Graphical Hydro Meteorological Discussion

281
FXAK68 PAFC 090101
AFDAFC

Southcentral and Southwest Alaska Forecast Discussion
National Weather Service Anchorage AK
401 PM AKST Mon Dec 8 2025

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

Key Messages:

Weather is slowly becoming less active as the Arctic trough dips
south. However, continued threats for strong winds and
dangerously low wind chills will linger through Tuesday. Winds
will begin to weaken later today, but remain gusty into the
overnight hours. Blowing snow will subside with decreasing winds.
Temperatures will become even colder through the week as a second
cold air mass descends into Southcentral.

...Active Warnings and Advisories...

- A High Wind Warning remains in effect for the Matanuska Valley
through 6AM Tuesday for 35 to 40 mph winds with gusts up to 75
mph.

- A Winter Weather Advisory remains in effect for Northeast Kodiak
Island including Kodiak City until 9PM tonight for snow and blowing
snow.

- A Cold Weather Advisory remains in effect for the Copper River
Basin until 4PM Tuesday for very cold wind chills as low as 40
to 50 below.

As mentioned before, the Arctic trough that brought gusty winds
to the Matanuska Valley, Anchorage and Kenai is moving south into
the Gulf. This will allow pressure gradients to loosen and winds
to decrease in strength through Tuesday. In Kodiak Island, chances
for light snow showers will taper off through the evening along
with winds. Thompson Pass winds will slowly diminish through
tomorrow, but will remain elevated through the week. After this
event is over, another round of Arctic air dips into Southcentral
for the rest of the week. Though the risk of wind chill
diminishes, ambient temperatures will dip as low as the wind
chills were during the event, so cold related risks will remain.
This cold is not showing any signs of ending with this pattern
remaining for the foreseeable future. A weaker shortwave will move
into Southcentral Wednesday night into Thursday, allowing for an
increase in gap winds in marine areas.

-JAR

&&


.SHORT TERM FORECAST SOUTHWEST ALASKA/BERING SEA/ALEUTIANS
(Days 1 through 3: This afternoon through Thursday evening)...

Cold temperatures and dry conditions will continue across the
Southwestern Mainland through much of this week. The gusty
conditions that brought instances of blowing snow across the coast
and Nelson Island will continue to abate through the rest of
today and this week. However, cold wind chills of 20 to 30 below
zero will be commonplace this week as the cold airmass is in firm
control. The coldest of the apparent temperatures will be felt
during nighttime and early mornings. A shortwave dropping in from
the north may clip northern portions of the Kuskokwim Valley
Thursday night into Friday morning bringing very light snow to the
area.

The next front/low combinations enter the western Bering Tuesday
afternoon into Wednesday morning, bringing a round of rainfall and
potentially some gale-force winds to the Western Aleutians.
Models are in fairly good agreement on the idea that the system
remains mainly confined to the Western Aleutians and the western
Bering as the strong upper level ridge remains centered over the
Aleutian Chain through midweek.

&&


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

The long term starts out with a deep blocking high over the Bering
Sea that will amplify as a strong upper level shortwave and arctic
airmass drops south over the state. This will lead to more of the
same conditions for the southern Mainland with potential for high
winds out of all of the north-south oriented mountain passes and
coastal gaps from the AKPen east into Southcentral. The main
weather threat will be cold wind chills and ambient temperatures
in addition to the strong winds. Virtually the entire forecast
area will remain dry (possibly for a few more weeks), but some
light snow is possible along the northern faces of the Alaska
Range, Chugach and Kodiak Island. Some forecast guidance indicates
the surface low(s) may retrograde back towards the east on
Monday, which would bring some light snow, but overall forecast
confidence in this feature is low and the pobabilities of this are
lower. Most things point to continued cold and breezy, with areas
of high winds possible.

-CJ

&&
.AVIATION...

PANC...VFR conditions with gusty northerly winds will continue
as stiff northerly winds come down the Knik Arm and clip the west
side of Anchorage. Winds decrease significantly going eastward,
such that there may be a noticeable difference in speed on the
west side of the terminal vs. east side at times. Winds diminish
after 09/09Z, becoming 10kts or less after 09/15Z.


