830
FXAK68 PAFC 191323
AFDAFC

Southcentral and Southwest Alaska Forecast Discussion
National Weather Service Anchorage AK
523 AM AKDT Fri Sep 19 2025

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

Wet weather will linger across Southcentral Alaska into the
weekend as rain continues to push north from the Gulf. Radar
imagery shows steady rain continuing to push into Southcentral
from the Gulf of Alaska, with lighter rain farther north. Showers
will persist through Friday before gradually tapering off Friday
night.

By late Friday night into Saturday morning, more coherent low
pressure tracks across the southern Gulf, weakening the southerly
flow along the north Gulf coast or even shifting flow to weak
northerly across Southcentral. This reversal of flow will result in
a drying trend both along the coast and inland for Saturday. The
break in active weather will be short lived as the pattern continues
to progress with the next upper level trough pivoting across the
Alaska Peninsula into the Gulf for Sunday. Rain again looks to fill
in across much of Southcentral as the formation of weak low pressure
in the northern Gulf and east to southeasterly flow aloft keeps the
region unsettled through the end of the weekend.

-Brown

&&


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

A weakening, stacked low currently resides over the eastern
Bering Sea to the north of Cold Bay this morning. A new low is
forming along the low`s occluded front to the south of Kodiak
Island. This new low forming at the frontal triple point will
continue to consolidate as the primary surface center as the upper
level support shifts from the eastern Bering/AKPen also shifts
towards the Gulf today. The decaying Bering low is embedded within
a much larger region of cyclonic flow extending across most of the
Aleutians and Southwest, with several embedded shortwaves helping
to support areas of light rain showers drifting around the main
low. The western Bering and Aleutians are experiencing calm and
partly cloudy conditions as a weak high pressure ridge moves over
the region.

By this evening, the eastern Bering low will open up into a
surface trough as it accelerates south across the AKPen. This will
temporarily increase the west-east pressure gradient in place as
is brushes past and heads into the North Pacific, resulting in
enhanced northwest gap flow past the eastern Aleutians and
southern AKPen tonight into Saturday morning. Sustained winds
will mostly stay in small craft range, but a short period of gales
will be possible south of Unimak Island as winds peak in
intensity late this afternoon into tonight. Showers across most of
Southwest will begin to dissipate tonight into Saturday as upper
forcing wanes and as a shortwave ridge moves into place.
Meanwhile, a shortwave trough currently over the northern Bering
will drop south into the eastern Bering on Saturday, sending
another wave of showers into the Pribilofs and the Kuskokwim Delta
Coast.

From Saturday night into Sunday, the aforementioned shortwave
trough will continue diving south into the North Pacific as upper
level ridging amplifies off to the west across most of the Bering
and Aleutian Chain. This will help reinvigorate northwesterly flow
across much of the outlook area as modest cold air advection also
begins to draw a cooler air mass south from the Bering Strait
down into eastern parts of the region through Sunday night. Winds
will again become strong and gusty along and south of the AKPen by
Sunday morning, with gusts to around 40 to 50 mph likely near
favored gaps and passes along the Pacific side. Out over the
western Aleutians, the outer reaches of a much stronger system
will begin to extend strong easterly winds and rain into the
region late Sunday night.

-AS

&&


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


Minor changes from previous discussion... Upper level low
pressure continues to linger in the Gulf of Alaska from the
weekend through mid-week. Shortwave troughs and embedded surface
lows will bring enhanced periods of rain and wind to the north
Gulf coast. The heaviest rain and strongest winds look to stay in
the Panhandle, but Prince William Sound and the Eastern Kenai
Peninsula will see plenty of moisture and wind in coastal waters
as well. There is some uncertainty in the orientation of the low
as it progresses through the beginning of the week, which will
greatly impact the ability for showers to develop across inland
areas. The suggestion of southwesterly upper level flow would be
favorable for precipitation up Cook Inlet and into the Mat-Su
Valleys, though rain should remain relatively light in these areas
if it does develop.

