Gale Warning 17, NWS Juneau, AK

Southeast Alaska Forecast Discussion
National Weather Service Juneau AK
241 PM AKST Tue Jan 8 2019

.SHORT TERM.../Through Thursday night/ A changing weather pattern
is on tap for the short range as a new front starts moving in from
the south over the next 24 hours. The first effects will be an
increase in outflow winds across the northern half of the
panhandle as the advancing front tightens pressure gradients.
Winds in Lynn Canal expected to increase to storm force by Wed
with equivalent winds out of Taku Inlet and other passes. High
wind watch up for the Skagway area for tomorrow as all the cold
air flowing down from Canada increases wind gusts to possibly 60
mph. High wind warning also remains up for downtown Juneau and
Douglas for high wind gusts (up to 75 mph) late tonight into Wed
evening as the Taku wind start acting up again.

In addition, the advancing front will start to spread precip
across the southern half of the panhandle tonight. Temperatures
should be cold enough for snow to start out with for many areas
even down to Ketchikan and Hydaburg. Decided to issue some winter
weather advisories for Prince of Wales, the Southern Inner
channels and Central Inner channels. Ketchikan, Metlakatla, and
Klawock will likely see around 3 inches of snow before warm air
get into the area enough to change it over to rain by midday Wed.
Petersburg, Wrangell, and Kake will have to wait until midday wed
before they start seeing the precip and precip rates will likely
stay low until Wed night when 3 to 6 inches of accumulation is
possible. Change over will then occur sometime Thu morning. Areas
farther north likely will not see precip until late Wed night at
least.

Changes mainly dealing with local effects with wind and snow. Used
Gfs and Nam for updates.

.LONG TERM.../Thursday through Monday as of 10 pm Monday/ Active
weather pattern likely through the long range across Southeast
Alaska. At the beginning of this period, a front with
significantly warmer temperatures over the southern panhandle will
get a push from a second front and continue moving northward.
Across the northern panhandle outflow conditions and colder than
normal temperatures will likely persist through the day Thursday.
Precipitation with this front, likely starting out as snow, will
quickly change over to rain early in most areas near sea level in
the southern panhandle. The rain/snow line will likely set up near
Sumner Strait through Friday morning. As the front progresses
northward, expect snow to spread across the northern panhandle by
late Thursday, increasing overnight into Friday. The rain/snow
line will continue to gradually push north, and by late Friday to
early Saturday be somewhere near Icy Strait. Models are currently
indicating some high QPF values over the 24-hour period from
Thursday night through Friday night, so will need to keep an eye
on chance of an overrunning accumulating snow event.

Another front looks to approach SE Alaska from the southwest late
Saturday. Upper trough sliding over the Gulf and into the
panhandle through early Sunday. Warmer air will continue to be
advected northward, likely pushing the rain/snow line near sea
level further north. Uncertainty in forecast this far out leads
us to keep rain/snow mix along the Icy Strait corridor northward
through the weekend and into next week. Long range model guidance
continues to suggest another front moves through Monday. Decent
agreement between the models Thursday, so opted use GFS and NAM
for updates through early Friday. The WPC solution was also used
later on for minimal updates to the previous forecast. Overall
forecast confidence is average.

&&

.AJK Watches/Warnings/Advisories...
PUBLIC...Winter Weather Advisory from noon Wednesday to 9 AM AKST
     Thursday for AKZ026.
     Winter Weather Advisory from 3 AM to noon AKST Wednesday for
     AKZ027-028.
     High Wind Warning from midnight tonight to 9 PM AKST Wednesday
     for AKZ025.
     Strong Wind from Wednesday morning through Wednesday afternoon
     for AKZ019.
     High Wind Watch from Wednesday morning through Wednesday
     afternoon for AKZ018.
     Strong Wind from midnight AKST tonight through late tonight for
     AKZ018.
     Wind Chill Advisory from midnight tonight to 6 AM AKST Thursday
     for AKZ018.
MARINE...Heavy Freezing Spray Warning for PKZ012-013.
     Storm Warning for PKZ012-013.
     Gale Warning for PKZ022-031-032.
     Small Craft Advisory for PKZ011-021-033>035-041>043-051.
     Small Craft Advisory due to Seas for PKZ052.

&&

EAL/DDH

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