Graphical Hydro Meteorological Discussion

279
FXAK68 PAFC 190137
AFDAFC

Southcentral and Southwest Alaska Forecast Discussion
National Weather Service Anchorage AK
437 PM AKST Tue Nov 18 2025

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

Generally speaking, the pattern this afternoon remains similar to
what we saw yesterday. Southcentral continues to sit within a
zone of southwesterly flow between a weakening low moving up the
western Alaska coast and an upper ridge focused over British
Columbia and Southeast. Relatively mild conditions in the 20s and
30s near the surface contrasting with much colder temperatures in
the mid to upper levels is continuing to support an unstable air
mass along with several areas of convective showers drifting north
from the Gulf into much of the Gulf Coast. A low-amplitude
shortwave trough progressing northeast from near Kodiak Island
into the Kenai Peninsula is helping to support more aggravated
shower activity near the Barren Islands and along the southern
coast of the Kenai Peninsula. Some of this activity will likely
shift north towards the eastern Chugach Mountains, Anchorage and
the Mat-Su Valleys this evening as the trough progresses towards
the Talkeetnas overnight.

While the exact track of individual shower clusters over the next
several hours is uncertain, no single location across the Mat-Su,
Anchorage and western Kenai Peninsula is expected to see much
accumulation tonight. The observed Anchorage sounding from this
morning also showed a dry layer from about 1000 to 5000 ft, and
this dry air prevented much of the snow that moved past the
Anchorage Bowl last evening from reaching the ground. It would
not be surprising to see this dry layer act as a spoiler for
heavier snow showers that try to move inland up towards Anchorage
and Palmer again tonight.

Looking to Wednesday and beyond, clarity is still rather lacking
for the evolution of a complex and much more active pattern taking
shape across the region. A shortwave trough with numerous smaller
embedded waves is expected to round the base of the longwave
trough sitting out over the Bering Sea between Wednesday and
Thursday, with the bulk of the energy expected to lift northeast
towards the AKPen. Several differing scenarios remain on the table
for how this system ultimately evolves, though the bigger picture
impacts to Southcentral will not differ too much overall in spite
of the poor model agreement. Guidance continues to struggle with
the location and track of a surface low expected to spin up ahead
of the incoming shortwave. The general consensus is now that the
surface low will initially form close to the southern end of the
AKPen on Wednesday evening, but solutions quickly diverge from
there, bringing the center somewhere between Bristol Bay and the
northern Gulf on Thursday.

In terms of the impacts from this system to Southcentral, there
are really still two but similar scenarios for how this plays
out. If the low takes the more northerly track into Bristol Bay
and the southern Cook Inlet, this would generally favor more warm
air making it into interior valleys, with more of a Chinook
pattern that could result in temperatures across much of the Kenai
Peninsula, Anchorage and Mat Valley warming a few degrees above
freezing on Thursday. This would also be more favorable for more
intense southeast winds to develop along the Turnagain Arm and
much of the Kenai Mountains. If the low skirts more south into
Kodiak Island and the Barrens, this would keep inland temperatures
cooler and snow levels lower across the Kenai and Chugach
Mountains. Either way, heavy precipitation enhanced by upslope
flow with increasing southeasterlies ahead of the low and its
front is expected along the coast from the southern Kenai
Peninsula out to Prince William Sound late Wednesday into
Thursday. There will also be a threat for periods of light
freezing rain/sprinkles to make it into parts of the western Kenai
Peninsula, Anchorage and the Mat Valley as a warm nose aloft
develops overtop a layer sitting at/below freezing close to the
surface on Thursday. Fortunately, it looks like anything that does
"spill over" from the mountains will stay fairly light, albeit it
does not take much freezing rain to create treacherously slick
surfaces.

From late Thursday into Friday, there is a loose consensus that
the low and supporting trough will continue to shift northeast
to somewhere in the vicinity of Prince William Sound. This could
entail a band of rain switching over to snow moving up into
western parts of the outlook area as a cooler air mass begins to
work in from the west. However, this will depend on how the system
evolves on Thursday and how quickly it shifts northeast, so the
details are still very difficult to pin down at this point.