Persistent northerly flow across western Alaska and the Bering
Sea will bring a cooling trend to the region as overnight lows are
expected to dip into the 30`s for portions of southwest Alaska.
The combination of cold air advection and a tight pressure
gradient will bring gusty winds through gaps and passes of the
Alaska Peninsula and Eastern Aleutians on Sunday to Monday and
again on Tuesday and Wednesday and another Bering Sea low passes
along the Aleutians and AKPEN through the end of the period. The
rest of Southwest remains dry for the remainder of the long term
forecast period.

&&
.AVIATION...

PANC...VFR prevails for Anchorage despite nearly continuous
rainfall through the evening and into the early morning. Should
the low-level (~2-4kft) southeast winds weaken, this will allow
ceilings to lower. There`s some uncertainty with the extent of
lowering today, but CIGs should drop into lower VFR or higher MVFR
territory today. Rain will very slowly diminish late in the day
or the overnight, though a rogue shower or two will remain
possible thereafter. Wind will remain on the light side, generally
out of the north and less than 10kts, though can`t rule out a
brief weak southeast push this afternoon after 03z with another
shortwave passage.

-Brown

&&
$$

369
FXAK67 PAJK 191309
AFDAJK

Southeast Alaska Forecast Discussion
National Weather Service Juneau AK
509 AM AKDT Fri Sep 19 2025

.SHORT TERM...Rain showers continue across the panhandle this morning
with some bringing moderate to heavy rain at times. These showers
are expected to continue as onshore flow persists allowing for
moisture to be pushed ashore. Across the area, winds continue to
remain mostly light for most locations but with the passing
showers, gusty conditions are being noted as the shower passes
overhead. Winds this morning are expected to increase as we see a
southerly push move through the Inner Channels bringing some
increased winds due to the front progressing through the area.
Most places are expected to stay below any significant thresholds
but might come as a surprise to some with the lighter winds
initially. As the low original low for this system dissipates, the
next low moves across the Gulf into the eastern Gulf. This next
low will be our next weather producer and will impact the area by
tonight. Rain is expected to continue for most of the panhandle
although some lower chances remain west of Yakutat.

.LONG TERM.../Saturday through early next week/...Little changes
made to the long term forecast as an active fall pattern persists
through the weekend with little to no breaks between them. The
precipitation amounts are looking to be impactful due to the
longer duration of moderate to heavy rainfall, with a flood watch
still in effect for the southern panhandle lasting through
Saturday. EFIs are showing an increasing trend of confidence of
extreme precipitation as the systems move through Saturday
evening.

GEFS and EC AR guidance continue to show potential for a moderate
AR event that will be long duration but with a lower peak in IVT.
Models still are showing a bit of spread in the precipitation
amounts across the panhandle, but there is increasing confidence
that the southern panhandle will see the highest storm totals, and
this is reflected in the updated flood watch product issued
Thursday afternoon.

Continuing from the short term, the highest rain rates are
expected to last into Saturday afternoon, with areas in the
central panhandle (Juneau, Sitka, and Petersburg) having a 40 to
50% chance of exceeding 3 inches by midday Saturday based upon NBM
5.0 and 4.3 probabilities. The southern panhandle, particularly
around Ketchikan, will continue to be monitored closely as
guidance narrows down on precipitation values for this time frame,
with NBM probabilities showing a 60% chance of exceeding 3 inches
in 24 hours, a 30 to 40% chance of exceeding 4 inches, and a 15%
chance of exceeding 5 inches in 24 hours. Most 24 hour
accumulations Friday afternoon through Saturday afternoon are
expected to be between 2 and 3.5 inches, though higher amounts
can be expected in higher terrain and overall totals could be
higher depending upon the duration that the moisture plume remains
over the area.

Once again there is little to no break between systems, as early
next week another short wave will rotate through and likely develop
into a gale force low in the eastern gulf. This will bring
another round of enhanced rainfall to the outer coast, with
heaviest rates once again aiming for the southern panhandle Sunday
night into early Monday morning. Due to the fast moving nature of
this short wave and associated front however, the heavy rainfall
is expected to occur over a shorter period of time and storm
totals are therefore lower, maxing out around 2 inches as of this
discussion, with locally higher amounts in higher terrain. This
early week system will still bring widespread light to moderate
rainfall to the rest of the panhandle as well. Overall a wet and
occasionally windy long term forecast for Southeast Alaska as
Fall takes center stage.

