Graphical Hydro Meteorological Discussion

935
FXAK68 PAFC 191220
AFDAFC

Southcentral and Southwest Alaska Forecast Discussion
National Weather Service Anchorage AK
420 AM AKDT Sat Sep 19 2026

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

A deep, upper-level trough is digging south from the western coast
of Alaska to the North Pacific. A potent upper-level low and
978mb storm-force low sit at the base of this trough, its front
beginning to occlude and push into the southwest Gulf of Alaska
south of Kodiak Island. Downstream, a rapidly weakening upper-
level shortwave and surface low have moved inland over the Copper
River Basin this morning, with rain over parts of the Basin and
lingering showers from Middleton Island into Prince William Sound
(PWS). A surface trough to the west of the these features is
draped over the Anchorage Bowl, with a few scattered, slow moving,
and locally heavy rain showers across East Anchorage north and
east to the Matanuska Valley. These showers are expected to taper
off by mid morning.

The front associated with the North Pacific low will continue to
lift north over the western Gulf today and over the northern Gulf
by late tonight. The upper-level and surface lows will trail the
front as its occludes, pushing into the southern Gulf by Saturday
night. By Sunday morning, the upstream trough is reinforced by an
arctic shortwave digging south over the eastern Bering and AKPen,
resulting in further amplification of the long wave pattern. This
amplification will allow the occluded front to stall along the
immediate Southcentral coast and Kodiak Island while the parent
low lifts north toward Middleton Island, eventually making
landfall around the Copper River Delta Sunday afternoon. There is
plenty of moisture along and out ahead of the front, allowing for
persistent rain along the coast (1 to 3" around PWS) and periods
of rain showers father islands through the weekend.

Models also continue to suggest that the atmosphere looks
conducive for marine lightning (70-80% chance) during this low`s
journey across the Gulf (Saturday afternoon through Sunday
afternoon), mainly due to the upper low component of the surface
low steepening lapse rates, and that the Gulf will be under the
influence of being below the left exit region of a 300 mb jet
streak, which will further enhance instability. Aside from that,
widespread westerly to southwesterly small crafts and gales are
also to be expected in the wake of this system across the Gulf as
the cold air advection associated with the arctic trough spills
southward starting Sunday afternoon.


-TM/AM

&&


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

Key Messages:
- Strong northerly to northwesterly winds develop across the
eastern Aleutians and AKPEN Saturday afternoon and evening, with
the strongest winds through favored gaps, including Cold Bay,
King Cove, False Pass and Sand Point.

- Colder air continues to spread south across Southwest Alaska and
the Bering through the weekend, with falling snow levels and
snow possible across higher elevations.

- Winds gradually diminish Sunday into Monday as high pressure
builds across the Bering, though cool and showery conditions
persist.

- A colder and increasingly windy pattern remains on track across
Southwest Alaska, the Bering and Aleutians this weekend. On
saturday, a strengthening low moves southeast of the Alaska
Peninsula and into the Gulf while high pressure builds across
the western and central Bering. The tightening pressure gradient
between these features will strengthen northerly to
northwesterly flow across much of the Bering, eastern Aleutians
and AKPEN. The latest guidance remains in good agreement with
the overall evolution of this system, though some differences
remain with the exact strength and position of the low.

The strongest winds Saturday afternoon into Saturday evening will
focus across the eastern Aleutians and AKPEN where terrain
enhancement will result in locally stronger winds through favored
gaps. Cold Bay, King Cove, False Pass and Sand Point will be among
the locations most susceptible to stronger gusts. Meanwhile,
colder air moving south across the Bering will maintain scattered
showers across the Aleutians and portions of Southwest Alaska.
There are gale-force winds developing along portions of the AKPEN
Saturday night as the pressure gradient tightens.

By Sunday, the low continues eastward into the Gulf while high
pressure remains over the Bering. Persistent northwesterly flow
will continue across the eastern Bering, eastern Aleutians and
AKPEN, though winds will gradually diminish through the day as the
pressure gradient relaxes. Cold air advection will keep
temperatures below recent values, with snow levels falling to
around 2000 ft or lower. This may allow showers to fall as snow
across higher elevations of Southwest Alaska and the AKPEN, with a
rain/snow mix still possible at times near portions of the
Kuskokwim Delta coast.

Heading into Monday, the initial low continues to pull farther
away while broad upper-level troughing remains across southern
Alaska. Winds continue to weaken across the eastern Bering and
AKPEN, with gradually quieter conditions compared with this
weekend. However, the lingering cold air mass and cyclonic flow
will maintain scattered showers across portions of SOuthwest
Alaska and the Aleutians through Monday evening. Attention then
turns farther west as the next disturbance begins approaching the
wester Bering/ Aleutians beyond the short-term period.