-AS

&&


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

Onshore flow in the wake of the low that brought active weather
across the area the last couple of days continues to bring showers
across Southwest Alaska this afternoon. Light rain showers across
Bristol Bay are beginning to diminish as the low continues to
pull off to the north into the Bering Strait, while snow showers
persistently continue across the Kuskokwim Delta. A more intense
band of snowfall for this afternoon and evening that model runs
have been depicting the past day or so has come to fruition, with
its axis of heaviest snowfall currently setting up from roughly
the mouth of the Kuskokwim River up through Kalskag. This band of
snow will slowly drift north across the Kuskokwim Delta and Lower
Kuskokwim Valley through this evening into tonight before it falls
apart ahead of an approaching front in the eastern Bering early
Wednesday morning. Based on current radar returns and
observations, areas within the heaviest axis of snow could see a
quick couple inches of wet, heavy snow accumulation through this
evening.

Further west, the front tracking across the Bering bringing gusty
southerly winds and rain has reached the Central Aleutians. The
front makes it to the Eastern Aleutians and Pribilof Islands by
late this evening, at which point a triple point low spins up
along the front just west of the Pribilof Islands. This will help
lead to a modest enhancement of rain and winds across the islands
overnight as the low tracks to between Nunivak Island and St
Matthew Island Wednesday morning. Colder air currently in place
over Southwest Alaska will retreat to the north through Wednesday
morning as a strong push of southerly flow will accompany the
front as it reaches the Southwest coast. Precipitation will first
begin to spread inland across Nunivak Island and the Kuskokwim
Delta by early Wednesday morning. Precipitation for these areas
likely begins as snow before the southerly flow erodes away the
colder air in place enough for a transition to a rain/snow mix
along the coast by mid to late morning. Most precipitation
associated with this front along the Bristol Bay coast also likely
falls as a rain/snow mix.

The pattern amplifies further on Wednesday night as the broad
upper-level trough complex across the Bering digs into the North
Pacific. A robust shortwave and associated strong surface low
pressure system will lift from the North Pacific to the Alaska
Peninsula (AKPEN) Wednesday evening. Strong gusty gale-force
southeasterly winds as well as heavy rain are likely along the
AKPEN starting Wednesday afternoon. While confidence for strong
winds and heavy rain is greatest along the AKPEN, there are still
questions about the exact track of this system. Confidence for
precipitation-type and precipitation intensity along Bristol Bay
and the Kuskokwim Delta/Kuskokwim Delta Coast for Wednesday night
and Thursday remains low at this time until there is more
confidence in storm track. Behind this low, a colder airmass will
spread across the Bering for Thursday night and Friday with
instability- driven showers likely across the Aleutian Chain,
Pribilof Islands, and southern AKPEN as mainland Southwest will
contend with wrap around moisture from the low that looks to be in
Cook Inlet or along the Kenai Peninsula early Friday morning.
Stay tuned for forecast updates as details on the exact track of
this low will hopefully become clearer with time.

&&


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

Only minor changes from previous discussion. Forecast confidence
remains generally low as the weekend starts and into early next
week. Generally expect stormy weather as a low impacts Southern
Alaska on Friday, followed by a brief break before the next storm
moves into the Bering Sea from the west.

Broad upper level troughing will be present over the Bering Sea
by the start of the long term forecast period. A robust shortwave
curving up from the North Pacific will spur the development of a
surface low near the Alaska Peninsula. However, model solutions
remain very divergent, which makes forecast details and potential
impacts difficult to pinpoint. Among the deterministic solutions,
low tracks range from the low curving up the Southwest Alaska
coastline, to the low moving onshore in Bristol Bay, to the low
curving up the Gulf coast towards Prince William Sound. Given the
strength of this low (minimum MSLP as low as 970-980 mb), gales
are possible, with sustained storm force winds likely. All told,
this will be a potentially impactful storm, and one to watch as
forecast confidence gradually improves.

