Sitka, Alaska 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

764
FXAK67 PAJK 211229
AFDAJK

Southeast Alaska Forecast Discussion
National Weather Service Juneau AK
329 AM AKST Thu Nov 21 2024

.SHORT TERM.../Through Thursday/... The forecast remains largely
unchanged, with an ongoing outflow even likely to continue through
the remainder of the week. A broad area of ridging over Alaska
remains entrenched, as a blocking pattern increasingly takes hold
with sharp areas of troughing on either side serving to mitigate
any imminent departure of the ridge. For SE AK, this means that
cold weather, clear skies, and wind look set to continue. The wind
will at least marginally diminish in some areas for much of
Thursday as the pressure gradient weakens somewhat in conjunction
with a decaying low located W of Washington State. However, the
decaying low will be replaced by a new low as cyclogenesis occurs
along the SE periphery of the trough axis, and so expect
wind speeds to begin ramping back up again by Thursday night into
Friday.

Still anticipate windy conditions for many land-based locations,
though think that at least for downtown Juneau and Douglas, wind
gusts will drop below 60 mph beyond early Thursday morning. Only
minimal changes were to made to the forecast - mainly to
temperatures through the current time frame in order to reflect
the (somewhat) warmer conditions caused by turbulent mixing.
Forecaster confidence is above average.

.LONG TERM.../Friday into early next week/... Blocking pattern
developing over the region means that conditions will remain
relatively unchanged through the weekend and into early next week
across the panhandle. High pressure will continue over the
interior, though may shift further east into British Columbia by
the start of next week. This could lead to a slight weakening of
northerly outflow winds, but enhance outflow winds from NE and
easterly oriented valleys and interior passes.

Any chance of precipitation returning to the panhandle rests on the
blocking ridge over the western gulf breaking down. Deterministic
models are attempting to do so, or at least weaken the ridge such
that a short wave can develop in the northern gulf. If this comes to
fruition, snow showers could be expected along the outer coast
sometime Monday into Tuesday with the potential to reach into the
Icy Strait corridor and central panhandle. However, ensembles
guidance are still leaning towards the ridge remaining strong into
early next week. For those looking for more snow, this potential
trough early next week looks to be fairly dry with ensemble
guidance suggesting 24 hr snow totals of 1.5 to 2.5 inches by
Wednesday.

This far out, there is a high confidence in the overall synoptic
pattern with outflow winds continuing and relatively dry conditions
through the weekend. With no significant storms currently showing up
in model guidance in the mid and long range, the blocking ridge
could be around for a while, which means generally below normal
temperatures and continuing dry conditions potentially into the
Thanksgiving holiday.

&&

.AVIATION...VFR SKC with outflow winds continuing. LLWS and
turbulence through the morning before winds at ridgetop diminish
for a few hours. Expect elevated NE winds at ridgetop to return
Friday.

&&

.MARINE...Gale force outflow winds through northern inner
channels and interior passes/river valleys for the northeast gulf
coast, and out of Cross sound. With the persistent winds in Lynn
Canal and down Chatham Strait, have enhanced seas through
Thursday. Winds diminish a bit on Thursday for some of the inner
channels before intensifying again late Thursday night into
Friday.

&&

.AJK WATCHES/WARNINGS/ADVISORIES...
PUBLIC...Strong Wind through this afternoon for AKZ318.
     Strong Wind until 6 AM AKST early this morning for AKZ319.
     High Wind Warning until 6 AM AKST early this morning for AKZ325.
     Strong Wind from 6 AM this morning to noon AKST today for AKZ325.
MARINE...Gale Warning for PKZ012-013-031-644.
     Small Craft Advisory for PKZ011-022-032>036-641>643-651-652-
     661>664-671-672.

&&

$$

SHORT TERM...GFS
LONG TERM....STJ
AVIATION...GJS
MARINE...GFS
HYDROLOGY...99

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