Petersburg, Alaska 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

146
FXAK67 PAJK 122245
AFDAJK

Southeast Alaska Forecast Discussion
National Weather Service Juneau AK
245 PM AKDT Mon May 12 2025

.SHORT TERM.../Through Tuesday night/ Mostly quiet across the
panhandle today though that is changing as a front moves across
the gulf. The mostly clear skies from this morning are becoming
overcast with higher level cloud cover this afternoon from the
approaching front. It has already started raining in Yakutat as of
10 am as well. Winds are also starting to pick up in the
northerly Lynn Canal and Skagway areas as surface pressures fall
in Canada ahead of the front. Into tonight, the front is expected
to push into the rest of the panhandle spreading rain as it comes.
Most of that rain will fall over the northern half of the
panhandle with around a quarter inch expected. The southern half
will not see much out of this system as a combination of diffluent
flow and the front fighting the ridging currently over the area
will weaken the precip enough that that area may only see some
light rain with around a few hundredths of an inch for amounts.

Not much expected for winds from this system. Except for the
southerly winds in Lynn Canal pre-front, Most of the winds will be
with the post-front west winds, particularly at Cross Sound and
Cape Decision areas late tonight into Tuesday and even then it
will mostly max out at 25 kt for various areas due to terrain
enhancement.

Winds and precip are expected to diminish into Tuesday night as
ridging rebuilds in the gulf behind the front.


.LONG TERM...Aside from a brief break on Wednesday, the active
weather pattern continues through the remainder of the week and
into the weekend, though another break in the weather may be
possible on Sunday.

In the wake of a front on Tuesday, ridging will briefly rebuild,
and by Wednesday morning, the panhandle will be enjoying a
transient break between systems, though some upper level cloud
cover and a few lingering showers are possible. A stronger front
from a low in the central to western gulf looks to move in from
the SW late Wednesday night into Thursday, bringing widespread
breezy and wet conditions. Unlike the previous front, this looks
to be a warm front, and will be complete with more robust moisture
support, although still nothing too exceptional. The breeziest
conditions look to be in the outer coastal and the southern
panhandle communities. Not anticipating particularly breezy
conditions in the far northern inner channels, as the front looks
to weaken as it arrives, and will stall over the central panhandle
through the day on Thursday. Operational guidance is falling into
line behind the idea of a short wave moving in behind the frontal
band late on Thursday and bringing a second round of heavier
precipitation along with the potential for some breezy conditions.
Onshore flow then continues through much of Saturday, keeping
chances of rain across the area to close out the week.

By the latter half of Saturday, onshore flow will be weakening,
and ridging may briefly rebuild on Sunday, resulting in drier
weather ahead of another frontal band which will arrive late
Sunday into Monday. A vertically stacked low will move over the
central gulf through the first half of the week, helping to keep
unsettled weather in the area.

&&

.AVIATION.../Until 00Z Wednesday/...A majority of SEAK is
currently seeing VFR conditions that will be lowering to MVFR as
a weak front passes through today. Effects will begin tonight for
Coastal and Northern regions, with Yakutat already seeing
precipitation and lower ceilings. Skagway will experience high
winds with gusts up to 35 kts as the pressure gradient tightens
over Lynn Canal. The front will continue to move southeast through
the panhandle into tomorrow, with the central inner panhandle
feeling the effects early Tuesday morning. A marine layer was
advected over coastal regions preceding the front, influencing the
ceilings in Sitka and Gustavus to preemptively drop to MVFR.
Gustavus and Juneau are currently experiencing sea breezes, though
they will switch E to SE with the front. Conditions will improve
post-front with the chance for showers in the longer term.

&&

.MARINE...
Eastern Gulf of Alaska...Increasing winds and seas expected
tonight behind a weak front. W winds will be increasing to around
20 kt by late tonight while seas, supported by a long west fetch
across the gulf, will build to 8 to 10 ft by Tuesday morning.
Gradually improving conditions expected into Tuesday night as seas
and winds diminish. There will be a wind direction shift to more S
or SE by late Tuesday night with increasing speeds into Wednesday as
the gulf start to see effects from the next front in line.

Inside waters...Mostly quiet inside waters forecast, except for
Northerly Lynn Canal where 25 kt small craft criteria winds from
the S are blowing due to falling surface pressures in Canada ahead
of the front currently in the gulf. These winds in Lynn Canal are
expected to last at least through early Tuesday afternoon before
diminishing as ridging slackens the pressure gradient along the
canal. Other areas of note are Cross Sound, Western Icy Strait,
and the Ocean entrances near Cape Decision when the post frontal
west winds start picking up there late tonight. Some terrain
enhancement will bring W winds of 20 to 25 kt (could get as high
as 30 kt briefly) to those areas from late tonight through
Tuesday afternoon before diminishing Tuesday evening as west flow
collapses. Lighter winds expected overall on Wednesday as ridging
in the gulf reestablishes itself. Increasing winds expected on
Thursday as a new front moves in from the gulf.


&&

.AJK WATCHES/WARNINGS/ADVISORIES...
PUBLIC...Strong Wind from 7 PM AKDT this evening through late tonight for
     AKZ318.
MARINE...Small Craft Advisory for PKZ012-013-021-022-641>644-651-652-
     661>664-671-672.

&&

$$

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

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