Graphical Hydro Meteorological Discussion

022
FXAK68 PAFC 041419
AFDAFC

Southcentral and Southwest Alaska Forecast Discussion
National Weather Service Anchorage AK
519 AM AKST Thu Dec 4 2025

.SHORT TERM FORECAST SOUTHCENTRAL ALASKA (Days 1 through 3)...

Key Points:

- Scattered showers lifting up across the Kenai Peninsula towards
the Mat-Su Valley combined with near freezing surface temperatures
have resulted in a glaze to a tenth of an inch of ice accumulation
on area roadways this morning. This will make for an icy morning
work and school commute for the western Kenai up through the Mat-Su
Valley.

- Southern Copper River Basin will likely see several days of light
snow from today and into the weekend, leading to overall
accumulations on the order of 6-12 inches.

- Increasing offshore winds will lead to frigid wind chills
(especially near the Alaska Range) and the potential for blowing
snow.

Discussion:

A large, nearly stacked, low spinning over the southern AKPEN
continues to eject shortwaves north towards Kodiak Island, Kenai
Peninsula, and western Gulf. The most recent wave overnight combined
with broad isentropic lift has resulted is scattered showers
developing from the Cook Inlet east into the northern Gulf. These
showers have been lifting north for much of the overnight period
with the northern edge starting to move into the lower Susitna and
Mat Valleys. Areas of dense fog that started the night along the
Knik Arm has since dissipated as showers moved in. Temperatures have
been holding steady in the low to mid 30s near Homer, near freezing
throughout the Anchorage Bowl, and in the upper 20s for Wasilla and
Palmer area. The result has been another round of freezing rain for
much of the wester and central Kenai Peninsula, Anchorage Bowl, and
lower Mat-Su Valley. Winter Weather Advisories have been issued for
these areas for light icing on roadways making for hazardous travel
conditions for the morning commute. A Winter Weather Advisory has
also been issued for Turnagain Pass down to about Moose Pass where a
mix of freezing rain and light snow could make for icy conditions.

As has been the case for the past week, deterministic model
guidance has been struggling to resolve these systems. Probabilistic
guidance has done slightly better. For the wave this morning,
precipitation has developed farther west and has progressed
farther north than anticipated. However, with the Arctic airmass
oozing south, showers should be limited in northward progress.
The 12Z PANC ROAB once again showed a decent warm layer from just
above the surface to about 3400 feet. Cooler midlevel air will
start to work in, helping to cool this layer a bit later today. As
such, should see rain showers transition over to a rain/snow mix
then light snow by mid to late afternoon. By then, this round of
precipitation should be winding down for western Southcentral but
working into the Southern Copper Basin. However, the Arctic front
will be quickly approaching from the NW this evening, helping to
tighten the baroclinic zone on this side of the Alaska Range.
Given this, wouldn`t be surprised to see a band of light snow
develop from the northern Kenai Peninsula and up through the Mat
Valley and central Copper Basin by late tonight. Snow will linger
for several days over the southern Copper Basin where snow
accumulations of 6-12 inches are possible.

The Arctic front push through Southcentral on Friday with
temperatures rapidly falling from north to south as the Arctic
airmass works into Southcentral. These temperatures will likely be
the coldest so far this season with many areas across
Southcentral seeing temperatures fall below zero. The Copper Basin
could see temperatures fall into the -20s and dangerous wind
chills of -30 to -35 degrees. Lastly, the Arctic airmass will also
result in strong north/south gap winds for the Alaska Range and
typical spots across the southern Southcentral.

- PP

&&


.SHORT TERM FORECAST SOUTHWEST ALASKA/BERING SEA/ALEUTIANS (Days
1 through 3)...

As the low pressure system south of the Alaska Peninsula continues
to steadily weaken, winds speeds will begin to similarly slowly
diminish. Drier, and colder conditions have settled over Southwest
Alaska, providing a reprieve from the precipitation, but
introducing a new concern with the incoming colder temperatures.
Through Thursday, lingering showers will affect Bristol Bay, and
much of the Alaska Peninsula as the low pressure system remains
relatively stationed just to the south of Unimak Island.
Northeasterly winds across the Central Bering and Pribilof Islands
have diminished, and will continue to do so as the low slowly
weakens.

