Graphical Hydro Meteorological Discussion

903
FXAK68 PAFC 060046
AFDAFC

Southcentral and Southwest Alaska Forecast Discussion
National Weather Service Anchorage AK
446 PM AKDT Sun Oct 5 2025

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

An unsettled pattern continues to take shape across much of the
forecast area this afternoon. The upper level pattern is
continuing amplify compared to yesterday as a deep, negatively-
tilted trough begins to enter the western Gulf as it runs up
against a stout longwave ridge centered over Northwest Canada. An
intense shortwave rounding the base of the trough has helped spin
up a gale force low near the Alaska Peninsula. An occluding front
extending from the low is already making rapid headway northeast,
currently sending a band of heavy rain showers across Kodiak
Island that is progressing quickly north towards the Cook Inlet
and Kenai Peninsula. Across the rest of Southcentral, bands of
rain showers are moving north within a belt of strong south to
southeast flow in between the approaching trough and upstream
ridge.

From tonight into Monday, the shortwave trough now approaching
Kodiak Island will lift rapidly northeast and become a closed off
upper level low as it heads into Southcentral. Before the low
arrives, a quick shot of locally heavy rain will move north along
the low`s front, speeding past the Kenai Peninsula, Prince
William Sound and Mat-Su Valleys from this evening into early
Monday morning. Farther south, a new low will spin up somewhere
just to the south of the Kenai Peninsula on Monday morning, then
drift towards Middleton Island by Monday evening. A combination of
rapid pressure rises and cold air advection behind the
front/trough passage will also support rather strong and gusty
westerly winds developing tonight and persisting into Monday
across Kodiak Island, Shelikof Strait and near the Barren Islands.
Winds blowing through the Kamishak Gap could also briefly extend
into Kachemak Bay, most likely during the afternoon and evening
hours on Monday. Otherwise, periods of steady rain will give way
to widespread showers behind the front as the complex upper low
moves overhead through Monday evening.

For Tuesday, conditions will quiet back down and begin to dry out
temporarily as a strong North Pacific ridge builds quickly back
into the southern Mainland and as the upper low exits to the east.
A powerful Bering low and trailing frontal system out west will
begin to flatten out the ridge by Wednesday morning as moisture
associated with an atmospheric river following ahead of the front
begins to spill across the Alaska Range into northern parts of
Southcentral. The low heading up towards the North Slope
contrasting with the strong high extending over the Gulf will
induce a strong south-north pressure gradient across the outlook
area as well, resulting in strong and gusty gap winds blowing into
Anchorage, the Mat Valley and Copper River Basin for most of the
day on Wednesday. The increasing moisture coupled with strong
southwest flow aloft will help rain redevelop through Wednesday
evening, primarily over parts of the Chugach and Talkeetna
Mountains where terrain provides forced lift.

-AS

&&


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


*** Coastal Flood Watch for the Kuskokwim Delta Coast and Nunivak
Island from Tuesday morning through Wednesday morning.


Rain showers persist into the overnight hours for the region as
multiple shortwaves progress eastward. Strong southwest wind flow
into the Upper Kuskokwim Delta early this week will result in
widespread coastal impacts through Wednesday.

Today`s Bering Sea low that brought rain and strong winds from
the Eastern Aleutians to the Bristol Bay coastline continues
to move through the lower Kuskokwim Delta. Widespread northwest
wind gusts to 55 mph were recorded in the portions of the Eastern
Aleutians and the Alaska Peninsula today. Rain showers and strong
winds will dissipate through the overnight hours as weak ridging
moves overhead. This ridging is replaced by zonal flow tomorrow
afternoon and back to a more southwest flow overnight into
Tuesday.

