312
FXAK67 PAJK 180621
AFDAJK

Southeast Alaska Forecast Discussion
National Weather Service Juneau AK
1021 PM AKDT Thu Sep 17 2026

.UPDATE...Update long range and for 06Z TAFS

&&

SYNOPSIS...

Key Messages:

- Gusty winds continue this evening with gales for northern Lynn
  Canal and a Wind Advisory for Skagway. Winds are likely to
  diminish late tonight into Thursday.

- Multiple systems to impact the region late week into the
  weekend, with the potential for heavy rain, gusty winds and
  increasing seas.

- Cooler but seasonable temperatures for the period, with daytime
  highs generally in the 50s.

&&

SHORT TERM.../Through Friday/...Windy and rainy conditions have
been the main story for the central and northern panhandle this
morning and afternoon. Winds from Juneau and north to Skagway have
been on the stronger side. Specifically near Skagway, wind gusts up
to near 45 mph have been measured. Similarly, winds over Lynn Canal
have seen gusts up to 45 kts (52 mph) observed. These stronger winds
and periods of moderate rain will continue into this evening before
weakening and diminishing. Thursday will then bring more of a break
across the area before a stronger system approaches this weekend.
There is a chance for rain showers to continue Thursday as onshore
flow continues over the gulf, and into SE AK.

As we head into Friday, a low pressure system moves northward into
the NE gulf coast. This low will once again bring stronger winds
with moderate to heavy rain. Currently 24 hour rain totals look to
be around 2 inches for the north/central panhandle and around 1 inch
for southern areas. For north and central areas, there is about a
60% chance of exceeding 2 inches in 24 hours and about a 30% chance
of exceeding 3 inches in 24 hours. For the southern panhandle there
is about a 20% chance of exceeding 2 inches in 24 hours. Although
periods of moderate to heavy rain are likely, no flooding is
anticipated at this time for the Friday system. Active weather will
then continue as a stronger low pressure system brings more strong
wind and heavy rain for the weekend. See the long term forecast
discussion for more information.

&&

LONG TERM.../Sunday through Thursday/...

The pattern on the synoptic scale moving on into next week remains
similarly active as this weekend. For Sunday and Monday the
agreement on an upper low being driven into the central Gulf is
fairly strong, but looking at Tuesday and onward, the eventual
path of this system is low confidence. As such, expecting a rainy
and windy situation to close out the weekend and start the
workweek. Rain rates will remain consistent, though not as heavy
as Saturday. The issue will become the persistence of rainfall, as
probability of 24 hr ARIs exceeding 2 years is increasing over
75% for much of the northern panhandle Sunday.

Some convective parameters are indicating support for convection
will exist, keeping coastal thunderstorms as a possibility for
much of the time period Sunday and Monday.

Because the early week system will not be passing its central low
directly through SE AK, winds will settle for the inside channels,
but coastal and offshore winds remain stronger over the Gulf. As
mentioned, there is low confidence in the track for the mid-week
system, but it also appears to be a more poorly formed structure,
and weather activity reduces late in the week.




&&

AVIATION... Behind yesterday`s front, flight conditions have been
fairly benign for this Thursday evening across Southeast Alaska.
A warm front approaching from the south is currently bringing some
high clouds to the Southern Panhandle, and perhaps some MVFR
ceilings to Sitka and perhaps Ketchikan and Klawock. Before the
next front arrives, the potential for fog development will have to
be monitored. As of now, the highest chances for fog looks to be
for Yakutat and Petersburg, but cannot be ruled out for Juneau.

Friday morning, the low pressure system and associated front will
begin approaching the Northern Panhandle from the South. The front
will initially bring gustier winds, and ceilings around 2500 feet,
with ceilings and visibilities dropping until after the front
passes. The strongest winds associated with this system may bring
some low-level wind shear concerns to Yakutat, and perhaps for
Sitka and Gustavus as well. As of now, confidence in LLWS
occurring in Sitka and Gustavus is on the lower side, but will be
monitored. The front will first bring lower conditions to the
Western portions of the area, and progress eastward through the
TAF period.


&&


MARINE...
Outside Waters: As the front tracks east across the panhandle this
afternoon, winds shifting from SW to W have maintained fresh to
strong breezes, though begin to quickly drop off tonight through
Thursday as the front exits the region. Winds begin to increase
again to moderate to fresh S to SE-ly Thursday night as a
strengthening low lifts north into the Gulf. Wave heights between 8
to 11 ft in the central and northern Gulf today begin diminishing
overnight to 4 to 6 ft by Thursday. Seas build again late Thursday
night across the eastern Gulf as the next low pressure system tracks
north Friday. Seas near ocean entrances building to 5 to 6 feet, and
up to 12 ft near the northern outer coastal waters.

Inside Channels: With the passage of the front, the strongest winds
have been observed near the intersection of Southern Lynn Canal, Icy
Strait and Northern Chatham Strait this afternoon, with near gale
sustained winds and gusts to 50 kts. Afternoon gales in North Lynn
Canal decreasing to 25 to 30 kt this evening, and to 15 to 20 kt by
tomorrow morning. Elsewhere, winds are expected to decrease and
become light to gentle across the panhandle as the front shifts
south and weakens. Predominately S to SE-ly winds will begin to
increase across the region late Thursday night as the next low
pressure system pushes north into the Gulf. Winds increasing to
fresh to strong by Friday afternoon with wave heights building to 3
to 4 feet within the larger N-S oriented channels.

&&


&&

.AJK WATCHES/WARNINGS/ADVISORIES...
PUBLIC...None.
MARINE...Gale Warning for PKZ644-651-652-664-671-672.
     Small Craft Advisory for PKZ011>013-021-031>034-036-053-641>643-
     661>663.

&&

$$

SHORT TERM...EAB
LONG TERM...VFJ
AVIATION...Musall
MARINE...BAS

Visit us at http://www.weather.gov/Juneau