Graphical Hydro Meteorological Discussion

260
FXAK68 PAFC 060100
AFDAFC

Southcentral and Southwest Alaska Forecast Discussion
National Weather Service Anchorage AK
400 PM AKST Fri Dec 5 2025

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

Weather still remains very active across Southcentral Alaska with
the threats of snow, blowing snow, strong winds, and dangerously
low wind chills through the end of the weekend.

...Active Warnings and Advisories...

- A High Wind Warning has been issued for the Matanuska Valley
from 8PM this evening to 11PM Sunday for 30 to 40 mph winds with
gusts up to 80 mph.

- A Wind Advisory has been issued for Anchorage and the NW Kenai
Peninsula from 11PM this evening to 11PM Sunday. North winds of
20 to 30 mph with gusts to 50 mph expected. Strongest winds
expected along the Knik Arm and West Anchorage and out along the
coast of the northern Gulf coast.

- A Blizzard Warning has been issued for Thompson Pass until 6AM
Sunday for blizzard conditions and 7 to 14 inches of snow. Winds
could gust as high as 60 mph. Wind chills falling to as low as
35 below zero by Sunday morning.

- A Blizzard Warning has been issued for Broad Pass, Richardson
Highway from south of Isabel Pass to Paxson, and along the Tok
Cutoff from Mentasta Pass to north of Gakona from 6PM this
evening to 9PM Sunday due to blowing snow with winds gusting to
50 mph. Wind chills dip as low as 15 to 25 degrees below zero,
falling further to 25 to 40 degrees below zero by Sunday.

- A Winter Weather Advisory remains in effect for the Copper River
Basin until 5PM Saturday for 2 to 10 inches of snow and blowing
snow. The lowest totals will be west of Glennallen, and the
highest totals will be south and east of Glennallen.


Discussion:

As of 3PM this afternoon, the remnants of a lingering surface
trough draped across the coast coupled with a Gulf low and its
front is producing widespread snowfall across eastern Prince
William Sound areas as well as the southern half of the Copper
River Basin, mainly south of the Glennallen. The original
thinking was the front/surface trough was going to move farther
inland, keeping the coldest air locked away for a little longer.
That did not materialize, which in effect has dragged the areas of
highest amounts of snow southward. Because of these players just
mentioned, the advertised arctic airmass is spilling into
Southcentral a little quicker than expected, as shown by latest
500 mb heights showing a faster progression of a digging arctic
trough. With the airmass coming in faster, this should allow for
much of the Copper River Basin`s snowfall to be confined south and
east of Glennallen with a northerly dry wind shutting off
snowfall sooner than expected. The 850 mb temperature gradient is
tightening as the Copper River Basin continues to dive into the
deep freeze with temperatures a good 10-15+ degrees warmer for
areas on the southern side of the Chugach. As the arctic trough
pinches off into a closed upper level low and greatly amplifies
the 500-850 mb pattern, a very strong northeasterly low level jet
and a roaring 500 mb jet begins to develop this evening. At the
surface, a strong thermal and pressure gradient will frame the
setup for a high wind event for the Matanuska Valley tonight into
Saturday morning - and to a lesser extent, the Anchorage area and
a few points north and south. For the Matanuska Valley, though the
most impactful element here will be wind, one cannot ignore the
magnitude of the arctic air moving across the region. Falling
temperatures and high winds mean the threat of dangerously low
wind chills, potentially pushing 20 degrees below zero. Likewise,
high winds will easily blow around the recent powdery snowfall
from last night along with any other transportable snow. Southward
to Anchorage and the NW Kenai Peninsula, the lower/upper level
jet looks to move over the Knik Arm, Glenn Highway, clip
Anchorage, and affect western most parts of the NW Kenai
Peninsula. The other big story with much colder air spilling
across the region is a significant increase in drainage gap winds
out of typical gap locations, which introduces the likelihood of
heavy freezing spray for marine areas such as the Copper River
Delta. For areas across eastern Prince William Sound into the
Valdez area, accumulating snowfall is looking increasingly less
likely, except for perhaps a short period late Saturday morning to
Saturday afternoon.

