093
FXAK68 PAFC 041323
AFDAFC

Southcentral and Southwest Alaska Forecast Discussion
National Weather Service Anchorage AK
523 AM AKDT Sat Oct 4 2025

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

A warm front currently over Kodiak Island will push north into
Southcentral today as the ridge that brought drier weather to the
region over the past few days gets pushed off to the east.
Precipitation will spread north with consistent upsloping rain
along the Gulf coast, Alaska Range and Susitna Valley. Shallow
low level southeasterlies across the Chugach and Kenai Mountains
will lead to some drying effect from the Mat Valley south through
Anchorage and into the western Kenai, but shortwaves moving
through the southerly flow will help bring periods of light rain
to these areas. If this were a wintertime set-up this forecast
package would more likely have lower PoPs (probability of
precipitation) for the downsloped areas, but given the warm and
moist environment with precipitable water between 1 and 1.5 inches
over the southern Gulf right now, moisture is likely going to be
able to overcome the southeasterlies. Additionally, there is a
deep fetch of southerlies to southwesterlies aloft, which will
help bring in more moisture to the Inlet. This pattern will
maintain through the weekend, but the southeasterlies are
stronger today than tomorrow, so of the two days, today might be
less wet.

Looking ahead into the start of the work week, forecast
uncertainty increases as the upper low with multiple embedded
shortwaves digs over Kodiak Island Monday morning before lifting
north into Southcentral later in the day. While the upper levels
look to be in good agreement overall between the GFS, GEMNH, and
ECMWF, the developing lee-side surface low will dictate the extent
of the precipitation. Some colder air also works back in, so
expect slightly cooler temperatures and a return of snowfall above
~3500ft.

&&



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

The near-term forecast remains on track as the strong Bering Sea
low to the west of St. Matthew Island continues to remain nearly
stationary through Sunday as it weakens in place. Peak winds are
reaching the Kuskokwim Delta Coast currently with southeasterly
gusts between 40 to 50 mph. Along with these winds, expect wave
heights between 6 to 10 feet in the coastal waters of the
Kuskokwim Delta Coast. Water-levels are expected to rise around 1
to 2 feet above the normal highest tide line with the peak
occurring late this morning. The threat for significant coastal
flooding remains low. However, localized low lying areas could
fill up with water and the high seas could produce localized areas
of erosion along the coast. Gusty winds slowly diminish and wave
heights slowly subside starting this afternoon. While the majority
of the precipitation associated with the big Bering low will
remain confined to the Kuskokwim Delta Coast and Nunivak Island,
light rain will make it inland across the rest of Southwest for
the morning. For the Aleutians, cold air wraps around the low and
through the western and south-central Bering through today as
showers will persist along the Aleutian Chain today through
Sunday.

Meanwhile, the synoptic pattern continues to amplify today as the
broad Bering Sea trough continues to dig farther south into the
North Pacific. A series of moisture-laden shortwaves will lift
northward through the North Pacific, across the Alaska Peninsula
(AKPEN), and into mainland Southwest Alaska today through Monday
morning. The result will be relatively widespread light to
moderate rain across the AKPEN and Southwest Alaska through this
weekend and into the beginning of the next work week. With regards
to Southwest Alaska, most rain associated with this series of
shortwaves will fall along Bristol Bay, interior Bristol Bay, as
well as the Kuskokwim Valley. Cold air moves back into the area
for Monday afternoon and evening as westerly flow keeps remaining
showery activity confined to the Western Alaska Range and Aleutian
Range.

The next weather-maker in this active pattern begins to gather
near the Kamchatka Peninsula Sunday afternoon as a low pressure
system there moves eastward towards the Bering Sea. A trough over
Kamchatka will dig into the North Pacific through Tuesday morning
as a ridge builds across the central and eastern Bering. This
will help to drag tropical moisture northward along with warm air
to the Bering Sea starting Sunday night. An atmospheric river
will develop and move eastward across the Western Aleutians and
western Bering Sea Monday and make it to the Central Aleutians
and Pribilof Islands by Tuesday. The parent low pressure looks to
move northward from the southern coast of Kamchatka to its
northern coast by Monday night before the system elongates further
east into the Bering near St. Matthew Island Tuesday morning.

In addition to the moderate to heavy rain across the
Western/Central Aleutians and Pribilof Islands, will be strong
gusty southerly to southwesterly winds across the North Pacific
and Bering Sea. These strong winds will be driven by the pressure
gradient between strong North Pacific high pressure building into
the Gulf of Alaska and the deepening low pressure near Kamchatka
and the Bering Sea. Mainland Southwest Alaska, most notably
Nunivak Island, the Kuskokwim Delta Coast, and Kuskokwim Delta
look to see light to moderate rain beginning Tuesday morning. How
the atmospheric river orients after Tuesday morning is still
somewhat uncertain which therefore makes the precipitation
forecast uncertain for the rest of mainland Southwest past Tuesday
morning. Stay tuned to forecast updates with this system as
attention slowly turns to a developing atmospheric river for next
week. The wet pattern continues across Southwest, the AKPEN, the
Aleutians, and Bering!

&&

.LONG TERM FORECAST (Days 4 through 7: Tuesday through
Friday)...

Southcentral will remain in a region of high pressure for much of
the long range forecast. With the exception of a trough through
Southcentral sometime during the middle to latter half of next
week, benign conditions are forecast. Instead, the focus will
remain west of the Alaska Range and across Southwest Alaska, the
Aleutians, and Bering Sea.

There have been hints in the long range guidance that Tuesday`s
western Bering low will be slower and deeper. Widespread showers
and strong winds will accompany the low`s front regardless, first
for the Western and Central Aleutians Tuesday morning, and then
for the Kuskokwim Coast and YK Delta Tuesday afternoon. There is
always some uncertainty with the long range forecast, especially
when it comes to nailing down timing and placement of impacts.
That beings aid, onshore flow remains forecast into the Kuskowim
Delta Tuesday and Tuesday night, which could coincide with high
tides to bring minor coastal flooding and erosion to the Kusko
Coast. Meanwhile, winds across the Western Aleutians are trending
stronger, with the potential to see southerly winds gusting up to
50 knots. The low and front depart Southwest Alaska and the
Aleutians Wednesday night

By the end of next week a strong Kamchatka low is forecast to
deepen with a broad front to push through the Bering and Aleutian
Chain with more showers and potential strong winds for the region.

BL


&&
.AVIATION...

PANC...A southeasterly Turnagain Arm wind intermittently affects
the terminal through the morning hours, with gusts as high as
25-30 kt. Periods of light rain with ceilings dropping below 5000
ft will be possible following the arrival of a front later this
morning, though conditions are expected to remain VFR. Winds
diminish at the surface as the Turnagain Arm wind shifts out of
the terminal this afternoon. This leads to increasing low-level
wind shear as southeasterly winds are likely to continue aloft.
Chances for MVFR ceilings increase with more persistent rainfall
potential on Sunday, particularly late in the day.

Quesada

&&


$$