Petersburg, Alaska 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

409
FXAK67 PAJK 191517
AFDAJK

Southeast Alaska Forecast Discussion
National Weather Service Juneau AK
617 AM AKST Fri Dec 19 2025

.SYNOPSIS...

Key Messages:


-Northerly outflow continuing through the weekend freezing spray
 becoming more widespread.

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

&&

.SHORT TERM...Cold air outflow continues through the weekend, as
the pressure gradient between a low in the gulf and a strong Yukon
High Pressure continue to drive cold air out of Canada and into SE
AK. Wind chills will reach below zero for many areas, and windy
conditions will persist across outflow areas around the inner
channels and along outer Coastal waters. A plethora of cold
weather products are in force through the weekend as a result,
with the coldest temperatures and windchills expected for the far
northern panhandle, especially along the Haines and Klondike
Highway. The low in the gulf will race south of the panhandle
through the day, and could bring a few snow showers to far
southern parts of the area.

These conditions have historically been conducive to Taku Wind
events for downtown Juneau, and confidence is growing that this
weekend will be no exception. With the low being situated to the
south and the strong surface high over the Yukon Saturday and
Sunday, strong northerly outflow across the northern panhandle
will make its way into the central panhandle through N/S
channels. A stronger gradient also sets up along the coastal
mountain area to the NE into Saturday morning, bringing stronger
winds coming out of Taku Inlet and the mouth of the Stikine River
with the gradient remaining strong into Monday morning. This
stronger gradient for this weekend will allow for some stronger NE
925 mb winds, which will increase from 30 to 35 kt Saturday to
around 45 kt by Sunday. This strong cross barrier flow increasing
into Sunday morning is also expected alongside weak 500 mb winds
as the trough sets up over the panhandle, creating a good critical
level from this no flow area just over Juneau. These ingredients
along with the inversion at 800-900 mb at the ridgetop continue to
show confidence at a Taku Wind event. Confidence has increased at
the timing of this event, with the overlap of the strongest cross
barrier flow and the critical level formation, makes the timing
of the Taku event more favorable for Sunday. The peak wind gusts
are expected late Sunday morning into Sunday afternoon as the
cross barrier flow strengthens before the 500 mb winds pick up
into Monday. At this time, uncertainty still remains at exactly
how strong these wind gusts will be and how early the event may
start Saturday night into the overnight hours, and low long Sunday
night into Monday morning they will last as the conditions for a
critical level begin to fall apart.

.LONG TERM.../Saturday through Monday night/...
Overall outflow conditions and well below normal temperatures are
the main impacts this weekend into early next week with strong
high pressure remains over the interior of Alaska and Yukon and
upper-level trough/low passing over the panhandle. A passing
surface low passing over Haida Gwaii could bring a few lingering
showers across the far southern panhandle Saturday morning,
otherwise, the cold, dry outflow conditions will persist across
the panhandle. 850 mb temps will dip down -20C or colder. Daytime
high temps will range from the single digits to lower teens across
the north, with teens to lower 20s across the south. Along the
northern highways, below zero temps are likely. Nighttime lows in
the single digits below zero to single digits above zero across
the north, with lows generally in the teens for the south. Again,
the northern highway could be colder with lows in the negative
teens. With the cold temps and stronger winds, dangerously cold
wind chills are expected to continue across much of the northern
panhandle. A Cold Temp Advisory has been issued for the Juneau,
Gustavus and Haines zones, with an Extreme Cold Warning for for
Skagway and especially the Klondike Highway.

In terms of winds, with the low being situated to the south with
the surface high over the Yukon Saturday and Sunday will allow
for strong northerly outflow across the northern panhandle and
making its way into the central panhandle through N/S channels. A
stronger gradient also sets up along the coastal mountain area to
the NE into Saturday morning, bringing stronger winds coming out
of Taku Inlet and the mouth of the Stikine River with the gradient
remaining strong into Monday morning. This stronger gradient for
this weekend will allow for some stronger NE 925 mb winds, which
will increase from 30 to 35 kt Saturday to around 45 kt by Sunday.
This strong cross barrier flow increasing into Sunday morning is
also expected alongside weak 500 mb winds as the trough sets up
over the panhandle, creating a good critical level from this no
flow area just over Juneau. These ingredients along with the
inversion at 800-900 mb at the ridgetop continue to show
confidence at a Taku Wind event. Confidence has increased at the
timing of this event, with the overlap of the strongest cross
barrier flow and the critical level formation, makes the timing of
the Taku event more favorable for Sunday. The peak wind gusts are
expected late Sunday morning into Sunday afternoon as the cross
barrier flow strengthens before the 500 mb winds pick up into
Monday. At this time, uncertainty still remains at exactly how
strong these wind gusts will be and how early the event may start
Saturday night into the overnight hours, and low long Sunday night
into Monday morning they will last as the conditions for a
critical level begin to fall apart.

