476
FXAK68 PAFC 101259
AFDAFC

Southcentral and Southwest Alaska Forecast Discussion
National Weather Service Anchorage AK
459 AM AKDT Wed Sep 10 2025

.SHORT TERM FORECAST SOUTHCENTRAL ALASKA (Days 1 through 3: Today
through Friday)...
The large low that is over Kodiak Island early this morning is the
remnants of former typhoon Peipah. This system remains laden with
tropical moisture and will take up residence in the northern Gulf
of Alaska for the rest of the week before finally dissipating
there this weekend. A cold upper level Arctic trough is in the
northwest part of the state and is digging southward and will be
phasing with the 500 mb low of the Kodiak low as the low weakens.
This will create cooling air aloft and a cold front edging into
Southcentral which will combine to keep rain in the region for
the next few days.

For today, the heaviest rainfall should occur in the eastern
Kenai Peninsula with Whittier and Portage likely seeing the
heaviest amounts due to the east-southeast flow. Areas in the lee
of the mountains in this flow are mostly seeing the rain showers
downsloping away this morning and therefore that is leading to an
expectation of scattered showers today for the western Kenai as
well as Anchorage and the matanuska Valley. This flow is then
upsloping along the western Alaska Range which is not good for the
Yentna and Skwentna Rivers as those headwaters are going to once
again get an inch or two of rain over the next few days.

As we head into Thursday and Friday, the digging Arctic trough
will enhance the rain over the Cook Inlet region and bring steady,
and perhaps heavy at times, rain for the western Kenai, Anchorage
and the Mat-Su regions. This is looking to be a prolonged event as
the low in the northern Gulf slowly dissipates and the colder air
filters into the area creating good lift over the area. All this
colder air aloft will also lead to the potential for
thunderstorms along the northern Gulf coast and into Prince
William Sound Thursday and Thursday night due to the increased
lapse rates. As is typical for September and October, the bulk of
the cold air in the lower atmosphere will get blocked by the
Alaska Range and not get a good push into Southcentral. This can
be seen in the forecasted 850 mb isotherms on the GFS and NAM with
a 6 to 7 degree temperature gradient right along the Alaska Range
on Thursday afternoon. However, there will be enough cold air
filtering in aloft that there is a distinct possibility that when
the clouds lift enough to see the tops of the mountains on Friday
or Saturday, Anchorage and the Mat-Su could witness the arrival
of the first termination dust of the season.

&&


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

The center of a stacked, weakening low now resides over the
southern side of Kodiak Island this morning. To the west of the
low, a still potent, northerly gale force wind field continues to
impact much of the Alaska Peninsula, eastern Aleutians and
eastern Bering Sea along a tight pressure gradient between the low
and a high pressure ridge out over the western Bering Sea. Cool
air is also continuing to stream south and around the low, and
this cold air advection is helping keep winds quite gusty along
the Southwest Coast and AKPen this morning. Winds have been
particularly intense where favored channeling through gaps and
bays along the southern side of the Alaska Peninsula has further
amplified northerly flow. Localized gusts overnight have reached
60 mph in spots such as False Pass and King Cove, and gusts up to
this threshold will likely continue on and off through much of
today into tonight. To the north of the low, bands of light rain
continue to move over mainly the Middle Kuskokwim Valley and
Bristol Bay. Rain will end fairly quickly from west to east today
as the low continues into the Gulf and as a cool, dry air mass
draws down into the region from an Arctic trough moving over the
western Interior.

Forecast thinking is still little changed going through the end of
the week. From tonight into Thursday morning, even colder air
will drive down into Southwest as skies clear out and as the
Arctictrough to the north dips down into the Lower Kuskokwim
Valley. Morning lows on Thursday will be around 10 degrees colder
compared to this morning, mostly in the mid 30s to low 40s.
Lingering northwesterly winds will likely prevent most locations
from seeing a hard freeze on Thursday, but that may not be the
case for Friday. Northwest flow will finally relax and allow winds
to go nearly calm on Friday morning, and this could yield the
first true frost/freeze for many across Bristol Bay and the Lower
Kuskokwim Valley, especially if skies manage to stay mostly clear.
Temperatures should stay a bit warmer and above freezing where
cloud cover is more likely to return Thursday night into Friday
along the Southwest coast and for the Kuskokwim Delta.