LM

&&


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

The longterm period beginning Tuesday morning will start out with
a longwave trough extending across much of Mainland Alaska down
into the Alaska Gulf. A Gale Force low will likely be maturing and
reaching maximum intensity somewhere over the central to eastern
Gulf. Current model consensus suggests this system will stall out
over open waters as it slowly weakens through the middle of next
week, resulting in limited impacts to Southcentral. Out to the
west, a longwave ridge is anticipated to be moving across much of
the Bering Sea in between the Gulf low and a shortwave trough and
attendant low evolving near the Kamchatka Peninsula on Tuesday.

Much of the remainder of the long term beyond Tuesday will hinge
heavily on the degree of interaction between the trough/low
moving off of Kamchatka into the western Bering and the remnants
of what is currently Typhoon Dujuan out in the West Pacific.
Dujuan will recurve north and east after making a close pass with
Japan this weekend, eventually approaching the western parts of
the Aleutian Chain after transitioning to an extratropical low
around Tuesday to Wednesday next week. Models are still struggling
quite a bit to determine how the remnants of Dujuan will behave
as the center gets closer to the separate low pressure system
progressing across the Bering. Some earlier deterministic
solutions and current EPS/GEFS ensemble members suggest that a
strong phasing interaction could occur between the two lows,
perhaps resulting in a much stronger low that deepens rapidly
somewhere across the southern Bering Sea and Aleutians/AKPen as
the two systems essentially merge. If this comes to fruition
(about a 20-30% chance), high winds and waves could become a
substantial hazard across a large portion of the Bering Sea,
Aleutians and possibly Southwest towards the middle to latter part
of next week.

In contrast to the scenario above, much of the 12z deterministic
guidance coming in today is depicting Dujuan`s remnants taking a
little more time to move northeast across the North Pacific,
effectively causing it to miss the stronger interaction with the
other low progressing across the Bering Sea. This version of
events (more likely scenario, around 70% chance) would keep
Dujuan tracking off to the south of the entire Aleutian Chain,
with an overall lower threat for strong winds and large waves
across the Bering Sea near the secondary low to the north. Even
so, the low moving off of Kamchatka could still pull a significant
amount of moisture north from Dujuan`s remnants as they pass to
the south, enough to support a heavy rain threat across parts of
the Pribilofs, Aleutians and Southwest sometime between Wednesday
and Friday as the system tracks northeast towards the western
coastline. The influx of warm, moist air could also help deepen
the Kamchatka system to a Gale Force low as it tracks across the
Bering, so the wind and wave potential across the Aleutians and
Southwest would certainly not be zero in this case. Bottom line,
anticipate a strong low to affect parts of the Aleutians, Bering
and Southwest next week, regardless of exactly how the remnants of
Dujuan play a role.

Meanwhile, much quieter conditions are expected for the most part
across Southcentral by the middle of next week. A seasonably cool
air mass will be in place across the region initially, but some
warming is likely towards Wednesday and Thursday as the Bering
ridge moves overhead. There could be a threat for strong southerly
gap winds to develop late in the week along with increasing rain
chances, but this will be highly dependent on the complex and
uncertain interaction between multiple systems out west as
described above.

-AS

&&


.AVIATION...

PANC...Light and variable winds combined with lingering low-level
moisture could result in patchy fog near or over the terminal
Saturday morning, otherwise mainly MVFR to low VFR ceilings are
expected through the morning hours. VFR Ceilings are likely to
prevail by this afternoon, although periods of MVFR ceilings
remain possible with any shower activity that is able to develop
this afternoon through this evening.

&&


$$

734
FXAK69 PAFG 191153
AFDAFG

Northern Alaska Forecast Discussion
National Weather Service Fairbanks AK
353 AM AKDT Sat Sep 19 2026

.KEY MESSAGES...
Central and Eastern Interior...
- Showers this morning will move towards the Koyukuk Valley
around midday with light snow and rain chances in Wiseman this
afternoon, dissipating overnight.

- Isolated showers remain over the Interior tomorrow with an
area of light rain in the Fortymile and around Eagle Sunday
morning. 0.10" to 0.25" of rain expected in Eagle.

- Showers continue on Monday, especially east of Fairbanks.

- Temperatures will be near average through Sunday with a drop
early next week. Most spots struggle to exceed the low 40s.

