956
FXAK68 PAFC 300034
AFDAFC

Southcentral and Southwest Alaska Forecast Discussion
National Weather Service Anchorage AK
434 PM AKDT Thu May 29 2025

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

Discussion:

Low pressure situated just south of Resurrection Bay this
afternoon is drifting slowly to the north-northwest. Ahead of this
low, bands of moderate to heavy showers continue to stream into
Prince William Sound and the eastern Kenai Peninsula. A coastal
ridge has also built along the Chugach Mountains. This ridge, in
combination with lower pressures inland due to a digging trough
over western Alaska, has resulted in strong southerly gap winds
from Turnagain Arm to the Kink River Valley and Copper River
Basin. Temperatures this afternoon are not quite as warm as
yesterday due to increased cloud cover.

Models are struggling just a bit when it comes to the exact track
of the low, with hi-res guidance driving the low north and the NAM
and GFS trying to continue its more westward jog. The overall
solution looks to be somewhere in the middle, as the center of
circulation inches closer to the coastline. Winds will continue to
ramp up this afternoon and evening as the low and upper-level
trough move inland and the coastal ridge builds to its maximum
extent. The winds are expected to slowly diminish from their peak
for the Anchorage Bowl and Matanuska Valley overnight; however,
the strong wind gusts should persist across the Copper River Basin
through at least mid-morning Friday. The gradient only weakens
though, so southeasterly winds and gusts will persist through
Friday, albeit a bit weaker than what has been observed thus far
today.

A few scattered showers, and perhaps an isolated thunderstorm,
will be possible across the northern Susitna and Copper River
Valleys through late this evening.

More widespread shower activity will then slowly move into the
western portions of Southcentral for Friday as the trough digging
south over Southwest Alaska negatively tilts and moves eastward
along with a newly developing surface low near the Barren Islands.
The southeasterly gap winds will likely keep the lower levels of
the atmosphere across the lee of the Chugach dry, leading to
mainly virga or a few sprinkles through late afternoon or evening.
A trailing wave moving east from Southwest Alaska will then catch
up to the first as it and the surface low both stall. Winds near
the surface then look to diminish as winds aloft shift more
southerly and southwesterly. This will likely lead to light rain
filling in from Northern Cook Inlet across Anchorage and the
Matanuska Valley late Friday into Saturday.

Models then diverge as to how quickly this trough lifts northeast
on Saturday. Showers will likely develop across the Copper River
Basin, but may also linger from the western Kenai peninsula north
into the Mat-Su Valleys if the slower solutions prevail.

-TM/PP

&&


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

An upper-level trough digging across Southwest Alaska is
supporting a band of stratiform rain along the Western Alaska
Range north and east of Iliamna, along with some scattered rain
showers across portions of Bristol Bay this afternoon. The trough
shifts east tonight, clearing out precipitation from west to east
through Friday morning. Behind the trough, cold air overspreading
the region will keep high temperatures to around 50 degrees or
lower this afternoon/evening as well as tomorrow. Overnight
temperatures are expected to approach freezing tonight, with
locations in the Kuskokwim River Valley and Kuskokwim Delta
dipping below freezing.

Weak ridging across the Bering Sea and Aleutians will keep
relatively calm conditions in place along with widespread stratus.
Breezy conditions for the eastern Aleutians and Alaska Peninsula
last through tonight with consistent northerly flow funneling
through favorable bays and passes. Then, a broad low drops down
from the northern Bering Sea on Friday, bringing widespread rain
and enhanced southwesterly winds to the western and central
Bering into Saturday. The southern reaches of this system will
lightly clip the Aleutian Chain, but largely stay offshore of
mainland Alaska. However, light onshore flow will combine with
very high astronomical tides to produce a coastal flooding threat
along the Kuskokwim Delta coast. Low-lying communities such as
Kipnuk and Kwigillingok are likely to see water levels 1.5 to 2.5
feet above the normal highest tide line during the high tide on
Friday afternoon, which could contribute to minor flooding. For
this reason, a coastal flood advisory has been issued. The light
southerly flow on Saturday will also warm temperatures back into
the 50s during the daytime for Southwest Alaska.

A North Pacific low lifts up early Saturday morning, bringing
more significant moisture and gale force winds to the eastern
Aleutians/Bering Sea and Alaska Peninsula heading into the
weekend. Energy from this system looks to phase with the broad
Bering low, pushing high-end gale force southeasterly winds up
along the Southwest coast Saturday night. The strong along-shore
winds will cause an onshore surge of water, keeping the Kuskokwim
Delta coast at risk for coastal flooding again Saturday and Sunday
afternoon/evening around high tide. Water levels are expected to
recede between the main high tides each day. Light to moderate
rain spreads inland with the front on Sunday morning. The front
slowly pushes inland through Sunday, keeping temperatures
moderated and gradually weakening through the day.

&&


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

On the Alaska Weather map, a broad upper level low stretches from
Siberia into Western Alaska. This is anchored by an unseasonably
deep closed low over the Southern Bering that weakens and slips
over the Alaska Peninsula into the Gulf of Alaska through
Thursday. A couple of significant troughs remain over the Bering
as some shortwaves pass through the pattern during the forecast
period. Forecast confidence rests with the GFS and Canadian models
with the larger features, but is mixed in conjunction with the
smaller details. An active weather pattern persists along and over
most of Southern Alaska through the week.