For the Bering and Aleutians, conditions will be a bit more
unsettled for the next few days, but still rather benign. A pair
of weak lows are expected to skirt along/north of the Aleutian
Chain from today into Friday, sending multiple rounds of rain
showers across the region from west to east. Winds will pick up
slightly as the initial low moves across the western and central
Aleutians from this afternoon through Thursday night. However,
both lows will stay very much on the weaker side, and winds will
generally stay at or below 25 kts for most of the central to
western Bering/Aleutians through Friday afternoon.

-AS

&&

.LONG TERM FORECAST (Saturday through Tuesday)...

Long term outlook remains active in both the Southcentral and
Southwest regions of Alaska. A trough lingers over the Gulf of
Alaska resulting in two areas of low pressure impacting
Southcentral this weekend. The first, and strongest of the two,
moves through the Barren Island then onshore bringing rain and
windy conditions to the area. Rainfall amounts currently are
light. The second low in the central Gulf of Alaska moves slowly
northward toward Hitchinbrook Island and the Western Prince
William Sound bringing rain to coastal areas.

To begin the next week, a strong low slowly rotates in the North
Pacific south of the Alaska Peninsula. The front associated with
this low brings another round of widespread rain showers and
strong wind form Kodiak Island to Prince William Sound.

-Johnston

&&
.AVIATION...

PANC...VFR conditions and steady northerly flow persist through
the day with periods of light rain.


&&


$$

074
FXAK67 PAJK 101333
AFDAJK

Southeast Alaska Forecast Discussion
National Weather Service Juneau AK
533 AM AKDT Wed Sep 10 2025

.SHORT TERM... / through Wednesday night / An early fall storm is
in the gulf presently centered near Kodiak Island with the frontal
band arcing across the Northeast Gulf Coast and eastern gulf. The
expectation is that the with a wave on the front the band will
stall over the northern panhandle from near Glacier Bay over the
Baranof and Chichagof Islands. All of this looks to be very close
to the forecast thinking from yesterday. Made few changes to the
forecast, so anticipating the moderate to heavy rains through
through the day with 2 to 4 inches or more for the north central
panhandle, and then spreading across the southern panhandle with a
slow eastward movement. Strongest winds likely over the outer
waters near the coast, but may see winds for the inner channels
increase to 20 to 30 kt range.

.LONG TERM.../through Sunday/...
Key Messages:
- A gale force front moves into the eastern Gulf
- Around 2 to 3 inches of rain expected in 48 hours, with select
areas seeing closer to 5 inches
- Inner channel winds will pick up to 15 to 25 kts and slowly
decrease Thursday

Details: A deepening upper level trough is directing a near 980mb
low along the western coast of the gulf, sending a gale force
front to the outer coast of the panhandle Tuesday night. This
system, stemming from the remnants of a tropical system from the
northern Pacific, will help to direct warm and wet southwest flow
into the panhandle for the remainder of the week. Sustained wind
speeds along the eastern gulf coast are expected to reach 35 to 40
kts overnight into Wednesday morning, decreasing as the front
moves inland, but still remaining between 20 to 25 kts in the gulf
until Friday. Inner channels can expect SSE winds to start
picking up to 15 to 25 kts Wednesday morning as the front
approaches, with 25 to 30 kt winds possible for channel entrances
and peaking Wednesday night. An MWS has been issued for strong
winds and high wave heights for the outer coastal waters.

Rainfall associated with this system will be significant,
especially given the partial tropical origins and sub-tropical
moisture connection feeding the incoming front. Yakutat will
receive the brunt of this system, toting a heavy rain hazard for
Wednesday into Thursday. Precipitation is expected to push into
the panhandle early Wednesday morning. Areas north of Cape
Decision will see the heaviest rain and highest accumulations
Wednesday, with between 2.5 to 4.5 inches expected for many
communities. The southern panhandle will see most of the impacts
on Thursday with between 2 and 3 inches expected. Yakutat,
downtown Juneau, and higher elevated areas are an exception to
this, as they are currently looking to receive between 5 and 6
inches in 48 hours, with a majority of this falling on Wednesday.
An SPS has been issued in preparation for potential river rises
associated with the increased precipitation. It is also important
to note that with the last 2 weeks of abnormally dry weather, low
river heights and dry ground conditions may make flooding more
prominent. Damp weather persists into the weekend with wet SSW
flow continuing to funnel into the panhandle.

