499
FXAK68 PAFC 121419
AFDAFC

Southcentral and Southwest Alaska Forecast Discussion
National Weather Service Anchorage AK
619 AM AKDT Sat Sep 12 2026

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

A weakening cold front is advancing south into the northern half
of Southcentral this morning, continuing to lose integrity as it
begins to shear apart over complex terrain. Rainfall along this
boundary has thus far proved to be rather unimpressive, with much
of the rain we are seeing reach the ground staying over the
Talkeetnas and parts of the Mat-Su Valleys. There is still a
chance for some light rain or sprinkles to work south into
Anchorage later this morning, but this potential is looking a lot
lower than it did yesterday. Parts of the Copper Basin are still
anticipated to see a few passing rain showers as a weak shortwave
impulse following the front shifts east into the region prior to
shearing out near the AlCan border. Farther south, some marine
stratus has sneaked up the Cook Inlet this morning, pushing low
cloud ceilings into Homer, Kenai and Anchorage. Cloud cover should
still mostly break up with time today as the frontal wave shifts
south and as drier air filters in from the northwest.

Otherwise, there is little change for the outlook extending
through the weekend. Zonal flow will persist in the wake of the
front through Sunday as the ridge of high pressure that has now
been flattened out by the frontal system attempts to rebound
across the eastern Bering and southern Mainland. This will foster
generally dry conditions with a few passing clouds for most of
Southcentral for the latter half of the weekend. A weak offshore
pressure gradient will also develop behind the frontal passage,
supporting gusty gap winds through Seward, Whittier and Valdez
from this evening through Sunday.

Between Sunday and Monday, what`s left of the front over the Gulf
will stall and then begin to lift back northwards as a warm front
while a low moving around the western side of the ridge
intensifies over the eastern Bering. Most places across the region
will remain dry through most of the day on Monday, but expect
cloud cover to increase yet again as the front lifts northeast. By
late Monday afternoon, chances for light rain will begin to tick
up across the Kenai Peninsula, shifting north into Anchorage and
the Mat-Su by the evening hours. Expect a continued unsettled,
blustery and wetter pattern to continue to unfold into the middle
of next week as the Bering low moves inland and heads across the
Interior.

-AS

&&




.SHORT TERM FORECAST SOUTHWEST ALASKA/BERING SEA/ALEUTIANS (Days
1 through 3: This morning through Tuesday morning)...

Key Message:

* A strengthening low which lifts across the Aleutians early
  Sunday morning and clips the YK Delta on Monday could bring
  small-craft advisory onshore winds, increasing the potential for
  a round of elevated coastal water levels. We continue to closely
  monitor this storm.

Discussion:

A mostly zonal front extends from Bristol Bay to Atka trailing
along a moisture fetch from the North Pacific this morning. This
will bring isolated showers to Aleutian Islands from Atka to the
AKPen through the day, with more scattered showers along the
Alaska Range down through the AKPen due to upsloping winds. On
Sunday, morning a weak low lifts into Bristol Bay bringing 0.25
to 0.30 inches of rainfall to much of the Southwest mainland.
This will be followed by a larger low that passes south of the
Pribilofs as it tracks toward the Kuskokwim Delta. The heaviest
rain from this second low will be concentrated along a swath
between Adak and Unalaska, and across the Pribilof islands with
rain totals of 0.50 inches up to 1.30 inches from Sunday through
Tuesday morning. Meanwhile, light showers are expected across
most of Southwestern Alaska during this period.

&&


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

Forecast models are coming into general agreement with the
synoptic pattern early next week with a developing trough over the
eastern Bering and a deepening surface low and front approaching
the YK Delta on Monday. As the low continues to deepen into into
Tuesday just southwest of the Seward Peninsula, its broad front
pushes across all of Southwest Alaska and the Alaska Peninsula
through Tuesday night. The same front moves into Southcentral by
the middle of next week, aided or reinforced by a shortwave trough
traveling along the front from the Gulf of Alaska, with the front
pushing into western Canada by Thursday evening.

While finer details remain unresolved, including small
differences in timing, the exact track of the low, as well as the
strength of the low and potential phasing with other shortwave
features, increased confidence exists that much if not all of
Southwest experience a period of rainfall and gusty winds Monday
into Tuesday, with these same hazards to impact Southcentral on
Wednesday.

Weak high pressure attempts to build into Alaska Thursday into
the end of the week. Residual areas of rain activity will likely
linger across parts of both Southwest and Southcentral on
Thursday, decreasing further by Friday. The only interesting
feature to note in the long term forecast is the arrival of yet
another North Pacific low lifting into the Western Aleutians at
the end of the forecast period.

-BL

 &&


.AVIATION...

PANC...Light and variable winds will persist through most of the
TAF period. Southeast winds this morning could approach 10 kts at
times before diminishing to light and variable by late this
morning to early this afternoon. MVFR ceilings are will persist
through much of the morning as a weakening front across Southwest
Alaska moves over the area. Rain chances are less (20 to 40%
chance) due to most of the moisture remaining over the Western
Alaska Range and the Chugach Range. MVFR ceilings will lift back
to VFR by late morning as the front moves east. High pressure,
clear conditions, along with weak flow aloft and at the surface
will move back into the area for Saturday afternoon through the
end of the TAF period Sunday morning. This setup could allow for
fog formation Saturday night into Sunday morning.

&&


$$