Winter Weather Advisory 49, NWS Juneau, AK

Southeast Alaska Forecast Discussion
National Weather Service Juneau AK
318 PM AKST Tue Nov 30 2021

.SHORT TERM...A second wave from the parent low near Cordova is
passing over our region through this evening, with the third front
passing Wednesday morning. After each wave passes, expect
temperatures and winds to increase. This was evident today, as
Ketchikan reached 50 degrees today and Wrangell experienced
strong wind conditions (Zarembo island recorded a gust to 47 kt)
on the south side of the low that came in with this wave.

Similar wind conditions are expect tomorrow, with strong winds
noted in Sitka, Port Alexander, Hydaburg, and Ketchikan, with
gusty conditions elsewhere. This next weak low is expected a
little further north tomorrow, resulting in stronger winds in
Sitka tomorrow than today. Gale-force winds are in the forecast
for early this evening for the gulf waters and pick up again
Wednesday morning with the third wave.

After the third wave passes tomorrow, expect a decrease in
temperatures. This temperature decrease will change the
precipitation type from rain to snow, resulting in the likelihood
of accumulating snowfall across the entire panhandle. From
Wednesday afternoon through Thursday afternoon, 4 to 8 inches
expected in Yakutat, Gustavus, Pelican, Juneau, Sitka, and
Petersburg with higher amounts in Hyder. For more details, please
see the Winter weather advisories posted.

Moderate confidence in winds, but lower confidence on timing of
the third wave and when we will see those temperatures start to
drop. Kept a rain/snow mix in longer during the day Wednesday to
accommodate the lower certainty in timing.

.LONG TERM.../Thursday through Saturday Night/...The mid-range
forecast begins with a vertically stacked low over the northern
gulf of Alaska. From Thursday through Friday, this area of low
pressure will weaken. The 500mb low will be absorbed into an
invading trough coming in from the north. The surface low tracks
eastward while fading out.

To simplify, the continued showery pattern continues for SE AK.

Only this time, ensemble average 850mb temps around the entire
panhandle for Thursday and Friday will range from at warmest -8C
in the south to -15C in the north. So, snow showers are much more
likely than rain/snow mix or rain showers.

But because of the showery nature, confidence for exact snowfall
amounts is low due to wide variability that showers create. So
overall, would expect a “1-4 inches of snow every 12-24 hours”
type of weather going into the weekend - just enough to keep us
busy but nothing super out of the ordinary for early December in
SE AK.

One exception would be Hyder where daily amounts could be higher.

&&

.AJK WATCHES/WARNINGS/ADVISORIES...
PUBLIC...Strong Wind until 6 PM AKST this evening for AKZ027-028.
     Strong Wind from Wednesday morning through Wednesday afternoon
     for AKZ027-028.
     Winter Weather Advisory until 11 PM AKST this evening for AKZ025.
     Strong Wind Wednesday afternoon for AKZ023.
MARINE...Gale Warning for PKZ022-036-041>043-310.
     Small Craft Advisory for PKZ021-031>035-051>053.

&&

KRT/GJS

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