Temperatures will be near to somewhat above normal for this time
of year with highs reaching the 60s from the southerly flow
bringing in a warm and moist airmass for the next week.

&&

.AVIATION.../through 12z Thursday/
Conditions along the Gulf coast and northern panhandle TAF sites
will continue to deteriorate Wednesday morning as a strong front
continues to push into the panhandle, with ongoing MVFR or worse
flight conditions and CiGS AoB 2500ft ongoing along the Icy Strait
Corridor northward. For the southern panhandle, generally better
conditions as of 12z Wednesday with CIGS AoA 3000ft, with the
exception of both PAPG and PAKT which have both had shallow stratus
layers AoB 1000 ft move in. While these initial layers are
expected to scatter out ahead of the front, anticipating
widespread showers across the panhandle with reduced flight
conditions MVFR or worse with ceilings AoB 2500ft, isolated
locations of IFR ceilings by mid to late Wednesday morning.

Winds up to 10 to 15kts with gusts up to 25kts are in store across
northern panhandle TAF sites, increasing further through 18z
Wednesday with strongest winds near 20kts and gusts up to 30kts.

Widespread LLWS will dominate the TAF period as the front swings
through and pushes into the SEAK panhandle. LLWS is ongoing in
the Yakutat area, gradually shifting eastward to the rest of the
northern panhandle within the next few hours, then into the
central and southern panhandle through 18z Wednesday.
Anticipating strongest LLWS along the coast through Wednesday
morning up to 40kts, up to 30kts across the inner channels into
Wednesday afternoon.

&&

.MARINE...
Inside Channels: Low southerly winds of 10 kt or less are the
current conditions across the inner channels. The exception to
this is Northern Lynn Canal where 20 kt Southerlies are blowing.
Will start to see increasing winds and seas as a strong front
moves in from the gulf. The northern inner channels will see it
first starting as early as Tuesday night. The southern inner
channels will wait until Wednesday morning. In any case, S to SE
winds of 20 to 25 kt will be common into Wednesday night for many
areas, but the southern panhandle and ocean entrances will see the
higher winds. Seas, mainly from the wind, will be up to 5 ft
during this time. Winds and seas gradually decrease Thursday into
Friday.

Gulf Waters: Gale force winds near Cape Suckling peaking between
40 and 45 kt by Wednesday morning before diminishing during the
day Wednesday. Seas likewise will be on the rise with seas of 12
to 15 ft likely by Wednesday for many areas of the gulf mainly
from the higher winds initially. The seas will show a gradual
diminishing trend into the late week, but will still be on the
order of 10 to 12 ft due to a SW swell of 7 to 9 ft (with a period
of 14 sec) lasting through Thursday at least.

&&

.HYDROLOGY...Still looking at around 2 to 4 inches of rainfall
expected for most areas of the panhandle from Early Wednesday
through Thursday night from an atmospheric river that is aimed at
the panhandle. Highest rainfall amounts look to be focused on the
outer coast from Baranof island northwestward. The timing of the
precip has the northern panhandle getting the rainfall first
followed by the southern panhandle about 12 hours or so later.
Most areas should see the rainfall stick around for around 18 to
24 hours or less. Area rivers and stream are expected to respond
with rising water levels and increased flow starting Wednesday
with high levels lasting possibly into late week for the slower
responding rivers.

&&

.AJK WATCHES/WARNINGS/ADVISORIES...
PUBLIC...None.
MARINE...Gale Warning for PKZ642>644-651-652-664-671-672.
Small Craft Advisory for PKZ013-021-022-031>034-036-053-641-
661>663.

&&

$$

SHORT TERM...Bezenek
LONG TERM...ZTK
AVIATION...STJ
MARINE...Bezenek
HYDROLOGY...EAB

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