Gale Warning 232, NWS Juneau, AK

Southeast Alaska Forecast Discussion
National Weather Service Juneau AK
1052 PM AKDT Wed Oct 11 2023

.UPDATE...Satellite imagery shows low pressure approaching 140W
late Wed evening. Latest surface analysis indicates pressure of
986mb. Models in good agreement with this low continuing to deepen
as it pushes into the SE gulf Thu. Latest guidance supports
earlier timing for increase winds along with stronger winds along
POW. Expanded high wind watch to include POW and adjusted for
earlier timing.

&&

.PREV DISCUSSION......ISSUED AT ...257 PM AKDT Wed Oct 11...

SHORT TERM...Pretty much as expected, with the exception of the
pesky low clouds and patchy light rains for the eastern zones, we
are getting the break in widespread precipitation and wind across
the Alaska Panhandle today. Unfortunately that break is short
lived as we see yet another gulf low moving up along 135W Thursday
bringing periods of heavy rain and wind to the region Thursday
into Thursday night. Strongest winds are expected for portions of
western Baranof Island Thursday afternoon and evening, where we
currently have a High Wind Watch posted. We expect periods of
strong winds 20-30 mph gusts to 50 mph) for some locations across
the central panhandle Thursday afternoon and evening as well. Over
the coastal and offshore waters, we expect solid gale force winds
over the eastern GulfAK Thursday into Thursday night with 25-30kt
winds over most inside waters with some of the longer fetch
channels getting gusts around 40 kts at times. We will have Small
Craft Advisories for the inside waters Thursday into Thursday
night as well, but a few of the longer fetch and exposed waters
could end up being updated to Gale Warnings as well...so stay
tuned to the latest forecast.

As for heavy rainfall, the main areas where we raised our rainfall
amounts totaling 2 to 3 inches Thursday morning to Friday morning
will be from Sitka east to Juneau and northward with some of the
higher amounts expected over the northern Panhandle from Gustavus
to Haines. We are expecting rises on many of our central and
northern Panhandle rivers by Friday morning, although mostly rises
to or slightly over bankfull expected with no significant
flooding anticipated at this time.

The low tracks fairly close to 135W through Thursday night slowly
weakening as it goes north of 58N early Friday morning.

LONG TERM.../Friday into early next week/...
Quick Hits:
-Storm system late Friday into Saturday looks to bring another round
of gale force winds to the coast.
-Inner channel winds expected to increase as the low moves through
the gulf.
-Land area wind gusts likely to reach 30-40 mph with evidence of
some southern areas seeing higher gusts.
-Sunday into next week, confidence in the forecast lowers due to
wide spread in next system's track and strength.

The Details:
Looking at the overall setup, a digging trough aloft
will set up multiple waves moving up from the south over the course
of the forecast period.

For late Friday into Saturday - good enough agreement between ENS
and deterministic models, and guidance from the WPC, that winds
up to 35 knots in the gulf felt needed. Inner channels are around
15 to 20 knots, these might need to be updated once access to hi-
res models becomes available.

Precip will be fading out or moving out of the area on Friday
with the next quick hit of rain expected with the next low Friday
night into Saturday. Amounts don't look too impressive with 24
hour amounts around 0.50 to 1 inch.

Sunday into next week has lowered confidence. GEFS and EURO ENS are
averaging an area of low pressure near the southwest gulf but
deterministic are hinting at embedded, quick-moving lows spinning
around the parent low. These smaller lows can have quite the
impact as they track through the area so be sure to stay plugged
into the forecast for the latest updates.

&&

.AVIATION...Lingering fog and low stratus early in the day lifted
for most locations and VFR conditions for the evening. Next gale
force front tracks in by Thursday morning with increasing rain
fall, increasing and lowering cloud cover and ceilings, increasing
surface winds and developing LLWS. Conditions dropping to MVFR to
IFR by mid morning but SE LLWS with speeds nearing 40 to 50 kt
will be main impact into Thursday evening. Heaviest rainfall will
be over the northern half of the panhandle. Improving weather with
decreasing winds, LLWS, and rain rates into Friday afternoon.

&&

.AJK WATCHES/WARNINGS/ADVISORIES...
PUBLIC...High Wind Watch from Thursday afternoon through Thursday evening
     for AKZ323-327.
     High Wind Watch from Thursday morning through Thursday afternoon
     for AKZ328.
     Strong Wind Thursday afternoon for AKZ328.
     Strong Wind Thursday afternoon for AKZ329.
     Small Craft Advisory from 6 AM to 6 PM AKDT Thursday for AKZ330.
MARINE...Gale Warning for PKZ641>644-661>664-671.
     Small Craft Advisory for PKZ012-013-021-022-031>036-651-652-672.

&&

SHORT TERM...JG
LONG TERM....GJS
AVIATION...PRB

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