544
FXAK67 PAJK 012338
AFDAJK

Southeast Alaska Forecast Discussion
National Weather Service Juneau AK
338 PM AKDT Thu Oct 1 2026

.SYNOPSIS...

Key Messages:

- A second release from Suicide Basin has started with an expected
  crest level of 10 feet early Friday.

- Onshore flow will keep mainly cloudy skies and rain showers for
  the northern panhandle on Friday, while high pressure ridge will
  bring partial clearing and drier conditions for the southern
  panhandle.

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

&&

.SHORT TERM.../through Saturday night/...Two main features
dominate the next three days:

A trough moving over the northern panhandle tonight, and a
stronger low pressure system moving into the central gulf this
weekend. For the trough tonight, cold temperatures aloft (around
-30 C at 500mb) with water temperatures still in the mid to upper
50s in the gulf will continue to yield occasional lightning
strikes and generally convective weather. Not expecting anything
greater than 20% chance, or isolated, along the NE gulf coast at
this time. May also see some increased winds as this trough moves
into northern British Columbia and the Yukon from rising pressure
in the southern panhandle.

Going into the weekend, a warm front pushes up from the south,
associated with a stronger low in the central gulf. Light to
moderate rain looks to be associated with the initial warm front
Saturday morning, which is then followed by an occluding front
that evening. Heavy rain looks to be associated with the second
round, with the possibility of embedded features producing rain
rates exceeding 0.3 in/hr. Rain totals look to be around 1.5 to 3
inches with 3.5-5 inches at higher elevations above 1000 ft. For
more information regarding hydrology, please see the hydrology
section.

.LONG TERM.../Sunday through Tuesday/...A low pressure system
will enter the Gulf of Alaska this weekend, bringing gale-force
winds to the outer coast along with periods of moderate to heavy
rainfall associated with a weak atmospheric river. A stronger
wave arrives by early Sunday morning. As the low slowly
dissipates near south-central AK, it will meander and track
multiple fronts across the panhandle. This setup, reinforced by a
consistent slew of upper level troughs and divergent flow aloft,
keeps precipitation in the forecast for the extended period,
although overall impacts are expected to diminish gradually
heading into next week. One thing of note is as the low
dissipates, the pressure gradient over the northern panhandle
becomes more north to south oriented, causing a potential increase
in winds within Lynn Canal through Monday and Tuesday.

Impacts associated with this weekend system will initially start
along the NE Gulf coast and as far south as Baranof Island, also
upwind of higher elevations. From Sunday through Monday, heavier
precipitation will push south across most areas, particularly
targeting the Misty Fjords region. The highest confidence for 24-
hour rainfall accumulations during Sunday`s stronger wave ranges
between 1.5 to 2.5 inches, with localized amounts reaching 4 to 5
inches over higher terrain. However, at this time there is a low
(25%) chance that lower elevation areas surrounding Icy Strait, such
as Juneau and Gustavus, could exceed 2.5 inches. A significant
southerly jet will move along the coast Saturday, shifting
southwesterly by Sunday morning and likely bringing 35 to 40 knot
sustained winds from Cape Spencer north to Cape Suckling. Overnight
Saturday into Sunday presents the greatest concern for elevated and
gusty winds over the southern panhandle and inner channels, then
trending on the decline Monday morning.

&&

.AVIATION.../Through 00z Saturday/...VFR to occasional MVFR
conditions prevail late this afternoon. Scattered showers also
continue to affect the region, particularly across the northern
and central panhandle. This trend will likely persist through the
evening hours. MVFR may become increasingly predominant after
09Z-12Z tonight under persistent onshore flow and a return to
lower ceilings, especially north. However, as a weak ridge slowly
pushes into the southern panhandle, there could be some
improvement in conditions after 15z-18z Friday.

