139
FXAK68 PAFC 300004
AFDAFC
Southcentral and Southwest Alaska Forecast Discussion
National Weather Service Anchorage AK
404 PM AKDT Tue Sep 29 2026
.SHORT TERM FORECAST SOUTHCENTRAL ALASKA (Days 1 through 3)...
The forecast remains on track with only a few changes. The
shortwave trough that brought light precipitation to the western
half of Southcentral this morning has since lifted east-
northeastward over the Copper River Basin, allowing for clear
skies this afternoon for the northern Cook Inlet region. Panning
out, this wave is embedded within a broad longwave trough that
stretches from the western Bering to the eastern Gulf. Within this
longwave, a more robust shortwave now over the Bering will round
the base of the trough through tomorrow morning as a surface low
continues to develop downstream across the far northern Gulf.
Starting midday Wednesday, models have come into better agreement
overnight and this morning in regards to the surface low
placement, and the consensus now is that most precipitation with
be mostly confined to the eastern Kenai Peninsula and Prince
William Sound locations. The progression of the upper level wave
has more clarity this afternoon as well in regards to timing as
models have converged on the wave passing over the area Wednesday
evening. The overall weak flow with this system will lead to the
western fringes of precipitation propagating westward to encompass
Anchorage and the Matanuska Valley as well Wednesday evening to
early Thursday morning, and a sharp cutoff in rainfall extent will
most likely line up just west of Anchorage.
Precipitation type from Wednesday afternoon through Thursday
morning will be largely elevation dependent. For lower elevations
areas such as the Anchorage Bowl northward to the Matanuska
Valley, only a cold rain is expected as snow levels will remain
too high and temperatures only drop to near 40 degrees F for
overnight lows Thursday morning. With snow levels bottoming out
anywhere from 1300 to 1800 feet during the bulk of the
precipitation duration, higher elevation locations like Thompson
Pass, South Fork Eagle River, Upper Hillside, and the Talkeetna
Mountains are on track to see 1 to 3 inches of snowfall with
isolated 4 inch amounts. Locations lower in elevation like the
Anchorage Hillside, Rabbit Creek, Turnagain Pass, and Talkeetna
will most likely see a rain/snow mix as temperatures and snow
levels fall Wednesday night through Thursday morning. All said,
there is a good amount of cold air advection aloft associated with
the incoming trough, the coldest air of the season for most,
however, it appears that the coldest air does not arrive until
much of the precipitation is on its way out on Thursday.
The trough axis takes a negative tilt over Southcentral and
begins to lift out of the region late Thursday morning to midday
Thursday as the surface low skirts eastward. This will shift the
precipitation eastward toward Valdez and Cordova; decreasing
precipitation coverage to the west.
-AM
&&
.SHORT TERM FORECAST SOUTHWEST ALASKA/BERING SEA/ALEUTIANS
(Days 1 through 3: Today through Thursday)...
Key Messages:
* Chance of marine lightning (10 to 20%) across the central Bering
Sea this afternoon and evening and progressing to the southeast
Bering Sea through Wednesday morning.
* Sub-freezing overnight temperatures move into Southwest Alaska
throughout the week.
* A front brings rain and a corridor of gale-force winds in the
western Bering Sea starting this afternoon for the rain and
tonight for the stronger winds. This spreads eastward through
Friday.
Discussion:
Current satellite imagery reveals a short wave digging
southeastward across the northwestern Bering Sea. There is a
strong 300mb jet streak accompanying this shortwave as well with
300mb winds approaching 130 kts. Cold air aloft and instability
will bleed in from the north as this feature works to the south
and east through Wednesday. With the unstable airmass associated
with this digging shortwave, a few lightning strikes are possible
(10 to 20% chance) across the central Bering this afternoon and
evening and across the southeast Bering through Wednesday morning.
A widespread lightning over water event is not anticipated. Aside
from marine lightning potential, the surface low associated with
the upper-level shortwave will also move from the north-central
Bering this afternoon and to the Alaska Peninsula (AKPEN) by
Wednesday afternoon. Rain will spread from the Pribilof Islands
this afternoon to the AKPEN this evening through Wednesday.
A follow-up shortwave, behind the initial shortwave causing the
potential marine lightning, drops down from Northern Alaska and
across mainland Southwest Alaska through Thursday. This feature
will bring cold temperatures across Southwest starting tonight and
lasting throughout the week. Daytime high temperatures will
struggle to get out of the 40s with nighttime/morning lows in the
20s. Due to cloud cover, temperatures across the AKPEN should stay
above freezing through the week.
