733
FXAK67 PAJK 241759
AFDAJK

Southeast Alaska Forecast Discussion
National Weather Service Juneau AK
959 AM AKDT Mon Jun 24 2024

.UPDATE...Update to aviation section to account for 18z TAF
issuance.

&&

.SHORT TERM...Minor changes to the ongoing forecast. For winds,
large scale thermal gradients from clearing skies in British
Columbia and the Yukon yesterday and again today will cause
enhanced wind speeds in the inner channels, particularly for Icy
Strait/Point Couverden area, northern Stephens Passage, and
northern Lynn Canal. Expect wind speeds to maximize during the
afternoon around 20 knots for any area mentioned.

For precipitation, made edits to PoPs to bring up chances around
Petersburg and Juneau during the early morning, and continuing the
trend westward across to Pelican through early afternoon. This is
due to some vorticity advection making its way westward, providing
some minor upward motion in a very moist atmospheric profile.

.LONG TERM...Continuing from the short range, the extended
forecast once again remains relatively unchanged with lingering
showers diminishing into Tuesday, followed by a warming and
drying trend. Models continue to come into agreement for a
surface ridge 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 and warmer
temperatures at 850 mb. High temperatures in general are set to
reach the upper 60s and low to mid 70s for a majority of the
panhandle in the latter half of the week. This will also lead to
generally light winds overall throughout the panhandle. With low
pressure developing during daytime over BC, there remains a slight
chance for showers to develop but are expected to struggle to
make it past the Coast Mountains. Expect the highest winds with
the usual sea breeze circulations in the afternoon and evening
hours, such as Taku Inlet. Being on the downstream side of the
ridge, the exception to otherwise clearer skies would be any
marine layer potentially moving into coastal communities which in
turn could limit daytime warming.

As is often the case, model guidance is not in full agreement on
the longevity of the blocking ridge in the upper levels and
subsequent surface high in the northern gulf. The strength and
position of this high pressure over the northern gulf will
strongly influence when more organized unsettled weather will
make its way back into the panhandle. Ensemble guidance is leaning
towards bringing a system into the southern gulf sometime
Friday/Saturday. Depending upon its strength and track, this could
cause easterly showers to develop and propagate over the southern
panhandle during this time.

&&

.AVIATION...../For 18z TAF issuance/...Aviation concerns this
morning are the low clouds. Surface stations are reporting cloud
decks around 1500 to 3000 feet with a few stations (Yakutat, Elfin
Cove, Juneau, Klawock as I write this) reporting ceilings of 600
to 1200 feet. Poking around the webcams over the marine inner
channels, estimate cloud decks are around 1500 to 2500 feet.

Visibility has been reduced mainly because of a few rain showers and
drizzle, down to around 3 miles with conditions improving over the
last few hours.

Wind speeds aren`t too high, mainly around 5 to 10 knots.

Going forward, not a lot...but some improvement is expected today.
IFR conditions are expected to improve to MVFR. Those with MVFR
conditions should see conditions improve to low-end VFR. Some spots
of low-end VFR this morning will more-or-less remain low-end VFR.

Later today into today, weak trough tracking north would lower
conditions tonight. So overall, expecting IFR to low-end MVFR again
tonight. For the northern half of the panhandle, isolated and
temporary LIFR cloud decks can`t be completely ruled out with LIFR
probabilities around 10 to 30% during the overnight hours.

&&

.HYDROLOGY...The Chilkat River continues to run right around
minor flood stage today and is expected to continue to fluctuate
right around minor flood stage into the early part of the week.
Temperatures aloft are expected to remain mostly high and are even
expected to increase later in the week as clouds depart the area
leading to more runoff from high elevation snow melt. As such the
river is expected to remain near or above minor flood stage for
the next few days at least. The result is that the Flood Advisory
has been extended again for the Chilkat. It now ends at 7 pm
Wednesday and may be extended further in the coming days depending
on how much snow is left to melt in the upper reaches of the
basin.

&&

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

&&

$$

SHORT TERM...NC
LONG TERM....STJ
AVIATION...GJS

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