798
FXAK67 PAJK 050630 AAA
AFDAJK

Southeast Alaska Forecast Discussion...UPDATED
National Weather Service Juneau AK
930 PM AKST Thu Dec 4 2025

.Evening and 06z Aviation Update...Few updates to the marine and
general public forecast going forward. Westerly flow aloft is
causing enhanced leeside troughing near Haines and Skagway, with
gradients between Juneau and Skagway around a 1 to 2 mb
difference. This is generating up to 15 knot winds for Lynn Canal
from the south, but expecting to see the winds relax as the
westerlies aloft relax. These southerly winds have not stopped
Haines and Skagway from decoupling, however. Looking towards the
latest sounding in Whitehorse, it is clear that an inversion up to
5500 ft with moderately cold temperatures is causing some
katabatic flow, undercutting the southerly, more unstable air.
Therefore, kept Skagway and Haines north and west through the
night with up to 10 knot sustained winds.

&&

.AVIATION.../through Friday evening/
A mixed bag of flight conditions this evening with persistent
low clouds and isolated showers across the panhandle. Looking at
obs around the area, TAF sites range from isolated areas of VFR &
IFR to predominate MVFR & LIFR. Flight conditions are highly
variable hour by hour with CIGS bouncing between 200ft to 3500ft
and visbys between 1/2 SM to 4SM within fog, rain, or mist.
Through Thursday night flight conditions will generally remain the
same or continue to worsen slightly, continuing the trend of
bouncing between MVFR to LIFR flight conditions with CIGS AoB
2500ft and intermittent visbys as low as 1/4SM in fog. By Friday
mid-morning, brief break in precip for the area with general MVFR
flight conditions across along the northern panhandle. Best
flight conditions will be across the southern panhandle, along a
line from TAF sites Sitka to Petersburg and southward seeing the
greatest chances of VFR conditions by Friday afternoon.

Winds should remain around 10 kts or less overnight, going near
calm and variable at most TAF sites. Main exceptions are the
usual culprits of Haines and Skagway which will to see increased
winds up to 20kts as drainage flow winds continue through the
night. No LLWS concerns through the TAF period, however front
pushes into the NE Gulf by late Friday evening.

&&

.PREV DISCUSSION......ISSUED AT 514 PM AKST Thu Dec 4 2025...

SYNOPSIS...

Key Messages:
 - Very light winds and weak onshore flow remain across the
   panhandle tonight into tomorrow.

 - Light mist with areas of fog are likely to continue across the
   panhandle with due to weak onshore flow.

 - Late week into next weekend, long range models are still
   suggesting a weather pattern that has been known to produce
   heavy snow. High uncertainty on timing and amounts, but details
   are being watched closely.

SHORT TERM...Light mist and rain continue across the panhandle as
onshore flow continues. The southern panhandle is seeing more of a
break from this light precipitation, but in turn they are seeing
continued areas of fog, at times dense below 1 SM. Along with these
lowered visibilities and onshore conditions, winds will remain light
across the area through tomorrow afternoon. The only exception to
this will be over the southern gulf waters as a quick moving, weak
low moves east south of the panhandle. This low will bring slightly
increased winds across the southern gulf to around 15 to 20 kts late
tonight into early Friday. Light winds of 10 to 15 kts, and weak
onshore flow, returns late Friday morning before a larger system
arrives Saturday.

On Friday night winds will begin to increase as a low pressure
system pushes into the north central gulf. This low will quickly
increase precipitation rates across the northern panhandle and
spread into the panhandle. Along with increasing precipitation
rates, decreasing temperatures will transition precipitation to snow
starting along the northern panhandle. Confidence is high for a long
lived snow even starting this weekend lasting into early next week.
Snow initially starts late Friday night, but the heaviest amounts
arrive later Saturday into Sunday. See the long term forecast for
more details on the snow forecast timing and intensity.

LONG TERM.../Saturday through Tuesday/...A pattern change going
into this weekend is still looking to bring cold temperatures,
heavy precipitation, and strong winds to the panhandle into early
next week. Confidence has improved for snow potential in Skagway
and Haines over the weekend, and even more for the northern
highways. A winter storm warning has been issued for these areas
over the weekend, and a watch has been issued for Yakutat. The
special weather statement was also continued for the NE gulf coast
and the Icy Strait Corridor.

A system sending a front into the panhandle overnight Friday is
still looking to stall in the northern gulf through the weekend,
funneling consistent moisture over the panhandle. This front will
bring moderate to heavy rain rates to the area, with around an
inch to an inch and a half of rain in 24 hours expected for a
majority of locations and persisting at similar rates through the
weekend. Though these rain amounts may seem typical for a 24 hour
period, the persistence at those rates lasting through the weekend
and into next week will be watched closely, especially at higher
elevations. A cold air mass aloft shifts into the Yukon and
continues to moves southward through the weekend. A tightening
pressure gradient over the northern panhandle will increase
outflow winds through the weekend, helping to funnel the colder
air south into the panhandle. Decreasing temperatures with ample
available moisture will increase the potential for heavy snowfall
in the northern panhandle, extending south through the weekend and
into next week. Highest confidence of snowfall remains in the N
Panhandle over the weekend. Forecast becomes more of a challenge
moving towards the Icy Strait Corridor, starting as rain and
transitioning into a mix by Sunday, limiting potentially
accumulations. Expecting a transition over to snow going into
Monday, though uncertainty remains as to how much available
moisture there will be, limiting appreciable amounts. As snow
level drops south following the colder temperatures, snow
potential will also move further south towards the corridor, and
the rain/snow mix will then follow into the central panhandle.
Stay tuned to the forecast moving into the weekend as details come
into clearer view regarding potential amounts and refined timing.