MARINE...Outside Waters: 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 a fresh to strong breeze as
the low the low in the gulf moves further southeast by Friday
night, with winds diminishing to a moderate to fresh breeze
through Saturday morning. Winds coming offshore and out of the
inner channels will remain a fresh to strong breeze into Saturday
with a slight lull in winds Friday afternoon through Saturday
morning before increasing again into Sunday as outflow conditions
strengthen once again. Gap winds coming off the NE Gulf coast will
also increase Saturday morning and remain at a gale to strong
gale along the outer coastline just to the east of Yakutat down to
Cape Spencer. 8 to 14 ft seas tonight expected to subside to
between 4 and 7 ft by tomorrow evening, increasing again to
between 10 and 16 ft Saturday into Sunday, with the highest seas
expected in the northern Gulf waters.

Inner Channels: Outflow conditions remain through the weekend,
with gale force winds from the north down Lynn Canal, Glacier Bay,
Stephens Passage, and coming out of Cross Sound. A brief lull in
the winds Friday into Saturday morning will decrease the wind
speeds coming out of the north to a strong breeze to near gale
across the panhandle, with gale force winds only remaining through
Lynn Canal, and the only area seeing a larger decrease in the
winds to a moderate breeze over Clarence Strait. A stronger E-W
gradient will also allow some strong breezes to near gales coming
out of the Stikine River into Sumner Strait. Winds will increase
again Saturday morning into Sunday as the outflow strengthens
again, with a strong gale being expected in Lynn Canal and near
gales to gale force winds across the rest of the N-S and NE- SW
oriented channels from this stronger outflow. 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.

&&

.AVIATION...Widespread VFR, windy conditions in channels and aloft, and the
slight chance for snow for the southern panhandle. Little to no
change to the on going TAFs with high confidence for on going VFR
for a majority of the panhandle. Expect to see widespread moderate
turbulence in the low levels (below 10000 ft) due to continued
strong cross barrier flow and stable conditions supporting mountain
waves. This can be confirmed by the numerous pireps for light to
moderate turb. Expecting to see these conditions to continue for the
next three days or more unfortunately. Could see some light snow
showers along the extreme southern panhandle with a compact low
passing south of the panhandle, but lack of moisture will most
likely limit any visibility drop; therefore, could see some MVFR
conditions late this morning, but did not have confidence to
raise this above 30%.

&&

.AJK WATCHES/WARNINGS/ADVISORIES...
PUBLIC...Extreme Cold Warning until noon AKST Sunday for AKZ318.
     Cold Weather Advisory until midnight AKST Saturday night for
     AKZ319.
     Extreme Cold Warning from midnight Saturday night to noon AKST
     Sunday for AKZ319.
     Cold Weather Advisory until noon AKST Sunday for AKZ320-322-325.
     Cold Weather Advisory from midnight Saturday night to noon AKST
     Sunday for AKZ321-323-326.
     High Wind Watch from Saturday evening through late Sunday night
     for AKZ325.
     Cold Weather Advisory from midnight tonight to noon AKST Sunday
     for AKZ327-329.
     Cold Weather Advisory from 6 PM this evening to noon AKST Sunday
     for AKZ331.
MARINE...Heavy Freezing Spray Warning for PKZ011.
     Heavy Freezing Spray Warning for PKZ012-013-031.
     Gale Warning for PKZ011>013-643-644-651-663-664-671.
     Small Craft Advisory for PKZ021-022-031-032-034-035-053-642-652-
     662-672.

&&

$$

SHORT TERM...EAB/GFS
LONG TERM...DS
AVIATION...NC
MARINE...EAB/GFS

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