Next up is an Arctic airmass pushing into Southwest Alaska from
the north. Temperatures will plummet into the weekend as an Arctic
trough dives into the region. Temperatures will drop below zero
across the Kuskokwim Delta and the Lower Kuskokwim Valley by
Friday night. Another effect of the Arctic trough will be an area
of gusty north to northeasterly winds re-initiating off of the
Kuskokwim Delta. These winds will reach gale to storm force in
strength and will stretch all the way down to the Aleutians.
Stronger gap winds out of favored southern channels in the
Aleutians are likely with these winds by Saturday. A consequence
of these offshore winds is the threat of extreme freezing spray
from Nunivak Island to Cape Newenham. A Marine Weather Statement
has been issued for Saturday through Tuesday detailing this
threat. Another consequence of the gusty winds and very cold
temperatures is wind chill. Wind chills could dip below -35F in
the Kuskokwim Delta by Saturday night into Sunday. Looking ahead,
it seems like the Arctic air mass will persist into next week,
potentially allowing for a long period of extremely cold
temperatures.

-JAR/CL

&&


.LONG TERM FORECAST (Days 4 through 7 - Sunday through Wednesday)...

A broad area of low pressure will fill most of the Gulf of Alaska
on Sunday and remain in place through next week. Forecast models
have various differences on when low pressure breaks down and
moves out of the Gulf. To the west, high pressure will persist
over the Bering while a weaker front systems track south of the
Aleutians. As has been advertised, beginning on Friday a
significant outbreak of colder air is forecast to spill out of
Canada and into interior Alaska, eventually reaching the eastern
Bering and Alaska Peninsula on Sunday. Cold temperatures are
expected to remain in place through early next week, with cold air
over the Alaska Peninsula to wrap back into the Gulf of Alaska
Sunday into Wednesday. Strong winds out of the interior are
forecast and there is potential for high winds into Southwest
Alaska. The strong northeasterly flow of colder temperatures atop
warmer Bering Sea waters will also promote ocean effect snow
showers for parts of the Aleutian Chain and Alaska Peninsula.
Meanwhile, the denser cold air over Southcentral will increase gap
winds through the usual locations and into the Gulf of Alaska.
With the colder temperatures, areas of snow will be possible for
numerous locations, but nailing down the when and where will
require further analysis of newer model data. The BLUF, it`s going
to be colder; there will be wind through the gaps; and snow
chances will continue to increase through the middle of next week.
Stay tuned.


-BL

&&
.AVIATION...

PANC...VFR to MVFR conditions are expected through the forecast
period. Light freezing rain is expected to become a mix with snow
by 18Z, then switch to all snow by 00Z Friday as weak northerly
flow brings in colder air. Accumulation is expected to be less
than one inch through 00Z Saturday.

&&


$$

663
FXAK69 PAFG 041230
AFDAFG

Northern Alaska Forecast Discussion
National Weather Service Fairbanks AK
330 AM AKST Thu Dec 4 2025

.SYNOPSIS...
Other than a few lingering pockets of stratus across Northern
Alaska, most of the area is clear with cooling temperatures. The
weather moving forward will be cold with little chances for snow.
Namely light snow in the Upper Tanana Valley/AlCan Border
Saturday into Sunday. This has been trending farther northwest
since yesterday but we do not expect snow as far northwest as
Fairbanks right now. Otherwise, the system bringing this snow will
interact with a strong high over Eastern Siberia resulting in
very strong wind to the Interior and West Coast this weekend. This
will likely mix down to the valley floors as well, making for
very cold wind chills and blowing snow.

&&

.KEY WEATHER MESSAGES...
Central and Eastern Interior...
- Mostly clear and cold weather, temperatures dropping as low as
to 30s and 40s below zero by this weekend.
- Clouds will be around in the Eastern Interior, limiting how
cold temperatures get. Snow will also try to move in on
Saturday (1 inch or less) from Delta east to the AlCan Border.

- N/NE wind increases significantly on Saturday from the Yukon
Flats southwest. Gusts above 1000ft may be upwards of 25 to 50
mph whereas valleys can see gusts up to 30 mph (IF the inversion
breaks). This continues into Sunday AM, then weakens.
- Ambient temperatures from today through Sunday, with no clouds
or wind, will drop into the 20s and 30s below zero. A few
colder spots, especially north and east of Fairbanks may hit 40
below.
- Wind chill values may be as low as 65 below zero from Tanana to
the Yukon Flats this weekend. Significant blowing snow is
possible in the higher terrain above 1000ft.
- This could be a significant wind event and end up being
impactful as it could lead to tree damage and power outages.
- Blizzard conditions are possible Friday and Saturday along the
Parks Highway from Carlo Creek to Cantwell and from Trims Camp to
Fielding Lake along the Richardson Highway.