West Coast and Western Interior...
- Rain showers from Eastern Norton Sound north/east. Snow
showers in the Bering Strait today, transitioning to rain
showers tomorrow. The Interior is dry from Sunday onwards.

- Showers continue on Monday, mainly along the coast with most
of the area dry on Tuesday.

- Today is warmest in the Interior with highs in the upper
40s/low 50s. Temps along the coast will be chilly, in the
upper 30s to low 40s. 40 to 45 degrees everywhere from Sunday
through early next week.

- A potentially strong Bering Sea Low arrives Thursday with
potential impacts being moderate to heavy rain, strong wind
and coastal impacts which are dependent on the track.

North Slope and Brooks Range...
- Snow showers along the Chukchi Sea Coast today and tomorrow
with accumulations around 1 inch or less.

- Light snow for the Brooks Range and Eastern Arctic Coast
Saturday evening through Sunday. Snowfall totals remain light
around 1 to 3 inches. Highest in the Brooks Range.

- A mix of rain and snow showers continues into early next week
with temperatures hovering near or slightly above freezing.

&&

.SYNOPSIS...
While the weather is relatively unimpactful, it is still active
with showers remaining over the Interior, snow showers over the
Chukchi Sea and Bering Strait and light snow in the Brooks
Range/Eastern Arctic Coast. The trend early next week is drier
overall, but we will continue to have isolated rain and snow
showers, especially on the North Slope and in the Eastern
Interior. It will be trending cooler, especially in the Interior
early next week with most spots outside of the Upper Tanana
Valley struggling to get out of the 40s. The temperatures across
the remainder of Northern Alaska will stay mainly stagnant.

&&

.SHORT TERM /THROUGH TUESDAY NIGHT/...
Why is the weather so active might you ask? Well, it is all
thanks to a broad, longwave trough which is stationed from the
North Pole to the Northern Pacific. Within this trough is an
Arctic front in the Chukchi Sea, a weak, open shortwave trough
in Western Alaska and a dousing of shortwave energy moving over
the Alaska Range. On top of this, there is a strengthening low
moving into the Gulf. All of the showery activity in the
Interior is being driven by the 500mb vorticity which is being
advected north and east as it get squeezed by the Arctic front
moving southeast and the Gulf low moving northeast. As the
Arctic front continues to trek southeast, we weaken a pressure
gradient this weekend which has been bringing a consistent
breeze from the Bering Strait Region northward. All of the
energy over the Interior will gradually shift north and east,
which will keep shower chances persistent but shift them towards
the Brooks Range and Eastern Arctic Coast today and tomorrow. As
the showers run into colder air up north, they will transition
to snow, even in Wiseman, but expect mainly light
accumulations around 1 to 3 inches north of Wiseman and maybe a
slushy coating to 0.5" in Wiseman. While this may sound like the
front is clearing the Interior making Sunday dry, we will
continue to see areas of showers due to the intrusion of a front
from the northerly moving Gulf low. Not to worry though, any
rain accumulations should be measured in the hundredths of
inches, with the exception of Eagle which may be upwards of
0.25". Regardless, most of the Interior should have some dry
time and it doesn`t appear to be a washout by any means. Heading
into Monday, temperatures for most of the Interior will be
dropping as the southeasterly moving Arctic front provides cold
air advection to the region. We`ll notice 850mb temperatures
dropping from about 0C to 5C this weekend, to 0C to -7C by
Tuesday night with a warming gradient from west to east. While
this may sound intimidating, we are only expecting sub-freezing
temperatures in the Interior overnight, especially Tuesday
night. Elsehwere across Northern Alaska, the Arctic Front is
already providing relatively cool weather, so there won`t be too
much change in temperatures this weekend into next week.

&&

.LONG TERM /WEDNESDAY THROUGH FRIDAY/...
The extended is a bit of a wild card. One thing we know for
certain is, there will be a low in the Bering Sea by the middle
and end of next week. There are signs that it can be moderately
strong, around 960mb and move east towards Western Alaska. But,
after those details it becomes fuzzy. Three factors that may
inhibit significant impacts from Hooper Bay northward are a
trough in the Arctic and a ridge moving into the Gulf and a
Pacific ridge. This Arctic trough will play its role as the
piece that tries to push the storm south towards the Aleutians,
while the ridge in the Gulf will try to limit quick eastern
motion and the Pacific ridge can also push a storm north or
south. From yesterday to today, guidance has had shown the
Pacific ridge weakening and the Arctic trough strengthening,
which would lead to a farther south storm. The ridge moving into
the Gulf may be strong enough to halt eastward progression, but
that could mean prolonged impacts from wind and rain. The ridge
will be pushing east gradually late next week, and opens the
door for the low to move into the Gulf. All of this to say,
there will be a strong storm in the Bering late next week, the
devil is in the details, but we are leaning towards a farther
south track, north of the aleutians but south of St. Lawrence
Island which can result in heavy rain and very strong winds
being the main concern. There is a potential for some coastal
impacts from Hooper Bay northward but that doesn`t appear to be
the main concern for most spots outside of the Yukon Delta
right now.