Farther west, the Aleutians will see a front from a Kamchatka low
moving into the western Aleutians this afternoon, and pushing
the exiting ridge east. Nonetheless, showers and southeasterly
to easterly small-craft winds are expected to accompany the
front, especially in the western Aleutians with gale-force winds
to the north in the offshore western Bering zone. The low
eventually becomes elongated and catches up to the front Wednesday
night. Higher chances for precipitation spread to the eastern
Aleutians and eventually to the Southern AKPen on Thursday as the
low continues east. The area of gale-force winds also moves east
to the central Bering by Wednesday evening and Thursday as high
pressure builds across the northern Bering and Bering Strait
region. Gales become more confined to the North Pacific south of
Nikolski/Unalaska Thursday night into Friday as the Bering Sea low
transfers it energy to a new developing low in the North Pacific
by then. Aside from the gusty gale-force winds, rain works from
the Western Aleutians this afternoon eastward across the rest of
the Aleutian Chain by Friday morning.
&&
.LONG TERM FORECAST (Days 4 through 7)...
Looking ahead toward this weekend, models are synoptically in
good agreement in the midrange forecast, featuring a low moving
toward Kodiak Island from the North Pacific and another low into
the Bering Sea from the west. Precipitation with east to southeast
winds will be more than likely for Southcentral, especially
closer to the Northern Gulf coast and Kodiak Island. By Sunday,
the front extending from the Bering Sea low reaches Southwest
Alaska and the Alaska Peninsula bringing rain, snow, and southerly
flow across the area. As the low sinks southward Monday, models
diverge on how far south the low will dip. Generally, the low
appears to pass through the Alaska Peninsula and near Kodiak
Island/Western Gulf. As this pattern sets up through the first
half of next week, cold air advection and northerly winds will
become enhanced through gaps along the Aleutians. If the low sinks
south farther east, the Alaska Peninsula would see more cold air
advection and those northerly winds. While temperatures overall
for southern Mainland are trending cooler in the short term, some
moderation of that trend is expected toward more seasonable norms,
but will remain on the cooler side.
&&
.AVIATION...
PANC...VFR with light northerly winds expected. Precipitation
chances increase Wednesday morning between 12 and 18Z. Rain, and
potentially lower ceilings (around 1000 feet), should be brief
and showery, tapering off throughout the day.
&&
$$
655
FXAK69 PAFG 292201
AFDAFG
Northern Alaska Forecast Discussion
National Weather Service Fairbanks AK
201 PM AKDT Tue Sep 29 2026
.KEY MESSAGES...
Central and Eastern Interior...
- Moderate to heavy snow in Isabel Pass through the end of the
week. First round is Tues PM to Wed AM with around 3" snow.
Second is Wed PM to Thurs night with an additional 6" to 11".
- Light snow showers above 1000ft today with a few flurries
possible this evening in the valleys. Accumulations around 1"
above 1000ft with a coating possible in the valleys.
- Additional Interior snow likely from Minto east Thursday
morning. ~0.5" to 1.0" possible in Fairbanks and surrounding
valleys with 1 to 3 inches possible over 1000ft, highest near
Eagle Summit.
- Temperatures drop below normal for the rest of the week with
high temperatures in the 30s to near 40, lows in the 20s.
West Coast and Western Interior...
- Breezy along the coast with northerly gusts from 25 to 35 mph.
Scattered snow showers as well with light accumulations of an
inch or less expected through Wed PM.
- Winds weaken Thurs with mixed clouds and sun. Clouds increase
Fri. High temperatures stay in the mid 30s to near 40 along
the coast with 30s and 20s inland. A few teens likely for lows
in the Kobuk Valley Thurs and Fri AM.
- A few rain and snow showers in the Interior today, especially
near the Brooks Range, otherwise dry through the end of the
week with clearing skies beginning this evening.
North Slope and Brooks Range...
- Cloudy with periods of light snow persisting through the week,
expect 1 to 2 inches of additional snow through Fri.
- High temperatures remain in the 20s to near 30 for most of the
coast, mid 30s from Kivalina to Point Hope with teens and 20s
in the Brooks Range. Lows will be largely in the 20s with some
single digits in the Brooks Range.
&&
.SYNOPSIS...