- The cold trend continues into next week and with weakening
winds/diminishing cloud cover, several areas will likely drop
into the 40s and 50s below zero.

West Coast and Western Interior...
- A cold trend continues through the weekend. Expect minimum
temperatures around or slightly below 0 along the coast and in
the teens to 30s below zero in the Interior Valleys.

- North-northeast winds increase this weekend and if these winds
can break through the inverted valleys, it will bump up
temperatures slightly, but wind chills would still be very cold.
Wind gusts may be up to 35 to 45 mph along the coast and in the
higher terrain.

- With temperatures below 0 and wind this strong, it could lead
to wind chills as low as -50F in some spots.

- Winter Storm Watches remain in effect for strong winds, blowing
snow, and very cold wind chills from Koyuk to Huslia and south
to the Yukon Delta from Friday night through Monday night.

North Slope and Brooks Range..
- A front moves from the Western Arctic Coast to the Eastern
Arctic Coast between today through tomorrow with areas of light
snow and stratus along the coast. Persistent onshore flow
follows afterwards with much colder temperatures this weekend.

- Expect temps in the negative teens along the coast with 20s
below zero inland through tomorrow, then widespread temps in
the 30s below zero with some 40F below readings possible in the
coldest locations this weekend.

- High pressure persists well into next week with dry and very
cold conditions, as well as northerly winds and wind chills as
cold as -60 F through Brooks Range Passes.

&&

.FORECAST ANALYSIS AND DISCUSSION...
As of 0300 AKDT, temperatures are from Kaltag to Kotzebue to Fort
Yukon are around 10F to 30F below zero. In the Tanana Valley,
temperatures are ranging from the single digits below zero to 15F
above zero with the warmest being in the Upper Tanana Valley.
Continuing through the day, temperatures stay cold and likely
don`t budge too much. Tomorrow will be similar but likely a bit
colder from Fairbanks to Northway. Otherwise, a low in the Gulf
will move northeast into the southern Yukon Territory bringing
clouds and light snow from Delta Junction east on Saturday.
Snowfall totals will be very light, around 1 inch or less. South
of Northway towards the Nutzotin Mountains will see heavier snow.
As a result of this, temperatures will moderate slightly towards 0
degrees. For the rest of the Interior, Brooks Range and along the
West Coast, north-northeast winds increase with gusts upwards of
50 mph in the higher terrain of the Interior as well as in the
Brooks Range Passes. This will warm up the ambient air
temperatures but wind chills will be dangerous, even in the
Interior Valleys where the inversion breaks. Some spots,
will experience wind chills as low as 65F below zero from Tanana
to the Yukon Flats and 50F below zero in the Western Interior. In
Fairbanks, wind gusts may be as high as 30 mph with wind chills
around 40F below zero. This continues into Sunday, but winds
weaken through the day. Winter Storm Watches remain in effect for
the possibility of significant blowing snow, dangerous wind chills
and strong wind. Afterwards, most wind goes calm and skies remain
clear across much of Northern Alaska. With 850mb temps around 20C
to 30C below zero, we can expect many valley locations to be in
the 40s and 50s below zero during the early and middle parts of
next week.

&&

.EXTENDED FORECAST DAYS 4-7...Monday through next Thursday.
High pressure over the Bering Strait with a low in the eastern
Gulf of Alaska looks to continue through next week. This will
bring prolonged cold to Northern Alaska. Winds look to diminish in
the Tuesday-Wednesday timeframe as the gradient eases. This will
allow for valley inversions to strengthen, and with 850 mb
temperatures -20 C or colder, conditions may support temperatures
in the 40s or 50s below.

Coastal Hazard Potential Days 3 and 4...None

&&

.AFG WATCHES/WARNINGS/ADVISORIES...
AK...Winter Storm Watch for AKZ848-850.
Winter Storm Watch for AKZ824>826-828>830-832>834-846-847-851-
852.
PK...Brisk Wind Advisory for PKZ802.
Brisk Wind Advisory for PKZ815-861.
Heavy Freezing Spray Warning for PKZ816-851.
Heavy Freezing Spray Warning for PKZ850.
Heavy Freezing Spray Warning for PKZ853.
&&

$$

Bianco

966
FXAK67 PAJK 041421
AFDAJK

Southeast Alaska Forecast Discussion
National Weather Service Juneau AK
521 AM AKST Thu Dec 4 2025

.SYNOPSIS...

Key Messages:

- Lingering rain and drizzle will diminish through the day.

