Sitka, Alaska 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

112
FXAK67 PAJK 250607
AFDAJK

Southeast Alaska Forecast Discussion
National Weather Service Juneau AK
907 PM AKST Wed Dec 24 2025

.UPDATE...After 06z TAF issuance..VFR Conditions continue through
tonight. Light snow wills spread through the coastal area of the
panhandle Thursday.


&&

.PREV DISCUSSION...ISSUED AT 343 pm Wednesday 24 December...

SYNOPSIS...

Key Messages:

- A low pressure will bring light snow accumulations to the
  outside coast for Christmas Day.

- The next impactful system moves in Friday bringing heavy rain
  and snow to the panhandle for the weekend.

- Temperatures warm up with the next incoming low bringing an end
  to the low teens and near zero temperatures.

SHORT TERM...Outflow conditions continue to weaken this
afternoon as the pressure gradient between the panhandle and the
Yukon continues to weaken. This brief weakening will be short
lived though as a surface low moves to the south and east from
Prince William Sound will start to increase the pressure gradient
across the panhandle. This low will bring some snow to the outer
coast for Christmas Day with 1-3" of snow possible for Sitka down
to the western PoW Island starting Christmas morning before
dissipating tomorrow evening. This low will also bring clouds to
other parts of the panhandle which will limit how much we cool
later tonight. By Friday morning, this low will have moved out of
the area and a shortwave ridge of high pressure will move into the
panhandle allowing for a nice break before the next system moves
into the area starting Friday.

LONG TERM...We continue to watch the upcoming shift in the
weather pattern that would give the next round of significant
snow to Southeast Alaska this weekend.

The next major system will begin to move into the Gulf of Alaska
Friday night from the west. In terms of winds, the northern and
easterly offshore flow will increase again ahead of the next low
moving in from the west. Winds begin to pick up across the entire
panhandle Friday night into the weekend as the stronger low
approaches, and a gale force front begins to move in from the
southwest into Saturday morning. These southerly winds moving into
the panhandle will allow for some warming across the panhandle
alongside bringing precipitation through from W to E with this first
front and the following wave moving through by Sunday.

As far as temperature relating to snow potential, the ensembles and
deterministic models have come into greater agreement over low
tracks and 500mb flow. The 500 mb flow continues to have the deep
trough further west, keeping a southwesterly flow into the panhandle
and allowing for deep moisture and warmer air to be moved in from
lower latitudes with the deep trough position, with the arctic
trough and 500 mb cutoff low over the Pacific to the southwest
connecting over the Kenai Peninsula down the west Gulf. Some of the
deterministic models still show the arctic trough separating from
this lower latitude troughing as it becomes a cutoff again and moves
southward, leaving a southwesterly flow into the southern panhandle
but the arctic trough allowing for colder arctic air to move across
the northern Gulf into the northern panhandle, bringing the
potential for cooling the north much sooner than the southern
panhandle into Monday. This only is beginning to show up on 30% of
the clusters with this separation and having an arctic flow into the
northern panhandle, while the rest of the 70% of the ensembles
keeping the deep connected troughing with SW flow move into the
whole panhandle with resulting warmer 850 mb temperatures. This
means that the timing of the cold air coming back into the northern
panhandle is still a bit uncertain for the period into early next
week, and seeming a bit more likely into mid week based on when the
ensembles agree on colder arctic air bringing down temperatures
again across the north.

Looking at the EFI tables, as well as looking at AR and IVT tools
for this heavier precipitation coming up this weekend, QPF amounts
have been increased over the northern panhandle (particularly
Yakutat and in areas closer to the coastal mountain range) as the
first wave hits Saturday with a bit less hitting the southern
panhandle directly until Sunday. Adjusted to keep the southern
panhandle at between 2 and 3 inches of liquid precipitation every 24
hours Saturday and between 3 and 4 inches in 24 hours Sunday. This
will down first as snow Saturday morning before quickly
transitioning to rain from the SW coastline inwards as the warm
front pushes through, with the switch to rain expected during the
morning hours for PoW and Sitka, into midday for areas like
Ketchikan and Wrangell that are a bit further inland. Overall the
heavy rain will begin for the southern panhandle Saturday, but the
next wave of precipitation pushing through will bring another round
of heavier rain on Sunday that has been primed by the first warm
front pushing through the day prior. The warm temperatures in the
high 30s to low 40s will continue into the early week as onshore
flow continues to bring in southerly warmer flow into the southern
half of the panhandle.

For the rest of the panhandle, which includes everywhere north of
Wrangell and Sitka, the snow will last into Saturday as that first
front moves in over the cold airmass in place, as the warmer
temperatures will not bring temperatures up into the mid to high 30s
until Sunday. This will allow for a switch to more of a mix
potentially becoming rain by Sunday afternoon/evening in the central
panhandle up to Icy Strait corridor. These areas will see between 12
and 18 inches in 24 hours Saturday into Sunday morning before
transitioning to rain/snow mix to potentially rain. Snow will start
off lighter and fluffier Saturday as snow liquid ratios remain high,
but as the area warms Saturday evening into Sunday, ratios will
decrease to become a heavier and wetter snow. Areas to the north of
Icy Strait corridor will remain snow the entire time through both
fronts moving through, giving a significant amount of snowfall to
the Skagway and Haines areas with between 12 and 18 inches in 24
hours both Saturday and Sunday with more expected along the Klondike
Highway, and moderate to heavy snow lasting into Monday. However
these amounts for all of the panhandle depend largely on how much of
the precipitation actually reaches parts of the panhandle,
particularly in these northern areas and especially the Haines
Highway and Skagway areas. There remains some uncertainty on exactly
how much snowfall there will be during this system and the exact
timing of a changeover to rain for the central parts of the
panhandle up to Icy Strait corridor on Sunday.