As the aforementioned low gradually weakens and exits out of the
Southern Mainland, a ridge will move in, followed by the front
from a strong low that moves in by late Saturday. Winds to storm
force are possible with this front, impacting the Western and
Central Bering/Aleutians. As the front approaches the Mainland by
Monday and Tuesday, secondary lows developing along the front will
lead to stormy weather along the Bering Sea, though uncertainty
with low tracks will once again lead to difficulty pinpointing
exact details. Overall, a low-confidence long-term forecast.

KC/DD

&&

.AVIATION...

PANC...Generally, VFR conditions are expected. However, skies
will clear tonight, which may lead to MVFR to IFR conditions
with fog and stratus possibly developing in the Inlet.

&&

$$

241
FXAK69 PAFG 190042
AFDAFG

Northern Alaska Forecast Discussion
National Weather Service Fairbanks AK
Issued by National Weather Service Anchorage AK
342 PM AKST Tue Nov 18 2025

.SYNOPSIS...

Little to no change in the forecast since the previous
discussion. A broad trough over the Bering Sea with an associated
area of low pressure has continued to support a series of low
pressure systems moving into Western Alaska, with gusty winds,
widespread snow, and warming temperatures along the West Coast,
Western Interior, Central/Western Brooks Range, and NW Arctic
Coast. An overlap of gusty winds and snow could lead to
significant reductions in visibility at times, although this
threat is diminishing as warmer air is being advected in from the
south and not allow for as much in the way of blowing snow.
However, these conditions are still possible, and Winter Storm
Warnings, as well as Winter Weather Advisories have remained in
place for the Yukon Delta north through the Seward Peninsula and
NW Arctic Coast for gusty winds and snow/blowing snow through
tomorrow. A rain/snow mix will be possible across southern
portions of the West Coast as warmer temperatures build in.

Across the Central/Eastern Interior, conditions have and will
continue to remain drier overall with more isolated to scattered
snow chances, as temperatures also see a warming trend. Best chances
for more moderate snow in this corridor will remain confined to
higher elevations and in the Brooks/Alaska Ranges.

Snow chances are expected to continue across Northern Alaska through
the rest of the week as a series of low pressure systems and
fronts in the Bering Sea and Gulf of Alaska continue to support
moisture transport into our region, but then going into the
weekend there has been increasing confidence of a strong area of
high pressure building in over Alaska starting early next week,
supporting cooler and drier conditions returning.

&&

.KEY WEATHER MESSAGES...

Central and Eastern Interior...

- Conditions remain mostly dry overall with isolated to scattered
snow showers possible through the weekend.

- A warmer airmass will continue to build into the Interior this
week, with highs reaching back into the single digits and teens
above zero and lows in the single digits above and below zero.

- A colder and drier airmass will return heading into early next
week as snow chances diminish.

West Coast and Western Interior...

- An active weather pattern continues through tomorrow across
Western Alaska as a series of storms in the Bering Sea bring
gusty winds, widespread snow, and warmer temperatures.

- Winter Storm Warnings and Winter Weather Advisories remain in
effect along the West Coast and at St. Lawrence Island, where
the heaviest snow and strongest winds are expected. Localized
blizzard conditions are possible at times.

- Strongest wind gusts through Wednesday night will peak around
30 to 50 mph, strongest offshore and at St. Lawrence Island
where gusts up to 60 mph are expected. A secondary system will
be moving in tomorrow, and reinforcing chances for more snow.

- Temperatures will continue to see a steady warming trend with
southerly flow. While predominant snow is expected, a rain/snow
in place. A mix will be possible across lowest elevations,
particularly the southern coastlines.

- Temperatures will begin to steadily drop off beginning this
upcoming weekend and going into the early part of next week, as
a cooler and drier pattern sets in.

North Slope and Brooks Range...