Otherwise, the remainder of Northern Alaska looks like there
will be a clearing trend with mixed clouds and sun. There may be
some snow showers for the North Slope, but it does not look like
much. Again, this is subject to change, especially if the Bering
Sea low pivots a bit farther north which would bring more
clouds and chances for precipitation. So, stay tuned to the
forecast. We will continue to monitor the progression of the
pattern very closely.

Coastal Hazard Potential...
As mentioned in the long term discussion, the strong low in the
Bering is trending south which would lead to a lesser extent of
coastal impacts. Currently, the favored wind direction is
south/southeast which for most areas, would lean towards some
higher water than normal, but nothing too concerning. The Yukon
Delta is the exception where water levels may be a bit higher in
this scenario. As far as exact impacts, once we have a better
grasp on the track and position of the low, there will be more
details. We will continue to monitor this as it evolves.

&&

.FIRE WEATHER...
Not much concern for fire weather as showers persist in the
Fortymile Country this weekend and into early next week. The
Upper Tanana will remain mostly dry. Temperatures are expected
to be in the low 50s in the Upper Tanana through Monday with
upper 40s to low 50s in Fortymile Country. Min RHs will bottom
out around 40% to 45% today then increase Sunday and Monday into
the 55% to 65% range. Winds get a little breezy in Fortymile
Country, around 10 to 15 mph with gusts to 25 mph today, then
weaken while the Upper Tanana will be light.

&&

.HYDROLOGY...
A Flood Advisory remains in effect for the Chena River upstream
of Moose Creek Dam. While we aren`t expecting widespread
flooding, minor pooling and ponding of water is expected in
low-lying, flood prone areas this weekend. Water levels will
crest in Fairbanks this afternoon then gradually drop
thereafter.

&&

.AFG WATCHES/WARNINGS/ADVISORIES...
AK...None.
MARINE...Small Craft Advisory until 6 AM AKDT Sunday for PKZ801-802-806-
850-854.
Small Craft Advisory until 7 AM AKDT this morning for PKZ803-
805-851-852.
Small Craft Advisory until 4 AM AKDT Sunday for PKZ804-853.
Small Craft Advisory from 1 PM to 4 PM AKDT this afternoon for
PKZ805.
Small Craft Advisory until 10 PM AKDT this evening for PKZ807-
808-817.
Small Craft Advisory from 1 AM to 6 AM AKDT Sunday for PKZ807.
Small Craft Advisory from 7 AM this morning to 10 PM AKDT this
evening for PKZ809.
Small Craft Advisory until 4 PM AKDT this afternoon for PKZ810.
Small Craft Advisory until 4 AM AKDT early this morning for
PKZ811.
Small Craft Advisory until 7 PM AKDT this evening for PKZ816.
Small Craft Advisory until 10 PM AKDT this evening for PKZ855.
Small Craft Advisory until 1 AM AKDT Sunday for PKZ856.
&&

$$

KEY MESSAGES...Bianco
SYNOPSIS.......Bianco
SHORT TERM.....Bianco
LONG TERM......Bianco
COASTAL........Bianco
FIRE WEATHER...Bianco
HYDROLOGY......Bianco

271
FXAK67 PAJK 191545 AAA
AFDAJK

Southeast Alaska Forecast Discussion
National Weather Service Juneau AK
745 AM AKDT Sat Sep 19 2026

.SYNOPSIS...

Key Messages:

- Multiple systems to impact the region through the weekend, with heavy
rain, gusty winds and increasing seas.

- A Flood Watch was issued for the northern panhandle due to heavy
rain and ice melt occurring through the weekend.

- A High Wind Watch was issued for the Skagway, and Haines areas
for wind gusts up to around 60 mph Sunday. Yakutat has a Wind
Advisory with gusts to 50 mph Sunday.

- Cooler but seasonable temperatures for the period, with daytime
highs generally in the 50s.