Rain and snow showers persist in the Interior as a front moves
through from west to east dropping temperatures below normal. A
few flurries or light snow showers are possible in the Central
and Eastern Interior valleys tonight into Wednesday morning with
little to no accumulation. The North Slope keeps periods of
light snow with chilly temperatures while the West Coast has
some breezy conditions and scattered snow showers. Wednesday and
Thursday will be notable in the Eastern AK Range as snow
develops and will be heavy at times, particularly in Isabel
Pass. There will be accumulating snow in the Central and Eastern
Interior once again Thursday morning with light accumulations
expected in the valleys from Minto east.
&&
.SHORT TERM /THROUGH FRIDAY/...
The ongoing pattern remains on track as a conglomerate of 500mb
vorticity is meandering around the Interior, a cold front
continues to move through the Interior while a trough dives
southeast from the Chukchi. The cold front will gradually move
through the Interior, dropping temperatures across most of
Northern Alaska before a front from the south provides moisture
overtop of the cold air. As a result, we can expect another
round of snow for the Interior. This one will have a fresh
injection of cold air ahead of it, therefore snow is expected
down to the valley floors Wednesday night and especially
Thursday morning. This won`t be a tremendous amount as there may
be 1 to 3 inches above 1000ft and an inch or less below 1000ft.
However, it will likely be the first accumulating snow for many
valley locations. One notable change is in the Eastern AK Range
where CAMs have begun to recognize the potential for
frontogenetic forcing as well as small amounts of CAPE (60 J/kg
or less) in and along the AK Range. This would help enhance snow
ratios and rates, particularly in the eastern AK Range and
Isabel Pass. Snow ratios will likely be between 10-15:1 with
snowfall rates around 0.5"-1.0"/hr at the peak, which would be
Wednesday night and Thursday morning. All of this, combined with
typical upslope flow will allow for significant snowfall
accumulations in Isabel Pass with amounts between 6" to 11" from
Wednesday afternoon through Thursday night.
Otherwise, Western AK and the North Slope remain fairly quiet
and seasonable with snow showers and breezy conditions along the
West Coast through Wednesday as well as periods of snow and
chilly temperatures on the North Slope. Looking towards Friday,
most of the area will be dry, especially Western AK and the
Interior, while the North Slope remains cloudy and chilly with
periods of light snow.
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
No significant weather expected this weekend into early next
week. One thing we will be monitoring, but aren`t too concerned
about is a low in the Bering. It could bring breezy offshore
winds from Hooper Bay northward with areas of rain in Western
Alaska. The overall trend has been south, so it isn`t a concern
for coastal impacts as of now. Otherwise, the rest of Northern
Alaska will be drying out with a slight warming trend this
weekend, but Saturday morning may be the coldest of the year so
far with clearing skies and temperatures approaching the single
digits and teens in the Interior. There may be some light snow
or rain early next week as a front drifts northward into the
Interior, but the North Slope looks mainly dry with increasing
easterly winds. Overall, not too much concern for significant or
impactful weather through next Tuesday.
Coastal Hazard Potential...
No coastal concerns for several days.
&&
.HYDROLOGY...
No hydro concerns expected.
&&
.AFG WATCHES/WARNINGS/ADVISORIES...
AK...Winter Weather Advisory from 4 PM Wednesday to 10 PM AKDT
Thursday for AKZ849-850.
MARINE...Brisk Wind Advisory until 4 PM AKDT this afternoon for PKZ815.
&&
$$
BIANCO
556
FXAK67 PAJK 300626
AFDAJK
Southeast Alaska Forecast Discussion
National Weather Service Juneau AK
1026 PM AKDT Tue Sep 29 2026
.SYNOPSIS...
Key Messages:
- Rain showers likely through the rest of the day Tuesday. Drier
at times along the northern gulf coast through Tuesday evening.
Another round of showers expected for Wednesday.
- Winds fairly benign across inner channels before increasing with
next front approaching Wednesday.
- Temperatures mainly seasonable with highs averaging in the 50s
and lows in the mid to low 40s.
&&
.SHORT TERM...The low in the northeast Gulf continues its slow
but inevitable decline. Accordingly, onshore flow and widespread
light showers continue for the entire region, though the position
of the low will cause some of that onshore influence to be lost in
the northern panhandle, leading to a few breaks in rain going
into tonight. On the other hand, a small zone of instability
remains offshore of the southern panhandle, so a slight chance of
thunder is maintained into the evening there, as well as some
opportunity for isolated heavy showers.
