Gale Warning 299, NWS Juneau, AK

Southeast Alaska Forecast Discussion
National Weather Service Juneau AK
402 PM AKST Wed Dec 12 2018

.SHORT TERM.../Through Thursday night/...The next in a series of
storm force lows will cross the eastern gulf tonight and come
ashore over southern Baranof Island early Thursday morning. The
low is forecast to weaken overnight, thus no high wind warnings
have been issued for the central or southern outer coast. Strong
wind gusts in excess of 40 mph are, however, expected for Prince
of Wales Island with emphasis on those locations vulnerable to a
west or northwest wind. Strong wind gusts in the vicinity of
Clarence Strait as well as downtown Juneau have been blowing all
day, but are expected to diminish later this evening. Winds
across Southeast Alaska forecast to diminish significantly on
Thursday night. The low will generate seas from 20 to 30 feet over
the southern half of the eastern gulf tonight with seas 10 to 20
feet for the northern half. Peak conditions expected to occur
before morning, and like the winds, will subside somewhat through
Thursday night.

Showers associated with the storm are forecast to produce snowfall
tonight through tomorrow mid afternoon with accumulations of up to
3 inches tonight and another 3 inches tomorrow for some locations.
Highest amounts forecast in Hoonah, Juneau, Petersburg, and Hyder.
Not advisory amounts, but possibly impactful because of their
occurrence overnight. A cooling trend will extend overnight lows
below freezing all the way down to the Dixon Entrance by Thursday
night, but by then, forecast PoP and QPF run out, so no meaningful
accumulations, if any at all, for the southern inner channels or
southern outer coast.

.LONG TERM...Friday through Tuesday/...Active and generally stormy
weather pattern for the long term period. Deep long wave trough
will exist at the start of the period over the eastern gulf with a
strong closed low likely existing to our south. Models are
struggling a bit with interaction between northern and southern
stream on Friday and thus with how far north precipitation from
this system will get. Thus elected to make minimal changes to
Friday at this time. Should the US models be correct, it will
likely be more clear and dry than our forecast currently depicts
with deep northerly flow promoting some outflow over the inside
waters.

Any clearing on Friday into Friday night will be short lived as
all guidance indicates the reinforcement of the deep long wave
trough over the Gulf through early next week. This will lead to
the return of southerly flow over the Panhandle and warmer,
wetter conditions. This pattern will also likely spawn one or two
deep surface lows lifting northward into the Gulf bringing more
strong winds and heavier precipitation. Some over-running snow
will be possible ahead of the first system on Saturday, however
with ridging building again in BC, there will be no mechanism to
keep continental air in place once the residual cooler, drier air
gets mixed out. Thus by Sunday into early next week, expect any
snow to be confined to the far north.

&&

.AJK Watches/Warnings/Advisories...
PUBLIC...Strong Wind Thursday morning for AKZ026.
     Strong Wind until 6 PM AKST this evening for AKZ025-027-028.
     Strong Wind from midnight AKST tonight through Thursday morning
     for AKZ027.
MARINE...Gale Warning for PKZ022-033-036-041>043.
     Small Craft Advisory for PKZ012-013-021-031-032-034-035-051-052.
     Small Craft Advisory due to Seas for PKZ053.

&&

Fritsch/DEL

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