The sharp upper trough/upper level low digging well into the Gulf
will help to spin up a a complex area of low pressure with
multiple compact low pressure centers Saturday morning. Windy
conditions along with a shield of snow will continue to overspread
eastern Prince William Sound to the lower Copper River Basin
through Saturday afternoon. Some of the high resolution guidance
wants to spin up a low much closer to the Prince William Sound,
and tries to retrograde the low and bring precipitation back
across the eastern Kenai Peninsula - though this solution is
looking less likely. Blowing snow and the threat of ground
blizzards is what prompted the Blizzard Warning for Broad Pass,
Richardson Highway from south of Isabel Pass to Paxson, and along
the Tok Cutoff from Mentasta Pass to north of Gakona. Again, this
is not for additional snowfall, but rather transportable snow that
has already fallen that will be kicked up with high winds. The
last main takeaway from this weather pattern shift is the
dangerously cold wind chills. In areas with wind chills falling to
as low as 35 below zero, frostbite may occur in as little as 10
minutes on exposed skin.

-AM

&&


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

The short term forecast is characterized by an Arctic trough
dropping into Southwest Alaska, bringing gusty winds and very cold
temperatures to much of the mainland and snow showers to the
Aleutians and Alaska Peninsula regions this weekend. Strong winds
in the Kuskokwim Delta may loft snow on the ground from the
previous weather event from Kipnuk north and west and north and
west of Bethel during the weekend. Due to the threat of blowing
snow, a Blizzard Warning has been issued for the aforementioned
regions. Also, the very cold air will move over considerably
warmer ocean temperatures (30s), leading to numerous snow showers
initially over the Eastern Aleutians and the Alaska Peninsula and
later the rest of the Aleutians. This, combined with strong winds
could lead to blowing snow and low visibility. A Winter Weather
Advisory has been issued for the Alaska Peninsula due to this
potential for blowing snow. Another threat with the cold and winds
is wind chill. The Kuskokwim regions could see wind chills 35F
below zero for a period. Bristol Bay will see wind chills from 20F
to 30F below zero, especially in the Dillingham region. A Wind
Advisory as been issued for the Dillingham area highlighting the
gusty winds and wind chill threat this weekend.

Monday sees winds start to lighten up as the Arctic trough moves
south of the Bering. However, the Arctic air mass will remain in
Southwest Alaska, so negative temperatures in the mainland will
persist into next week. It is likely that a long duration of cold
temperatures will persist even past next week as a large blocking
high sets up in the Bering, allowing Arctic air to continue
spilling into Southwest Alaska.

-JAR

&&


.LONG TERM FORECAST (Days 4 through 7: Tuesday through Friday)...

The long-term pattern will favor mostly quiet conditions across
the Southern Mainland. However, gusty gap winds will continue to
filter through the favored terrain and gaps as a cold airmass
looks to linger across the area. This is especially true for the
gaps across Southcentral such as Seward, Valdez Narrows, Whittier,
Thompson Pass, and the Matanuska Valley. Where some active
weather will occur will be across the southern Alaska Peninsula
and Eastern Aleutians as a shortwave drives southward from Siberia
to over the area Wednesday. This weak system could bring brief
visibility reduction with snow showers moving from north to south
off the Bering Sea. Also on Wednesday, a Kamchatka low sends a
front eastward across the Western Aleutians bring a round of gusty
southeast winds and gale-force winds across the marine zones of
the Western Aleutians. This front weakens as it moves eastward
through Friday. There is still some uncertainty on the eastward
progression due to the strength and progression of a broad ridge
over much of the Bering and mainland Southwest Alaska.

&&
.AVIATION...

PANC...VFR conditions will persist through the afternoon today.
Northerly winds coming out of the Matanuska Valley look to
increase this evening and clip the terminal. Initially, with
freshly fallen snow from last night, visibilities may be reduced
to high-end MVFR in blowing snow this evening into the overnight.
Any lingering MVFR conditions due to blowing snow will abate very
early Saturday morning with VFR returning predominantly through
the rest of the TAF period. Northerly wind gusts between 40 and 50
mph will be common Saturday morning. Wind gusts diminish to 30 to
40 mph Saturday afternoon before picking back up to 40 to 50 mph
late Saturday evening through Sunday morning.

&&


$$

424
FXAK69 PAFG 052114
AFDAFG

Northern Alaska Forecast Discussion
National Weather Service Fairbanks AK
1214 PM AKST Fri Dec 5 2025

.SYNOPSIS...
Cold and windy conditions expected through the weekend, especially
in the Interior. Gusty winds lead to dangerous wind chills and
areas of reduced visibility due to blowing snow, especially a
higher elevations in the Interior and where much of the recent
snow from earlier this week fell. Winds peak Saturday, decrease
slightly Sunday, and decrease significantly Monday. The cold
conditions continue well into next week.

