197
FXAK67 PAJK 080625 AAA
AFDAJK

Southeast Alaska Forecast Discussion...UPDATED
National Weather Service Juneau AK
925 PM AKST Sun Dec 7 2025

.UPDATE...Aviation section updated for 6z taf issuance.

&&

SYNOPSIS...

Key Messages:

 - Moderate to heavy snow continues over the northern panhandle
   and will continue to spread southward into central and southern
   panhandle as temperatures decrease.

 - Cold temperatures moving into SEAK to start the week, with many
   areas seeing single digits or sub zero temperatures. Wind
   chills along White Pass dipping below -25 Sunday night.

SHORT TERM...Complicated pattern through Monday with multiple
hazards, primarily delineated between the north and south
panhandle.

Overall, we have a decaying low pressure in the western gulf,
generating multiple shortwaves moving into the panhandle from the
southwest, bringing both additional waves of moisture and showers.
In Canada to the north, a deep inversion up to 700 mb is generating
strong katabatic flow out of interior passes. This arctic air is the
main element which is contributing to the very cold temperatures in
the north, and more rounds of snow for the south. At time of
writing, the arctic boundary is currently north of Petersburg over
to just south of Sitka.

For the north, very cold katabatic flow is currently generating
gusts up to 30 mph, low 20s weather with dewpoints in the low single
digits for both Haines and Skagway, the two towns mostly exposed to
the gradient direction. Currently expecting the temperature to
further drop through tomorrow from the cold pool in the Yukon
continuing to strengthen, radiative cooling from skies clearing
tomorrow morning, and present snow preventing any small amount of
solar radiation from being able to be absorbed by the ground.
Looking to see temperatures well below 0 on the Klondike Highway,
single digits in Haines and Skagway and teens in Icy Strait tonight,
dropping collectively around 10 degrees for tomorrow nights low.
This combined with strong winds, particularly on the Klondike, is
expected to cause wind chills exceeding -40 F by tomorrow night.
Several cold weather advisories have also been issued for Haines and
Juneau.

For the south, however, Monday will see a developing low move in
quickly from the southwest over southern Prince of Wales Island.
This in combination with the arctic boundary, which is expected to
drop into Sumner Strait by tomorrow morning, look to generate
moderate to strong snow rates for mainly northern Prince of Wales
Island, Wrangell, and Petersburg. Certainly a good deal of
uncertainty associated with this system, as too much cold air, or
the low pressure passing much further south than expected, will sap
any moisture pushing up from the south. As it stands now, the warm
front pushing up from the south ahead of the low will set up over
Prince of Wales Island from about Craig to Ketchikan. South of this
line is expected to be mainly rain, driven by the warm temperatures
aloft, north of this line as it pushes northward, is expected to be
either mix or snow. Therefore, the northern half of Prince of Wales
Island appears to initially be in the line of fire for this event.
Strong liquid equivalent rates possibly exceeding a tenth of an
inch and lighter winds look to keep temperatures north of the line
well below freezing.

As the low moves in, currently expecting to see the main band of
precipitation rotate to vertically to move the trowal axis to north
south, with southeasterly winds further enhancing the topographic
effects on the eastern side of the island. The big question is
whether the temperatures will be able to hold of for long enough to
stay all snow, to which cause PoW will receive warning levels of
snow. Unfortunately, confidence was not high enough for this
solution, and therefore an advisory was issued instead. This will
need to be watched carefully going forward.

For Wrangell, expecting to see outflow out of the Stikine valley
to keep at least the airport as all snow, and this location will
be highly dependent on how fast this low pressure system moves
eastward. For Petersburg, the strength of the arctic boundary
throws uncertainty into the total snow amounts, with possibly
sub-saturation keeping snow type as mainly plates with much less
accumulation. This is entirely assuming that the cold air does not
entirely evaporate any falling precipitation into Petersburg.

Ultimately, any amount of snow for any of the aforementioned areas
is expected to be roughly a 6 to 9 hour window of heaviest rates,
mainly associated with the warm push northward beginning during the
day on Monday and continuing through the evening.

LONG TERM...An arctic boundary continues to move southward over the
southern panhandle at the start of the mid range and will likely
move south of the panhandle by mid week. Building high pressure in
NW Canada and interior Alaska is creating offshore flow and ushering
colder continental air through the northern panhandle. This air is
very cold with 850 mb temps plummeting into the -15 to -25 C range
by mid week across the northern panhandle and near -10 C over the
south. At sea level this will translate to overnight lows ranging
from single digits above or below zero for the north to teens and
20s for the south.

Daytime highs will struggle to reach the 20s for the north and into
the 30s for the south as we progress through the week. Coldest
temperatures look to occur Monday night through Wednesday night, but
sub freezing temperatures are likely to stick around into next
weekend as well. The panhandle from Icy Strait northward will be
watched closely as many locations will be approaching their
criteria for cold weather advisories or extreme cold warnings
(especially the Haines and Klondike Highways) from early to mid
week. As of this forecast discussion, an extreme cold warning was
issued for the Klondike Highway from Monday night through Tuesday
morning for extremely cold temperatures with wind chills as low
as -40 degrees.