&&

.AVIATION...Aviation weather is somewhat poor though it is
improved over what was observed overnight. Widespread MVFR
ceilings (down to 1000 ft), and occasional MVFR/IFR Vis or IFR
ceiling are the norm with breezy winds and low level wind shear
(mainly speed shear) in the south. These conditions are expected
to continue and will likely get worse in the late morning or early
afternoon as a new frontal band moves in from the gulf bringing a
new batch of moderate to heavy rain. Expect widespread MVFR to IFR
ceilings and vis as heavier rain moves in that will continue,
especially for the south into Saturday morning. Winds will also
remain somewhat gusty at times (up to 30 kt mainly), especially
for the south and outer coast, into Saturday morning. Low level
wind shear (mainly speed shear with winds at 2000 ft ASL averaging
around 30 to 40 kt out of the SE) and turbulence is also expected
to continue through Friday night with the active weather.

&&

.MARINE...
Outside (Gulf and Coastal Waters): Winds along the outer coast and
Gulf continue to remain between fresh to strong breezes while closer
towards the exiting front, some near gales remain this morning. Seas
across the area continue to be between 10-14 ft according to buoys
in the Gulf. Seas should eventually diminish somewhat through today
but are expected to remain between 7-10 ft for most places. Winds
are expected to remain onshore through the daytime hours with fresh
to strong breezes persisting before switching around in response to
the next low that is expected to move into the eastern Gulf waters
this evening and into the overnight. Near gales and some pockets of
isolated gales along the backside of the low are possible as it
moves closer to shore. This low will slowly weaken as it remains in
the Northern Gulf before the next one moves into the area Sunday
night bringing another round of gale force winds.

Inside (Inner Channels): Light winds persist this morning for the
Inner Channels with the exception of Scull and Ship Islands as well
as the Point Couverden area. These areas range from moderate breezes
around Point Couverden up to strong breezes near Ship and Scull
trying to see how close it can get to gales without reaching gales.
A southerly surge of wind is expected later this morning for the
Inner Channels which is expected to bring fresh to strong breezes
but some near gales can`t be ruled out. Seas during this time could
get a little rowdy due to the surge of winds. Behind this surge,
winds will remain elevated before diminishing and starting to flip
around in response to the new low moving into the eastern Gulf
tonight. Wave heights are expected to remain around 3-5 ft for most
channels. Locations south of Icy Strait are expected to remain out
of the south as the low tracks to the north closer to Yakutat Bay
but remains offshore.

&&

.HYDROLOGY...Rain showers continue to move onshore behind the main
front that has exited most of the area. These convective showers
have brought periods of moderate to heavy rain to locations across
the panhandle allowing for significant rain accumulations with some
of the heavier periods bringing 0.25-0.5" an hour. These showers
will continue today and are expected to bring around 1" of rain for
the central panhandle; areas north of Icy Strait including Juneau
see 1-2.25" of rain today with the exception of Northern Lynn canal
while the southern panhandle is expected to see 2-4" of rain today.
As we head into the evening hours tonight, the next front moves into
the area bringing a reinforcing boost of moisture to the area as a
stream of 1-1.5" of precipitable water moves in. This will be what
helps to bring the heavier rain to the Southern Panhandle this
evening before move north and east. Showers will then continue as
the associated front moves through bringing some periods of heavier
precip but also introducing some periods of breaks.

&&

.AJK WATCHES/WARNINGS/ADVISORIES...
PUBLIC...Flood Watch through Saturday evening for AKZ326-328>332.
Strong Wind until 4 AM AKDT early this morning for AKZ328.
Strong Wind from this evening through late tonight for AKZ332.
MARINE...Gale Warning for PKZ644-651-652-664-671-672.
Small Craft Advisory for PKZ012-022-031>036-053-641>643-661>663.

&&

$$

SHORT TERM...SF
LONG TERM...STJ
AVIATION...EAL
MARINE...SF
HYDROLOGY...SF

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