High Wind in Alaska, February 14 to 15, 2019

Southeast Alaska Forecast Discussion
National Weather Service Juneau AK
249 PM AKST Thu Feb 14 2019

.SHORT TERM...A low that produced snow over the southern half of
the Panhandle yesterday continues to move off to the southeast.
High level clouds continue to flow north from the low over the
Panhandle, however the primary wind regime is a stiff
north or northeasterly outflow wind. The dry, interior airmass is
doing a thorough job of drying out the panhandle and dissipating
the low and mid level clouds. The lower airmass is thoroughly
mixed and quite windy in some spots, so fog is not a concern for
this short term forecast period. Overnight lows will drop lower
than last night owing to the cold interior airmass flowing over
the panhandle as well as the clearing skies. With thorough
vertical mixing, no nocturnal inversions are expected anywhere
with an appreciable about of wind tonight. Windy spots include
those places closest to the Coast Mountains - Skagway, Juneau,
Taku Inlet, and other interior passes such as the Stikine River
Delta. Even Hyder at the north end of Portland Canal is gusting to
near 30 mph this afternoon. Strong wind headlines issued for
Skagway and Juneau. Strongest winds for the northeast gulf coast
were far enough east of Yakutat and any populated area that the
headline for zone 17 was omitted. Gales or small craft advisories
for the northern and central inner channels. Storm warning
through this evening for southern Lynn Canal where sustained winds
have been consistently at or above 50 kt all day long with gusts
in the 70s. Cold air temperatures and winds this strong will
result in some freezing spray.

Used an ensemble approach to update for pressure with little
change from previous forecast. Manual updates to winds on the
inside. Used latest NAM Nest for winds over the gulf. Temperatures
adjusted down in response to clearing skies and cold outflow
winds. Overall forecast confidence is above average. No
precipitation potential till Saturday night.

.LONG TERM.../ Saturday to Thursday / Aloft the upper level trough
along the coast will be moving east into the western Canada and
Pacific Northwest. A ridge with a high amplitude from the central
pacific to the Arctic Ocean Saturday will be flattened and shoved
eastward by a trough exiting from a low from the far western
Bering Sea. The trough by early monday will move through with a
general zonal type flow pattern, and 150+ kt jetstream headed east
to the western gulf.

Mid range models have fairly good agreement to late Sunday, with
a surface low tracking across the northern gulf along the central
gulf coast. The front will sweep across the panhandle. A second
low and system is trailing over Bristol Bay. The second front will
move into the area on Tuesday.

With the colder air entrenched over the panhandle, expect the
precipitation to start as snow, Saturday to Monday. There is some
warming, incoming with the from front mainly from south and along
the southern coast so it may mix with rain. Will need to keep an
eye on this system as the potential for heavier snowfall.

In the  later time periods the model solutions are not in that
good of agreement so the longer range model adjustments was based
on a blend of the ensemble means.

&&

.AJK Watches/Warnings/Advisories...
PUBLIC...Strong Wind through Friday afternoon for AKZ018-025.
     Strong Wind until 3 PM AKST this afternoon for AKZ017-019.
MARINE...Storm Warning for PKZ013.
     Gale Warning for PKZ012-022-031-032.
     Small Craft Advisory for PKZ021-033-034-041>043-051.

&&

Fritsch/JB/DDH

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