Storm Warning 23, NWS Juneau, AK

Southeast Alaska Forecast Discussion...CORRECTED
National Weather Service Juneau AK
559 AM AKDT Tue Oct 29 2024

.SHORT TERM...Forecast package has not changed much from prior
discussion in an overall sense, however, specifically focusing on
Lynn Canal and Haines, large changes to the short term were
necessary. Currently, expected southerly flow in Lynn Canal is
slightly more southwesterly than expected, with stronger
northwesterly flow coming out of the Chilkat Valley, around 10
mph. Unfortunately, this makes all the difference when it comes to
precipitation type. As westerly flow is more stable, particularly
noted by the inversion present and local dryline around Haines and
Lutak. As warm air lifted over the stubborn stable layer, it lead
to the development of a warm nose and persistent freezing rain
just west of Haines. As the front approaches, easterly gradient
will begin to strengthen, strengthening the winds aloft to mix out
any cold air. Current thinking is this will occur within hours of
posted AFD time.

Other changes made around Lynn Canal was to gradually diminish
winds over the course of the day before the full switch to
northerly. As the low pressure system begins to drift
southeasterly, pressure gradients become parallel with Lynn Canal.
With diminishing low level flow, winds will begin to gradually
decrease in the afternoon before flipping tonight.

.LONG TERM...The low in the gulf will continue to weaken
through Tuesday. You can expect precipitation and winds to lighten
throughout Tuesday before leaving the panhandle Wednesday. Strong
breezes will stick around Wednesday along the coastal waters
before diminishing that afternoon. A ridge will then build in the
gulf transitioning winds to become light and southeasterly.

Midweek will then stay fairly dry for the panhandle. An exception
will be Yakutat and the far northern panhandle who will have
higher chances of precipitation as a low starts to develop along
the Aleutian Islands during this time. No impactful precipitation
amounts are expected. Winds during this time will also stay fairly
calm giving a nice break before our next system that heads toward
the panhandle Friday.

The weather pattern becomes more active early this weekend as
that low near the Aleutian Islands makes its way closer to the
panhandle. A front associated with this low will make its way
north to south increasing precipitation amounts and wind. Another
system will then impact the panhandle later in the weekend.

&&

.AVIATION.../Until 12Z Wednesday/...CIG and VIS conditions
primarily within the MVFR category are expected for the majority
of the forecast period from the approaching storm force frontal
system. At the SFC, windy conditions out of primarily a southeasterly
to easterly direction for most locations are also expected for
the timeframe. The exception will be PAGY, which will be out of a
more southerly direction. LLWS magnitudes of between around 35 to
50 kt are expected out of a mainly southeasterly direction. The
exception will be over PAYA, which will be out of a more easterly
direction.

&&

.MARINE...A storm force low is expected to move into the Gulf
during the overnight hours tonight. As this low moves into the
Gulf, it is expected to strengthen bringing stronger winds to the
outer coast waters. Besides the winds, seas are expected to
build with this low with there potentially being 30ft seas. For
the Inner Channels, winds will come up in response to the low
moving closer to the coast. Most locations could see 25-35 kt
winds with the strongest winds being through east-west oriented
channels. Seas through these areas will also build during this
time.

&&

.AJK WATCHES/WARNINGS/ADVISORIES...
PUBLIC...Strong Wind through this evening for AKZ317.
     Winter Weather Advisory until 7 AM AKDT this morning for AKZ319.
     Gale Warning from 1 PM this afternoon to 10 PM AKDT this evening
     for AKZ322.
     High Wind Warning from 10 AM this morning to 7 PM AKDT this
     evening for AKZ323.
     Strong Wind from this evening through late tonight for AKZ323.
     Strong Wind from 1 PM AKDT this afternoon through this evening
     for AKZ325.
     Strong Wind from 1 PM AKDT this afternoon through late tonight
     for AKZ327.
     High Wind Warning from 1 PM this afternoon to 10 PM AKDT this
     evening for AKZ328.
     Strong Wind from 1 PM AKDT this afternoon through this evening
     for AKZ330-332.
MARINE...Storm Warning for PKZ641-642-644-652-661-662-664-671-672.
     Gale Warning for PKZ022-031-035-036-053-643-651-663.
     Small Craft Advisory for PKZ011>013-021-032>034.

&&

SHORT TERM...NC
LONG TERM....EAB
AVIATION...JLC

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