Graphical Hydro Meteorological Discussion

947
FXAK68 PAFC 020247
AFDAFC

Southcentral and Southwest Alaska Forecast Discussion
National Weather Service Anchorage AK
547 PM AKST Mon Dec 1 2025

.SHORT TERM FORECAST SOUTHCENTRAL ALASKA (Days 1 through 3:
This afternoon through Thursday afternoon)...

Winter Weather Advisories are now in effect for as the next front
approaches Southcentral Alaska. Here are the Advisories in
effect:
* Anchorage, Eagle River, and Lower Matanuska Valley (including
Palmer and Wasilla): Rain/freezing rain coinciding with near-
freezing temperatures tomorrow morning, bringing the potential
for additional icing on roads.
* Along the Parks Highway from Houston north to Talkeetna: Snow
and freezing rain from late tonight through early Wednesday
morning, with 2-4 inches of snow and up to 0.15 inches of ice.
* Northern Copper Valley (Richardson Highway mile markers 150 to
200) and Northern Susitna Valley (north of Talkeetna): 6-8
inches of snow from late tonight through Wednesday morning.

Precipitation has largely tapered off as a shortwave ridge begins
to move into the Southcentral Mainland, bringing a short break in
precipitation for tonight. Clear skies have given rise to areas of
low stratus and fog, with patchy fog (which may be dense at times)
possible along Cook Inlet from Anchor Point north to Anchorage and
into the Lower Matanuska Valley. A Dense Fog Advisory remains in
effect for the Anchorage Bowl. When the fog will dissipate remains
uncertain, but it could linger through tomorrow morning as there
won`t be much wind to scour it out.

Later this evening, a front will begin progressing northeastward
into the Gulf, reaching Kodiak Island just before midnight. Steady
precipitation begins early tomorrow morning as the front makes
its way into the Southcentral Mainland. Overall, with the front
weakening before it reaches the Southcentral Mainland, there won`t
be very much wind or warm air advection. As such, expect
temperatures to remain much the same as we`re seeing right now.
This will be a problem for the Anchorage area up to the Mat-Su
Valleys as this rain will be falling in areas where temperatures
are near or below freezing, and onto already-icy side and
neighborhood streets. For Susitna Valley in particular, localized
colder conditions near Willow will likely lead to higher ice
accumulations, especially with heavier precipitation in that area.
Further north, upslope flow onto the southern face of the Alaska
Range will lead to higher snow accumulations near Broad and
Isabel Passes.

-Chen

&&


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

A significant low level inversion persists over Southwest Alaska
this afternoon, in advance of a strong North Pacific low that is
moving toward the eastern Aleutians. This is setting up Southwest
Alaska for rain in the warmer air around Bristol Bay and a
significant ice storm for the Kuskokwim Valley and Delta. As this
low drives northward, it will elongate as it reaches the Aleutians
and pushes into the high pressure over the Arctic. This will
greatly enhance the pressure gradient and bring widespread Gale
and Storm force winds to the Bering Sea and adjacent coasts.

The biggest concern for the weather tonight into Tuesday night is
for the Kuskokwim region where this storm pumps in warm air aloft
over the cold surface air. This will result in a long-duration
freezing rain event for Bethel and along the Kuskokwim River from
tonight into Wednesday morning. Ice accumulations are expected to
one-half to three-quarters of an inch for this time period,
resulting in an Ice Storm Warning. To the north and west of the
Kuskokwim River in the Delta region, the arctic front will stall
out and create a significant thermal boundary. This is expected to
create Blizzard conditions for Nunivak and Nelson Islands
tomorrow. This change from freezing rain to snow/blowing snow will
likely be a sharp boundary, but Nunivak and Nelson Islands are
expected to see the worst of the blizzard conditions. By
Wednesday, the low center will still be in the Unalaska area, but
will have weakened enough to bring marine winds to Gale force and
allow the temperatures over the Kuskokwim region to fall below
freezing at all levels of the atmosphere which will end the
freezing rain threat. The Bristol Bay region will be slower to
cool off and may keep precipitation type as rain until Thursday,
especially for coastal areas. After Thursday, this the entire
region will drastically cool down and get quite cold for the
weekend.

&&


.LONG TERM FORECAST (Days 4 through 7 - Friday through Monday)...

