Gale Warning 2, NWS Juneau, AK

Southeast Alaska Forecast Discussion
National Weather Service Juneau AK
256 PM AKST Sun Dec 31 2023

.SHORT TERM...Calm winds and cloudy skies continue this afternoon
as satellite imagery shows a decaying closed low moving north
into the gulf of Alaska. This low will bring the return of active
weather to the area starting in the southern panhandle before
working northward. Light rain is already being reported in places
like Hydaburg and Ketchikan. This rain is expected to move north
during the evening and overnight hours but decreasing in coverage
as it does so. As this precipitation moves north, it will switch
to more of a mix of rain and snow or just snow the farther north
you get. The reason for this is the colder temperatures aloft as
well colder surface temperatures will be more supportive to frozen
precipitation. Winds with this low will increase as well but the
strongest winds are expected to remain offshore. For the outer
coast, small craft conditions of 25 to 30 kts as well as elevated
seas are expected while most of the Inner channels stay below
that. The exception being Clarence Strait and Cross Sound.

After the low weakens and dissipates, a deeper low will move into
the western gulf causing a tightening pressure gradient. This
tightening gradient will cause wind speeds to increase the panhandle
as higher pressure sets up over Canada and the low remains closer to
Kodiak Island. Outflow winds are expected to develop across the
panhandle during this time. By Monday evening, an approaching front
with the low over the western gulf will enter the gulf bringing gale
force winds to the outer coast while also increasing the chance of
precipitation for the panhandle. Currently, precipitation
accumulations look to remain on the lighter side, but some snow
accumulations are possible with this front as colder air will remain
over the panhandle. The exception to this being the southern
panhandle near sea level which will see more rain than snow.

.LONG TERM.../Tuesday through Friday morning/ Continuing from the
short range, a low end gale force front will make its way towards
the SE gulf coast late Monday into Tuesday. As the parent low
remains further west, northerly outflow winds will combine with a
tightening pressure gradient across the panhandle leading to an
increase in winds coming out of Cross Sound along with northerly
outflow winds along Lynn Canal. A barrier jet is also expected to
form along the front as it approaches the northern gulf coast
west of Yakutat. This first system will bring widespread gale and
small craft conditions to coastal waters and briefly to the inside
waters, mainly Lynn Canal and the Icy Strait corridor. By Tuesday
afternoon/evening, winds will start to slacken as the front
dissipates along with shower activity.

A well organized high end gale force front will then swing towards
the panhandle Wednesday morning, with coastal waters seeing gale
force winds through Wednesday night out of the SE before finally
beginning to slacken and shift out of the SW on Thursday. This
Wednesday system will bring more enhanced precipitation than the
Tuesday system, but will be overall warmer, therefore more areas
are likely to see rain or a rain snow mix, with only the far
northern panhandle and highways at elevation likely to see
appreciable snow accumulation as of this forecast. Outside of the
widespread gale force winds which may briefly push into the
inner channels Tuesday, or more likely Wednesday, there are no
hazards expected related to precipitation at this time. While
locally heavy amounts are possible with the Wednesday system, IVT
values remain low from ensemble guidance. Overall lighter showers
will continue from Thursday into the weekend, with some isolated
post frontal thunderstorms possible along the outer coast Thursday
afternoon.

Overall the panhandle will see some warming, especially in the
south, heading into and during the storm Wednesday with snow
levels rising to around 1,500 ft along Icy Strait and around 3,000
ft in the far southern. Temperatures will once again trend
downwards to be more seasonably cold along with snow levels heading
into the weekend.

&&

.AVIATION...As expected, limited flight hazard during the day and
that will continue into tonight and Monday. Should see a few areas
of light precipitation, that will offer reduced visibility if you
end up in the showers. Lighter low level winds reducing the
potential for low level wind shear or turbulence over the
panhandle into Monday afternoon. A band of stronger winds with an
approaching low towards the southeastern gulf will bring those
near Prince of Wales Island late Monday.

&&

.AJK WATCHES/WARNINGS/ADVISORIES...
PUBLIC...None.
MARINE...Gale Warning for PKZ661-672.
     Small Craft Advisory for PKZ022-036-053-641>644-651-652-662>664-
     671.

&&

SHORT TERM...SF
LONG TERM....STJ
AVIATION...Bezenek

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