Sitka, Alaska 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

384
FXAK67 PAJK 200531
AFDAJK

Southeast Alaska Forecast Discussion
National Weather Service Juneau AK
831 PM AKST Fri Dec 19 2025

.UPDATE...
Aviation 06Z update:
As of 0530Z VFR conditions along and north of Sumner Strait. Light
snow is making its way north from Annette Island, bringing MVFR
CIGS and VSBY down to 4SM-2SM, primarily impacting areas south of
Sumner Strait into Saturday morning. Expect to see widespread
moderate turbulence in the low levels (below 10k ft) due to
continued strong cross barrier flow and stable conditions
supporting mountain waves. LLWS was included for the northern TAF
sites with winds 2k ft aloft 20-30kt. Winds generally 5-15kt.
Stronger winds up to 25g40kt continue for PAGY.

&&

.PREV DISCUSSION......ISSUED AT 434 PM AKST Fri Dec 19 2025...

SHORT TERM...Cold weather continues through the short term
period and beyond. All models are in good agreement that
temperatures aloft at 850mb will trend down over the coming days
and bottom out Sunday night, placing the coldest morning of the
period early Monday morning. This will continue with extreme cold
warnings and cold weather advisories for a good chunk of the
region and more locations are likely to be added as confidence
continues to grow. Even before reaching the local criteria for the
southern panhandle, these temperatures are reaching record levels
and thus impacts to infrastructure are possible, including to
pipes/plumbing and wooden vessels. All are encouraged to check on
their property every day and check on vulnerable neighbors.

The cold outflow winds have been causing ocean effect clouds and
lee side low pressure over the eastern gulf. As a result many
places down south have had a deck of low to mid level clouds.
There could be some flurries out of these clouds but not much more
than expected.

Taku winds are expected for downtown Juneau this weekend, peaking
Sunday night. Criteria points to a high end event with gusts of
65-75 mph, potentially higher. Other locations in SE could also
see mountain wave gusty winds. Please see the marine section below
for more detail.

LONG TERM...For next week, we`ll be watching the potential for a
slight shift in the weather pattern that could bring the next round
of snow to the panhandle along with some marginally warmer temps.

The long range computer models, both deterministic and ensembles,
are trying to put a low pressure center in the northern Gulf of
Alaska in the second half of next week. This would allow for the
flow to switch to a more onshore pattern. This would weaken the
pressure gradient over the panhandle, allowing for wind speeds to
weaken a bit beginning around the Tuesday/Wednesday time frame.
If/when the low continues its journey eastward, the pressure
gradient would tighten up again, allowing for wind speeds to pick
back up for the later days of the week.

As far as snow potential, the EURO and Canadian develop a low in the
northern Gulf as early as Wednesday. Their respective ensembles
mirror this story. The outlier is the GFS. The latest deterministic
run keeps the panhandle dry until next Friday. The GFS ensemble
average develops a low Thursday with an averaged low pressure center
remaining in the gulf through the weekend.

For now, moisture amounts are hinting at if the panhandle sees any
snow later next week, it wouldn`t be too much for what is normal in
SE AK until Friday and the weekend.

The 75th percentiles for the EURO and GFS ensembles give the
panhandle less than a tenth of an inch of QPF for Wednesday through
Wednesday night, which would give around 1 to 2 inches of snow. For
Thursday into Thursday night, the 75th percentiles are giving the
area around a quarter to just over a half inch of QPF, with the
greater amounts in the GEFS, which would give 2 to 6 inches of snow
over 24 hours. For Friday into Friday night, the 75th percentiles
are giving the area around a half inch to over an inch of QPF, which
would give upwards of 10+ inches of snow over 24 hours.

So what are the main takeaways off all this data? For starters,
the 75th percentile is an upper bound. So the amounts mentioned
above would be on the high-end for current estimates. Secondly,
snow is possible as early as Wednesday but majority of the data is
pointing to it not being much much if it does happen. Thursday
could be a wildcard day that is worth watching closely. Friday and
next weekend could be a snowy few days so that will be worth
watching closely.

As far as the slightly warmer temps are concerned, there is a
warming trend but most of the panhandle is still likely to be below
freezing. Monday`s highs will be generally in the single digits to
teens but by Friday, highs could be in the teens in the far north,
20s and 30s elsewhere. For overnight lows, Monday nights forecasted
lows are in the single digits above and below zero with warmer teens
to 20s for Friday night. So warmer but still colder-than-normal.