A well developed surface low in the West Central Bering wraps a
front across the Northern Bering into Southwest Alaska. The front
continues to stretch along the Southcentral coast with moderate to
locally heavy rain. Showers are expected across the Southern half
of the state, with possible thunderstorms South of the Alaska
Range. A second portion of this low spreads moderate to locally
heavy rain and gusty winds over the Central and Eastern Aleutians
that will move over the AKPEN into Southwest Alaska Tuesday and
Wednesday. After a loop around Bristol Bay late Tuesday into
Wednesday, the low will cross the AKPEN and continue the moderate
to heavy rain and gusty winds over Kodiak Island and across the
Gulf of Alaska through Thursday. A new North Pacific low and front
push towards the Central Aleutians for Thursday.

- Kutz

&&

.AVIATION...

PANC...VFR conditions will persist through much of the TAF period.
Breezy southeast winds out of the Turnagain arm have already
produced gusts in excess of 35 kts and will continue to do so
through the early overnight hours before moderating a bit. A
trough may bring some light precip to the area overnight into
tomorrow morning, but should remain light enough such that
conditions remain VFR. Another trough passage is expected to bring
rain and somewhat lower cloud cover later on Friday.

&&


$$

885
FXAK67 PAJK 301121
AFDAJK

Southeast Alaska Forecast Discussion
National Weather Service Juneau AK
321 AM AKDT Fri May 30 2025

.UPDATE...Update to the Aviation section to include the 12z TAF
issuance.

&&

.PREV DISCUSSION......ISSUED AT 105 AM AKDT...

SHORT TERM...An incoming gale force low, currently developing
500 NM SW of Haida Gwaii, will move up along the gulf coast Friday
morning. An associated front will be in the process of occluding
as it moves along the coast, generating gale force winds up
Clarence Strait, and gusty winds up to 45 mph to the southern
panhandle communities exposed to south winds. This low looks to
become vertically stacked and begin to rapidly diminish SW of
Baranof Island, faster than expected. Going into Saturday, the
low is expected to become a longwave trough and slide eastward
into British Columbia, which will bring enhanced winds in
northern panhandle marine areas and Skagway.

Changes to the forecast include reducing rain rates for the
northern half of the panhandle due to the weaker than expected
system going into Friday afternoon and evening. Additionally,
increased winds in Skagway as the low becomes a trough in British
Columbia as building ridging will increase the gradient in this
area. More changes are made in the marine section.

LONG TERM...The start of the mid and long range period will
likely be our driest part of the forecast as ridging builds across
the gulf Saturday into Monday. However, the ridge is rather flat
so overall flow will likely stay more onshore then not keeping
cloud cover in the forecast with temperatures staying relatively
cool for this time of year (though if any substantial breaks
develop afternoon temps could be warmer). Some showers along the
higher elevations are not out of the question during this period
as well as the onshore flow interacts with the mountains.

Active wet weather returns for mid week and beyond as a parade of
fronts move across the gulf though none of them appear to be very
strong at this time. Some uncertainly on the first one or two
fronts on how strong or weak they will be when they get to the
panhandle as both will be fighting the ridging over the gulf to
get here. Front number one looks to arrive Monday night, but will
have lost most of its strength by the time is gets here. Front
number two is a rather weak feature moving across the northern
gulf late Tuesday and how it plays out is rather uncertain just
due to how weak it is. A more substantial low/front moves in for
Wed night into Thursday, though even that one looks to be sub-gale
force with more rain then wind. EFI indices for this third system
are pinging some higher possibilities of heavier rainfall
especially for the higher elevations.

AVIATION...VFR and MVFR conditions continue this morning as rain
is expanding northward ahead of our next system that is supposed
to move into the area today. With the approaching low and
associated front MVFR CIGS are expected to become more predominant
across the panhandle as well as some potential lowered VIS. The
threat for LLWS is also expected to increase this morning for
locations south of the Icy Strait corridor. AAWU forecasts for
this morning show an increasing potential for turbulence and
icing as the low moves northward.

MARINE...Inside Waters: Early on Friday, a gale force system
moves up from the southwest, introducing near gale to gale force
winds yet again to the Clarence Strait area. One change to this
system is it looks to rapidly diminish and shear apart upon moving
into the Coastal Mountains. Reduced wind speeds in the Icy Strait
to around a moderate breeze. Lynn Canal is expected to be mostly
light during this time due to competing low pressures to the south
and north, keeping the pressure gradient light. For Saturday,
changed the northern panhandle to mostly reflect what typically
goes for a summer time pattern, with strong breezes near Eldred
Rock and moderate to fresh breezes from Cape Spencer to Point
Couverden and up to Little Island.

Outside Waters: Less changes to the outside waters. Still
expecting a gale force front to mostly impact the entrance to
Clarence Strait near gales to gales along the coastline west of
PoW Island. Once change is as the low is weaker than expected,
only expecting fresh to strong breezes out of Cross Sound and not
the gale force originally anticipated. Beyond Friday, ridging
builds in the southern gulf, generating up to fresh NW breezes for
the outer coast.

&&

.AJK WATCHES/WARNINGS/ADVISORIES...
PUBLIC...Strong Wind from 7 AM to 10 AM AKDT Friday for AKZ328.
Strong Wind from 7 AM AKDT Friday through Friday afternoon for
AKZ332.
MARINE...Gale Warning for PKZ036-641-642-661-662.
Small Craft Advisory for PKZ031-034-035-643-644-651-652-663-664-
671-672.

&&

$$

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

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