&&

.KEY WEATHER MESSAGES...
Central and Eastern Interior...
- Cold everywhere with the coldest spots being in the valleys,
especially the Yukon Flats.

- Some thin low clouds in Interior Valleys Friday keep
temperatures slightly warmer by

- Wind increases this weekend with significant blowing snow
possible in the Southern AK Range Passes, White Mtns and Dalton
Highway summits. Very cold wind chills expected for most of the
Interior as well.
- N/NE wind increases significantly on Saturday from the Yukon
Flats southwest. Gusts above 1000ft may be upwards of 30 to
50 mph whereas valleys can see gusts up to 35 mph (WHEN the
inversion breaks). This continues into Sunday PM, then
weakens.
- Ambient temperatures 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 60 below zero from Tanana
to the Yukon Flats this weekend. Significant blowing snow is
expected in the higher terrain above 1000ft. Periods of
blizzard conditions are expected along
- 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 expected Friday night through Sunday
afternoon along the Parks Highway from Carlo Creek to Cantwell
and from Trims Camp to Fielding Lake along the Richardson
Highway. Through Sunday night along the Dalton/Steese Summits.

- Cold weather continues into next week with temperatures
dropping into the 40s and 50s below zero in the Central and
Eastern Interior Valleys.

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

- North-northeast winds increase this weekend. Wind gusts may be
up to 35 to 45 mph along the coast from the Seward Peninsula
south and in higher terrain.

- Winter weather advisories have been issued for the Middle to
Lower Yukon Valleys and the Eastern Norton Sound for blowing
snow and dangerous wind chills. Gusts of 35 to 50 mph could lead
to periods of blowing snow and wind chills as low as -50F.

- Blizzard warnings have been issued for the Upper Kuskokwim and
Western Brooks Range. Recent snowfall increases the risk for
prolonged periods of blizzard conditions. Valleys and channels
open to the northeast are most likely to see the worst
conditions. Wind gusts of 35 to 50 mph could lead to wind chills
as low as -50F.

- Winds weaken Monday and temperatures decrease again next week.
Lows potentially in the 30s/40s below zero in the Interior and
single digits/teens below zero along the coast.

North Slope and Brooks Range..
- Areas of light snow possible today as a front moves overhead,
especially from Deadhorse east and the Eastern Brooks Range.
Snow accumulations up to 1 inch.

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

- Northerly winds increase today up to 10 to 15 mph along the
coast and up to 25 to 35 mph through Brooks Range passes. Wind
chills fall to as cold as -60F through the Brooks Range passes.

&&

.FORECAST ANALYSIS AND DISCUSSION...
For Friday through Monday.
At the start of the forecast period Friday, the overall pattern is
dominated by a strong 555 decameter upper level high over the
Chukotsk Peninsula and a weak trough over the Eastern half of the
state. A 502 decameter upper level low moves through the trough
Friday night into Saturday pulling very cold air with 850mb
temperatures around -30F across the Interior towards the Alaska
Peninsula. The cold, dense air that is being pulled along with
this low brings gusty winds across the Interior Friday night
through Sunday and sets up a high amplitude pattern over the
Western Interior supporting a very strong upper level jet. These
strong winds aloft promote slightly weaker winds at elevation and
may occasionally mix all the way to valley floor, especially for
valleys open to the northeast. Frequent gusts up to 50 mph above
1000 feet are expected with occasional gusts of 30 to 50 mph
possible in Interior Valleys. Recent snowfall from the system
earlier this week is likely to blow creating periods and areas of
low visibility due to blowing snow. Areas that received more
substantial snow and are at a greater risk of seeing more frequent
gusts are currently under blizzard warnings Friday night through
early Sunday. The strongest winds diminish slightly Sunday and
weaken significantly Monday.

Ambient temperatures in Interior Valleys are likely to warm into
the teens to 20s below 0 due to these winds weakening strong
temperature inversions. Sunday night into Monday winds will have
weakened enough that ambient temperatures will fall once more as
those inversions recover and strengthen. Winds, however will not
be a factor by then and so dangerous wind chills are not expected.
These colder temperatures continue through most of next week and
perhaps even further.


