Graphical Hydro Meteorological Discussion

652
FXAK68 PAFC 241440
AFDAFC

Southcentral and Southwest Alaska Forecast Discussion
National Weather Service Anchorage AK
540 AM AKST Wed Dec 24 2025

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

For the short-term outlook, little change is expected until Thursday
when an upper level jet streak rounding the strong upper ridge out
west will shift east into Southcentral, resulting in another
temporary increase in gap winds for parts of the region. This will
be unlikely to cause gusty winds anywhere over interior valleys,
including the Mat Valley. The strongest northerly winds will be
almost entirely focused along the coast, including near Valdez,
Whittier, Seward and much of Kodiak Island. As an upper level ridge
to our west moves overhead, coastal gap winds will continue to
weaken. Prevailing flow becomes more westerly and will moderate
temperatures a bit today into tomorrow.

By late today into Thursday, another trough dropping into
Southcentral from the Arctic will bring a reinforcing shot of frigid
air into the region. The Alaska Range will wring out the majority of
the moisture from the front, but some lingering moisture may result
in light snow across the northern slopes of the Talkeetnas.
Farther east, light snow is likely from the northern Copper River
Basin by Isabel Pass eastward through Mentasta Pass, Nabesna, and
Chisana as this front moves through. The remainder of the area will
remain cold and dry. This trough will reinvigorate the outflow gap
winds in all the usual places into the Prince William Sound and
northern Gulf. Chances for the next measurable snowfall are
improving for Friday afternoon, but further details will depend on
the track of a surface low in the northern Gulf.

&&


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

The overall forecast remains on track, with few changes to the
previous forecast. Here are the major weather headlines through
the end of the work week:

* Winter Storm Watch continues for the Pribilof Islands from
Thursday morning through Friday morning.

* Blowing snow and heavy snow possible for Bristol Bay and the Alaska
Peninsula late Thursday night through Friday.

* Wind chills as low as -35 to -45 possible for the Kuskokwim
Delta and the Kuskokwim Valley as early as Friday afternoon.

* Extreme freezing spray possible along the Eastern Bering
Sea/Southwest Alaska coastline from east of St. Matthew Island
south to Bristol Bay from Thursday night through Monday morning.

The previous forecast discussion, with minor edits, is copied
below and still applies:

High pressure continues to be centered south of the eastern
Aleutians, keeping a bubble of relatively quiet conditions in
place across much of the Bering Sea and Southwest Alaska. A low
tracking from the Chukchi Sea along the North Slope is helping to
draw warm moist air across the Bering Sea into Southwest Alaska.
This has brought very light precipitation and widespread fog to
the Kuskokwim Delta, which is expected to continue until the cold
front associated with the low drops south through today. The
front brings increased chances for some light snow, with
accumulations up to around one inch, before the colder, drier air
moves in to mix out the fog and low stratus, giving way to sunnier
skies and cooling temperatures.

Out west, a developing low lifts toward the Aleutians, spreading
primarily rain and strengthening winds along the islands through
Thursday (Christmas Day). Further north on the Pribilof Islands,
colder air will mean precipitation that initially starts as rain
Wednesday night transitions over to snow by Thursday (though
quicker further north for Saint Paul). Winds, which increase to
gale force, will then cause significant visibility reductions for
the Pribilof Islands, reducing visibility below one mile and
potentially even leading to blizzard conditions. There is some
uncertainty given that temperatures are likely to remain above
freezing until sometime Christmas Day, which contributes to lower
confidence on the start time of the worst conditions. Later in the
day and into Thursday night, however, temperatures dropping into
the 20s will make for much better conditions to blow snow around,
which will reduce visibility to at least half a mile. Visibility
increases on Friday as precipitation comes to an end from north to
south as cold air surging in from the north causes the front to
drop southward.

