650
FXAK67 PAJK 222247
AFDAJK

Southeast Alaska Forecast Discussion
National Weather Service Juneau AK
247 PM AKDT Sat Jun 22 2024

.SHORT TERM.../Through Sunday night/ Damp short range forecast
in the works for the rest of the weekend. A slowly weakening low
in the southern gulf is continuing to swing showers up into the
panhandle with measurable rain seen as far north as Elfin Cove
and Juneau today. Winds have been mostly low with the highest wind
observed in the southern panhandle with 20 kt around Clarence
Strait.

General trend through Sunday night is watching the southern gulf
low drift toward Haida Gwaii and slowly weaken while watching to
see what it drags in from Canada. Widely scattered showers are the
order of the day for most areas through Sunday night, but there
are two stronger features of concern that are being watched. The
first is a front like feature that tries to stall out along the
Canadian border just north and west of Haines Sunday. Most
guidance wants something there, but whether it just stalls there
or wavers back and forth will have implications on how much
rainfall (ranging from 0.25 to 0.75" or higher) is introduced to
the Chilkat River valley. Decided to have some higher pops in that
area for the forecast but have a little more middle of the road
approach for qpf. Feature number two is a short wave coming into
the central panhandle from the east on Sunday into Sunday night
mainly aimed in the area of Angoon to Petersburg to Wrangell.
There is some disagreement on how far into the panhandle it gets
and where it goes once it gets here. Solutions range from it not
getting into the panhandle at all to it getting here, but either
heading south or heading out to sea. Generally kept 40 to 70
percent pops in that region for Sunday into Sunday night to
account for the forecast spread there.

As for winds, generally expecting mostly low winds (less then 15
kt most areas). Highest winds will be this evening in Clarence
Strait where some lingering 20 kt southerlies could still be
blowing. Otherwise just the usual sea breeze circulations in the
afternoons and evenings for the most part.

.LONG TERM...Extended forecast remains relatively unchanged for
next week with lingering showers Monday diminishing into Tuesday,
followed by a warming and drying trend. For the big picture, the
showers to start the period are due to energy from an easterly
wave mentioned above in the short term discussion. After this, a
surface ridge is expected to build in over the gulf which will
bring clearing skies to the inner channels and overall warmer
surface temperatures due to abundant summer sunshine. Being on the
downstream side of this developing ridge, the one exception to
clearer skies may be the chance of a marine layer developing and
pushing into coastal communities. This will also lead to generally
light winds overall throughout the panhandle. Expect the highest
winds with the usual sea breeze circulations in the afternoon and
evening hours. Being on the downstream side of the developing
ridge, the exception to otherwise clearer skies would be any
marine layer potentially moving into coastal communities.

As is often the case, model guidance is not in full agreement on
the longevity of this blocking ridge over the gulf. However, the
first indications of unsettled weather returning to the panhandle
do not show up until the end of next week as of this forecast
issuance. Overall shaping up to be a fairly dry, warm and not so
windy week to end the month of June!

&&

.AVIATION...Generally MVFR most sites tonight with CIGS AOA 2500
ft agl. A few sites may experience local effects for fog and low
ceilings tonight, but we are not seeing much signal in the model
data to support this. Otherwise scattered showers over the area
this afternoon will gradually diminish in areal coverage after
00Z tonight as the upper low over the SERN Gulf makes general
process eastward. Winds are expected to remain generally light
except in a few spots in the next 6 hrs that see some minor
diurnal response (like Skagway). No LLWS concerns for the next 24
hours at this time.

&&

.HYDROLOGY...Chilkat River remains above minor flood stage today
due to higher elevation snow melt. The expected daily peak this
morning was lower then several of the previous days due to cooler
temperatures from cloud cover and that will likely be the case for
tomorrow as well if snowmelt continues to be the only input. The
fly in the soup is how much rain the upper reaches of the Chilkat
basin will receive from a stalled weak frontal feature Saturday
night into Sunday. Possible amounts range from as low as 0.25" to
0.75" or higher through Sunday afternoon. With the combined
snowmelt and the added rain input the Chilkat River is expected to
remain above minor flood stage (but below moderate) peaking just
below 127.0 feet by early Monday, but could be lower or somewhat
higher if the expected rain input is lower or higher then
expected.


&&

.AJK WATCHES/WARNINGS/ADVISORIES...
PUBLIC...None.
MARINE...Small Craft Advisory for PKZ661.

&&

$$

SHORT TERM...EAL
LONG TERM....STJ
AVIATION...JG

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