&&


$$

534
FXAK69 PAFG 091348
AFDAFG

Northern Alaska Forecast Discussion
National Weather Service Fairbanks AK
448 AM AKST Tue Dec 9 2025

.SYNOPSIS...
Cold weather continues across Interior Alaska, with most such
areas in the negative teens or colder, and the Upper Tanana Valley
around -50F. The North Slope by contrast is in the single digits
and teens above zero as a round of light snow shifts eastward
across the area through Wednesday morning. Thereafter, colder air
moves in behind a cold front, dropping much of the North Slope too
into the negative teens. This will quickly change from Thursday
through the weekend as a low off Siberia shifts east and brings
increased cloud cover, widespread snowfall of at least an inch,
and much warmer temperatures to Alaska north of the AK Range. On
the North Slope, winds will also rise, which could result in
blowing snow and reduced visibilities at times, especially where
they combine with falling snow. Moving into next week, very cold
conditions could drop temperatures into the -40s or -50s F in
much of Eastern Alaska, even outside typical cold spots.

&&

.KEY WEATHER MESSAGES...
Central and Eastern Interior...
- Cold weather will continue across the Interior through
Wednesday. Cold valley locations will see lows in the -30s and
-40s, with the Upper Tanana Valley falling to around -50.

- Beginning on Thursday, another system will move into the area
and yield snow totals widely of around 1 to 3 inches through the
weekend, with higher totals of over 4 inches possible from the
north slopes of the Western AK Range to the White Mountains.

- Considerably warmer temperatures are likely on Friday with this
system, with highs widely rising into the positive single or
double digits.

West Coast and Western Interior...
- Cold weather with lows in the negative teens and 20s will
continue through Wednesday night ahead of the next system.

- From Thursday through the weekend, much warmer temperatures
with increasing clouds and 1-4 inches of light snow will be
brought in as the next system moves into the area.

North Slope and Brooks Range...
- Light snow will continue across the eastern North Slope through
Wednesday before colder air is ushered in by a cold front in
its wake. Accumulations will generally be light.

- A more robust wave of snow is expected from Thursday into the
weekend as a low moves along the Arctic coast. 2 to 4 inches of
snow are widely possible across the area. Higher totals are
possible in the Brooks Range and Arctic plains, mostly east of
the Dalton Highway.

- As the low moves along the coast, widespread winds of 25 to 35
mph, with higher gusts, will shift from SW to W and could
combine with falling/fresh snow to blow and reduce visibilities.

&&

.FORECAST ANALYSIS AND DISCUSSION...
A positively-tilted ~550 dm ridge at 500 mb is currently focused
over the Bering Sea. A broad area of troughing is extending from a
height minimum of ~497 dm over the Canadian Archipelago southeast
toward Nunavut, then southwest into Yukon. Temperatures at the 850
mb level are in the mid -20s C over the eastern Fortymile Country
and the Upper Tanana Valley, where surface temps are near -50F.
Moving through today and tomorrow, a cold front shifting southeast
across the North Slope will continue to bring up to a couple
inches of light snow to those areas before ushering in a return of
temperatures in the negative teens in its wake.

Otherwise, cold weather is expected across Northern Alaska until
the next system moves off of Siberia in the form of an upper 990s
mb surface low on Thursday. The low, which is expected to track
along the Arctic coast, will bring elevated sustained winds of
around 25-35 mph (with higher gusts) to the North Slope as it
transits east. It will initially bring snow to Western Alaska
Thursday morning, spreading east into the Central Interior / North
Slope by Thursday evening and reaching the eastern border by
early Friday morning. While there is some uncertainty on
accumulations through the weekend, across the Interior, many/most
areas could see at least 1-3 inches of accumulation, with a narrow
band of up to 4-6 inches extending from the northern slopes of
the Western AK Range northeast to the White Mountains. On the
North Slope, totals could widely reach 2-4 inches, with 6+
possible in the Eastern Brooks Range and parts of the Arctic
plains just east of the Dalton Highway. Given the amount of
snow/snowfall rates and the potential for falling snow to combine
with elevated winds, there will be the potential for visibility-
limiting blowing snow at times across the Arctic coast. Snow
totals of around 4 inches will also be possible on the Chukchi Sea
and southern Seward Peninsula coasts.