&&

.MARINE...
Outside:
Current SITREP across the mighty Gulf Thursday early afternoon:
southwest winds of moderate breezes, with dominant seas out of the
southwest 5 to 7 ft near 7 to 9 seconds. Underneath these seas
are swell groups from the central and south Pacific. Thursday
afternoon the parent low continues to decay along the northern
coast, expecting a surface high to dominate the southeastern gulf,
limiting the surface pressure gradient allowing winds and seas to
diminish further. For Friday morning, expecting wind at or below
moderate breezes, with seas at or below 5 ft. A short break.

Attention turns to a strong-gale force low developing along the
Aleutian Storm Track which will push into the western Gulf by
Saturday morning. Watch those winds Friday night, south-southwest
becoming southeasterly will signal the approaching front, with
winds increasing to strong breezes over much of our coastal zones
through early Saturday morning. Folks transiting the PWS Cross
Sound route will see gale force condition by Saturday morning,
with conditions continuing to diminish further through the day.
Current forecast Saturday afternoon/evening has trended sustained
winds up, to strong-gales, with gusts to storm force.

Winds continue to build through the day Saturday for the coast of
the Alexander Archipelago, with gale force forecasted for the
Fairweather Grounds by Saturday afternoon, with gales spreading
south through Saturday night.

5 ft seas along the coast Friday build to large and confused seas
of 15 to 20 ft from Fairweather Grounds to Cape St. Elias coast
by Saturday late afternoon, with 12 to 15 ft short period seas
along the remainder of our coast. These significant wave heights
will ultimately depend on where the strongest winds associated
with the front setup along our coast, stay tuned. Either way, 15
ft fresh seas are guaranteed, with the challenge trying to nail
down where 18 ft to 20 ft seas could propagate; much higher
confidence for the northern coast.

Inside:
Certainly, a tricky forecast over the next 48 hours for the
inside. Simply put, portions of the northern inner channels will
continue to hold onto about 15 to 20 knots of wind through
Saturday as a low shifts off into Canada. Main problem areas will
be northern Stephens, Lynn Canal, and northern Chatham. For areas
along and south of Frederick Sound, expecting winds at or below
15 knots.

Additional forecast focus continues to be a developing gale force
low and assortment of fronts south of the Aleutians, which will
shift into the Gulf over the weekend. Expect southeasterly winds
to begin to ramp up over much of the inner channels early Saturday
afternoon, becoming widespread fresh breezes, with localized
areas of strong breezes. As a front moves across the region
Saturday evening, expecting winds to reach strong breezes, with
localized areas of near-gale force from Icy Strait south.
Southeasterly winds shift to more southerly, flowing up Lynn Canal
Sunday and building to near-gale force in Clarence Strait.

&&

.HYDROLOGY...Incoming short duration plume of moisture for
Saturday into Sunday Icy Strait and southward. IVT values looking
to exceed 500 kg/ms for roughly a 6-12 hour period. This is mainly
due to a strong warm front moving up from the south, increasing
snow levels to 6000-8000 ft. This is allowing increased moisture
presence, with PW values around an inch, which is roughly 80th to
90th percentile compared to climatology. While this is not
entirely unusual for this time of year, wind transport up to 50
knots is contributing to the previously mentioned 500 kg/ms
exceedence. This combined with continued rainfall and saturated
soils means that any rainfall will likely translate directly into
runoff, and smaller streams likely responding quite quickly.
Biggest areas of concern are in the Icy Strait corridor, although
recent guidance have the heaviest rain shifting southward
somewhat out of this area. Currently expecting to see some river
rises, particularly small streams, but confidence was not high
enough to see any river flooding at this time. Therefore, a flood
watch has not been issued, but upcoming conditions will continue
to be monitored.

&&

.AJK WATCHES/WARNINGS/ADVISORIES...
PUBLIC...None.
MARINE...None.

&&

$$

SHORT TERM...NC
LONG TERM...BAS
AVIATION...MJB
MARINE...AP
HYDROLOGY...NC

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