- Onshore flow will keep the warmer-than-normal temps in place.
Colder weather begins to slide south into the area Friday
night.

- This weekend into next week, long range models are still
hinting at a weather pattern that has been known to produce
heavy snow. High uncertainty at this time but worth watching
closely

&&

.SHORT TERM.../through Thursday night/...
The front has exited the region, however, ridging, lighter
onshore flow and warmer-than-normal temps will persist in its wake.
Satellite imagery and model soundings are indicating a lack of
mid to high clouds across the region, but low-level moisture and
low clouds persist. Looking at surface obs, area 12Z soundings
and webcams, drizzle, mist and occasional fog/low stratus are
present across most, if not all of SE AK this morning. Little
change is expected through tonight with drizzle/mist/light rain
and occasional fog persisting.

.LONG TERM.../Friday through Monday/...A pattern change going
into this weekend is looking to bring cold temperatures, heavy
precipitation, and strong winds to the panhandle into early next
week.

A system advancing into the northern gulf through Friday will
send a front into the panhandle overnight Friday before stalling
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 expected for a
majority of locations and persisting at similar rates through the
weekend. 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 across the far N
Panhandle and a Winter Storm Watch has been issued for Haines and
Skagway starting Friday night, continuing through Saturday.
Looking elsewhere, Yakutat will also see higher amounts of snow,
but currently expecting just below warning levels. Forecast
becomes more of a challenge moving towards the Icy Strait
Corridor, starting as rain and transitioning into a mix by
Saturday, limiting potential amounts initially. Snow level drop
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 for the Icy Strait
Corridor and Yakutat.

As the gale force low moves into the northern Gulf and a high
sets up to the north of the panhandle into this weekend, 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. Winds will
increase in Skagway at this time, however the stronger sustained
winds will likely stay below 30 mph, with the northerly wind not
being expected to be strong enough to dry out the air too much
enough to reduce the snowfall amounts. 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.

&&

.AVIATION.../through Friday evening/ Not a great morning to be
flying across the panhandle this Thursday. A wide variety of
flight conditions are present, though generally between LIFR and
MVFR as onshore flow keeps low clouds, mist, and isolated showers
across the panhandle. Looking at obs around the area, TAF sites
range from isolated pockets of LIFR and IFR to a few pockets with
CIGS AoB 2500ft. VISBYS are fluctuating from place to place, with
areas seeing 6SM one ob, then plummeting the next. Through the
remainder of Thursday morning, expect conditions to continue to
remain subpar, with low ceilings persisting; some minor
improvement in VISBYS and low CIGS are expected Thursday
afternoon. and visbys slow improving through Thursday afternoon.
Winds should remain on the lighter side, with most TAF sites
seeing 5-10 kt through the day on Thursday. Thursday night, expect
many sites to once more see CIGS and VIS deteriorate,
particularly those in the central and northern panhandle as
onshore flow lingers here. Potential for some improvement in
conditions by late Friday morning as winds begin strengthening
ahead of an approaching system. No LLWS concerns through the TAF
period.


&&

.MARINE...
Outside Waters:
Winds continue their downward trend Thursday as ridging passes
over the Gulf waters with seas 7 and 9 ft by. Winds and seas look
to rise Thursday night into Friday, especially from Cape Edgecombe
south, as a low is projected to pass through the southern Gulf and
towards Haida Gwaii. For the weekend, a forecasted low near the
northern Gulf will give the eastern Gulf waters 25 to 35kts and a
building southwesterly swell, with seas becoming 15+ ft by Sunday.
These elevated winds and seas will last into next week.

Inside waters:
Winds continue their diminishing trend across the inner channels
Thursday as ridging sets up in the Gulf. However, winds are
expected to begin to increase Thursday night and Friday morning
across the southern inner channels with a system passing south of
the panhandle near Haida Gwaii, with brief northerly/easterly
outflow developing to the north. Southerly winds return by Friday
morning but Friday night, northerly flow returns to Lynn Canal.
Speeds in the inner channels pick up to 20 to 25 kts by Friday
night with the weekend seeing 25 to 35 kts.

&&

.AJK WATCHES/WARNINGS/ADVISORIES...
PUBLIC...Winter Storm Watch from late Friday night through late Saturday
night for AKZ318-319.
MARINE...Small Craft Advisory for PKZ022-053-641>644-651-652-661>664-671-
672.

&&

$$

SHORT TERM...DS
LONG TERM...ZTK
AVIATION...GFS
MARINE...DS

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