&&

.EXTENDED FORECAST DAYS 4-7...
After the low exits the area on Saturday, most snow will end
across Western and Interior Alaska with the exception of some
patchy light snow Saturday evening across parts of Western Alaska
as a weak low transits south along the coast. The North Slope by
contrast could see repeated periods of light snow into next week as
weak surface lows / upper-level shortwaves move along the coast.
In the Interior, cold air will reconsolidate, with widespread lows
down into at least the -30s and -40s F in the Central and Eastern
Interior and the negative teens in the Western Interior. Early
next week, models depict a strong ridge over the Bering Sea and
Siberia with extensive and very cold troughing over northwestern
Canada. With a large, dry, and very cold air mass aloft from
Mon Dec 15 through at least Wed Dec 17, -50s F are not out of the
question for much of the Eastern Interior and eastern North Slope
even outside of just the typical cold spots. The western extent of
this cold air is still an open question, but there is a chance it
could extend into the Central Interior/North Slope if the ridge
is farther west. Beyond then, there are model disagreements on
how persistent the airmass is.

Coastal Hazard Potential Days 3 and 4...None

&&

.AFG WATCHES/WARNINGS/ADVISORIES...
AK...None.
PK...Heavy Freezing Spray Warning for PKZ817.
&&

$$

DS

754
FXAK67 PAJK 090531
AFDAJK

Southeast Alaska Forecast Discussion
National Weather Service Juneau AK
831 PM AKST Mon Dec 8 2025

.UPDATE...Update to the Aviation section with the issuance of the
06z set of TAFs

&&

.PREV DISCUSSION......ISSUED AT 415 PM AKST Mon Dec 8...

SHORT TERM...Currently looking at the strong system that moved
into the southern panhandle making its exit into British Columbia,
leaving residual onshore flow and soon to be lighter snow for the
Petersburg and Wrangell areas. With its exit, the southern
panhandle is looking at a resurgence of northerly winds and colder
temperatures. These northerly winds will be key in bringing stable
air into Prince of Wales, Ketchikan, and Annette Island. At this
time, currently expecting the arctic winds to reach south of
Annette Island, but the big question on this forecasters mind is
how strong and stable the dry air will be. Current thoughts is
fairly strong, as ridging aloft in British Columbia look to build
in high pressure, which looks to help bring down the cold air via
katabatic winds.

Tuesday sees the new shortwave moves along the southwesterly flow,
generating a new surface low. A similar setup to today, a band of
heavy precipitation is expected to setup over Ketchikan, Annette
Island, and Prince of Wales Island. Currently, only expecting
eastern PoW to stay snow, as the northerly flow through tomorrow
night is expected to keep cool temperatures in place. Ketchikan
and Metlakatla is the most uncertain, particularly in areas
exposed to southeasterly winds. If the cold, stable air from the
northeast indeed is strong enough, then the warm southeasterlies
are expected to decouple and lift, driving much of the stronger
rates. Downtown Ketchikan is mostly sheltered from northeasterly
winds, and is therefore the most likely to transition over to a
rain/snow mix or primary rain. South Tongass and North Tongass,
however, are more exposed to northeasterly winds, and therefore
are expected to stay snow longer. Similar story to the Ferry
terminal on the northern side of Metlakatla, which is exposed to
the northeast narrow channel.

LONG TERM.../Wednesday through Sunday/...Very little changes
made in the long term forecast as the arctic boundary that pushed
down into the panhandle over the weekend continues to march
southward through midweek. Wednesday a quick moving low will
finish dropping snow in the southern panhandle before moving
inland over British Columbia and ushering in a cold dry second
half of the week. Building high pressure in NW Canada and
interior Alaska supported by a deep arctic trough in the upper
levels is creating offshore flow and ushering colder continental
air through the northern panhandle. This air is very cold with 850
mb temps plummeting into the -15 to -25 C range by mid week
across the northern panhandle and near -10 C over the south. At
sea level this will translate to overnight lows ranging from
single digits above or below zero for the north to teens and 20s
for the south.

Daytime highs will struggle to reach the 20s for the north and into
the 30s for the south as we progress through the week. Coldest
temperatures look to occur Monday night through Wednesday night, but
sub freezing temperatures are likely to stick around into next
weekend. The panhandle from Icy Strait northward will be watched
as many locations will approach their criteria for cold weather
advisories or extreme cold warnings (especially the Haines and
Klondike Highways) through at least mid week. As of this forecast
discussion, an extreme cold warning for Skagway, primarily along
the Klondike Highway, was extended through noon Wednesday for
extremely cold temperatures as low as 45 degrees below.