Monday evening through Wednesday: A 978 mb Kamchatka low just
north of Shemya tomorrow afternoon moves northwest of St. Matthew
Island and deepens to 962 mb by Wednesday evening. Simultaneously,
a North Pacific 1038 mb high intensifies to 1040 mb as it slowly
moves eastward Wednesday evening. These two systems will cause
persistent southwest flow from Adak to Unalaska northeastward to
the Pribilof Islands and Nunivak island Monday evening through
Tuesday morning. Heavy rainfall and strong winds are expected
during this time for these area. Gale to storm force winds are
expected from west of Unalaska to the Pribilof Islands. Tuesday
afternoon into Wednesday morning, this area of strong southwest
winds shift to area between Toksook Bay and Quinhagak. Onshore
flow during this time will result in coastal impacts. Wind gusts
reaching 50 knots, wave heights from 8 to 12 feet are expected
during this time period. A wave of moisture from this southwest
atmospheric river wind flow brings a period of heavy rain to the
region Tuesday night into Wednesday morning. Gale to storm force
winds in the Bering Sea and Aleutians gaps and passes remain
likely overnight into Wednesday, too.

&&

.LONG TERM FORECAST (Days 4 through 7: Thursday through
Sunday)...

High pressure ridging will push into Southcentral Alaska by mid-
week, bringing drier conditions for low elevation areas with
chances for light precipitation along the mountain tops through
the end of the week. A weakening front stretching across the
western half of the state, will help develop low pressure that
will bring rains back into the region this weekend.

Multiple fronts are expected to move across the Bering Sea into
Southwest Alaska through the end of the week and into this
weekend pulling abundant amounts of moisture from the North
Pacific. Moderate-to-heavy precipitation and gusty winds are
expected across the Aleutian Islands and coastal Southwest Alaska.
Precipitation is expected to spill further inland across Southwest
as the front(s) move onshore. Continued unseasonably warm and wet
weather will continue through the extended forecast.

&&

.AVIATION...

PANC...Light north to northwesterly winds will persist through
about 06-08Z as the Turnagain Arm winds bend down Cook Inlet. A
low lifting over the area overnight will then allow for winds
bending into the terminal at times with gusts of 20 to 25 kts
through 18Z Mon before weakening. Ceilings and visibility will
remain mostly VFR but periods of MVFR may mix in as the low moves
through. The terminal may see a brief break in rain showers before
the next round moves in later tonight with occasional light
showers lingering through Tues afternoon/evening.


&&


$$

474
FXAK69 PAFG 052332
AFDAFG

Northern Alaska Forecast Discussion
National Weather Service Fairbanks AK
332 PM AKDT Sun Oct 5 2025

.SYNOPSIS...
Not a whole lot of change to the forecast, mostly increasing
confidence for the track and strength of the coastal storm as well
as impacts for the entire state. Along the West Coast, this storm
will impact every community bringing significant flooding and/or
erosion as well as strong winds and heavy rain. On the Western
North Slope and north of the Seward Peninsula, the chance for
significant coastal flooding and/or erosion is increasing as well,
especially as the winds turn northwest Wednesday into Thursday. In
the Interior, there will be an abundance of rain and wind midweek
with the strongest being in the AK Range Passes. Light to moderate
snow is expected in the Central/Eastern Brooks Range with heavy
snow in the Western Brooks Range.

&&

.KEY WEATHER MESSAGES...
Central and Eastern Interior...
- A quiet day with only isolated to scattered rain showers and AK
Range winds gradually diminishing.

- Similar story tomorrow with a weak front bringing chances for
rain showers, mostly north of Fairbanks.

- Moderate to heavy rain in the Interior Tuesday night through
Thursday with upwards of 1-2 inches of rain possible.

- Strong winds across the Interior Tuesday afternoon through
Wednesday, gusts as high as 35 possible in the valleys
(including Fairbanks), up to 50 mph in the White Mountains and
Dalton Highway Summits, up to 70 mph in the AK Range Passes.

West Coast and Western Interior...
- Improving conditions today and tomorrow along the coast, another
round of rain in the Interior tomorrow, mostly east of the
Nulato Hills.