Strong outflow winds will be ushering in these frigid temperatures,
blowing along many northern panhandle channels, with gale force
winds lasting through most of the week. The strongest winds will
be located along Lynn Canal and Chatham Strait, with elevated
winds also coming out of Taku Inlet as well as blowing out into
the gulf from gaps along the NE gulf coast. A strong 1035 mb high
in the Yukon is the main driver of this outflow and it will persist
and strengthen to 1050 mb by late next week. Expect gusty winds
out of many of the outflow areas in the northern panhandle to
start with, but expect outflow out of areas farther south through
the week as the Yukon high expands into northern British Columbia
by late week. With these winds and the cold air that it is
bringing, a few secondary effects will be noticeable. First, wind
chills will be rather frigid reaching into the negative teens and
possibly colder in the north most of the week. Second, is that
freezing spray will become a more widespread problem for many
marine areas in the inner channels and along the NE gulf coast.
The freezing spray could become heavy at times in Lynn Canal, near
Taku Inlet, and northern parts of Glacier Bay throughout the
week.

Otherwise, most of the panhandle will be dry through the mid and
long range except for possibly the south. A series of lows track
into the BC coast and could send some of their precip into the
southern panhandle throughout the week. Given how cold the
atmosphere is expected to be the precip, when it does fall, will
mostly be in the form of snow. Highest accumulations would likely
be earlier Tuesday, while additional accumulations will likely be
low for the mid week period. There is the possibility of a
another snow event for the south next Friday into Saturday with a
couple inches of accumulation possible but storm track is
uncertain at this time for that system.

AVIATION...Aviation weather is a mixed bag of varying ceilings,
visibility and precip type as another band of precipitation moves
north through the central and northern panhandle while cold air is
being introduced at lower elevations. Rain/snow line has been
inching southward through the evening and has reached Kake as of 9
pm. north of that line ceilings and vis have dropped to MVFR and
IFR due to snowfall up to Hoonah and Juneau (VFR north of that due
to the strong outflow drying things out) while south of that line
occasional MVFR, but mostly VFR conditions are present with less
organized and less frequent rain showers moving in from the gulf.
Periods of precipitation expected to continue from Icy Strait
southward tonight with MVFR to IFR in snow while VFR to MVFR
conditions will continue where it rains with the rain/snow line
continuing to inch southward. Into Monday expect more VFR
conditions for the north, but a lot of outflow winds through
passes and channels (up to 30 to 40 kt) some low level wind shear
as well from stronger n winds blowing over mountain tops and ridge
lines. Highest of these winds will likely be Monday afternoon and
evening. Meanwhile the south will see another surge of precip move
in and with the cold air still moving south many areas will see it
as snow with the accompanying drop in vis and ceiling (likely to
IFR) starting in the morning and lasting into the evening.

MARINE...
Outside (Gulf and Coastal Waters):

The outside waters forecast will largely be dominated by the
outflow winds from density differences between the panhandle and
north into Canada. Strong gales to storm force winds are expected
out of interior passes, Cross Sound, and Chatham Strait for the
next 36 hours. Expecting to see an increase in winds tomorrow from
cold temperatures further being enhanced in Canada. For more
information, see the short term. For seas, expecting to see
upwards of 15 ft seas associated with winds blowing out of
interior passes for the next few days.

Inside (Inner Channels):

Expecting to see a mostly stagnant pattern over the next few days,
but an impactful one. Northerly winds in Glacier Bay, Lynn Canal,
and Taku Inlet are all expected to exceed gale to strong gale for
multiple days, with the upper arms of Glacier Bay and northern
Lynn Canal expected to see heavy freezing spray for multiple days.
Looking to see the stronger northerlies to extend south over the
next 36 hours as the Monday low/energy departs into British
Columbia. Light to moderate freezing spray is expected to stick
around for the central panhandle into mid week.

&&

.AJK WATCHES/WARNINGS/ADVISORIES...
PUBLIC...Cold Weather Advisory until 6 PM AKST Monday for AKZ318.
     Strong Wind until midnight AKST tonight for AKZ318.
     Extreme Cold Warning from 6 PM Monday to noon AKST Tuesday for
     AKZ318.
     Cold Weather Advisory from 3 PM Monday to 3 PM AKST Wednesday
     for AKZ319.
     Cold Weather Advisory from midnight Monday night to noon AKST
     Tuesday for AKZ320-325.
     Winter Storm Warning until midnight AKST tonight for AKZ321.
     Winter Weather Advisory until midnight AKST tonight for AKZ322.
     Strong Wind until 3 AM AKST Monday for AKZ325.
     Winter Weather Advisory from 9 AM to 9 PM AKST Monday for AKZ326-
     329.
     Winter Weather Advisory until 6 AM AKST Monday for AKZ327.
     Winter Weather Advisory from 3 AM to 3 PM AKST Monday for AKZ328.
     Winter Storm Warning until 9 PM AKST Monday for AKZ331.
MARINE...Heavy Freezing Spray Warning for PKZ012.
     Storm Warning for PKZ651.
     Gale Warning for PKZ011>013-021-022-031>033-053-641>644-661>664-
     671.
     Small Craft Advisory for PKZ034>036-652-672.

&&

$$

SHORT TERM...NC
LONG TERM...STJ/EAL
AVIATION...EAL
MARINE...NC

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