drying trend. When all is said and done, about
0.50 to 1.5 inches of rain will fall across Southwest from early
Thursday morning through early Saturday morning, with localized
higher amounts around 2 inches likely along the Western Alaska
Range.

Another push of warm, moist, tropical air moves into the southern
Bering from the North Pacific Saturday morning through Saturday
evening. Another upper level low will track across Kamchatka
Saturday morning and move into the extreme western Bering through
Saturday evening. Both the upper level system and surface low look
to be weaker Saturday in contrast to the current system.
Nonetheless, rain will move into Shemya by Saturday morning and
advance north and eastward across the Bering to near the Pribilof
Islands by Saturday evening. Sustained winds with this system look
to be small-craft or less at this time. Stay tuned for forecast
updates as the stormy pattern across the Bering continues to
unfold.

&&

.LONG TERM FORECAST (Days 4 through 7: Monday through Thursday)...

The progressive pattern looks to continue through late Tuesday or
early Wednesday as multiple upper-level waves move southeast from
the Chukchi Sea to the Alaska Panhandle. This will generally
bring periods of active weather, with some lulls between systems.

The combination of cold air advection, a northwesterly low-level
jet, and a shortwave trough through the northwesterly flow, will
lead to and increase in northwesterly winds through the Barren
Islands and around Kodiak Island/the AKPen, as well as northerly
and westerly gap winds for Seward and Whittier by late Monday.
Clouds and scattered showers will linger across portions of
Southcentral Alaska as these waves move through, especially for
the higher terrain and through the Copper River Basin.

Farther west, an upper-level ridge will build over the North
Pacific, extending across the Aleutians, by late Monday. A warm
front attached to a Kamchatka Low will move overtop the ridge and
into the southern Bering for Tuesday morning. This feature looks
to transition into an elongated surface low as it phases with a
shortwave trough moving southeast through the Y-K Delta, brining
more rain and gusty winds from Bristol Bay to Kodiak Island.

Model agreement then falls apart late Tuesday through Thursday.
The biggest question will be how amplified the longwave pattern
gets as the aforementioned ridge begins to extend north and east
ahead of a deepening trough over the far western Aleutians. Most
guidance is beginning to advertise a ridge axis moving over
Southcentral with multiple upper-level waves and resultant surface
lows moving into the western half of the Bering from the North
Pacific. The surface fronts associated with these surface
features look to move as far east as western Alaska Wednesday and
Thursday with additional rounds of heavy rain and gusty south to
southwest winds.

- TM

&&

.AVIATION...

PANC...VFR conditions and light winds will persist through
tonight. Rain is then expected to spread across the terminal
tonight with periods of light to moderate rain showers Friday
morning through Friday evening. The best chance for heavier rain
showers will be after midnight through around 6 AM Friday and
again Friday afternoon. MVFR ceilings and visibility are likely
is any steadier rainfall. A strong southeasterly wind
through Turnagain Arm will quickly develop this evening. These
winds are expected to move over the terminal tonight and continue
through Friday night before diminishing. Expect winds similar to
those of two day's ago, with sustained SE winds 20 to 35 mph with
gusts 35 to 50 mph.

&&