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Southeast Alaska Forecast Discussion...UPDATED
National Weather Service Juneau AK
1112 AM AKDT Thu Jul 3 2025

.UPDATE...For 18Z Aviation Package and Marine Update...

&&

.AVIATION UPDATE...General trend through the next 6 hours will be
to see the breaks in the low cloud cover increase most areas in
the southern half of the Alaska Panhandle as drier air works in
from the eastern GULFAK. To the north, light northeasterly flow is
helping to keep cloud generation going for Juneau and
Gustavus...but even there we are trending up to MVFR early this
afternoon. We do expect to see some areas of fog overnight where
we can get some generation of fog in light flow under the high
pressure ridge...mainly the central Panhandle to include Gustavus,
Juneau, Sitka, and Petersburg.

&&

.MARINE UPDATE...generally light morning winds over most areas
under the weak high pressure ridge developing across the Alaska
Panhandle and coastal waters. With breaks in the low clouds
working in for some areas, there will be spots that could see
localized winds to 15 kts this afternoon from the west to south
depending on terrain and orientation. Otherwise, still not much
of significant impact that we can see in the marine forecast for
the start of the 4th of July weekend.


&&

.PREV DISCUSSION...ISSUED AT 550 AM AKDT Thu Jul 3 2025...

SHORT TERM...A weak ridging pattern has moved over the
panhandle overnight, bringing some drier weather ahead for the
majority of the panhandle today and into tonight. Throughout the day
there will be some slight chances for rain showers in parts of the
panhandle, with the highest potential being for just some sprinkles
moving into tonight. This will begin to clear up along the coast and
southern panhandle by tonight, with the main chance of precipitation
being for the far northern panhandle by Skagway late tonight into
tomorrow as some showers have potential to move into the area from
Canada. This morning into the afternoon will begin to see some
clearing in the skies in the southern panhandle and parts of the
central panhandle, with the breaks in cloud cover becoming more
widespread by later tonight. The northern panhandle, particularly
areas north of Icy Strait Corridor, will hold onto the cloud cover
for longer into tonight, particularly over Skagway. This will give
less of a chance for the northern panhandle to see as warm of high
temperatures during the day today, but the south and central
panhandle will likely see warmer temperatures and potential for sea
breezes from having more breaks in the cloud cover.

The ridging over the panhandle will result in some lower wind
speeds, some areas expecting to stay calm throughout the day,
however the lack of wind alongside the moisture still in the air may
bring some fog to parts of the central panhandle, Icy Strait
Corridor, and Yakutat later tonight. The only location expecting to
see some increased winds today is Skagway and along northern Lynn
Canal as the ridge creates a tightening in the pressure gradient
with a low that is situated to the northeast over Canada. A low to
the west will continue pushing into the central Gulf today, but will
stay further to the south as it slowly moves eastward, not bringing
any impacts to the panhandle yet outside of increased winds in the
southern parts of the eastern Gulf. For more information on winds in
the Gulf and Inner Channels today into tonight, check out the Marine
discussion below.

LONG TERM...Key messages:
- A drier trend is expected this weekend with times of light showers
  still expected.
- Temperatures slightly increase to the end of the week into the
  weekend.
- The next low pressure system enters the gulf at the start of next
  week.

Details: Precipitation chances diminish into the weekend as an area
of weak high pressure remains over the eastern Gulf of Alaska. Even
with diminishing precipitation chances, that does not mean that the
panhandle will remain completely dry. Isolated light to moderate
showers will remain possible across the panhandle in the afternoon
hours. Minimum QPF is expected with no impacts. Along with light
showers, an upper level trough will continue to bring increased
cloud cover with broken to overcast skies. Temperatures at the end
of the week begin to return to near typical values for this time
of year with maximum temperatures in the mid to high 60s. Low
temperatures will remain in the low to mid 50s to end out the
week.

Toward the end of the weekend, a low will slide into the northwest
gulf and a trough extending from it will bring a shift to more
southerly flow over the panhandle and increasing precipitation
rates. The heaviest precipitation currently looks to be more
focused on the northern panhandle than the central and southern
areas for Sunday. Another system will move into the southern gulf
early next week bringing widespread moderate to heavy rain. Some
model discrepancies still exist with the placement of this
feature, however models continue to trend towards winds increasing
along the eastern gulf to fresh to strong breezes by Tuesday.
With continued model spread for this low pressure system just
under a week away, we will continue to monitor it`s development.

AVIATION...MVFR to VFR conditions will improve through the
morning hours on Thursday into more widespread VFR conditions a a
remnant low over the panhandle dissipates and offshore flow begins
to clear out some of the cloud cover which has been lingering
around the area. A few areas of fog which formed overnight will
dissipate Thursday morning. As the low falls apart, shower
coverage will diminish, although a few scattered showers continue
to remain possible through Friday. Winds will be on the lighter
side for most locations on Thursday, barring sea- breeze impacted
areas, which will see said sea breezes during the afternoon and
evening hours.

Fog and low-stratus decks will develop across many areas Thursday
night, bringing with them the potential for sharp restrictions to
visibility and ceilings but this will dissipate through the morning
on Friday, setting the stage for more widespread VFR conditions,
although, as mentioned previously, the occasional shower remains a
possibility. The upper level cloud decks begins to rebuild through
the latter half of Friday, and by Friday night, chances of showers
grow across the far southern panhandle.

MARINE...
Inner Channels: Northern Lynn Canal and the near the ocean
entrance around Cape Decision have continued to see increased
winds early this morning of 15 kts, but have already began to
slowly diminish to 10 kts by the morning. Into this morning, the
majority of the panhandle will continue to see less than 10 kt
wind speeds, with some areas seeing variable and calm conditions
throughout the day and into tonight. This afternoon into the
evening there is going to be an increase in the winds in Lynn
Canal to 15 kts as the pressure gradient increases, before
diminishing again by later tonight. In some areas around southern
Clarence Strait, Stephens Passage, Chatham Strait near Rocky
Island and near Point Gardner, will all see an increase of winds
to around 10 to 15 kts as the gradient tightens with a low to the
northeast over Canada before returning to more relaxed speeds by
tonight. Some areas in the southern panhandle may see enhanced
winds to between 15 and 20 kt due to a sea breeze during the
afternoon and evening as surfaces heat up during breaks in the
cloud cover.

Outer Waters: Largely calmer and variable winds right along the
outer coastline lasting into tonight, while areas further out
past around 90 NM of the coast will see winds from the SE between
15 and 20 kts as the surface low moves into the central Gulf
during the day. These winds will largely be impactful in the
offshore waters and the southern Gulf, with some elevated winds
beginning to impact the southern coastline late tonight. These
winds will shift from SE to E by late tonight, as the low begins
to move southward tomorrow. This system will bring 4-6 ft seas to
the majority of the waters off the outer coast, and 6-8 ft seas to
the more offshore waters that will diminish to 6 ft by tonight as
the low moves southward. A 2 to 3 ft SW swell at around 13 to 16
sec will persist for the central Gulf waters today into tonight,
moving into the waters around the southern coastline by late
tonight.

&&

.AJK WATCHES/WARNINGS/ADVISORIES...
PUBLIC...None.
MARINE...None.

&&

$$

SHORT TERM...Contino
LONG TERM....EAB
AVIATION...GFS
MARINE...Contino

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