Juneau Alaska Weather Forecast Discussion

125
FXAK67 PAJK 071804
AFDAJK
Southeast Alaska Forecast Discussion
National Weather Service Juneau AK
1004 AM AKDT Tue Oct 7 2025
.UPDATE...Update to include 18Z TAF issuance...
&&
.SHORT TERM...Satellite and radar imagery show cloud cover
rebuilding from N to S as a weak low over the northern gulf dives
into SE AK. As the low moves in, expect widespread rain showers
to return through the day, with brief periods of moderate rainfall
not impossible under stronger convective cells. As the low moves
south, winds will diminish, and ultimately turn more northerly. By
Tuesday night, the low will be departing the area, and a building
ridge across the Gulf will bring with it clearing skies. With
these clearing skies, anticipate widespread fog across SE AK,
including both land-based locations and many of the inner
channels. Drier weather is anticipated for Wednesday.
.LONG TERM.../Wednesday through Monday/ Upper level pattern
across the gulf and panhandle later in the week is dominated by
an upper ridge that has parked itself over the Gulf of Alaska.
This feature will stay fairly persistent through the forecast
period with the exception of a few short wave troughs flattening
the ridge late week into the weekend as they move W to E along the
N gulf coast. Of the two troughs that do so, the Thu into Fri
feature is the strongest with a pronounced vorticity max
associated with it. Looking into the late weekend, there are
indications that the upper ridge may not last with a strong trough
running into it from the W late Sunday. However, there are some
scenarios where the ridge rebuilds into next week as the trough
passes.
At ground level, generally we are looking at a rather dry period
for Wednesday into the first part of Thursday with the surface
reflection of the upper ridge over the gulf keeping most rain and
clouds at bay. May be some lower marine layer clouds and drizzle
for the outer coast at times though. That starts to change later
into Thursday as low level flow start to become more onshore
rather then along shore in direction ahead of the next system. The
NE outer coast may start to see more clouds and drizzle as that
happens, and more substantial rainfall will start of move into the
area (Yakutat first Thursday evening and the northern panhandle
late Thursday night). Not expecting much rainfall or wind as the
system will be fighting the ridge the whole way and will be
weakening as it moves farther east. Total rainfall will likely be
in the realm of around a quarter to half inch at most. Winds will
likely top out at 25 to 30 kt in the gulf (20 kt at most in the
inner channels) before diminishing.
Behind the system is a brief shot of cooler air coming in from
the Bering Sea area. This will briefly raise surface pressures in
the southern Yukon on Saturday resulting in weak outflow winds
through the northern inner channels. Nothing more then 25 to at
most 30 kt in Lynn Canal expected at this time though 15 to 20 kt
northerlies could extend down Stephens and Chatham Strait as well.
In addition, freezing levels will be dropping to around 1000 ft
by Saturday morning. Most of the precipitation should be over with
by that point though so no major snow accumulation are expected
for the northern mountain passes, However some light accumulations
could show up at White Pass Friday night into early Saturday and
that area may experience an extended period of temperatures near
or below freezing as well this weekend.
Late weekend into early next week, uncertainty on how an ex-
tropical system will interact with the storms over the Bering Sea
next weekend is trickling down into SE`s forecast. Most guidance
is currently trending toward a rather wet scenario for the NE gulf
coast coast later Sunday into Monday with some of that extending
into the rest of the panhandle. Timing and placement of the system
is still uncertain though so how wet the rest of the panhandle
gets varies depending on what you look at, but the trend is still
mainly toward wetter early next week.
&&
.AVIATION.../Through Wednesday morning/...Majority VFR conditions
are expected through the period. A weaker front associated with a
surface low that has moved into the northeastern gulf coast is
pushing SE through the panhandle Tuesday. As the front passed over
this morning, CIGs dropped to MVFR with light rain and lower few
layers. The majority of these CIGs have raised to VFR conditions
at this point, though these minor impacts will linger in Klawock
and Juneau through the morning. Skies behind the front are
beginning to lift, though the occasional scattered showers will
still follow in the wake. Dry air following the front will end
shower potential by late afternoon, allowing skies to fully clear
out. Clear skies in the afternoon will be conducive to fog
development overnight and into Wednesday morning, which could
reduce VIS to 2 SM or less. Areas of dense fog with 1/2 SM of VIS
are possible, particularly in the interior panhandle. Low ceilings
will move in along the gulf coast and into cross sound overnight
and into the early morning hours of Wednesday.
&&
.MARINE...
Inside Waters: Strong breezes of 22 to 27 kts across the northern
inner channels through early Tuesday morning begin to diminish as
a low moves over the area and then heads southward. As ridging
builds over the Gulf in its wake, wind speeds diminish and the
prevailing wind direction will ultimately flip to N through
Tuesday night. In the wake of the low, wind speeds will remain
around 5-10 kt for the inner channels on Wednesday. Fog is also
expected for many of the inner channels Tuesday night into
Wednesday morning, as clearing skies take hold behind the
departing system.
Outside Waters: A low pressure system in the northern gulf will
move SE through Tuesday. This will lead to elevated winds of 25 to
30 kts with gale force gusts along the far offshore waters, and
winds of 20-25 kt for the inner coastal waters. Winds greatly
diminish by Tuesday night with the developing ridge. Through the
morning hours on Tuesday, still expect significant wave heights of
12 to 14 ft with 16 ft in the far offshore waters with a
southwest swell. Winds and waves both diminish through the latter
half of Tuesday and into Wednesday as the low departs the area.
Wave heights subside to 7-10 feet (with higher waves further into
the open Gulf), and winds become NW 10-15 kt S of Kruzof Island
and W for areas to the N.
&&
.AJK WATCHES/WARNINGS/ADVISORIES...
PUBLIC...None.
MARINE...Small Craft Advisory for PKZ022-053-641>644-651-652-661>664-671-
     672.
&&
$$
SHORT TERM...GFS
LONG TERM...EAL
AVIATION...ZTK
MARINE...GFS
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