Area Forecast Discussion
Issued by NWS Juneau, AK

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FXAK67 PAJK 212258
AFDAJK

Southeast Alaska Forecast Discussion
National Weather Service Juneau AK
258 PM AKDT Thu Mar 21 2024

.SHORT TERM.../Through Friday night/ Very quiet short range
forecast today with mostly light winds and mostly clear skies
continuing. Temperatures once again are shooting up into the 40s
and 50s after morning lows below freezing. Temperature pattern is
expected to remain mostly the same through Fri night with
overnight lows near or below freezing and daytime highs reaching
up into the 40s and low 50s again (raised Fridays highs compared
to previous forecast using a more persistence approach). Some
more higher clouds expected overhead Friday may cool highs by a
few degrees, but it will not be by much.

Only other concern is the marine layer clouds and fog that
persists in the gulf. This morning it invaded Yakutat, Cross
Sound, Pelican, and briefly western Icy Strait before retreating
back out into the gulf by afternoon. It will make another run
tonight but a little more offshore flow may keep it out over the
gulf for most areas other then Yakutat and maybe Cross Sound
before it retreats again Friday afternoon. Friday night features
a little more onshore flow so the marine layer clouds will likely
invade further into the Icy Strait, and Peril Strait areas late
Friday night.

.LONG TERM...
As a Rossby wave shifts east across the northern Pacific, the jet
stream will begin to steer the storm track into the area,
bringing a 976mb surface low in the Bering Sea through Saturday
night. While most impacts will remain west of our region, a
tightening pressure gradient at the surface will bring enhanced
winds and increase the southwest swell along our northern coast.
Current prognosis indicates SW 10-12 feet around 12-15 seconds by
Sunday afternoon. If the low shifts further east than anticipated
and dynamics aloft can further reduce the surface pressure,
higher significant wave heights of 12-14 feet could form west of
Yakutat. Confidence is very low in this outcome.

While the parent storm in the Bering Sea stalls Monday, a series
of secondary lows will migrate east across the Gulf into the
Pacific northwest, bringing periods of somewhat active weather
through the midweek. The most potent of these storms will transit
south of the Gulf Wednesday, with uncertainty in how far north it
will shift. Current ensembles favor a more southerly trajectory
which would drastically limit wind impacts for our marine zones.
If this storm lifts further north than anticipated, it will bring
stronger winds to the southern coast and inner channels near Dixon
by later Wednesday.

Regarding precip, our remarkable dry streak will try to end
Sunday night into Monday as some moisture is carried into the
Panhandle; however, rates and 24-hour totals look very limited.
850mb temperatures are also indicative of rain for most locations,
with current ensemble solutions highlighting a mean snow level
somewhere near 1000 to 2000 feet. With that said, snow concerns
remain very low for the majority of the region outside of the
northern coast, but sea level locations will struggle to pick up
any impacts. Some light rain, to perhaps dry conditions and a
marine layer along the coast, prevails Tuesday afternoon into
Wednesday morning. All remains quiet on the southeast front.

&&

.AVIATION...Low to mid level flow across SE Alaska is generally a
light northerly and that is expected to continue over the next 24
hours. Some locations have seen a shift to their sea breeze
direction during the daytime followed by a light reversal/drainage
direction in the evenings. Marine layer clouds pushed into Yakutat
late last night then progressed halfway down Icy Strait through
Thursday morning and around Kruzof Island near Sitka. Less
confident in how far it will spread Friday morning, but they often
repeat or expand for a couple nights. Will be keeping a close eye
on the night-time microphysics satellite imagery to see how much
is expands.

&&

.AJK WATCHES/WARNINGS/ADVISORIES...
PUBLIC...None.
MARINE...Small Craft Advisory for PKZ661>663.

&&

$$

SHORT TERM...EAL
LONG TERM....AP
AVIATION...Ferrin

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