&&

.SHORT TERM.../ through Monday night / The remains of last
night`s front with waves on it, is finishing moving through the
panhandle this morning. Expect a brief break from winds and heavier
rain today. The next frontal band is wrapping up nicely about the
central low that is about about 200 NM south of Kodiak Island. That
system is tracking into the central gulf and should be rolling into
the Northeast Gulf Coast tonight. The main weather front will be
leading the way with strong winds to the coastal areas, expecting
gusts to 50 mph or so around Yakutat. The front will sweep into the
panhandle and this will push the wind speeds up through the inner
channels. Northern Lynn Canal may be pushing to gusts of 60 mph
tomorrow afternoon so a High Wind Watch remains in effect.

High levels of expected ARIs from the guidance for the northern
panhandle with moderate to heavy rainfall. A flood watch is out
for the rivers and streams over the Northern panhandle area.


.LONG TERM.../Monday through Thursday/...A more active pattern
continues into next week as a low redevelops in the Gulf Monday
into Tuesday, with continued onshore flow between waves of
precipitation through early to midweek. Once the low redevelops,
it will bring another more organized band of precipitation
through Tuesday followed by a few less organized waves Wednesday
into Thursday. The confidence on this midweek low looks to be a
bit more aligned today between models, with the more organized low
center location and main precipitation band moving through
Tuesday. Some uncertainty still remains on timing and rainfall
amounts, especially due to the more showery regime expected
midweek and spread on the low`s track. The low also becomes more
poorly formed and uncertain Wednesday onwards, as some solutions
keep it stronger for longer and moving towards the panhandle while
others have it falling apart further offshore or just south of the
panhandle. Generally though, rainy conditions and elevated winds
are expected to continue through midweek, only beginning to
diminish by late week as this low begins to fall apart.

The convective potential remains for Monday along the coast,
keeping the chance for thunderstorms developing over the waters
and pushing into the outer coastline through the day, gradually
shifting southward as the day goes on before diminishing into the
night.


&&

.AVIATION.../Through 12z Sunday/...Lowered conditions persist this
morning as a front continues to move northward through the
panhandle and another, stronger front moves in Sunday night. Most
sites are currently seeing MVFR to IFR conditions, which are
generally expected to stay lowered as rain continues and winds
increase through the day. There may be a very short break behind
the current front and before the next front, but this may not even
improve conditions above MVFR. Through this evening, the next
front is expected to bring lowered CIGs of 1500 to 2500 ft and
restricted VIS with periods of heavy rain and strong southeasterly
gusts of 20 to 30 kts to much of the panhandle. 45 to 50 kt
southeasterly winds aloft prompted the addition of LLWS for many
locations Sunday night as the front moves through. Lowered
conditions will continue into Monday.

&&

.MARINE...
Inside (Inner Channels): There will be short lull in the marine
winds, still remaining around 10 to 15 kts, until the
next/stronger low pressure system moves through the gulf. Overall
winds will once again increase Saturday afternoon into Sunday as a
low around 980 mb pushes into the northern gulf. Southernly and
easterly winds across the channels will be around 20 to 30 kts
with the strongest winds over Lynn Canal and Clarence strait up to
35 kts. For Clarence Strait, the strongest winds are anticipated
for Saturday night. Then Lynn canal will start to see winds
continue to increase Sunday morning with strongest winds most
likely Sunday afternoon. Winds then diminish late Sunday into
Monday with a short break over the panhandle. Active weather is
expected again to continue for next week.

Outside (Gulf and Coastal Waters): Waves and winds have already
subsided and diminish and will continue Sat morning to 4 to 6 ft.
The next strong low pressure system is not far behind as winds and
waves once again increase and build late Saturday morning and
Saturday afternoon. This low will bring wide spread gale force winds
of 35 to 40 kts, with gusts up to 55 kts, and wave heights of 15 to
20 ft. Strongest winds and highest seas are most likely to occur
Sunday morning before diminishing Sunday afternoon into Sunday
evening. The gulf will then get a brief break from strong winds late
Sunday into Monday. Active weather is still in store for next week
as winds once again increase across the gulf into Tuesday.

&&

.AJK WATCHES/WARNINGS/ADVISORIES...
PUBLIC...Wind Advisory from 4 AM to 4 PM AKDT Sunday for AKZ317.
Flood Watch from late tonight through late Sunday night for
AKZ318-319.
High Wind Watch from late tonight through Monday morning for
AKZ318-319.
MARINE...Gale Warning for PKZ012-036-644-651-652-663-664-671.
Small Craft Advisory for PKZ011-013-021-022-031>035-053-641>643-
661-662-672.

&&

$$

SHORT TERM...Bezenek
LONG TERM...Contino
AVIATION...ZTK
MARINE...Bezenek

Visit us at http://www.weather.gov/Juneau