Overall this will start as a heavy snow event for the entire
panhandle Saturday morning, before becoming a heavy rain event for
the southern panhandle from Sitka and Wrangell southwards later
Saturday and lasting through Sunday with the next heavier round of
precipitation. Expecting between 3 and 7 inches of snow accumulation
for Sitka, Annette Island, and PoW Saturday morning before
transitioning to rain in the late morning to midday. For Petersburg,
Wrangell, and Ketchikan an expected 8 to 12 inches of snow will
accumulate Saturday before they too begin to transition to rain by
the evening hours. This timing could change for Wrangell and
Petersburg depending on when the warmer air pushes in and for how
long they hold onto snow into Saturday evening.

AVIATION.../Until 00Z Friday/...VFR CIGs & VISs are anticipated
through the 24-hour TAF period. Light snow showers will occur during
the day tomorrow for Outer Coast areas, including PASI, which will
potentially lower conditions down to the MVFR category. Low-level
turbulence & wind shear values up to around 30KT will also last
through this evening for the PAJN & PAWG areas, which are areas that
are prone to gap winds. The LLWS will start diminishing around the
mid-afternoon through the evening timeframe. Strong northerly
outflow winds of up to around 30G50KT continue for the PAGY &
northern Lynn Canal area through the early evening hours,
diminishing to around 20G35KT starting late this evening & lasting
through the end of the TAF timeframe.

MARINE...
Inside (Inner Channels): Wednesday afternoon, we continue to see
gale force conditions in Lynn Canal, Glacier Bay, and major river
inlets; however, winds are starting to slowly trend down.
Expecting winds to briefly diminish to moderate breezes tonight
into Thursday morning for Lynn Canal as a gale force system slides
along the northern coast, bringing a more west-to- east pressure
gradient over the Panhandle. Main message is that winds will
subside in Lynn Canal but they will increase back to gale force by
late Thursday, so dont get fooled. Over the weekend a storm
force system will move into the gulf, increasing winds across the
region to strong-breeze to gale force. For areas south of Icy
Strait, expecting a southerly regime, with easterly winds in Icy
Strait. We will continue to maintain northerly gale force winds in
Lynn Canal through the weekend, building to strong gales by
Sunday.

Outside (Coast and Gulf): Current sea state along the coast shows
2-4ft significant wave heights, dominated by a westerly swell at
7 to 10 seconds, masking an underlying northeasterly outflow wind
chop. Cross Sound is seeing NE sustained near-gale force winds
bringing fully developed seas near 10 ft at 6 to 8 seconds. In
the central gulf we are seeing higher northerly seas from outflow
along the northern coast with more organization and energy at 10
seconds. Overnight Wednesday a gale force low will develop near
Cape St. Elias, transiting east along the northern coast.
Expecting northwesterly winds to increase through the central
gulf to near-gales, with easterly-northerly outflow winds
strengthening to gale force for major bays/inlets along the
northern coast. Westerly swell continues but will be masked by
northwesterly fresh seas of 12 to 15ft, with the main wave energy
focused from the central gulf toward Haida Gwaii.

Seas briefly diminish Friday afternoon before a storm force low
approaches the gulf, driving 25 ft ESE fresh seas along the
northern coast Friday night into Saturday, becoming 15 to 20ft
from the SW by Sunday into the start of next week. Storm force
winds are forecasted to be coming out of Cross Sound/Palma Bay by
Saturday, creating large and confused seas through the Fairweather
Grounds.

&&

.AJK WATCHES/WARNINGS/ADVISORIES...
PUBLIC...Winter Storm Watch from Friday afternoon through Sunday
     afternoon for AKZ317>322-325-331.
     Cold Weather Advisory until 5 PM AKST Thursday for AKZ318.
     Cold Weather Advisory from midnight tonight to 3 AM AKST
     Thursday for AKZ320-325.
     Winter Storm Watch from Friday evening through Sunday morning
     for AKZ323-324-326>330-332.
     Extreme Cold Warning until 9 PM AKST this evening for AKZ325.
     Cold Weather Advisory from 3 PM to 6 PM AKST Thursday for AKZ325.
     Cold Weather Advisory until 3 AM AKST Thursday for AKZ329.
MARINE...Heavy Freezing Spray Warning for PKZ011.
     Heavy Freezing Spray Warning for PKZ012.
     Heavy Freezing Spray Warning for PKZ031.
     Heavy Freezing Spray Warning for PKZ053.
     Gale Warning for PKZ012-053-643-644-651-652-663-664-671.
     Small Craft Advisory for PKZ011-013-021-022-031-032-036-661-662-
     672.

&&

$$

SHORT TERM...SF
LONG TERM...Contino
AVIATION...JLC
MARINE...AP

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