&&

.EXTENDED FORECAST DAYS 4-7...
For Monday night through next Friday.
At the start of the extended forecast period, Monday night, cold
conditions across the region continue under high pressure. A ridge
pattern in the Bering Sea supports rising pressure across the
region which will help keep the area cold. Models begin to have
significant difficulty determining how to handle shortwave
features and weaker lows that move through the pattern around the
ridge Thursday and Friday. Should these features rotate further
south over the top of the ridge and reach into the Interior,
significant warming is to be expected. If these features instead
move further north and pass the region, then the cold weather
could continue well into mid December. The North Slope is most
likely to see some of these systems bringing warmer temperatures
and some light snow late next week.

Coastal Hazard Potential Days 3 and 4...None


&&

.AFG WATCHES/WARNINGS/ADVISORIES...
AK...Cold Weather Advisory for AKZ809>811.
Blizzard Warning for AKZ848-850.
Blizzard Warning for AKZ851-852.
Winter Weather Advisory for AKZ824-829-830.
Blizzard Warning for AKZ832-834.
Cold Weather Advisory for AKZ833-838>847.
PK...Brisk Wind Advisory for PKZ801-853.
Brisk Wind Advisory for PKZ802-804-805-852.
Brisk Wind Advisory for PKZ803.
Heavy Freezing Spray Warning for PKZ816-850-851.
Small Craft Advisory for PKZ850.
Brisk Wind Advisory for PKZ858.
&&

$$

Stokes

763
FXAK67 PAJK 060802 AAA
AFDAJK

Southeast Alaska Forecast Discussion...UPDATED
National Weather Service Juneau AK
1102 PM AKST Fri Dec 5 2025

.Evening and 06z Aviation Update...
The forecast remains on track with minor changes made to the timing
of the Winter Storm Warning over the Haines Highway as moderate to
heavy snow has already began to fall. Accumulations of 1 to 2 inches
have already fallen along the highways with snow beginning to
accumulate at sea level. As of early this evening snow began at sea
level in both the Haines and Skagway Boroughs. Visibilities have
greatly decreased due to this heavy snow with areas below 1 SM. We
are continuing to watch Yakutat as ENE winds have begun allowing for
temperatures to drop. The precipitation type over Yakutat is
expected to transition to snow late tonight/very early Saturday
morning, with these falling temperatures. In Yakutat, with
temperatures around freezing, snow will continue to be wet with
low snow ratios through Saturday.

&&

.AVIATION.../through Saturday evening/
Better flying conditions than expected across the panhandle this
evening, predominately MVFR to VFR with CIGS AoB 5000ft with
isolated LIFR flight condition visbys due to ongoing snowfall or
freezing fog at Haines and Skagway. Overall low to medium aviation
forecast confidence through tonight as low tracks in the NE Gulf
Coast. Model guidance continues to cold start, progging persistent
IFR to LIFR flight conditions not matching current conditions.
Forecast through tonight will be pessimistic, expecting the VFR
conditions becoming predominate MVFR through Friday night and into
Saturday mid morning as the aforementioned low weakens and moves
inland near Cape Fairweather. IFR to LIFR flight conditions will
continue through the TAF period for Haines and Skagway with heavy
snowfall expected to continue through Saturday. Transiting south,
visbys will decrease starting 00z Saturday to around 3 to 5SM with
a gradual transition from rain to rain snow mix and eventually
snow along the Icy Strait corridor TAF sites like Gustavus and
Juneau into late Saturday evening. Precipitation type transition
for Yakutat will be tricky, heavily relying on a more ENE wind to
produce snow. Currently seeing that and expecting to continue, but
would like to see a more predominant NE direction. Still thinking
a transition to rain snow mix will occur sometime after into
early Saturday with snowfall expected by Saturday afternoon. For
Sitka eastward to Petersburg and southward, expecting
precipitation to remain all rain through Saturday.

Winds across the N panhandle will elevate through Saturday
morning and remain elevated through the day due to aforementioned
passing low and increasing pressure gradient with sustained winds
around 15 to 25kts with gusts up to 25 to 35kts. Strongest winds
will remain near TAF sites like Haines and Skagway, continuing
through the TAF period. Winds across the S panhandle expected to
be lighter through Saturday morning, around 10kts, increasing into
Saturday evening to match the northern panhandle.

&&

.PREV DISCUSSION......ISSUED AT 353 PM AKST Fri Dec 5 2025...

SYNOPSIS...

Key Messages:

- Low pressure system in the Gulf brings a front eastward across
the panhandle Friday evening through Saturday, bringing
moderate to heavy snow to the northern panhandle and moderate
to heavy rain for the southern panhandle.

