Gale Warning 15, NWS Juneau, AK

Southeast Alaska Forecast Discussion...CORRECTED
National Weather Service Juneau AK
816 PM AKST Sat Jan 1 2022

.SHORT TERM.../Through Sunday night/...The parent low from the
New Year's storm has morphed into several circulations over the
northern gulf, with the most robust circulation well SW of Yakutat
this afternoon. This has opened the door for onshore showers to
rotate into the Panhandle. In addition to the onshore flow, and
cold air advection aloft, there is local surface convergence and
terrain that will work to enhance the snow showers. The showers
are expected to continue through midnight for the northern zones,
Sunday morning for the central zones, and Sunday evening for the
southern zones. For the northern zones, precipitation type is
expected to be mostly snow with these showers with up to 3 inches
possible overnight. A Winter Weather Advisory was issued for
Juneau for 3-5 inches of new snow as there is higher confidence
that accumulating snow will fall there. For the central and
southern zones, as the band slides south, the forecast is for rain
to transition back to snow, with around 2 inches of snowfall
before ending. Trends will need to be monitored for precip-type
surprises - if rain transitions back to snow sooner than forecast,
snow amounts overnight into tomorrow will be higher. After the
areas of low pressure over the gulf slide south, support for snow
will shut off and we get into part two of the short term forecast.

The next forecast concern becomes the northerly outflow setup. An
upper level trough over the region will become highly amplified
opening the gates for deep arctic air to spill into the
panhandle. A surface high in the Yukon (modeled around 1052mb)
along with low pressure south of the panhandle makes for an
impressive North-South pressure gradient. Storm force northerly
winds are forecast to develop in Lynn Canal on Sunday with gales
in the other northern inner channels (Stephens, Icy Strait, Cross
Sound, Chatham Strait). Storm force winds are also in the forecast
for the outside waters in the outflow areas. Heavy freezing spray
will also become a concern for Lynn Canal, Glacier Bay, and the
outside waters. High winds are expected for Skagway and the Taku
wind area in Downtown Juneau / Douglas. There is less confidence
on timing for Downtown Juneau, but periods of high winds are
likely. See the high wind warnings for details on the timing.
Elsewhere it will be breezy / windy at times, and with all the new
snow on the ground, expect plenty of blowing snow. Add very cold
air (lows near or below zero Sunday night) and the weather is
expected to become very harsh, even for SE AK standards.

.LONG TERM.../Monday through Thursday Night/ As has been the case the past
several days, the forecast challenge for the long term will be the
winds, namely where and how long they will last. Winds look to be
far more impactful through the northern portion of the panhandle as
high pressure in the Yukon continues to build creating a rather
impressive pressure gradient. This should promote storm force winds
through Lynn Canal and gales through the inner channels to the
south. For downtown Juneau, cross barrier flow should be well
established and guidance is indicating that a critical level could
be fluctuating in and out which could be the precursors for a Taku
wind event for Downtown Juneau. This uncertainty regarding the CL
really only gives us enough confidence to carry a High Wind headline
for Juneau into Monday night. The High Winds blowing out of Skagway
and White Pass on the other hand, could very well carry on for a few
days if the pressure gradient remains at the current forecast
strength. While further extensions of the warning may become
necessary as new guidance comes in, have for now opted to extend it
to noon on Tuesday and then carry strong winds for the duration of
the forecast period. Fresh snow in many locations where these
stronger winds are expected will also bring about blowing snow which
will likely lead to decreased visibility and yet another hazard to
travel.

Aside from the winds, the only other notable feature of the forecast
is the much below normal temperatures featured in the forecast.
Offshore flow around the high will be pushing exceptionally arctic
air over the region. The forecast remains unchanged as no
qualitative adjustments could be determined with current model runs,
it's just too darn cold, try not to be out in it for much time if
you can help it. If you required any more prodding to stay indoors,
many areas could see very uncomfortable and in some cases dangerous
wind chills. One further impact for marine interests, the
combination of the wind and cold will also lead to freezing spray
which will likely become heavy in some locations.

&&

.AJK WATCHES/WARNINGS/ADVISORIES...
PUBLIC...Strong Wind from 3 AM AKST Sunday through late Sunday night for
     AKZ026.
     High Wind Warning from midnight tonight to 9 PM AKST Monday for
     AKZ025.
     Winter Weather Advisory until midnight AKST tonight for AKZ025.
     Strong Wind from Sunday morning through late Sunday night for
     AKZ020>022.
     Strong Wind from Sunday morning through late Sunday night for
     AKZ023.
     Strong Wind from 9 PM AKST this evening through late Sunday
     night for AKZ019.
     High Wind Warning from midnight tonight to noon AKST Tuesday for
     AKZ018.
     Winter Storm Warning until 9 PM AKST this evening for AKZ017.
MARINE...Heavy Freezing Spray Warning for PKZ053.
     Heavy Freezing Spray Warning for PKZ051.
     Heavy Freezing Spray Warning for PKZ011-013.
     Heavy Freezing Spray Warning for PKZ012.
     Storm Warning for PKZ012-013-043-051.
     Gale Warning for PKZ011-021-022-031>034-052-053-310.
     Small Craft Advisory for PKZ035-036-041-042.

&&

BFL/JDR

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