- A series of systems moving north across Western Alaska will
continue to support widespread snow moving into the
Central/Western Brooks Range (including Atigun Pass) and NW
Arctic Coast through tomorrow, and then chances of snow will
gradually taper off by later in the week into the weekend and
beyond.

- Gusty winds are expected today into tomorrow across higher
elevations and coastal regions, leading to areas of blowing snow
and significant reductions in visibility at times.

- Colder and drier conditions are expected to continue in the
Eastern Brooks Range and NE Arctic Coast.

- Temperatures will continue to see a warming trend overall this
week, with highs by Wednesday reaching back into the teens and
20s above zero and lows in the single digits and teens, but then
begin to drop off this upcoming weekend into early next week as
a much colder and drier pattern establishes itself over the
region.

&&

.FORECAST ANALYSIS AND DISCUSSION...Tonight through Thursday.

Models are gradually coming into better agreement with the next
storm that is set to move up from the Bering Sea on Wednesday.
There remain some track and even shape differences with the low;
as such, forecast confidence seems to be lowest for St. Lawrence
Island. With models trending towards stronger winds around this
low, blizzard conditions are looking increasingly likely for
portions of Yukon Delta, St. Lawrence Island, and communities
around Norton Sound.

The forecast for snow amounts looks to be on track. For some of
the higher elevations within the Seward Peninsula, there could be
a few areas receiving as much as 2 feet of snow through tomorrow.
Otherwise, generally additional amounts 6 to 9 inches can be
expected for most of the southern facing slopes, and generally 3
to 6 inches for the lower elevations within the Y-D Delta, through
tomorrow. There may also be some localized areas of blizzard
conditions possible at times, although the warming of the airmass
with the more southerly flow in place will help to mitigate this
potential threat or keep blizzard conditions more short-lived.
Strong and gusty winds are still jamming just off the northern
coast of St. Lawrence Island and towards Savoonga, with occasional
gusts up to 50 mph. These winds are expected to weaken, and
conditions will improve tonight going into tomorrow and the low
continues to fill and move northeast.

&&

.EXTENDED FORECAST DAYS 4-7...Friday night through next Tuesday.
Ensembles have been persistent in showing a rather strong ridge
moving up from the Bering Sea into the Chukchi Sea, which is going
to allow for a more stable and much colder pattern beginning this
upcoming weekend and going into early next week. Chances of snow
will remain mostly confined over the Upper Tanana Valley, and
Yukon Flats along the Alcan Border, as well as portions of the
eastern Interior, otherwise, most of the region is expected to
remain mostly dry with colder temperatures setting in over the
Mainland under a very strong longwave ridge that will continue to
build in over the state going into the early part of next week.

Coastal Hazard Potential Days 3 and 4...None

&&

.AFG WATCHES/WARNINGS/ADVISORIES...
AK...Winter Weather Advisory for AKZ814>819-824>826.
Winter Storm Warning for AKZ820>823-827.
PK...Brisk Wind Advisory for PKZ801-855.
Brisk Wind Advisory for PKZ802.
Brisk Wind Advisory for PKZ803-804.
Small Craft Advisory for PKZ805.
Heavy Freezing Spray Warning for PKZ805.
Gale Warning for PKZ806-816-851.
Heavy Freezing Spray Warning for PKZ806-817-852-854.
Heavy Freezing Spray Warning for PKZ807.
Brisk Wind Advisory for PKZ808.
Brisk Wind Advisory for PKZ809.
Small Craft Advisory for PKZ810.
Heavy Freezing Spray Warning for PKZ810.
Brisk Wind Advisory for PKZ811.
Small Craft Advisory for PKZ812-850-857-858.
Heavy Freezing Spray Warning for PKZ812-856>858.
Heavy Freezing Spray Warning for PKZ816-851.
Gale Warning for PKZ817.
Gale Warning for PKZ852.
Small Craft Advisory for PKZ853.
Gale Warning for PKZ854.
Brisk Wind Advisory for PKZ859.