As the gale force low moves into the northern Gulf and a high
sets up to the north of the panhandle into this weekend, a tight
pressure gradient allowing for northerly flow begins to set up
over the northern panhandle into Lynn Canal. This cold air mass to
the north contributes to the colder temperature trend over the
weekend and into early next week, alongside bringing stronger
winds down Lynn Canal. These winds will begin to increase Saturday
into Sunday with northerly gales in northern Lynn Canal with 35
to 40 kt winds by Sunday afternoon as the gradient tightens over
the northern panhandle. These gale force winds will last into the
beginning of next week as the gradient remains. Winds will
increase in Skagway at this time, with 25 to 35 mph sustained
winds possible Sunday and Monday. A decent 850-750 mb inversion
setting up over Whitehorse to the northeast will allow for these
winds to impact Skagway not only from the strong pressure
gradient, but from a decent density difference, allowing for more
confidence at Skagway having elevated winds over this timeframe
with gusts reaching up to 40 to 50 mph at times. Other land areas
will see an increase in SE winds as the front moves through, with
diminished winds between the waves of precipitation that push
through this weekend into early next week. Overall the outflow
pattern over the northern panhandle is expected to last into
midweek, with more northerly winds and offshore flow beginning to
move southward to around Icy Strait Corridor Monday onwards. This
cold dry air will help to lessen the precipitation amounts across
the northern panhandle midweek into the end of the week when
looking ahead.

MARINE...
Outside Waters: Calmer conditions tonight into tomorrow last over
the Gulf as a weak high remains over the area, before being
pushed out by the oncoming system moving in from the west by
tomorrow night. This next system will bring southwesterly to
southerly fresh to strong breezes (17 to 27 kt) across the Gulf
tomorrow night and becoming more southerly by Saturday. As the
pressure gradient tightens between the low in the Gulf and the
high to the north over Canada Saturday night into Sunday,
northeasterly near gale to gale force (30 to 40 kt) offshore winds
and gap winds will occur along the NE Gulf Coast between Yakutat
Bay and Cape Spencer. The southeastern Gulf will also see an
increase from near gales to gales (28 to 36 kt) as a front moves
through Saturday night into Sunday morning and again Sunday night
into Monday. Seas between 5 and 8 ft tonight will quickly increase
tomorrow night into Saturday as the system moves in to between 10
and 14 ft. The seas will continue to see an increase into Sunday
to 12 to 16 ft. Southwesterly swell continues tonight through the
weekend.

Inner Channels: Predominantly calmer winds tonight and tomorrow
anticipated to see a sharp increase Friday night into Saturday as
the next system moves into the area. This will bring southeasterly
winds across the inner channels between a moderate to fresh
breeze into Saturday, and up to a strong breeze (22 to 27 kt) for
northern Lynn, Frederick Sound, Stephens Passage, and near the
ocean entrances. The channels will see a brief increase as the
fronts move across the panhandle this weekend into early next
week. Northerly outflow begins to set up over northern Lynn Sunday
as the pressure gradient begins to tighten, bringing near gales
in the morning becoming gales into the day Sunday. Largely
expecting between 35 and 43 kt winds down Lynn Canal lasting from
Sunday into early next week, with the stronger northerlies moving
southward down to Point Couverden Sunday night into Monday. This
will allow some lower level convergence right around Point
Couverden from the southeasterly winds up Chatham Strait and the
northerly outflow coming down out of Lynn Canal, bringing winds
around Rocky Island to around 25 to 30 kt. Frederick Sound near
Point Fanshaw and up along Stephens Passage will continue to see
strong breezes to near gales throughout the weekend, alongside
Clarence Strait seeing near gales as the fronts move through and
bring stronger southeasterly winds.

&&

.AJK WATCHES/WARNINGS/ADVISORIES...
PUBLIC...Winter Storm Watch from late Friday night through late Saturday
     night for AKZ317.
     Winter Storm Warning from 10 PM Friday to 3 PM AKST Sunday for
     AKZ318.
     Winter Storm Warning from 3 AM Saturday to 3 PM AKST Sunday for
     AKZ319.
     Dense Fog Advisory until 3 AM AKST Friday for AKZ328-330-332.
MARINE...Small Craft Advisory for PKZ661.

&&

$$

UPDATE...NC
SHORT TERM...EAB
LONG TERM...ZTK
AVIATION...NM
MARINE...Contino

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