An initial trough should be lifting into Southcentral on Friday
with light to moderate rain pushing into the coastal mountains
and a chance for a rain/snow mix for interior locations of the
Copper Basin, Anchorage and the MatSu Valley. On a slightly more
optimistic note, the time period from Friday into the weekend may
bring an end to the unseasonably warmer temperatures Southcentral
and Southwest Alaska have been experiencing as of late. A
previously active pattern trough over the Aleutians is forecast to
become closed off, allowing an arctic trough over the Seward
Peninsula to dive southward into the southwest coast. Much cooler
temperatures over Canada, previously shunted east of the ALCAN
border will spill into interior Alaska Friday into early next
week. Ensemble guidance and deterministic models all show a broad
trough overspreading the Gulf of Alaska Saturday into Sunday, with
a closed surface low developing somewhere east of the Kenai
Peninsula, south of Prince William Sound. This will open the door
for various scenarios to play out, conditional on the exact
placement of the closed low. A low further east may allow colder
temperatures to spread across the region more quickly while a low
further north might favor increasing snow chances for much of
Southcentral. Despite the uncertainties, a pattern change appears
likely during the long term forecast period with a significant
cool down in the not too distance future.

-BL

&&
.AVIATION...

PANC...The forecast for the remainder of this afternoon and
evening is quite challenging. Fog has settled in across the
Anchorage Bowl in a moist and stable environment. There is very
little change in the environment until low level flow strengthens
overnight. Thus, expect fog will linger. The fog is shallow, so do
suspect there will be some erosion from the edges, with improving
conditions as we head into and through tonight.

Another round of rain is on the way for tomorrow, with arrival at
the terminal at around 15Z. Assuming there is no clearing skies
this evening, surface temperatures will hover near or slightly
above freezing, then very slowly rise tomorrow morning. Thus,
conditions are not as favorable for freezing rain, though some
surfaces might be cold enough initially for some of the rain to
freeze on contact. Precipitation will be light and will end by
late tomorrow morning as downslope flow increases ahead of an
occluded front. As the front passes late Tuesday evening, may see
a weak wind coming off Turnagain Arm, which would likely warm
temperatures into the upper 30s. Should light north-northwesterly
remain at the surface, low-level wind shear will be possible.

-SEB/Rux

&&


$$

762
FXAK69 PAFG 020046
AFDAFG

Northern Alaska Forecast Discussion
National Weather Service Fairbanks AK
346 PM AKST Mon Dec 1 2025

.SYNOPSIS...A strong storm moving toward the Aleutians will bring
a well developed moisture plume north to interact with remnant
moisture and a cold front over the Interior. Winter Storm
Warnings and Winter Weather Advisories are in effect for most
locations south of the Brooks Range for areas of heavy snow, mixed
precipitation including accumulating ice, and strong winds. High
pressure builds in later this week, bringing clearing skies and
much colder temperatures.

&&

.KEY WEATHER MESSAGES...

Central and Eastern Interior...

- Snow chances continue to increase across the Interior today into
Tuesday, continuing through Wednesday, with a light wintry mix
likely from Fairbanks south beginning Tuesday evening

- Total snow accumulations through Wednesday around 3-5" with
highest totals around 5-8" north and west of Fairbanks and in
the Alaska Range and lowest totals around 1-3" SE of Fairbanks.

- Southerly winds increase through Alaska Range Passes tonight
into Tuesday, with gusts up to 55 mph possible especially north
of Isabel Pass along the Richardson Highway. Blowing and
drifting snow is possible through Alaska Range passes, leading
to poor travel conditions.

- Temperatures fall rapidly Wednesday night into Thursday as
increasing high pressure building in will cause clouds to clear
and lead to much colder and drier conditions. Temperatures in
Interior Valleys dropping to around -20F to -40F later in the
week.

West Coast and Western Interior...

- Snow continues to increase in coverage across Southwest Alaska
and the Western Interior today into Tuesday, continuing through
Wednesday, with a wintry mix possible across the Southwest
Interior and Lower Yukon/Upper Kuskokwim Valleys. Conditions
remain mostly dry across the Seward Peninsula and NW Arctic
Coast.

- Highest snow totals through Wednesday are expected along a
corridor extending northeast from the Yukon Delta into the
Western Interior, where around 5-10" of snow is expected with
2-5" along the peripheries.

- Total ice accumulations across the Southwest Interior and Lower
Yukon/Kuskokwim Valleys around 0.05-0.20".

- Elevated N/NE winds with gusts up to 55 mph will continue across
the West Coast through Wednesday. Areas of fog, isolated snow
showers, and blowing snow will lead to periods of reduced
visibility at times, especially for the Bering Straight, St.
Lawrence Island, and Southern Norton Sound/Yukon Delta Coast.

- Increasing high pressure out of the northwest will lead to
colder and drier conditions across the NW Arctic Coast,
expanding further south Wednesday through the end of a week.
Coldest locations dropping to around -10F to -25F mid to late
week.

North Slope and Brooks Range...

- Temperatures continue on a cooling trend early this week, with
areas of low stratus and scattered snow showers expected as a
low pressure system works east through the Arctic Ocean.

