Petersburg, Alaska 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

600
FXAK67 PAJK 041309
AFDAJK

Southeast Alaska Forecast Discussion
National Weather Service Juneau AK
509 AM AKDT Fri Apr 4 2025

.SHORT TERM.../Through Friday night/

Key Messages:
- A strong low has moved into the Gulf of Alaska bringing Gales to
the eastern coast.
- Rain will fall across the entire panhandle by the end of Friday.
- Rain will begin in the northern panhandle near Yakutat and along
the coast.

Details: The break in weather comes to an end today as a strong low
in the gulf brings a front toward the eastern gulf. Winds offshore
will continue to increase this morning to southeasterly gale force
winds with strong gales in the northern Gulf of Alaska. By early
this afternoon, these gales will reach the coast. At this time winds
along the southern inner channels will start to increase to fresh to
strong breezes. These winds will then stay elevated through the rest
of Friday into Saturday.

For precipitation, rain will begin in the Yakutat area and along the
coast, before reaching the rest of the panhandle by the end of
Friday. Areas farther south and east, like Ketchikan and Petersburg,
will be some of the last locations to receive precipitation. The
heaviest precipitation will be located in the northern panhandle and
along the coast with times of moderate rain possible. 24 hour QPF
totals remain around 1 to 3 inches with no flooding concerns. See
the hydrology discussion for more information.

.LONG TERM...The deep low currently situated south of the Aleutian
Islands is continuing to move northeast. A front extending from
this low pressure center will move into the eastern Gulf along the
outer coastline by Friday night, with gale force winds being
expected just along the outer coast and lasting into Saturday
morning. A weak to moderate atmospheric river is expected to bring
up plenty of moisture into this system, however the majority of
the moisture is expected to stay just off the outer coast of the
panhandle. The highest precipitation rates will be just west of
Yakutat, with Yakutat itself being expected to see around 2 inches
of total liquid precipitation throughout the weekend. The rest of
the outer coastal areas as well as POW, Ketchikan, and Annette
Island will see some decent amounts of precipitation during this
weekend, between 0.5 to 1 inch of liquid precipitation in 24 hours
on Saturday, before dissipating into Sunday. The front will push
through the panhandle Sunday into Monday morning, bringing some
lighter rates of rainfall as it pushes northeast. This will also
bring some precipitation to the border of the Klondike Highway,
which along with lower snow levels of less than 3,000 feet and wet
bulb temperatures of less than 32, will likely fall as a rain
snow mix with very little of it actually accumulating by Monday
morning.

An active weather pattern is expected to continue after this first
system with another front being expected to move into the northeast
and hit the panhandle Monday night into Tuesday. The majority of the
panhandle is expected to remain wet for most of this week as the
deep low in the Gulf is expected to stay stagnant off the west
coast, while smaller lows are expected to track up into the eastern
Gulf coast and bring even more precipitation by the end of the week.
This is largely due to the deep trough sitting over the Gulf and
bringing more of these lows up along the east Gulf coast from the
south.

&&

.AVIATION...

VFR flight conditions this morning across majority of the
panhandle will quickly come to an end. By mid morning,
anticipating flight conditions to deteriorate to predominate MVFR
as precipitation overspreads the area, with reduced CIGS AoB
5000ft and visibilities down to 3SM as a front draped over the
eastern Gulf pushes into the AK panhandle through Friday
afternoon and evening.

Winds increase through mid morning and into the afternoon, with
strongest sustained winds up to 15kts and isolated gusts up to
30kts. Biggest aviation concern through the period will be
strengthening easterly to southeasterly LLWS around 2000ft for
coastal and southern TAF sites like Yakutat, Sitka, Klawock, and
Ketchikan. Expect LLWS to continue around 30kts through mid
morning, increasing to near 40kts by Friday afternoon, increasing
further to near 50kts by 09z to 12z Saturday morning for the
southern panhandle TAF sites as a reinforcing shortwave pushes
near the southern coastal panhandle.

&&

.MARINE...
For the Gulf: Southeasterly gale force winds continue to move
toward the eastern Gulf of Alaska. The strongest of these winds
will be located in the far northern gulf with strong gales
developing Friday into Saturday. Waves of 22 to 25 ft seas will
develop near Cape Suckling. The rest of the coast will have seas
developing to 18 to 20 ft throughout the day. Southeasterly swell
will accompany these gales and high seas with this front.

Inner Channels: Southeasterly winds will increase Friday afternoon
and evening for the inner channels south of Icy Strait. These
winds will increase to fresh and strong breezes lasting through
Saturday morning before starting to diminish. Seas for the inner
channels along the coast at ocean entrances will increase to 8 to
10 ft this evening. These conditions will continue into Saturday
as the front moves over the region.

&&

.HYDROLOGY...
1) Flooding is not anticipated.
2) Snow levels above 3000 ft for the majority of the panhandle,
reaching 8000ft for the central and southern coast.
3) 1 to 3 inches of 24 hr QPF at sea level, with the heaviest
amounts along the coast. Less moving into the interior panhandle.

After the onset of precipitation west of Yakutat on Friday, we will
begin to see a shift to a much higher availability of moisture
Friday night as an atmospheric river moves up into the eastern Gulf.
This will bring more moderate to even heavy precipitation Saturday,
with the majority of the heaviest rates being just west of Yakutat
and around Cape Suckling. The CW3E guidance shows both the EC and
GFS in agreement of it being a weak (AR-1) to potentially moderate
(AR-2) atmospheric river event for the northeast and southern
coasts, though with most of the moisture not making it into the
panhandle but rather staying further off the coast. This will still
bring 1 to 3 inches of rainfall to Yakutat and the northeast Gulf
coast during the weekend, and up to 1 inch of rainfall for the rest
of the region. Rivers may rise following this system, but flooding
is not anticipated at this time due to the dry soils at sea level
and mature snowpack at elevation that is likely to withstand the
rain.

As expected with most atmospheric rivers, we will see warmer air
moving into the region alongside higher snow levels as the system
comes in Friday. The snow levels Friday will be around 2000 ft,
before rapidly increasing to around 7000 ft along the coast into
Saturday morning. The northern panhandle will see snow levels get to
above 3000 ft before settling around 1500 to 2000 ft as we move into
next week. The snow level around the Klondike Highway will dip below
3000 ft on Friday, before increasing to 3500 ft on Saturday, before
dropping again to below 2000 ft Monday. This will give us some light
snow overnight on Friday along the higher elevations of the highway
near the border, before transitioning into rain into Saturday
afternoon. This will return to a mix by the start of the week, but
with little snowfall accumulating this event due to the lighter
precipitation rates, more hours of sunlight, and warmer road
surfaces moving into the daylight hours. For anyone at higher
elevations, above 4000 ft in the northern panhandle such as those
in the Chugach or St. Elias Mountains, expect feet of heavy and
wet snow.

&&

.AJK WATCHES/WARNINGS/ADVISORIES...
PUBLIC...Strong Wind from this evening through late tonight for AKZ323.
MARINE...Gale Warning for PKZ641>644-651-652-661>664-671-672.
     Small Craft Advisory for PKZ021-022-032-034>036-053.

&&

$$

SHORT TERM...EAB
LONG TERM....Contino
AVIATION...NM
MARINE...EAB
HYDROLOGY...AP/Contino

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