- Bering Sea low moves northeast tomorrow afternoon, rain and
mostly weak wind moves into St. Lawrence Island during the
afternoon.
- The low rapidly strengthens tomorrow night, periods of heavy
rain and wind gusts to 60 mph move into the Yukon Delta, St.
Lawrence Island and Norton Sound as early as Tuesday morning.
- Rain and wind gets to Kotzebue as early as 12PM on Tuesday.
- There will be a prolonged period of wind gusts of 40 to 60+ mph
from the south/southwest from the Yukon Delta northward from
Tuesday afternoon through late Wednesday night. Strongest winds
will be in the Yukon Delta, St. Lawrence Island and through the
Bering Strait.
- Though most gusts will be capped around 60-65 mph, some gusts
may be as high as 75 mph, especially in typical windy
spots/higher terrain in the Bering Strait Region, and Yukon
Delta.
- Rainfall totals through Wednesday afternoon will be around
0.50 to 1 inch in St. Lawrence Island, Bering Strait and
northern Seward Peninsula, up to 1.50 inches everywhere else.

- Coastal impacts will be discussed in the "coastal hazard
potential" section.

North Slope and Brooks Range..
- Mostly quiet weather today, but gusty east/northeast winds
continue through the afternoon along the coast then diminish
tonight. Light rain and snow diminishing in coverage as well.
South winds ramp up Tuesday PM and continue through at least
Wednesday night. Gusts upwards of 45 mph in Atigun Pass and 55
mph along the Chukchi Sea/Western Arctic Coast.

- Widespread rain for the North Slope and snow in the Brooks Range
develops Tuesday afternoon and progresses northeast through the
night. Snow will be heavy at times north/east of Shungnak with
light to moderate snow north of Coldfoot (Atigun Pass). Snow and
rain will continue through Wednesday, then turn more showery
heading into Thursday.
- Storm total snow accumulations still seem to be 1 to 3 inches
in Anaktuvuk Pass and the North Slope, 4 to 9 inches in Atigun
Pass and potentially upwards of 18 to 24 inches in the Western
Brooks Range north/east of Shungnak.

- Coastal impacts for the big storm Wednesday/Thursday will be in
"coastal hazard potential" section.

&&

.FORECAST ANALYSIS AND DISCUSSION...
A rapidly weakening low in the Bering is moving out of the area to
the north. A 993 mb low in the Aleutians is moving into South-
Central tonight. This low will provide our support for isolated
to scattered showers later today and through Tuesday morning in
the Central and Eastern Interior. With the ridge moving off to
the east, our pressure gradient across the Alaska Range will
slack, and our current threat of gap winds will subside gradually
this afternoon and tonight.

Looking towards Monday, a 980 mb low will move over Shemya on the
Aleutian Islands. This low will move into the Central Bering
overnight Monday. During this time the low will begin to rapidly
intensify. The 12/18z Deterministic suite of models all strengthen
the low to 959 to 964 mb in the center of the Gulf of Anadyr. The
ECMWF Deterministic is the strongest at 959 mb while the CMC is
the "weakest" at 964 mb, but the strength isn`t the concern with
this storm, it`s the track. While the models have come together
well with the strength, which will be around 960 mb, they have
also come together on the track. Just as we thought the last few
days, the models caught up and the low will track into the Gulf of
Anadyr by Tuesday afternoon. Given the consistency in the models,
our confidence has dramatically increased for a strong, impactful
storm for most of the coast. Past Tuesday, the ensembles and
deterministic models are in generally good agreement that the low
will move west of St. Lawrence Island then just north of the
Bering Strait. With this track there will be a large fetch of
strong southwesterly winds into the West Coast. The warm front
that is connected to this low is accompanied with a very potent
850 mb jet. This jet is 60 to 75 knots that will stretch from the
Bering Sea to the Kuskokwim Valley and then the Tanana Valley.
With heavy rainfall expected to accompany this front, we are
expecting winds to be able to freely mix down. There will be an
atmospheric river that is feeding moisture into Mainland Alaska.
This atmospheric river is producing precipitable water anomalies
of 3 to 5 sigma across the Interior. Widespread 1 to 1.5 inches of
rain is likely with some areas receiving up to 2 inches of rain,
especially in any terrain above 1000 feet. The impacts from this
system will be a multi-day event stretching from Monday night to
Thursday morning.