- An arctic front tracking east across the North Slope through
Wednesday will support an additional 1-3" of snow for the
Central/Eastern Arctic Coast/Plains and Brooks Range. Drier
conditions are expected to continue further west.

- Breezy winds across the Arctic Coast and in the Brooks Range
could lead to areas of blowing snow and reduced visibility at
times through Wednesday night.

- Increasing high pressure out of the northwest Tuesday into
Wednesday will lead to much colder and drier conditions to
finish out the week. Coldest locations dropping to around -20F
to -40F mid to late week.

&&

.FORECAST ANALYSIS AND DISCUSSION...High pressure extends north
from the north pacific high near 45 degrees north across Interior
Alaska, though the main weather maker over the next three days is
a 967 mb low currently 450 miles south of King Cove. This system
has a warm sector that is bringing a well developed moisture
stream northward, which will interact with cold air in place to
form a band of moderate to heavy precipitation Tuesday and
Wednesday. This will bring moderate to heavy snow as well as areas
of freezing rain and light ice accumulations, mainly southwest of
Minchumina. Strong high pressure building in Wednesday afternoon
and evening over the Arctic Plain will push snowfall and clouds
rapidly east with clearing skies and much colder temperatures
behind the band of snow. As the high drifts east to the eastern
Brooks Range at 1035 mb, a brief period of gusty northeast winds
is likely over Dalton and Elliott Highway Summits Thursday through
Saturday.

&&

.EXTENDED FORECAST DAYS 4-7...Friday through next Monday...
Troughing will rapidly develop Friday across Northern Alaska,
pushing southwest from the northern Yukon Territory. Models are in
good agreement on this, with the base of the trough eventually
developing into a closed low over Bristol Bay. This will keep
temperatures below normal across the forecast area, though the
eastern Interior may receive light snow over the weekend depending
on the track of a number of weaker systems moving west to east
across the Gulf of Alaska. The trough looks to persist over the
Mainland through Monday with a ridge of high pressure building
over the Bering Sea and slowly drifting east. Expect clearer skies
to the west and more clouds to the east. If the trough and high
pressure moves east a couple hundred miles, the result would be
very very cold temperatures and clear conditions. Will continue to
monitor this, but at this time it does not look likely.

Coastal Hazard Potential Days 3 and 4...None

&&

.AFG WATCHES/WARNINGS/ADVISORIES...
AK...Winter Weather Advisory for AKZ824-829-832>835-837>850.
Winter Storm Warning for AKZ825-826-830-851-852.
Winter Weather Advisory for AKZ820-821-827.
PK...Gale Warning for PKZ801.
Gale Warning for PKZ802.
Gale Warning for PKZ803-852.
Brisk Wind Advisory for PKZ804-805.
Gale Warning for PKZ806-816-817-850-851-853-854.
Heavy Freezing Spray Warning for PKZ806-810-816-817-850-851-853-
854-856.
Gale Warning for PKZ807.
Brisk Wind Advisory for PKZ808-855.
Small Craft Advisory for PKZ810.
Brisk Wind Advisory for PKZ811-857.
Brisk Wind Advisory for PKZ815-861.
Gale Warning for PKZ856.
Heavy Freezing Spray Warning for PKZ858.
&&

$$

Chriest

485
FXAK67 PAJK 020750 AAA
AFDAJK

Southeast Alaska Forecast Discussion...UPDATED
National Weather Service Juneau AK
1050 PM AKST Mon Dec 1 2025

.Evening and 06z Aviation Update...
No major changes to ongoing forecast this evening. With high
pressure moving in across the panhandle, starting to see low
clouds and dense fog develop with visibilities around 1 to 4 miles
near Yakutat, Haines, Gustavus, with worst visibilities around
1/4 mile near Petersburg. Not anticipating much improvement
overnight for over land or marine areas, so went ahead and issued
the Dense Fog Advisory through Tuesday morning for the Petersburg
area and added areas of fog into the marine forecast for Sumner
Strait, Frederick Sound, Glacier Bay, and Stephens Passage. Moving
into the overnight hours, would not be surprised to see further
expansion of the Dense Fog Advisory. Winds through tonight will be
largely 10mph or less across the panhandle, outside of Haines and
Skagway which will see increased drainage winds, around 15mph.

&&


.Aviation.../through Tuesday evening/
Main aviation concern will be IFR to LIFR ceilings and visbys
developing through Tuesday morning.

