897
FXAK67 PAJK 210627
AFDAJK

Southeast Alaska Forecast Discussion
National Weather Service Juneau AK
1027 PM AKDT Sun Sep 20 2026

.UPDATE...

Winds have slackened considerably and the impressive amount of
thunderstorms have all but ceased for the night, though a rare
bolt of lightning may be visible in the night with decent clearing
and visibility.

&&

.AVIATION...

The center of this weekend`s strong low has moved onshore in south
AK, and has begun to weaken. The further distance and weakening
pressure gradient have slackened winds as a whole for the region, a
bit ahead of the previous forecast. PAGY/PAHN are gusting just above
20kt. The impactful precipitation has all but moved on from this
system. A look at satellite reveals isolated showers peppering the
Gulf and coastal areas, while the more widespread consistent rain
from earlier has moved further inland. These showers may have some
blustery winds around them, and temporary vsby drops are possible
within the core of them, but without the diurnal heating support of
this afternoon, the cores are struggling to achieve the updraft and
heights to allow for lightning formation. Come daytime Monday, there
may be a resurgence of thunderstorms but not nearly to the frequency
and strength of earlier Sunday afternoon.

All that said, with low cloud coverage and a modestly convective
environment, cigs have risen above 3kft for a majority of the
region, leading to MVFR/VFR flight conditions tonight. With the
greatly diminished wind environment, so too has gone the concern for
wind shear. PIREPS regarding turbulence have all but ceased, with a
few noting a smooth approach in descent.

&&

SYNOPSIS...

Key Messages:

- Thunderstorms mostly along the outer coast for the NE gulf coast
  and some parts of the inner channels

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

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

SHORT TERM...The low pressure that has been affecting Southeast Alaska
has started to weaken as it interacts with the northern Gulf coast.
This low will continue to weaken through the overnight hours this
evening as the center moves towards Prince William Sound. While the
low remains in the area, showers and thunderstorms will still be
possible going into tomorrow for the panhandle. Some of these
showers could be gusty and have heavy periods of rain. As the low
moves back into the Gulf on Monday, it is expected to interact with
the next low moving into the Gulf of Alaska Monday night into early
Tuesday morning. With this next system, there could be some gusty
winds, especially for locations along the outer coast but the
gradient otherwise looks to be less significant than what we`ve seen
today. The pattern for the short term continues to look active with
more rain and wind moving into the area heading into the middle of
the week.

LONG TERM.../Wednesday through Saturday/... Wednesday will see the
tail end of an active weather pattern from a low pressure system
in the gulf, with rain and wind diminishing through the day. This
low is expected to move south out of the area through the
day Thursday, which looks to be a period of drier conditions and
calmer winds. The upper level flow looks to shift to be more
southerly, but not fully offshore, so the southern panhandle,
especially, could see more showery conditions. Late Friday or
overnight into Saturday, another front looks to move across the
panhandle, bringing elevated winds back to the inner channels, up
to about 20-25kts, with periods of heavier rain. This system is
not expected to bring unseasonable amounts of rain, so there is no
major flooding concern at this time.

AVIATION...

The center of this weekend`s strong low has moved onshore in south
AK, and has begun to weaken. The further distance and weakening
pressure gradient have slackened winds as a whole for the region, a
bit ahead of the previous forecast. PAGY/PAHN are gusting just above
20kt. The impactful precipitation has all but moved on from this
system. A look at satellite reveals isolated showers peppering the
Gulf and coastal areas, while the more widespread consistent rain
from earlier has moved further inland. These showers may have some
blustery winds around them, and temporary vsby drops are possible
within the core of them, but without the diurnal heating support of
this afternoon, the cores are struggling to achieve the updraft and
heights to allow for lightning formation. Come daytime Monday, there
may be a resurgence of thunderstorms but not nearly to the frequency
and strength of earlier Sunday afternoon.

All that said, with low cloud coverage and a modestly convective
environment, cigs have risen above 3kft for a majority of the
region, leading to MVFR/VFR flight conditions tonight. With the
greatly diminished wind environment, so too has gone the concern for
wind shear. PIREPS regarding turbulence have all but ceased, with a
few noting a smooth approach in descent.

MARINE...
Inside(Inner Channels): A strong low continues to push inland near
Prince William Sound Sunday afternoon. An associated front has
lifted inland over the panhandle, bringing persistent southerly
and easterly winds throughout the day. The strongest winds will
continue along Lynn Canal Sunday night, particularly in the
vicinity of Taiya Inlet which will see sustained winds up to 35 kt
and gusts up to 45 kt through late tonight. Winds will diminish
late Sunday into Monday with a short break over the panhandle
before the next system moves into the area by Tuesday.

Outside (Gulf and Coastal Waters): Winds and waves have started to
trend downwards as the low in the northern gulf continues to push
into Prince William Sound. As of this discussion, winds in the
gulf have fallen to 25 kt or less, but erratic gusts up to gale
force or stronger are still possible in the vicinity of strong
convective showers that continue to develop, and remain possible
through Monday morning. Along with these strong winds,
significant wave heights that reached as high as 15 to 20 ft
across the gulf have begun to subside and will continue to do so
through Monday. Active weather is still in store for mid week as
winds once again increase across the gulf into Tuesday.

&&

.AJK WATCHES/WARNINGS/ADVISORIES...
PUBLIC...Wind Advisory until 4 AM AKDT Monday for AKZ318-319.
     Flood Watch until 4 AM AKDT Monday for AKZ318-319.
MARINE...Gale Warning for PKZ012.
     Small Craft Advisory for PKZ011-013-021-022-031>034-053-641>644-
     651-652-661>664-671-672.

&&

$$

SHORT TERM...SF
LONG TERM...AGP
AVIATION...VFJ
MARINE...STJ

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