Strong outflow winds of at least gale force will be blowing along
many northern panhandle channels through most of the week. A
strong 1035 mb high in the Yukon is the main driver of this outflow
and it will persist and strengthen to 1050 mb by late week. Expect
gusty winds out of many of the outflow areas in the northern
panhandle to start with, but expect outflow out of areas farther
south through the week as the Yukon high spreads into northern
British Columbia by late week. Gaps along the NE gulf coast will
serve as outlets for strong winds as well through the period. Aside
from the above mentioned hazardously cold temperatures, freezing
spray will become a more widespread problem for many marine areas in
the inner channels and along the NE gulf coast. The freezing spray
could become heavy at times in Lynn Canal, near Taku Inlet, and
northern parts of Glacier Bay throughout the week.

The continuing outflow will also keep most of the panhandle dry
through the mid and long range except for possibly the far south.
There is the possibility of a another snow event for the south
next weekend that is highly dependent upon an upper level ridge
moving over the panhandle at the start of the weekend followed by
another arctic trough replacing the one that dominates the state
for most of the week. One thing is for certain, winter has come to
southeast Alaska.

AVIATION.../through Tuesday evening/...Flying conditions continue
to improve this evening as the heavy band of snow that was set up
earlier across the central panhandle has diminished. VIS across
the Petersburg and Kake areas have been improving while the snow
has stopped in most other locations. Along with improving VIS,
CIGs have improved to VFR for some locations across the southern
panhandle while MVFR does remain very prevalent. Across the
northern half of the panhandle, VFR conditions remain but some
areas continue to experience strong outflow winds as well as some
LLWS from these winds, particularly Juneau and Yakutat. Conditions
for the southern panhandle are expected to deteriorate later this
evening as the next wave of snow will move in during the early
morning hours reinforcing MVFR conditions or potentially dropping
conditions to IFR with some LIFR conditions possible. Turbulence
and icing continue to be a concern from the AAWU especially for
icing across the southern panhandle while turbulence is possible
for the entire panhandle

MARINE...
Outside: Strong outflow winds continue to dominate the eastern
gulf coastal waters through Tuesday. Gale to storm force winds
with strong storm force gusts are blowing out of interior passes,
as well as any available drainage channel. Only a minor reduction
in strength is expected through Thursday, but winds are overall
expected to stay elevated through the week. Wave heights are
around 7 to 10 ft through the majority of the gulf, with areas
affected by the outflow winds seeing up to 15 ft waves persist
through the week. Freezing spray is possible with strong wind
gusts, mostly along the coastal waters. The central gulf is more
calm, only experiencing disorganized moderate breezes as the low
in the western gulf dissipates.

Inside: Strong gale to storm force outflow winds have persisted
through Monday and are expected to continue through the week. A
very strong pressure gradient in the northern panhandle is forcing
northerly storm force winds with gusts in the 60 kt range down
through Lynn Canal and Stephens Passage, as well as strong gale
force winds with storm force gusts out of Taku Inlet and through
the rest of the inner channels. Wave heights between 8 to 10 ft
are expected in areas of the strongest winds, with the rest of the
channels seeing around 6 ft or less and diminishing overnight.
Channel entrances may see up to 15 ft waves at their peak. The
pressure gradient is expected to only slightly relax overnight,
continuing gale force outflow winds in Lynn Canal and Stephens
passage and strong breezes to near gale force winds for the rest
of the channels through the week.

&&

.AJK WATCHES/WARNINGS/ADVISORIES...
PUBLIC...Strong Wind until 9 PM AKST this evening for AKZ318.
Extreme Cold Warning until noon AKST Wednesday for AKZ318.
Cold Weather Advisory until 3 PM AKST Wednesday for AKZ319.
Cold Weather Advisory from midnight tonight to noon AKST Tuesday
for AKZ320-325.
Strong Wind until 6 AM AKST Tuesday for AKZ325.
Winter Storm Warning until 9 PM AKST this evening for AKZ326-329-
331.
Winter Storm Warning from 9 AM Tuesday to midnight AKST Tuesday
night for AKZ328-330-332.
Winter Weather Advisory from 9 AM Tuesday to 3 AM AKST Wednesday
for AKZ331.
MARINE...Heavy Freezing Spray Warning for PKZ011>013-031.
Heavy Freezing Spray Warning for PKZ021.
Heavy Freezing Spray Warning for PKZ021.
Heavy Freezing Spray Warning for PKZ032.
Storm Warning for PKZ012-013-651.
Gale Warning for PKZ011-022-031>034-053-643-644-663-664-671.
Small Craft Advisory for PKZ021-035-036-641-642-652-661-662-672.

&&

$$

SHORT TERM...NC
LONG TERM...STJ
AVIATION...SF
MARINE...ZTK

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