Petersburg, Alaska 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

029
FXAK67 PAJK 201903
AFDAJK

Southeast Alaska Forecast Discussion
National Weather Service Juneau AK
1003 AM AKST Sat Dec 20 2025

.UPDATE...Update to include the 18Z TAF issuance...
Only minor edits to the forecast this morning. Lowered today`s max
temps as we are starting off a bit colder this morning than what
was forecast. Temps were mainly lowered for Hoonah. A lot of cold
hazard products were expanded and upgraded during the overnight to
include all but the far southeast AK. The start time for the High
Wind Warning for downtown Juneau and southern Douglas Island was
also moved up to begin today as the strong winds are expected
earlier.

&&


SYNOPSIS...

Key Messages:

- Widespread cold temperatures and cold wind chills last through
  the weekend and into next week.

- A Taku wind event will bring potentially damaging wind gusts
  65-75 mph this weekend for downtown Juneau and southern Douglas
  Island.

.SHORT TERM...

Cold weather and cold wind chills continue through the short term,
with a mixture of cold weather advisories and extreme cold
warnings spread across most of SE AK. A positively tilted trough
anchored over the area is diverting the normal storm track into
the West Coast of the CONUS. Concurrently, the Yukon High driving
the northerly outflow winds responsible for the cold weather will
remain anchored in place through at least the first half of next
week, resulting in continued frigid weather. Skies will clear
across the southern panhandle as the remnants of a low depart the
area, though a few snow showers may linger for Ketchikan, Annette,
and Hyder through early Saturday morning. Otherwise, dry weather
and clearer skies will be the prevailing weather through the next
several days.

Alongside the cold, the other big story is the wind. In
particular, confidence is high in a Taku Wind event for downtown
Juneau and Douglas on Sunday, 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 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.

.AVIATION.../through Sunday afternoon/...
Mainly VFR conditions with higher winds in the channels and
aloft across the central and northern panhandle. MVFR CIGs and a
slight chance for snow for the far southern panhandle through
tonight, then becoming VFR tomorrow. LLWS was included for PASI
and the northern TAF sites with winds 2k ft aloft 25-40kt. Strong
cross barrier flow will likely result in mountain wave activity,
especially for the Gastineau Channel near PAJN. Few to sct mid to
high level clouds 4-10k ft across the north. Winds generally
5-15kt. Stronger winds 25g40kt continue for PAGY.

.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 ends on Saturday morning. 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. 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. Winds will be slowly diminishing to moderate to fresh
breezes through Saturday morning.

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...Cold Weather Advisory until noon AKST Monday for AKZ317-322-323-
     328-329-331.
     Extreme Cold Warning until noon AKST Monday for AKZ318.
     Cold Weather Advisory until midnight AKST tonight for AKZ319-320-
     325-327.
     Extreme Cold Warning from midnight tonight to noon AKST Monday
     for AKZ319>321-325>327.
     Cold Weather Advisory until midnight AKST Sunday night for
     AKZ324.
     Extreme Cold Warning from midnight Sunday night to noon AKST
     Monday for AKZ324.
     High Wind Warning until 9 AM AKST Monday for AKZ325.
MARINE...Heavy Freezing Spray Warning for PKZ011>013-031.
     Heavy Freezing Spray Warning for PKZ032.
     Heavy Freezing Spray Warning for PKZ053.
     Heavy Freezing Spray Warning for PKZ651.
     Storm Warning for PKZ651.
     Gale Warning for PKZ011>013-022-031-053-643-644-663-664-671-672.
     Small Craft Advisory for PKZ021-032>035-652.

&&

$$

SHORT TERM...GFS/Ferrin
LONG TERM...GJS
AVIATION...DS
MARINE...GFS/EAB

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