Another low approaches from the western Gulf, into largely the
same position where the current one is dissipating. Much the
similar impacts are expected into the late week, with more onshore
flow and more generally light showers across the region. Nothing
else major to speak of, with seasonal temperatures staying in the
forecast.
.LONG TERM.../Friday through Monday/...A low pressure system
originating from a mid-level North Pacific trough will move along
the Alaska Peninsula and into the Gulf of Alaska this weekend.
Reinforced by a stronger system behind it, it will produce
prolonged rainfall from Saturday into early next week, fueled by
tropical moisture and weak but continuous divergent flow aloft.
Models continuing to favor landfall along the north-central coast
near Cordova. The system could bring moderate to heavy rain, with
the highest totals expected along the northeast Gulf coast and
higher terrain, though most of the region will be impacted. Warm
advection seems apparent through many levels of the atmosphere
along this system, which will allow for a very slight warming in
temperatures, but not expecting much of a difference due to
persistent cloud coverage across the region this weekend.
Climatological guidance is trending higher, though values remain
within seasonal norms. The NE Gulf Coast may see locally heavy,
long duration rainfall instead of showery bursts due to limited
cold air aloft and minimal convective activity. For the heaviest
period (Saturday evening to Sunday evening), 24-hour QPF averages
1.5-3 inches, with up to 4-5 inches at higher elevations. GEFS and
Euro ENS indicate PWATs around 175% of normal. The GEPS is
trending more aggressive, while the GEFS and Euro ENS align more
on timing and intensity. Stronger winds and building seas are also
increasingly likely along the outer coast and northern inner
channels ahead of the low. The active pattern will persist into
next week as the following Bering Sea low reinforces onshore flow,
though rain chances should taper off by mid week.
&&
.AVIATION...After 06z TAF package Issuance.
Scattered to Isolated showers moving into the panhandle from the
eastern part of the gulf. A few of the showers are more enhanced
based on satellite imagery. There is some spotty MVFR ceilings of
1500 to 3000 feet, and very localized visibility restrictions.
Conditions should continue through Wednesday with mainly VFR
flight conditions anticipated with scattered shower activity.
&&
.MARINE...Outside (Gulf and Coastal Waters): The system in the
eastern gulf continues to weaken Tuesday, with the low center
rotating offshore of the northeastern gulf coast. Westerly fresh
to strong breezes (17 to 27 kts) and 8 to 9 ft seas persist
through the southeastern gulf Tuesday, with fresh breezes (17 to
21 kts) and 6 to 7 ft seas along the gulf coast of Baranof Island
and easterly out of Cross Sound. Winds will weaken overnight as
the low diminishes, being replaced by a developing low near Prince
William Sound Wednesday morning. This will bring southwesterly
moderate to fresh breezes (11 to 21 kts) with 6 to 7 ft seas
through the gulf Wednesday. Southwesterly 3 to 4 ft swell at a
period of 8 to 10 seconds will decrease to 2 ft at 5 to 7 seconds
by Thursday, with gulf winds and seas also decreasing by Thursday.
Inside (Inner Channels): South to southeasterly moderate breezes
(11 to 16 kts) and 3 ft seas continue for parts of the southern
and central inner channels Tuesday, mainly up through Clarence and
Sumner Strait and out of Frederick Sound and Stephens Passage.
Other than Young Bay holding on to sustained 20 kt easterly winds,
the rest of the northern inner channels are relatively light and
variable Tuesday. Winds and seas are expected to decrease Tuesday
night before jumping back up through midday Wednesday with another
system in the western gulf. This frontal passage will bring 15 to
20 kt southerly winds into the northern and central inner
channels, with Lynn Canal expected to be closer to 25 kts through
Wednesday evening. Seas will also increase to 4 to 5 ft in areas
of the strongest winds. Winds and seas will generally diminish
Thursday, though Lynn Canal will stay elevated up to 15 to 20 kts
into Friday. The southern panhandle will avoid most of these winds
through midweek. Ocean entrances exposed to the SW or W will see
higher seas up to 7 ft due to W swell invading from the gulf, but
those seas will be gradually diminishing Wednesday as swell
subsides.
&&
.AJK WATCHES/WARNINGS/ADVISORIES...
PUBLIC...None.
MARINE...Small Craft Advisory for PKZ012-013-641-661-662.
&&
$$
SHORT TERM...VFJ
LONG TERM...BAS
AVIATION...Bezenek
MARINE...ZTK
Visit us at http://www.weather.gov/Juneau