For Friday, cold air surges south toward the Aleutians and Alaska
Peninsula, with the front aligning along an axis from the eastern
Aleutians up into portions of Bristol Bay. Temperatures will be
low enough for the majority of locations receiving precipitation
to see it in the form of all snow, with blowing snow being a
potential concern further south and west, where winds will be
strongest. Further north, temperatures will be colder, with wind
chills/apparent temperatures dropping to near or below 40 degrees
below zero in the Kuskokwim Valley and potentially parts of the
Kuskokwim Delta as well. Along the Southwest coast, the cold air
and gale force winds combine to produce a heavy to extreme
freezing spray hazard.

-Quesada/Chen

&&


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

An amplified upper level pattern sets in late this week as a
strong ridge builds over the Aleutians and Bering Sea while a
trough digs south across the Interior, supporting an upper level
low centered over the western Gulf. A surface low lifting out of
the North Pacific into the Gulf will take advantage of this upper
level support, bringing a renewed threat for high winds later this
week across typical locations including the Matanuska Valley,
Valdez area/Thompson Pass, and along the southern AKPen and Gulf
coast through the weekend. Although most of the moisture
associated with this low will be directed towards Southeast
Alaska, Southcentral will see increased chances for snow as the
low drifts south of Prince William Sound. The greatest chance for
snow will be along the Gulf coast and Prince William Sound, while
confidence remains low on the inland extent of snowfall as this
will be highly dependent on the track of the low. Further west, a
tightening pressure gradient between the strong ridge centered
over the western Bering and trough over the Mainland will promote
strong north-northeast winds across the central and eastern
Aleutians Saturday into Sunday. The Arctic airmass associated with
this trough will keep temperatures below average across southern
Alaska, with the coldest areas being the Copper River Basin and
interior Southwest Alaska, where ambient temperatures will hover
in the range of 20 to 30 below zero. Persistent troughing in the
Gulf lasting through the weekend will allow for enhanced gap winds
to continue into early next week across the Eastern Aleutians,
southern AKPen, and Gulf coast.

&&
.AVIATION...

PANC...VFR conditions and light winds will persist through the
period.

&&


$$

374
FXAK69 PAFG 241523
AFDAFG

Northern Alaska Forecast Discussion
National Weather Service Fairbanks AK
623 AM AKST Wed Dec 24 2025

.SYNOPSIS...
A snowy start to Christmas Eve this morning across the Tanana
Valley. A warm front is bringing moderate to heavy snow, gusty
winds, and blowing snow to the Eastern Interior. This front will
move southeast today, with it exiting the region Thursday
afternoon. Moderate snowfall is expected to continue in Fairbanks
until 8 am when the front begins to move to the southeast. Light
snow will remain behind the front, and will continue through
tonight. Heavy snowfall will start at Denali Park later this
morning, and will continue through the afternoon. After this warm
front moves through the region, arctic air will rush back into
Northern Alaska with temperatures rapidly cooling Thursday night.

&&

.KEY WEATHER MESSAGES...
Central and Eastern Interior...
- Warmer temperatures are expected today, with highs at or above
zero across much of the Eastern Interior. The Upper Tanana and
Fortymile Country will remain below zero. Thursday night
temperatures will drop back into the 20s to 40s below zero.
These cooler temperatures will stick around for most of next
week.

- Snow is ongoing the in the Fairbanks North Star Borough. Snow
accumulations across the Eastern Interior are expected to be 6
to 12 inches. The highest totals will be near Denali Park.
- As of 6:00 AM there has been 5.0 inches of snow at the
office.

- Locations above 2000 feet will see wind gusts up to 35 mph. This
could create areas of blowing snow reducing visibilities below
1/2 mile at times. Valley locations will see light winds below
15 mph, but paired with heavy snowfall and visibilities could
drop to 1/2 mile or less.

West Coast and Western Interior...
- Colder temperatures will return to the region Thursday.
Nighttime lows along the coast will be in the 10s to 20s below
zero, and the Western Interior seeing 30s and 40s below zero
return.