&&

$$

862
FXAK67 PAJK 190640
AFDAJK

Southeast Alaska Forecast Discussion
National Weather Service Juneau AK
940 PM AKST Tue Nov 18 2025

.UPDATE...Aviation & Winter storm update...

Pulled back slightly on snow ratios for this upcoming winter storm
for Haines Highway. Both temperatures aloft and magnitude of warm
air advection have been trending slightly warmer, due to a
slightly stronger jet aloft. While this may seem like a small
detail, small details matter a lot for this winter storm. As a
precipitation rate driven event reliant on snow melt cooling for
accumulating snow, increases in temperatures aloft could convert
precipitation over to mostly rain, or to a surface wetbulb not
supporting of much, if any, snow accumulation. Therefore, pulled
back snow ratios, as well as storm coverage to only be around the
Haines Customs area. Still expecting very dense, wet snow for this
event; however.

&&

.SHORT TERM...A strong system currently developing in the north
pacific will push northeast over the next 12 hours, driving high
wind and bringing heavy precipitation back to the region
Wednesday morning into Thursday. Touching on snow first, cool
northerly flow combined with heavy precipitation rates Wednesday
morning will help drive snowfall for the Chilkat Valley into the
border, with a forecasted 6 to 8 inches of wet dense snow by
Wednesday evening. Given the S-SW flow Klondike highway looks to
be sheltered from more intense snow impacts; an advisory is issued
for near 5 inches of wet and dense snow developing Wednesday into
Thursday morning. For sea level communities along the Icy Strait
corridor and south, all rain is forecasted through Thursday
morning, with 24 hour totals near 1 to 2 inches.

As this system moves into the southern gulf, winds will pick up
out of the southeast Wednesday morning with the highest winds
expected along the outer coast. A high wind warning has been
issued for Prince of Wales Island as well as Sitka for wind gusts
up to 60 mph, with the strongest winds expected later Wednesday
morning into the afternoon. Strong winds will continue to build
eastward into Clarence Strait with Ketchikan and Metlakatla seeing
wind gusts reaching up to 50 mph.

Elsewhere across the panhandle, gale force wind gusts will progress
northward along the inner channels before the surface front is
expected to stall around Icy Strait, with northerly winds
persisting along Lynn Canal through Wednesday night. This is due
to the orientation of the flow aloft as well as the location and
track of the parent low in the gulf. Overall this will turn out to
be a seasonable wet and windy middle of the week across southeast
Alaska. For what to expect towards the end of the week, see the
long term discussion.

.LONG TERM...A mixed bag of conditions is in store for the long
range forecast. On one hand, the active weather pattern continues
through the remainder of the week and the first half of the
weekend as a negatively tilted trough sets up over the Bering Sea.
On the other hand, the potential for a break is looming beginning
on Sunday as the previous steering flow breaks down and is
replaced by a rex-block over the Interior.

The long range forecast starts off with a degree of uncertainty, as
operational guidance is struggling to resolve the timing and
position of a low which will move into the panhandle on Thursday.
While confidence is high in the low`s associated front arriving
Wednesday (see the short term for further details), two separate
solutions have emerged for the parent low`s trajectory on Thursday.
Solution one - the GFS/Canadian solution, would have the low
decouple from its parent front and veer off into the SE Gulf
before weakening and steering back north, ultimately arriving in
the panhandle as an open trough. Should this solution verify,
cooler temperatures are possible along the Klondike highway and
winds generally across the inner channels would be weaker than
forecast as the S pressure gradient is weakened. The second
possible solution, favored by the NAM and Euro models, features
the low remaining in sync with its advancing front and moving up
into the NE Gulf Coast by Thursday morning. This solution would
result in stronger S winds and the potential for a warmer
Klondike Highway. For the time being, am leaning towards the
NAM/Euro solution. This not only poses a challenge for wind speed
forecasts in the inner channels - but it also poses a challenge
for snowfall totals on the Highways. Especially along the Klondike
Highway, the potential does exist for significant accumulating
snow on Thursday (6-12 inches). However, confidence is low, as
depending on the previously mentioned system track, temperatures
may be too warm to allow for significant accumulations after warm
air advection moves in Thursday morning. Stay tuned for further
updates.