&&

.EXTENDED FORECAST DAYS 4-7...
The Bering Sea low will continue to move northward and bring strong
west/northwest winds up to around 35 mph sustained and 50 mph gusts
to much of the Arctic Coast through the weekend. With the amount
of moisture that this coastal storm will be bringing in, rain
showers, or even snow showers at high elevations, are likely for
the majority of the state. By Thursday afternoon, around 2 inches
of total rainfall are expected for most of the Interior. Southerly
gap winds in the Alaska Range passes are likely to gust up to 70
mph from Tuesday through Thursday morning with strong south winds
likely to reach Ft. Greely as well.

Looking even further into the extended, the next Bering Sea system
will arrive late Friday and primarily impact the West Coast. This
system will likely bring additional rain and strong winds.

&&

Coastal Hazard Potential Days 3 through 5...
Coastal Flood Watches will remain in place today and will be
upgraded to warnings or advisories tomorrow. There is still quite
a bit of spread for how high the water levels will get at each
community. And the difference between warning/advisory doesn`t
mean "impactful/non-impactful". This WILL impact every community
in different ways, including significant flooding and/or
significant erosion. While some places won`t see "warning level
flooding" there will be significant impacts to beaches, air
strips, dumps, and more. Details below.

We are anticipating 2 to 3 high tides that will see higher waters.
For communities that are south of the Bering Strait, these high
tides will be Tuesday afternoon, Wednesday morning, and Wednesday
afternoon. North of the Bering Strait it will be the two Wednesday
high tides. There will still be concerns Thursday morning
particularly when the winds turn northwesterly from the Northern
Seward Peninsula to the Western Arctic Coast. Hooper Bay to Nunam
Iqua is expected to see 4 to 7 feet above mean high water (MHHW).
Stebbins to Shaktoolik will be 4 to 9 feet above MHHW. Koyuk will
have the highest water of 5 to 10 feet above MHHW. Elim to Wales
will see 4 to 8 feet above MHHW. Gambell and Savoonga will have 2
to 5 feet above MHHW, highest in Gambell on the west side.
Shishmaref to Kotzebue is expecting 3 to 8 feet above MHHW. Kotzebue
specifically should be prepared for flooding rivaling the
flooding event of 2024 as water levels may approach or exceed that
level (which was 6.5 feet). Red Dog to Point Lay is expecting 4
to 8 feet above MHHW. Wainwright to Utqiagvik is expecting 2 to 5
feet above MHHW.

We are expecting significant erosion for many along the coast
with coastal flooding likely, especially in more vulnerable
locations. Preparations should be made NOW for a strong coastal
storm everywhere along the coast as most, if not all communities
will see some sort of impact.

.AFG WATCHES/WARNINGS/ADVISORIES...
AK...Coastal Flood Watch for AKZ801>803-815>818.
Wind Advisory for AKZ849.
Coastal Flood Watch for AKZ820>822-824-825-827.
PK...Small Craft Advisory for PKZ802-850-851.
Small Craft Advisory for PKZ812-814.
Small Craft Advisory for PKZ813-815-858.
Small Craft Advisory for PKZ859-860.
Gale Warning for PKZ861.
&&

$$

Bianco
Srinivasan - Extended

260
FXAK67 PAJK 060024
AFDAJK

Southeast Alaska Forecast Discussion
National Weather Service Juneau AK
322 PM AKDT Sun Oct 5 2025

.SHORT TERM...
Key Points:
- A front continues to push into the panhandle bringing moderate
to heavy rain and increased winds.
- A low pushes into the panhandle behind the front keeping winds
elevated into Tuesday.

Details: The front continues to push into the panhandle and has
reached the central panhandle. Moderate to heavy rain with this
front is bringing 0.1 to 0.15 inch per hour rates as it moves across
the panhandle. These rates will continue as they reach the southern
panhandle this evening into tonight. Rain rate overall decrease
Monday night. Although weaker, a second wave of precipitation will
push into the panhandle Monday as the low pushes into the panhandle
behind the front.