- This weekend through next week, models continue falling into
line behind a weather pattern that has been known to produce
heavy snow. Higher confidence in totals for the northern
panhandle, but still some uncertainty remains about timing and
amounts as cold air pushes southward.

SHORT TERM...The main changes made to the short term forecast
today were to narrow down precipitation timing and amounts for
the incoming system.

A low pressure system has advanced into the north central gulf,
sending a front into the northern panhandle before spreading
southeast through Friday night. This front is expected to bring
moderate to heavy rain rates with increasing wind speeds
overnight. Looking at half an inch to an inch of rain for the
northern panhandle Friday night, largely spreading to the rest of
the panhandle through Saturday morning and bringing around another
inch to an inch and a half Saturday. The system is reinforced
through Saturday and continues to stall in the gulf into the
extended period, continuing to funnel consistent moisture and
strong winds into the panhandle. An area of deep upper level
troughing is beginning to shift over the panhandle, bringing
colder temperatures and increasing outflow winds through the
weekend and into next week. These cold temperatures steadily move
southward through this period, and in combination with the
abundance of available moisture, precipitation will begin to
transition into snow.

Communities in the far northern panhandle are starting to see
this transition tonight, with Skagway already reporting light snow
beginning to fall. A winter storm warning was issued for heavy
snow accumulation in Skagway and Haines through Sunday, with the
greatest accumulations and heaviest rates expected to fall on the
higher elevations of the Klondike and Haines Highways. Consistent
moderate to heavy snowfall is looking to bring accumulations of
between 18 and 28 inches to Skagway and 15 to 22 inches to the
Haines Borough, with the higher amounts expected at higher
elevations of the highways. For Skagway at sea level and along the
highway, and from Haines down along the Chilkat Peninsula, wind
gusts up to 45 mph are possible Sunday which may result in some
blowing snow following the fresh snowfall. Yakutat is also
expected to dip below freezing temperatures overnight and begin
accumulating advisory level snowfall of around 3 to 5 inches
through Saturday. Confidence has increased that the Icy Strait
Corridor, including the cities of Gustavus, Hoonah, Tenakee
Springs, Elfin Cove, Pelican, and Juneau, may see significant
snowfall accumulations starting Sunday. A watch has been issued
for potentially heavy snow from Sunday morning into Monday night,
with accumulations between 11 to 16 inches possible. Cold
temperatures continue to drop southward into the central panhandle
as another system advances from the south, sending another front
with similar rain rates into the southern panhandle. The pattern
continues to persist through the long term, increasing confidence
of a long duration snow and rain event. See the long term for more
information on how this pattern will continue into next week.

LONG TERM.../ Sunday to Tuesday /
The arctic boundary continues to move southward with the
northerly outflow trying to set up. Expect snow to develop Sunday
from Pelican-Elfin Cove east towards Juneau ( the Icy Strait
Corridor) and continue through much of Monday to Tuesday.
Significant snowfall may fall Sunday to Monday evening, so a watch
has been issued.

Cold air will continue to push south Tuesday, and spread the snow
into the southern panhandle by Tuesday.

Gusty north winds from the outflow, with gusty winds to 40 to 45
mph perhaps so possibly blowing snow, if snow characteristics are
right, or freezing spray down Lynn Canal.

MARINE...
Outside Waters: Lighter conditions will continue across the gulf
from a ridge moving through Friday. This will quickly be displaced
by an oncoming system from the west Friday night into Saturday.
Winds will shift south southwesterly and increase to fresh to
strong breeze (17 to 27 kt) by early Saturday. These stronger
winds will last through Saturday and 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 will quickly increase tonight 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.

Inside Waters: Lingering fog and low stratus continues to plague
parts of the inner channels Friday afternoon, particularly along
Icy Strait as well as Frederick Sound in the vicinity of
Petersburg. Calmer surface conditions that allowed for this fog
development will give way to 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 (11 to 21 kt) 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 Weather Advisory from 3 AM to 9 PM AKST Saturday for
AKZ317.
Winter Storm Warning until 3 PM AKST Sunday for AKZ318-319.
Winter Storm Watch from Sunday morning through Monday afternoon
for AKZ320>322-325.
MARINE...Gale Warning for PKZ652.
Small Craft Advisory for PKZ012-013-022-031-034-053-641>644-651-
661>664-671-672.

&&

$$

UPDATE...EAB
SHORT TERM...ZTK/Contino
LONG TERM...Bezenek
AVIATION...NM
MARINE...STJ

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