Gale Warning 290, NWS Juneau, AK

Southeast Alaska Forecast Discussion
National Weather Service Juneau AK
312 PM AKST Sat Dec 8 2018

.SHORT TERM...The active weather pattern continues through the
short term with Winter Storm Warnings and High Wind Watches all in
effect over the next 24 hours.

Current satellite imagery depicts robust activity over the gulf
and northern Pacific with multiple low pressures systems visible,
as well as a storm force weather front stretching along the
eastern gulf waters. This front will push inland through the
evening hours raising many of the inner channels to gale force
winds and producing strong winds across much of the Panhandle.
Two winter storm warnings are in effect associated with this
front, as well tonight through tomorrow morning. The first is for
the high elevations of the Klondike Highway primarily near White
Pass, where cooler temperatures and abundant moisture will
provide favorable conditions for around 1 foot of snow to fall by
late tomorrow morning. Visibility may become a concern during the
periods of heaviest snowfall, as sustained winds remain between
20 and 30 mph. The second winter storm warning is for the Haines
Highway primarily near the border with Canada. Cooler temperatures
currently in place coupled with enhanced cooling through
precipitation are expected to bring surface conditions back below
freezing this evening allowing better 5 and 8 inches of snowfall
to accumulate by late Sunday morning. At low elevations elsewhere
all precipitation should fall as rain.

Tomorrow another low pressure system develops rapidly over the
northern Pacific and looks to track inland near Cape Decision.
Strong winds and a possibility of High Winds are associated with
this low. The ultimate track of this system remains uncertain with
models continuing to trend the system northward; however, high
winds are possible especially from the back side of the low as a
sting jet likely develops. This supports a strong likelihood of
storm force winds developing briefly near Cape Decision as well as
strong gales and possibly storm force winds for Clarence Strait,
Sumner Strait, Southern Chatham, and Frederick Sound. High wind
potential is greatest for Prince of Wales Island as well as areas
near Ketchikan dependent upon the ultimate track of the system.
Besides the wind there is a slight chance of thunderstorm
development on the back side of the low which could track a few
cells into Prince of Wales Island and Southern Baranof Island.

While a slight break will occur in-between systems, Monday does
not offer much of a reprieve as yet another storm force front
enters the gulf by Monday Afternoon. Overall forecast confidence
remains high through Sunday morning with above average confidence
in Sunday's forecast, but below average confidence in the exact
track of the storm. Monday's forecast can best be described by
average confidence as timing and placement of the front are likely
to see some change still.

.LONG TERM.../Monday through Saturday/...Wet and windy pattern
likely to continue through next week across Southeast Alaska.
Large scale pattern seems to remain fairly consistent with a broad
upper low over the Bering and a strong North Pacific flow
transporting a series of progressive systems through the Gulf.
Snow levels expected to lower across the northern panhandle by mid
week, but snowfall at sea level expected to be confined to the
far north.

Models are in good agreement of a strong polar jet entering the
western Gulf early Monday. As the jet slides across the southern
Gulf, an upper wave develops and spins up a strong low pressure
system into the Gulf Monday. A strong front, possibly storm
force, is expected to move into the eastern Gulf and progress
eastward through the panhandle sometime Monday night into early
Tuesday. Model solutions are not in very good agreement though
with the strength and track of the surface low. Ensembles and
model guidance suggest upper troughs rotating around the mean low
will continue through late week. Strong fronts will possibly move
through late Wednesday into early Thursday, and again sometime
Saturday. Forecast confidence is average through the mid-range.

&&

.AJK Watches/Warnings/Advisories...
PUBLIC...High Wind Watch from Sunday morning through Sunday afternoon for
     AKZ026>028.
     Strong Wind through late tonight for AKZ023-026-027.
     Strong Wind from 6 PM to 9 PM AKST this evening for AKZ024.
     Strong Wind from midnight AKST tonight through late tonight for
     AKZ024.
     Strong Wind until 9 PM AKST this evening for AKZ022.
     Strong Wind Sunday afternoon for AKZ023.
     Strong Wind until midnight AKST tonight for AKZ017-021.
     Strong Wind through late tonight for AKZ028.
     Winter Storm Warning from 6 PM this evening to 9 AM AKST Sunday
     for AKZ018-019.
MARINE...Storm Warning for PKZ036-041>043-051.
     Gale Warning for PKZ022-031>035-052-053.
     Small Craft Advisory for PKZ011>013-021.

&&

JB/DDH

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