- Another round of northerly winds through the Bering Strait
Thursday night is expected. This could create areas of reduced
visibility due to blowing snow. These winds will weaken by
Friday afternoon.

North Slope and Brooks Range..
- Another storm system will bring additional widespread snowfall
and gusty winds to the Western Arctic Coast and Western Brooks
Range through Wednesday.
- The heaviest snow is expected along the southwestern slopes
of the Western Brooks Range with 4 to 8 inches possible.
- Gusty winds could lead to periods of reduced visibility due
to blowing snow.
- Atigun Pass to Deadhorse and Prudhoe Bay will see 1 to 3
inches on Wednesday with southerly winds up to 30 mph
Wednesday morning. This could lead to a period of reduced
visibility through the pass. A Winter Weather Advisory is in
effect late Tuesday night through early Thursday morning.

- Blizzard conditions are looking more likely for Wednesday and
Thursday around Barter Island. A Blizzard Warning is now in
effect from Wednesday morning through Thursday morning.

&&

.FORECAST ANALYSIS AND DISCUSSION...
A 1000 mb low is quickly racing east across the Arctic Coast this
morning. This low has a warm front moving through the Eastern
Interior this morning. As the low moves farther to the east
towards the Canadian Archipelago the warm front will quickly
undergo frontolysis. This front will stall at the northern slopes
of the Alaska Range later this afternoon, where it will weaken
completely overnight.

Moderate snowfall is occuring in the Fairbanks North Star Borough
with snow rates up to 0.5 inch/hr. As the warm front moves off to
the southeast expect snow rates to decrease but snow ratios will
drastically increase. With light snow for the rest of the day
expected and high ratio snow, a couple of inches of accumulation
is possible. Once this front weakens, expect temperatures to
rapidly cool behind it as arctic air returns. If cloud cover can
clear Thursday night then temperatures will return to the -20s to
-40s below zero across the Interior.

A shortwave trough stemming from the Polar Low will quickly rotate
southeast through the Interior towards the Gulf of Alaska by
Saturday. There will be a warm front stretching into the Southeast
Interior from this system. The Upper Tanana Valley and eastern
portions of the Fortymile Country could see up to 4 inches of snow
with this front through Monday morning.

&&

.EXTENDED FORECAST DAYS 4-7...
Sunday night a trough will move overtop the ridge in the Bering
Sea, brining an arctic front into the Northwest Arctic Coastline.
This front would move southeast bringing light snow to the West
Coast and much of the Interior by Monday night. Snow totals with
this system would be light, but would offer a brief reprieve from
the colder temperatures.

By Tuesday another arctic front has the potential to bring snow
and blowing snow to the West Coast. There is a large model spread
on the impacts from this system, but there is agreement between
the model suites that there will be a system moving on top of the
high pressure during this time. We will continue to monitor this
system into the weekend for developments.

Coastal Hazard Potential...
Minor coastal flooding is possible on the Baldwin Peninsula this
morning, as west-northwest winds bring higher waters to the area.
The surf is anticipated to be 3 to 4.5 feet above the mean high
tide marker. We will see water on top of the nearshore ice.
Coastal erosion and flooding of low lying areas is also possible
with this event.
&&

.AFG WATCHES/WARNINGS/ADVISORIES...
AK...Coastal Flood Advisory for AKZ817.
Winter Weather Advisory for AKZ804-808-809.
Winter Storm Warning for AKZ832-839>847.
Blizzard Warning for AKZ834-838.
Extreme Cold Warning for AKZ835.
Blizzard Warning for AKZ805.
PK...Brisk Wind Advisory for PKZ807-856.
Brisk Wind Advisory for PKZ808-809-855.
Brisk Wind Advisory for PKZ814.
Gale Warning for PKZ815-861.
Heavy Freezing Spray Warning for PKZ816-854.
Heavy Freezing Spray Warning for PKZ851.
Brisk Wind Advisory for PKZ860.
&&

$$

Dennis

965
FXAK67 PAJK 241409
AFDAJK

Southeast Alaska Forecast Discussion
National Weather Service Juneau AK
509 AM AKST Wed Dec 24 2025

.SYNOPSIS...

