Angoon, Alaska Weather Forecast Discussion

902
FXAK67 PAJK 251813
AFDAJK
Southeast Alaska Forecast Discussion
National Weather Service Juneau AK
1013 AM AKDT Thu Sep 25 2025
.UPDATE...
High Wind Watch has been upgraded and expanded for the southern
portion of the panhandle. Sustained winds depending on zones 30
to 45 mph with gusts of 60 to 80 mph. Warnings are in effect
starting 7 am or 10 am Friday and run to 7 pm or 10 pm.
Marine forecast will be being upgraded shortly especially over the
southern half of the zones. Winds increasing to either max gales,
or storms, and up to Hurricane force for Friday as a very strong
fall storm move to and makes landfall in the central panhandle.
Mariners should take appropriate actions.
Update for 18z TAF package. Showers today improving slightly.
Winds of the next incoming system, starting for Prince of Wales
Island an Ketchikan TAF sites right at end of the 24 hour period.
Expect condition to become much worse for the Sitka/Wrangell and
Petersburg TAF as they are in the windiest locales, but the other
sites will see a big shift as well. Northeast gulf forecast
remaining fairly consistent this afternoon into the overnight
time frame. Wind shear and early today, and will see a return late
tonight with the incoming storm for the southern panhandle.
&&
.PREV DISCUSSION......ISSUED AT 541 AM AKST 25 Sept 2025...
SHORT TERM.../through Thursday night/...
Key Points:
- Today is the quiet before the storm.
- General onshore flow will keep clouds and showers over SE AK.
- Wind speeds will decrease today ahead of the next big storm.
Details:
Area of low pressure spinning in the northern Gulf will keep the
onshore flow in place for SE AK. This will keep the rain showers
in place so expect on-and-off rain today as showers pass over your
area. Wind speeds will decrease as the low weakens. Afternoon
temps will be seasonal for late September.
To sum it up, today is the calm and quieter weather before the
next big storm expected late tonight into tomorrow. More
information on the incoming hurricane force low is in the next
sections.
LONG TERM...Active pattern to begin the long term section, with
a hurricane force system moving up from the south Friday morning.
This system looks to be a developing warm core system, with
highest wind speeds associated with the southeast section. For
specific details regarding this system, please see the marine
section. Fortunately, this system on Friday looks primarily a wind
threat, with little associated moisture. Additionally, due to the
fast moving nature of the system, any moderate to heavy rain is
only expected to stay in one area for 12 or less hour.
Furthermore, likelihoods for 6 hour rain rates exceeding one inch
in any given location are no more than 30%, with the highest
likelihoods near Ketchikan. Given that recent rainfall along with
anticipated rainfall leading up to the event looks unimpressive,
not expecting any flooding issues.
One thing to note about this system is the thunderstorm potential in
wake of the system. Lapse rates between 700-500 mb have an 80%
chance to be greater than 7 C/km, with CAPE values around 300-500
mb. Furthermore, there is impressive speed shear, with surface to
3km values exceeding 60 knots. Therefore, expecting at least a 40%
chance at thunderstorm development between Sitka and Craig during
the afternoon hours. Furthermore, as usual with these types of
systems, there is a dry slot between 700-400 mb. For thunderstorm
development, any cells that do develop could have wind gusts up to
45 mph associated with downdrafts from rain cooled parcels.
Looking beyond the Friday system, a vertically stacked low looks to
stick around in the central gulf, keeping cloud cover over the
panhandle and rain in the forecast. Not expecting any impactful
systems beyond typical September weather.
&&
.AVIATION.../through 12z Friday/
Across the northern panhandle TAF sites, a band of showers pushing
onshore could bring MVFR flight conditions through the morning,
with CIGs and VIS improving this afternoon. For Yakutat, CIGs
will dip down to IFR at times with steadier rain and with the flow
becoming slightly onshore. A few strikes have also been observed
near Yakutat, but confidence not high enough for thunderstorms
near the airport to include in the TAF. LLWS concerns could
linger, mainly for Yakutat through the morning and Haines and
Skagway for the period.
General MVFR flight conditions across the S panhandle TAF sites this
morning with CIGs AoB 3500ft and Visbys as low as 4SM as front
continues to exit stage left out of the panhandle. Through Thursday
afternoon, anticipating scattered to isolated showers to prevail
under predominate MVFR flight conditions with CIGS AoB 2500ft across
S Panhandle TAF sites. Potential for intermittent breakouts to VFR
through afternoon. No significant LLWS concerns through Thursday
afternoon, but will see broad SW-ly flow aloft around 25 to 35kts
resulting in general mountain wave turbulence. Near the end of
the TAF period, a strong low will push northward out of the
Pacific and into the E Gulf of Alaska, with rapidly deteriorating
flight conditions and increasing LLWS for Prince of Wales Island,
Annette Island, and Ketchikan Borough near 12z Friday.
&&
.MARINE...When looking at the whole marine forecast, today
(Thursday) will be the relatively quiet day. Some spotty areas of
southerly winds around 20 to 30 kts are still lingering around
this morning, mainly Lynn Canal, near Young Bay, and Clarence
Strait. But going forward, overall winds around the panhandle will
decrease to around 15 to 20 kts for the afternoon.
But it will be a very different weather story beginning late
tonight. Confidence continues to grow in the development of a
hurricane force low that will track into the eastern Gulf of
Alaska from the south late Thursday night into Friday. Storm
tracks are starting to hone in on the low moving across the
southern outside waters and inland in vicinity of Cape Decision,
but there is still some evidence that the low could track farther
north and go inland near Sitka. A marine weather statement is in
effect for this event with additional information. Mariners should
exercise extreme caution for this upcoming system. Now is the
time to prepare your vessels by checking lines and bilges.
For the outer coastal waters and Gulf of Alaska. Potential for
thunderstorms, and associated gusty winds, return once the area
gets to the backside of the low Friday afternoon. Winds for the
Friday low, a swath of sustained speeds of up to 45 to 65 kt are
possible as the system moves through. Seas will build near the low
center 20-30ft, possibly higher. Strongest winds and seas will be
with the westerlies on the south side of the low.
For the Inner Channels. Southerly winds will continue today with
showers causing occasional gustier winds. As the low approaches
on Friday, expect winds to shift through most of the inner
channels out of the north. Then as the low moves through, winds
will shift sharply back to the S-SW and increase again. Timing of
this wind shift, how strong it is, and how far north the surge of
southerly winds reach will be determined on the final low track.
Please stay tuned to the latest forecast update or reach our to
our office for more details.
&&
.AJK WATCHES/WARNINGS/ADVISORIES...
PUBLIC...High Wind Warning from 10 AM to 7 PM AKDT Friday for AKZ323.
     High Wind Warning from 10 AM to 10 PM AKDT Friday for AKZ326-327-
     329.
     High Wind Warning from 7 AM to 7 PM AKDT Friday for AKZ328-330-
     332.
MARINE...Gale Warning for PKZ661.
     Small Craft Advisory for PKZ022-036-053-641>644-651-652-662>664-
     671-672.
&&
$$
SHORT TERM...GJS
LONG TERM...NC
AVIATION...NM/DS
MARINE...Ferrin/GJS
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