Confidence is higher in another front moving in on Thursday proper
after the previous low pressure. Anticipate more rain (and
potentially snow for the Klondike Highway), followed by showers
through Friday and into Saturday. One final short wave will likely
move through on Friday, bringing another round of heavier and more
organized precipitation.

Showers diminish through the latter half of Saturday, and Sunday and
Monday will likely be mostly dry as a rex block sets up over the
Gulf and the Interior, setting the stage for weak Northerly outflow.

.AVIATION...Through Wednesday evening...
Generally MVFR flight conditions across the southern panhandle
tonight will expand north through the morning hours as strong
front pushes into the panhandle. Periods of IFR VIS and CIGs are
possible under steadier rainfall. Rain could mix with or change
over to snow for PAHN and PAGY.

Winds generally 10kts or less across the northern panhandle and
PAYA for the period. Winds will increase across the central and
southern panhandle to 15-25kts gusting 25-35kts by Wednesday
morning as the front approaches, continuing the through the day
and into the evening hours.

Main aviation concern will be the increasing SE-ly LLWS along the
central and southern panhandle TAF sites, from Icy Strait
corridor on south, as winds 2kft aloft increase to 35-50kts by
late Wednesday morning. Strongest LLWS expected along the coast
of Baranof and Prince of Wales Island and south of a line from
Sitka over to Petersburg through the rest of Wednesday afternoon.

.MARINE...
Outside (Gulf/Coastal waters): A weakening low moved
inland over Yakutat Bay Tuesday afternoon with weakening southerly
flow in the northern gulf. Another system will move in from the
south Wednesday morning, with southerly strong- gales likely for
much of the coast. Southeasterly seas will build to near 23 to 28
ft with the associated fetch duration and wind, with storm force
gusts along the outer coast. Winds and seas to gradually diminish
Wednesday night before another gale force front pushes through the
gulf from the west.

Inside (Inner Channels):
Winds will gradually diminish across the northern inner channels
through Tuesday night as a weak low pushes into inland over the
far northern panhandle. The strongest of these winds are over Lynn
Canal that is keeping areas of strong breezes, up to 25 kts, as of
Tuesday afternoon. The southern inner channels will not see much
of a break This storm force low moves into the gulf early
Wednesday bringing gale force wind gusts to much of the central
and southern inner channels. The strongest of these winds are
likely to occur Wednesday afternoon as the associated front pushes
across the panhandle, though are expected to stall around Icy
Strait. A healthy fetch of strong- gale force winds in Queen
Charlotte Sound/Hecate Strait will drive stout southeasterly seas
of 12 to perhaps 18 ft into southern Clarence.

&&

.AJK WATCHES/WARNINGS/ADVISORIES...
PUBLIC...Winter Weather Advisory from noon Wednesday to 6 AM AKST
Thursday for AKZ318.
Winter Storm Warning from 6 AM to 6 PM AKST Wednesday for AKZ319.
Strong Wind from 6 AM AKST Wednesday through Wednesday morning
for AKZ323-328.
Strong Wind Wednesday afternoon for AKZ323.
High Wind Warning from 9 AM to 3 PM AKST Wednesday for AKZ323.
Strong Wind from 6 AM AKST Wednesday through Wednesday afternoon
for AKZ327.
High Wind Warning from 9 AM to 6 PM AKST Wednesday for AKZ328.
Strong Wind from Wednesday morning through Wednesday afternoon
for AKZ330-332.
MARINE...Gale Warning for PKZ036-641>644-661>664-671-672.
Small Craft Advisory for PKZ022-033-035-053-651-652.

&&

$$

UPDATE...NC
SHORT TERM...AP/STJ
LONG TERM...GFS
AVIATION...DS
MARINE...STJ

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