631
FXAK67 PAJK 302356
AFDAJK

Southeast Alaska Forecast Discussion
National Weather Service Juneau AK
356 PM AKDT Wed Sep 30 2026

.SYNOPSIS...

Key Messages:

- Onshore flow bring rain showers tonight into Thursday. Gusty
  winds and moderate showers possible for northern panhandle.

- High pressure will bring a bit of clearing and drier weather for
  southern panhandle by Thursday and central panhandle by Friday.
  Northern panhandle will remain cloudier with showers.

- A stronger system and weak atmospheric river will bring gusty
  winds, elevated seas and moderate to heavy rainfall for the
  weekend.

&&

.SHORT TERM.../through Friday/...Showers have picked up in
intensity across the gulf coast this afternoon as previously
forecast with continuing southwesterly onshore flow. An upper
level trough will help to push a surface front into the northern
panhandle and outer coast tonight into Thursday. Cooler air aloft
pulled in behind the front combined with the lift from the
elevated trough will lead to decent instability for thunderstorm
potential along the northern gulf coast, spreading down to around
Cape Spencer. By Thursday afternoon the thunderstorms are expected
to diminish, though rain showers will continue across the
northeast coast and most of the northern 2/3rds of the panhandle
as the upper level trough pushes inland. This will also lead to
increased surface winds across the inner channels with
particularly windy conditions expected in the usual spot, Skagway.
A wind advisory was issued from 7am to 1pm Thursday when the
strongest winds are expected with gusts up to around 40 mph.

Onshore flow will continue into Friday across the panhandle,
though with some variation in weather from Thursday. Rain shower
coverage is expected to primarily continue north of Frederick
Sound in the inner channels and northwest of Cape Decision on the
outer coast. This change is due to a weak ridge of high pressure
building in over southern BC and pushing up into the southern
panhandle briefly Friday. This should limit shower development and
weaken onshore flow for the period, as well as clear out some of
the cloud cover. However, with the timing of clearing, some fog
development cannot be ruled out for the southern panhandle for
Friday morning. A more potent pair of systems is expected to bring
moderate to heavy rain to the majority of the panhandle this
coming weekend. For more information, see the long term discussion
and stay tuned for future forecast updates.

.LONG TERM.../Saturday through Monday/...A low pressure system
originating from a mid-level North Pacific trough will move along
the Alaska Peninsula and into the Gulf of Alaska this weekend.
Reinforced by a stronger system behind it, it will produce
prolonged rainfall from Saturday into early next week, fueled by
tropical moisture and weak but continuous divergent flow aloft.
Models continuing to favor landfall along the north-central coast
near Cordova. The system could bring moderate to heavy rain, with
the highest totals expected along the northeast Gulf coast and
higher terrain, though most of the region will be impacted. Warm
advection seems apparent through many levels of the atmosphere
along this system, which will allow for a very slight warming in
temperatures, but not expecting much of a difference due to
persistent cloud coverage across the region this weekend.

Climatological guidance is trending higher, though values remain
within seasonal norms. The NE Gulf Coast may see locally heavy,
long duration rainfall instead of showery bursts due to limited
cold air aloft and minimal convective activity. For the heaviest
period (Saturday evening to Sunday evening), 24-hour QPF averages
1.5-3 inches, with up to 4-5 inches at higher elevations. GEFS and
Euro ENS indicate PWATs around 175% of normal. The GEPS is
trending more aggressive, while the GEFS and Euro ENS align more
on timing and intensity. Stronger winds and building seas are also
increasingly likely along the outer coast and northern inner
channels ahead of the low. The active pattern will persist into
next week as the following Bering Sea low reinforces onshore flow,
though rain chances should taper off by mid week.

&&

.AVIATION.../Through 0z Friday/...VFR to MVFR conditions continue
for the panhandle, with scattered showers bringing CIGs down to
1500 to 3000 ft as they pass through. Showers are still heavy at
times, which may drop VIS to 2-4SM. More significant breaks are
being observed in between showers, with multiple layers of broken
CIGs persisting for most sites. Gusty winds are still possible for
much of the northern and parts of the central panhandle with
these showers, and PAGY and PAHN will continue gusting up to 25 to
35 kts overnight. A more organized band of precipitation is
sitting just offshore this afternoon, and will be pushing into the
northern and central panhandle through the next few hours. This
will bring much of the panhandle down to MVFR conditions, with
CIGs of 1500-2500 ft expected overnight and into early Thursday
morning. Some of the southern panhandle is seeing a break for the
next few hours, but will have a chance of seeing some of these
lower conditions creep into the area through the early morning.
Conditions should improve behind the bulk of the showers towards
the end of the period.

&&

.MARINE...
Outside:
For Wednesday, a low continues to persist along our coast, driving
onshore flow and continued showers. Winds are at moderate breezes
along the coast, with dominant seas out of the WSW focused 5 to 7
ft near 9 seconds. Underneath is the usual southerly swell from
the south Pacific with some energy focused near 15 to 18 seconds
from tropical activity in the central and eastern Pacific.

Wednesday night, expect westerly winds to build in in the central
Gulf to fresh breezes, helping increase WSW seas a bit, perhaps 7
to 8 ft near 9 seconds. Winds and seas begin diminishing again
Thursday morning into Friday. Through Friday a gale force low will
slide along the Aleutian Storm Track, with winds becoming
southerly in the eastern Gulf. Anticipate easterly gales to build
along Cape St. Elias by Saturday morning. From Cross sound south
to Dixon, southeasterly winds build to near gale force to strong
breezes. Large and confused seas near 11 to 14 ft impacting much
of our coast Saturday into late Sunday.

Inside:
Simply put, Friday will likely be the best low wind day across
the inside. The exception, per usual, is northern Lynn Canal where
we will likely hold on to fresh breezes into Friday.

For Wednesday, a low-pressure system along the northern coast
will keep the northwest-southeast pressure gradient over the
region, driving southerly flow through the inner channels and
easterly flow out of Icy Strait/Cross Sound. Overall, winds
strengthen through Wednesday night, driving fresh to strong
breezes over much of the central and northern inner channels.
Dominant feel of Lynn Canal will be strong breezes, with a few
hours of near-gale force conditions tonight. Thursday afternoon,
winds start to diminish over the region as high-pressure forms
over the area, bringing a break from higher winds into Friday
night. By the weekend a gale force low will position itself in the
Gulf, freshening up southerly winds across the inside once again;
strong breezes to near-gale force likely with areas of gale
force.

&&

.AJK WATCHES/WARNINGS/ADVISORIES...
PUBLIC...Wind Advisory from 7 AM to 1 PM AKDT Thursday for AKZ318.
MARINE...Small Craft Advisory for PKZ012-013.

&&

$$

SHORT TERM...STJ
LONG TERM...BAS
AVIATION...ZTK
MARINE...AP

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