Sitka, Alaska 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

519
FXAK67 PAJK 232352
AFDAJK

Southeast Alaska Forecast Discussion
National Weather Service Juneau AK
252 PM AKST Sat Nov 23 2024

.SHORT TERM...Winds across the panhandle today have started to
trend downward but some areas are still seeing strong winds. With
the winds trending down, we have been able to let the high wind
warning expire for Juneau. With the decreased winds and clear
skies for the area, temperatures will remain cold during the
overnight hours. With the continued cold and clear pattern, only
minor changes were made to the wind and left the rest of the going
forecast. The only changes made for the short term was to
increase the possibility of precipitation for the NE Gulf coast as
chances are starting to increase late in the period.

.LONG TERM.../Monday into Thanksgiving/...

Any chance of precipitation returning to the panhandle rests on the
blocking ridge over the western gulf breaking down. Ensemble models
are trending towards a stronger shortwave moving down from the
Bering Sea, successfully bringing some precipitation chances to
the northern half of the panhandle. Current forecast continues to
reflect pessimistic snowfall totals for Monday through Tuesday.
While the forecast leans toward higher snow totals, the story of
snow is actually much more uncertain. While the overall setup for
heavy snow is present, ultimately, what hinges on this forecast is
the available moisture for snow development. 850 mb winds from the
S to SW flowing over a reinforcing stable layer from northerly
winds down Lynn Canal will remain persistent for more than 24
hours. Currently, just north of Icy Strait, impressive
frontogenesis at 850-700 mb looks to stick around, driving
heavier snowfall. Furthermore, maximum omega, around -30 ubar/s at
 -10 degrees C. At this point, most moisture is in the lower
levels of the atmosphere with relative humidities above 700 mb
being increasingly uncertain. If the profile is more moist than
expected, then northerly winds along with moderate to heavy
precipitation rates will keep the entire event for the Icy Strait
Corridor as snow.

Following the initial shortwave, a secondary shortwave moving
along the initial ridge Wednesday and Thanksgiving may reignite
snowfall for the Juneau area, may push the main snowfall band
southward, or may be weak enough that northerly dry air will limit
any precipitation from developing. Ultimately, observing upstream
how each shortwave behaves will be paramount to determining how
each system next week will behave. Stay tuned for updates.

&&

.AVIATION...VFR conditions with clear skies and full visibility
will continue here in SE AK through tonight. Still dealing with the
strong outflow winds this afternoon but the LLWS looks to lighten
up this evening. Smoother flying weather in store late Saturday
night into Sunday.

&&

.MARINE...Outflow winds are expected to continue through the
evening but have already started to trend downward across
portions of the panhandle. Elevated winds and seas are still
possible through the Inner Channels as well as along the outer
coast near entrances to the Inner Channels. Winds will continue
their downward trend as the east west channels become more
favored. These channels will still see some strong winds but
should still a trend downward headed into next week before our
next system moves into the panhandle.

&&

.AJK WATCHES/WARNINGS/ADVISORIES...
PUBLIC...Strong Wind until 3 PM AKST this afternoon for AKZ318.
     Strong Wind from Sunday morning through Sunday afternoon for
     AKZ318.
     Winter Storm Watch from late Monday night through Tuesday
     evening for AKZ320>322-325.
     High Wind Warning until 3 PM AKST this afternoon for AKZ325.
     Strong Wind until 9 PM AKST this evening for AKZ325.
MARINE...Gale Warning for PKZ012-013-662.
     Small Craft Advisory for PKZ031>034-641>643-661-663.

&&

$$

SHORT TERM...SF
LONG TERM....NC
AVIATION...GJS
MARINE...SF

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