MARINE...
Inside Waters: Outflow conditions remain through the weekend, with
gale force winds from the north down Lynn Canal, Glacier Bay,
Stephens Passage, through Icy Strait, and then out of Cross Sound. A
brief lull in the winds has begun as of this afternoon and will
continue into Saturday morning. Even though this is the lull in the
winds, strong breezes to near gale of 23 to 33 kts continue across
the panhandle, with gale force winds continuing through Lynn Canal,
The southern inner channels, over Southern Chatham and Clarence
Strait, are seeing the largest decrease in winds to around 10 to 15
kts. A stronger E-W gradient will also allow some strong breezes to
near gales coming out of the Stikine River into Sumner Strait.

Winds once again increase Saturday morning into Sunday as outflow
strengthens again. This will bring back strong gales of 40 to 47 kts
into Lynn Canal and near Point Couverden. Winds across other north
to south facing channels, Chatham Strait and Stephens Passage, and
out of cross sound, will increase again to near gales to gale force
winds, 28 to 40 kts. Fully developed seas expected down Lynn Canal
and Stephens Passage this whole outflow period, with the highest
seas of 14 to 16 ft expected in southern Lynn early Friday morning
subsiding to 7 to 12 ft before the outflow strengthens again on
Saturday. Widespread freezing spray for many channels will continue,
with heavy freezing spray for Glacier Bay, Lynn Canal, and Stephen`s
Passage in particular.

Some models are pointing at a weakening pressure gradient mid to
late week next week. This would allow for a break in outflow
conditions with diminishing winds. Behind that couple day break, the
gradient does strengthen once again. We will continue to monitor
this potential break from these strong outflow winds.

Outside: Offshore flow continues, bringing increased gap winds off
the NE Gulf Coast and stronger NE outflow winds coming out of Cross
Sound into the Gulf waters. Winds in the southern and central Gulf
will remain around fresh to strong breezes as the low in the gulf
moves further southeast. Winds then continue to diminishing to
moderate to fresh breezes through Saturday morning. Winds coming
offshore and out of the inner channels will remain around fresh to
strong breeze into Saturday with a slight lull in winds Friday
afternoon through Saturday morning. With weakening winds, seas
continue to subside tonight with significant seas around 4 to 7 ft,
the highest of these in NE gulf where gap winds are commonly
produced.

Outflow gap winds coming off the NE Gulf coast will increase
Saturday morning to gale force to strong gales along the outer
coastline, to the east of Yakutat down to Cape Spencer. As well as
increase wind speeds, wave heights once again build to between 10
and 16 ft Saturday evening into Sunday, with the highest seas
expected in the northern Gulf waters.

&&

.AJK WATCHES/WARNINGS/ADVISORIES...
PUBLIC...Extreme Cold Warning until noon AKST Monday for AKZ318.
     Cold Weather Advisory until midnight AKST Saturday night for
     AKZ319.
     Extreme Cold Warning from midnight Saturday night to noon AKST
     Monday for AKZ319.
     Cold Weather Advisory until noon AKST Monday for AKZ320-322-325-
     331.
     Cold Weather Advisory from midnight Saturday night to noon AKST
     Monday for AKZ321-323-324-326.
     High Wind Warning from 3 AM Sunday to 9 AM AKST Monday for
     AKZ325.
     Cold Weather Advisory from midnight tonight to noon AKST Monday
     for AKZ327-329.
MARINE...Heavy Freezing Spray Warning for PKZ011.
     Heavy Freezing Spray Warning for PKZ012-031.
     Heavy Freezing Spray Warning for PKZ013.
     Heavy Freezing Spray Warning for PKZ013.
     Heavy Freezing Spray Warning for PKZ013.
     Heavy Freezing Spray Warning for PKZ021.
     Heavy Freezing Spray Warning for PKZ032.
     Heavy Freezing Spray Warning for PKZ651.
     Gale Warning for PKZ012-651.
     Small Craft Advisory for PKZ011-013-021-022-031-032-034-053-643-
     644-652-663-664-671-672.

&&

$$

SHORT TERM...Ferrin
LONG TERM...GJS
AVIATION...AP
MARINE...EAB

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