Land winds with this front will increase to 10 to 15 mph. Stronger
land winds will arrive Monday for the northern panhandle due to a
tightening pressure gradient. On Monday afternoon, the strongest
winds are likely to occur near Skagway with sustained winds of 15 to
20 mph and gusts up to 35 mph possible. Along with land winds, the
strongest inner channels winds will also be located over the
northern panhandle with increased southerly winds throughout north
to south facing channels. These winds will begin to decrease Monday
night into Tuesday.

.LONG TERM...
Tuesday a long wave trough will be carrying a low and fronts
across the region, with widespread stratiform precip transitioning
to showers, a result of the cool unstable post frontal airmass.
Freezing levels continue to drop, likely reaching 3,000 to 4,000ft
Tuesday morning for the north. Main threat to see a dusting of
snow will be along the upper portions of White Pass but weak
snowfall rates and warm soil temperatures will limit any
significant impacts to roads. Showers decrease late Tuesday as a
ridge builds across the Gulf, bringing stout northwest winds to
the coastal waters and drier/cooler conditions to the Panhandle.
Another weak system impacts the region late Thursday into Friday
bringing warmer onshore flow and rain; snow to areas above
3,000ft.

Attention turns to the potential for our first cold outflow event
this fall; at this time the source region of the air mass,
surface high, and duration leave much to be desired in terms of
seeing long duration (12+ hours) gale to storm force winds.
Current forecast reflects a short period of northerly gale force
conditions Friday into Saturday for Lynn Canal, with further trend
analysis required moving through the week. For reference, most
guidance has agreement on peak sea level pressure difference
between CYXY-PAJN at 9mb and PAGY-PAJN near 5mb, which
historically signifies sustained gale force winds this time of
year. Main impact is colder surface temperatures for the northern
Panhandle, with overnight temps likely reaching into the 20s this
weekend, particularly concerning for our unhoused community.

&&

.AVIATION...A front continues to push through the panhandle
tonight into Monday morning, bringing MVFR to at times IFR CIGs
and VIS flight conditions. Gusty winds possible across northern
TAF sites through Monday. Reduced (mainly MVFR) flight conditions
are expected to continue in the wake of the front across much of
southeast AK on Monday and possibly into Tuesday as the moist
onshore flow continues ahead of an approaching low out of the
northern Gulf. LLWS values around 20kt up to 2000ft will be
possible across the southern peninsula beginning this evening as
the front drops south through early Monday morning.

&&

.MARINE...
Inside Waters: As the front continues to move across the panhandle,
winds across the inner channels will increase to fresh to strong
breezes of 17 to 27 kts. These winds will remain elevated into
Monday morning before the southern channels start to see decreasing
winds. For the northern channels, winds will continue, even slightly
increase, as the north to south pressure gradient gets stronger.
Strong winds will continue over N. Lynn Canal, slightly increasing,
as southerly strong breezes of 22 to 27 kts with near gale wind
gusts up to 33 kts. Other northern and central channels will see
fresh breezes with winds near 15 to 20 kts. Winds will begin to
diminish Monday night into Tuesday.

Outside Waters: Behind the front, fresh breezes around 20 kts
continue in the gulf before the next low pressure system arrives
Monday morning. As this system pushes to the east, winds will
increase to 25 to 30 kts with gale force gusts along the far
offshore waters. Similar to the inside waters, winds greatly
diminish Monday night into Tuesday. Significant wave heights
slightly subside this evening before the next system. As the next
system arrives Monday, seas build to 12 to 14 ft with 16 ft in the
far offshore waters due to a southwest swell.

&&

.AJK WATCHES/WARNINGS/ADVISORIES...
PUBLIC...None.
MARINE...Small Craft Advisory for PKZ012-013-022-031-641>644-651-652-
661>664-671-672.

&&

$$

SHORT TERM...EAB
LONG TERM...AP
AVIATION...DS
MARINE...EAB

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