Petersburg, Alaska 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

625
FXAK67 PAJK 280027
AFDAJK

Southeast Alaska Forecast Discussion
National Weather Service Juneau AK
Issued by National Weather Service Anchorage AK
427 PM AKDT Tue May 27 2025

.SHORT TERM...
Windy and wet midweek for the panhandle as multiple shortwaves
will move along the longwave trough in the Gulf of Alaska.
Currently on satellite, a departing front over the northern
panhandle and NE gulf coast continues to weaken, while the main
moisture tap pushes south into Haida Gwaii. Into Wednesday,
divergence aloft along with another negatively tilted shortwave
will generate another surface low to move northward along the gulf
coast. This low will result in greater IVTs being pushed into the
southern panhandle, increasing rain rates. Along with the
developing wave, stronger wind gusts will push northward,
primarily impacting the southern panhandle, outer coast, and Icy
Strait area with wind gusts up to 45 mph. Special mention to
Yakutat, which may be seeing wind gusts up to 50 mph.

.LONG TERM...Looking towards the end of the week, the rainy weather
looks to stick around for a few more days.

Key points:
- Another system enters the gulf Thursday, precipitation continues
  until Sunday.
- Ridging may allow for dry period Sunday into Monday.

Details: A less-organized low pressure system will track
northeast through the gulf and jump onshore, allowing for a dirty
ridge to set up into next week.

Into Thursday, the upper level pattern looks to break down
slightly with the stagnant upper level low lifting northwards and
a shortwave ridge forming over the panhandle. While surface winds
should slacken as a result, the continued onshore flow means light
shower activity will continue. This ridging is quickly replaced
with a more shallow trough which is expected to steer another
system into the Gulf from over the western Aleutians and up from
the south, with the associated front reaching the outer coast of
the panhandle by early Friday. This system is not expected to last
as long and should bring most of the precipitation to the
southern and central panhandle. Winds will pick up for the outer
coast and channel entrances with the front. The EFI tables show
higher-than-normal amounts of precipitation and wind speeds over
the southern and central panhandle through Saturday night,
indicating potential for 24 hr total precip to reach 1.5 inches
with gusts up to 35 kts along the outer coast and channel
entrances. There is potential for this system to be aided by a
weak AR, though the path remains slightly south of the panhandle
at this time.

The low is looking to jump onshore over the central panhandle
mid- weekend and quickly dissipate, allowing for a ridge to build
up over the Pacific Northwest and northwards towards the
panhandle. This ridge looks to be the best chance of seeing some
drier weather Sunday into Monday, with EFI tables currently
remaining in agreement for some much-needed sun in SEAK. Another
potentially impactful system looks to set up in the Bering Sea
Tuesday. Though lots of uncertainty still remains in the path of
the next low this far out, guidance is suggesting potential for a
weak AR to impact the northern coast of the panhandle. Overall the
rest of this month looks to be both a tad bit more windy than
normal with slightly below normal temperatures. CPC guidance
suggests that while the northern and outer coast of the panhandle
will receive above normal precipitation for the rest of the month,
the southern half has potential to see normal to slightly below
normal precipitation.

&&

.AVIATION...
Predominate Low VFR to low MVFR flight conditions expected across
the area through Thursday night as a potent front pushes into the
southern panhandle, with flight conditions and CIGS dropping AoB
5000ft by 12z. Can`t rule out the brief drops into IFR flight
category with reduced visiblities near 2SM within heavier showers
and CiGs AoB 1000ft through early Wednesday morning. Winds will
remain generally elevated through the period, with sustained winds
10 to 20kts and gusts up to 30kts, strongest winds will be across
the southern panhandle.

Main aviation concern continues to be prolonged LLWS for the
panhandle, with strongest southeasterly LLWS expected across the
southern TAF sites through Wednesday afternoon. Anticipating LLWS
to increase through 12z, maximizing around 50kts near Ketchikan
and Klawock, gradually diminishing through the afternoon on
Wednesday.

&&

.MARINE...
Outer Waters: A developing wave Wednesday morning will move up
along the gulf coast, generating gale force winds for Clarence
Strait and western PoW Island. Main changes to the forecast is to
extend the thin line of gales to the west of PoW Island to also
include the outer waters of Sitka Sound. Furthermore, as this low
looks to develop closer to the coastline than originally
anticipated, near gale to gale force NE winds are expected out of
Cross Sound, which will quickly transition to gale force SE winds
as the front pushes northward.

Inner Waters: The aforementioned developing wave moving northward
Wednesday morning will bring gale force winds to Clarence Strait
before diminishing in the afternoon hours. Ahead of this front,
winds in the central and northern inner channels will lax and turn
north to northeast to a maximum of 10 knots. Between midnight
tonight and 11 am tomorrow morning, a southerly surge of strong
breezes will push up through the inner channels to the northern
Lynn Canal area. Highest uncertainty for winds is the timing
surround the Lynn Canal wind shift, as warm air advection may keep
stable surface air in the channel for longer than expected,
preventing higher wind speeds from mixing down.

&&

.HYDROLOGY...
Rather impressive atmospheric river for this time of year will be
redirected at the panhandle beginning Wednesday morning. Both the
EPS and GEFS point to an 80% chance of IVT above 700 kg/ms with a
developing wave. The result is expected to be widespread heavy
rain, with the heaviest rain in the southern panhandle. Ketchikan
in particular can expect up to 0.4 inches of rain per hour. Expect
rain rates to lessen the further north in the panhandle, with
Juneau expecting rain rates up to 0.15 inches per hour. All in
all, expecting upwards of 4.5 inches for the Ketchikan area, with
places at elevation such as Ward Lake expecting upwards of 6
inches through tomorrow night. Areas around Juneau, Gustavus, and
Hoonah are expected to receive 1.5 to 2.5 inches of rain through
tomorrow night.

&&

.AJK WATCHES/WARNINGS/ADVISORIES...
PUBLIC...Strong Wind Wednesday afternoon for AKZ317.
     Strong Wind Wednesday morning for AKZ323.
     Strong Wind from late tonight through Wednesday morning for
     AKZ327.
     Strong Wind from 1 AM AKDT Wednesday through Wednesday morning
     for AKZ328-329.
     Strong Wind from 10 PM AKDT this evening through Wednesday
     morning for AKZ330.
MARINE...Gale Warning for PKZ036-642-644-651-661-664-671.
     Small Craft Advisory for PKZ013-021-022-031>035-053-641-643-652-
     662-663-672.
$$


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