Key Messages:

- Outflow winds beginning to weaken and temperatures start a
warming trend mid week.

- Increasing potential for a pattern change for the end of the
week into the weekend.

- Potential for snow event for the central and northern panhandle;
southern panhandle could see snow turning to rain.

&&

.SHORT TERM.../Through Wednesday night/ Northerly outflow
continues to blow through the northern inner channels this
morning with gales observed in Lynn Canal and out of Taku Inlet.
This is still bringing areas of freezing spray to many of the
inner channels this morning as well. Gusty winds are still at
Skagway as well where gusts to 60 mph have been observed most of
the night. Those winds are expected to begin a diminishing trend
over the next 24 hours as the strong cold area of high pressure in
the Yukon begins to weaken. By late Wednesday night, pressure
gradients across the panhandle are expected to weaken enough that
most outflow winds will have nearly shut off completely having
weakened to around 15 to 20 kt in Lynn Canal by that point. As a
result the areas of freezing spray are also expected to decrease
by late tonight though some areas of light freezing spray will
still be around the northern inner channels even then with the
cold air still around.

Cold air also lingers across the panhandle this morning through
temperatures are not as low as they were yesterday at this time.
Several marine areas and adjacent land areas have warmed to the
teens and 20s this morning due to mixing from wind, but really
cold air is pooling in various valleys of the north including the
Mendenhall Valley and the Chilkat Valley where temperatures are
still below zero in both places. Temperatures are expected to
continue to gradually warm through Thursday as a weak system
moves into the area from the NW Wednesday night, though there may
be one more night, Wednesday night, where some wind sheltered
areas may reach near or below zero again across the north again
before the cloud cover moves in. Cold weather Headlines remain
mostly unchanged from the previous forecast.

Speaking of the weak low, It will start to move SE across the
northern gulf Wednesday night. It will be south of Yakutat by
early Thursday morning spreading mainly cloud cover over the
northern half of the panhandle by this point. It will spread some
light snow (across the outer coast and south), clouds, and fuel a
resurgence of outflow winds in the north on Thursday.

.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.

The next major system will begin to move into the Gulf of Alaska
Friday, following behind the weak low clipping the panhandle
Thursday. As the weaker low moves southeast, before the larger low
approaches from the west Friday night, there will be another brief
lull in the winds into Friday along the southern waters, while the
northern offshore flow will remain stronger 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. These southerly winds moving into the panhandle will
allow for some warming across the panhandle alongside bringing
precipitation through from W to E into the start of the weekend.

As far as temperature relating to snow potential, the EURO and GFS
ensembles and deterministic models have come into greater agreement
over low tracks and 500mb flow. The Canadian remains the outlier.
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
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 next week. This has not
been shown on the ensembles as of yet, and is seen on the EC
deterministic run and not the GFS one, so the certainty of the
timing of the cold air coming back into the northern panhandle is
still a bit uncertain for the period into early to mid next week.

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 adjusted to keep the southern panhandle at between 2.5 and
3.5 inches of liquid precipitation every 24 hours, coming 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. This is from the extreme and AR tools showing a
higher confidence of a shift of tails for QPF for the southern
panhandle, particularly near the Ketchikan area, with an increased
confidence from yesterday`s model runs. Overall the heavy rain will
begin for the southern panhandle Saturday, but the next wave of
precipitation pushing through will bring another round of heavy rain
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, 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 up to Icy Strait corridor. These areas will
see between 8 and 14 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 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 10 and 18 inches in 24
hours both Saturday and Sunday with more expected along the Klondike
Highway. 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. Overall the
northern half of the panhandle will see 1.5 to 3 inches of liquid
precipitation during this system, but there remains uncertainty on
how much snowfall there will be exactly during this system and the
exact timing of a changeover to rain for the central parts of the
panhandle. Overall this will remain more of a heavy rain event for
the southern panhandle from Sitka and Wrangell southwards Saturday
into Sunday, with only about 3 to 7 inches expected for Ketchikan
Sitka and PoW Saturday morning before transitioning to rain, and 6
to 12 inches for Wrangell possible before they too transition to
rain.

