Gale Warning 239, NWS Juneau, AK

Southeast Alaska Forecast Discussion...CORRECTED
National Weather Service Juneau AK
712 AM AKDT Mon Oct 16 2023

.SHORT TERM...Areas across SE AK are starting off to a foggy
morning in places where winds remain relatively calm and skies
have cleared out. This fog is dense in some areas and as such, a
dense fog advisory has been issued in response. This fog is
expected to only last through the morning as our next system
approaches the area. A low moving north along the coast of Haida
Gwaii is expected to enter the gulf this morning bringing gale
force winds to the outer coast as well as 20-30 knot winds to the
inner channels during the day today. As this low raises north, it
will also bring more rain to the area. While this system is not
expected to bring as much rain as the remnants of Typhoon Bolaven,
it still should provide a quarter to half an inch of rain for
most places with some localized spots of heavier accumulations.
With the low racing north, most of the impacts will be felt during
the day and will come to an end by this evening. As these impacts
come to an end, the remnants of Typhoon Bolaven will start to
affect the area with more precipitation and increasing winds.

.LONG TERM.../Tuesday to the weekend/...
Quick Hits:
-Moderate to heavy rain and windy weather is still expected this
week.
-At this time, Typhoon Bolaven is still projected to track into the
northern Gulf of Alaska. This will be our main weather maker this
week.
-The leftovers of Bolaven will last into Thursday, then next Friday
into the weekend will see much colder air move into SE AK.

The Details:
The long range forecast was mainly focused on the remnants of
Typhoon Bolaven. At this time, confidence is very high that this
storm will track into the southern Gulf of Alaska then turn north
towards the coast. As it does, heavy rain is expected for the
panhandle. At this time, 1-2 inches is a safe bet for 24 hour
amounts over the three days. However, 90th percentile QPF amounts
are well over 2 inches. This shows while computer model ensembles
are averaging 1-2 inches, there is potential for amounts to be
much higher.

Amounts of 2-3 inches in 24 hours would put recurrence intervals
around 2 to 5 years, which would means river levels would rise and
flooding would be a possibility.

Marine wind speeds are looking to reach gales (35+ knots) along the
coast and into some inner channels. If the track shifts to the east,
then those stronger wind speeds would be more widespread in the
inner channels.

It all adds up to a very rainy and active few days in SE AK in the
middle of next week - very much worth paying close attention to this
evolving forecast.

As the leftovers of Bolaven fade out, the weather pattern looks to
shift to a more west to northwesterly flow. This change will drive
much colder air into the panhandle. Current projections give the
northern panhandle lows in the low to mid 30s with higher elevations
dipping into the 20s. Stay tuned in for the chilly details.

&&

.AVIATION...Fog and its associated reductions in visibilities and
and ceilings will give way through the morning hours on Monday.
Any improvement in conditions will be short-lived however as a
system which has already begun to advance into the panhandle from
the S continues to move north through the day. Anticipate
widespread LLWS to follow the system as it moves N, with some
areas already experiencing elevated winds aloft ahead of the
system as the warm front advances. Anticipate rain and windy
conditions with this system will concurrently move N through the
day, and ceilings will slowly diminish during its passage. Barring
areas dealing with fog (which will experience IFR and LIFR
conditions while fog is present), overall conditions will slowly
deteriorate from VFR and MVFR to more MVFR and perhaps even IFR in
some locations through Monday.

&&

.MARINE...A surface low lifting north off the coast of Haida
Gwaii early Monday morning will bring near- gale force winds to
Dixon and 10-14ft southerly swell to coastal waters.

In response to this surface low, northerly winds in the inner
channels will strengthen through the morning Monday, with a
fresh- to- strong breeze in Lynn and Chatham canals, along with
portions of Frederick Sound and Stephens Passage. Winds reach
their max northerly potential Monday afternoon before
transitioning to southerly winds Monday evening ahead of ex-
Typhoon Bolevan.

Southerly winds settle in early Tuesday morning reaching gale
force through Dixon Entrance and southern coastal waters. Along
with 34-40knot winds, 11-15ft seas from the south- southeast
begin to impact the southern gulf and coastal waters,
transitioning to 18-22ft seas Tuesday evening. For inner channels,
details remain somewhat fuzzy, but confidence is higher for gales
to reach into Clarence and southern Chatham. Another consideration
is a stronger ebb tide from our waxing crescent moon will create
locally higher seas near ocean entrances and passes.

As the cyclone makes landfall sometime Wednesday across the
northern Gulf expecting to see long duration southwest near gale
winds dominate the pattern, keeping a 16-18ft southwest swell
through the Gulf before seas diminish late Thursday evening.

Changes in track and speed of the cyclone moving across the Gulf
will influence wind strength, direction, and duration and thus
wave heights. Stay tuned to weather.gov/juneau for latest
information on this developing situation.

&&

.AJK WATCHES/WARNINGS/ADVISORIES...
PUBLIC...Dense Fog Advisory until 10 AM AKDT this morning for AKZ320-325-
     326.
     High Wind Watch from Tuesday morning through late Tuesday night
     for AKZ328-330-332.
MARINE...Gale Warning for PKZ644-661-664.
     Small Craft Advisory for PKZ036-641>643-651-652-662-663-671-672.

&&

SHORT TERM...SF
LONG TERM....GJS
AVIATION...GFS

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