As of 1030pm, a full range of flight conditions across the
panhandle this evening, isolated VFR to predominate MVFR to LIFR
with CIGS AoB 1500ft and visbys between 1 to 4SM, with pockets of
fog developing near Petersburg reducing them down to as low as
1/4SM. Through Monday night, flight conditions will continue to
worsen as ridging moves aloft and precipitation comes to an end,
with high confidence of low stratus deck continuing AoB 1500ft
through mid morning Tuesday. Winds will remain 10kts or less,
going near calm and variable overnight for majority of the
panhandle. No major LLWS concerns through the period, however, a
front pushes into the Gulf Coast by 06z near the tail end of the
TAF period.

.PREV DISCUSSION......ISSUED AT 250 PM AKST Mon Dec 1 2025 ...

SYNOPSIS...

Key Messages:

- Diminishing trend in winds and precipitation tonight into
tomorrow. Lingering rain primarily across northern panhandle.

- Another front arrives late Tuesday into Tuesday night, bringing
predominantly rain and continued warmer-than-normal
temperatures into midweek.

- Late week into next weekend, 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 Tuesday night/...Overall, the weather isn`t
looking too exciting for the later parts of Monday into Monday
night. Continued onshore flow will keep the light rain/light rain
showers dotting the landscape. However, a building ridge of high
pressure is bringing a diminishing trend to the rain for tonight.

Along with the decreasing rain, the wind speeds will be on the
decrease as well. Overnight temps will be warmer-than-normal with
lows in the upper 30s to low 40s for most of SE AK. A touch warmer
for those on Prince of Wales Island with overnight lows in the mid
40s.

LONG TERM.../through this weekend/...
The upcoming week is looking like another cloudy and rainy week.
There will be lulls between the frontal passages, with
precipitation chances mainly limited to western facing mountains,
but the overall trend in the long term forecast is cloudy and
rainy this week. But late this week into next weekend, ensembles
are hinting at a weather pattern that has been known to produce
heavy snow.

Friday into the weekend, the overall weather pattern looks to
change. Ensembles are hinting at a upper air low pressure
descending south out of central Alaska. Run to run ensembles have
increasingly placed this low to the west of Anchorage, but cluster
analysis has this low as far east as Prince William Sound, around
a 40% or less chance of occurrence. What this translates into
sensible weather for the panhandle is how deep will the cold pool
in Canada get. The further east the low center is, the more the
cold pool in Canada will be developed, and the further south the
southwesterly flow will be. The stronger the cold pool in Canada
is, the further south the associated arctic boundary will be,
which will dictate what part of the panhandle will get the most
snow. At this point, guidance is backing off on the low placement
to west of Anchorage as the more likely scenario, which would
bring warmer temperatures further north, keeping the arctic
boundary near the northern panhandle.

Confidence is low for placement of heaviest snow, with confidence
intervals for the northern half of the panhandle being between
all rain with little to no snow accumulation to nearly 12 inches
of snow in 24 hours.

Furthermore, there is evidence that if this upcoming weekend
system does not generate substantial snowfall for the panhandle,
early to mid next week is shaping up to keep this pattern going,
which would result in multiple rounds of snow. These upcoming
systems will be carefully watched over the following days.

Stay tuned.

MARINE...
Outer waters: Persistent westerly flow to 20 knots in the gulf
waters are expected to continue through the evening and slowly
diminish into the morning hours Tuesday. Seas look to follow this
trend, enhanced by the long fetch and duration of westerlies in
the gulf. Primary swell is currently a southwesterly direction to
around 8 ft, for a combine wave height of around 11-13 ft. Not
expecting any improvement in seas as winds collapse and shift to
the SE for the frontal passage tomorrow. Along the front,
expecting to see 25-30 knot sustained winds moving eastward across
the gulf into the evening hours tomorrow, before moving overland
tomorrow night.

Inside waters: The diminishing trend continues for the inside
waters as gradients relax and winds aloft reduce in lieu of the
incoming front tomorrow. Expecting to see around 10 knots maximum
across the panhandle tonight with plenty of low clouds. The one
exception is Lynn Canal, as westerly flow aloft looks to keep
southerlies up to 15-20 knots in the channel. That being said,
Taiya Inlet down to Eldred Rock have high uncertainty on how
stable the low level atmosphere will be. Currently, expecting a
relatively stable environment, which will result in decoupled
winds near Haines and Skagway and relatively light winds. South of
this point; however, southerlies up to 20 knots are currently
occurring.

&&

.AJK WATCHES/WARNINGS/ADVISORIES...
PUBLIC...Dense Fog Advisory until 9 AM AKST Tuesday for AKZ326.
MARINE...Small Craft Advisory for PKZ022-053-641>644-651-652-661>664-671-
672.

&&

$$

UPDATE...NM
SHORT TERM...GJS
LONG TERM...NC
AVIATION...NM
MARINE...NC

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