&&

.AVIATION.../12z Wednesday to 12z Thursday/... VFR flight conditions
expected through the forecast period.

The only area of concern where high-end MVFR is possible is in far
southern southeast Alaska where snow showers could bring brief MVFR
VIS/CIGs.

Low level turbulence and wind shear will also persist into the
afternoon with winds aloft around 25-35kts for the Gustavus and
Juneau areas, in southern SE AK, and in areas prone to gap winds.
LLWS will begin to diminishing late this afternoon.

Strong winds 25g50kt continue for PAGY with breezy outflow winds 10-
15G20-25kt for PAHN, PAWG and PAKW. Less than 10kt elsewhere.

&&

.MARINE...
Inside waters: Northerly outflow with freezing spray continues
across the north. Lynn Canal and Taku Inlet are still showing gale
force winds this morning while 25 kt winds extend down to
Frederick Sound and Southern Chatham Strait. These winds are
expected to slowly diminish through the next 24 hours with outflow
nearly shutting off by late Wednesday night (winds down to 15 to
20 kt in Lynn Canal and Taku Inlet) as the Yukon high weakens.
This low period will be somewhat short as the weak low moving SE
across the gulf Thursday will strengthen the outflow again by
Thursday afternoon with gales again in Lynn and Taku Inlet before
diminishing again on Friday. Freezing spray is still ongoing, but
with warmer temperatures across most marine areas, the heavy
freezing spray is mainly limited to Northern Lynn for this
morning. Otherwise expect the areas of freezing spray to diminish
as the outflow wind diminish through early Thursday. Seas are
still somewhat high in Lynn and Stephens passage this morning
(reaching 13 ft in some areas) but those seas are expected to also
subside as the winds do by early Thursday.

Gulf Waters: The gulf waters will be seeing a change from
northerly winds to more westerly winds by Thursday as a weak low
moves SE through the eastern gulf Wednesday night into Thursday.
These W to NW winds will increase to 30 kt across the central gulf
waters Thursday before diminishing and then switching to southerly
on Friday ahead of the next front. Highest seas are still
currently associated with what is left of the outflow that makes
it into the gulf out of Cross Sound and Chatham Strait with up to
10 ft seas. These will subside as the winds do down to 4 to 6 ft
by late Wed night. The seas will then start building again to 8 to
12 ft by Thursday afternoon due to the increased W winds at that
time.

&&

.AJK WATCHES/WARNINGS/ADVISORIES...
PUBLIC...Extreme Cold Warning until 6 AM AKST early this morning for
AKZ318.
High Wind Warning until 6 AM AKST early this morning for AKZ318.
Strong Wind until 3 PM AKST this afternoon for AKZ318.
Extreme Cold Warning until noon AKST today for AKZ319.
Cold Weather Advisory until 6 PM AKST this evening for AKZ320-
321-323-326-327-329.
Extreme Cold Warning until 7 PM AKST this evening for AKZ325.
Strong Wind until 3 PM AKST this afternoon for AKZ325.
Cold Weather Advisory until 9 AM AKST this morning for AKZ328-
330-332.
MARINE...Heavy Freezing Spray Warning for PKZ011.
Heavy Freezing Spray Warning for PKZ012.
Heavy Freezing Spray Warning for PKZ031.
Gale Warning for PKZ012-013.
Small Craft Advisory for PKZ021-031>034-036-641>643-661>663.

&&

$$

SHORT TERM...EAL
LONG TERM...Contino
AVIATION...GJS
MARINE...EAL

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