Gale Warning 271, NWS Juneau, AK

Southeast Alaska Forecast Discussion
National Weather Service Juneau AK
303 PM AKST Sun Nov 22 2020

.SHORT TERM...A weakening low south of Sitka will fall apart as it
pushes east into the south central panhandle. Rain associated with
this trough has pushed as far north as Gustavus and Juneau. Am
expecting this to continue through the evening before precipitation
dissipates ahead of the next approaching frontal band.

The Monday front will have ample wind and seas associated with it.
Outer coastal winds to 35 to 55 kt winds, with the strongest winds
in the northeast gulf. The parent low will continue to move
southeast and this will increase winds again Monday night for the
southeastern gulf. With all of this wind, we should see higher seas
as well. Expect to see 25 to 33 ft seas for coastal areas south of
Sitka and eastern portion of the offshore marine zone.

Rains will be the primary precipitation type for much of the
panhandle. Forecast totals range from 1 to 2 inches. Misty Fjords
and the northern panhandle will start as snow, with the rain-snow
line pushing north and east on Monday changing precipitation over to
rain or mix. Only Northern Lynn Canal area is expected to stay snow,
however the majority of the energy and moisture will also be
tracking more southward. Should see the Haines Highway receive 3 to
5 inches and roughly 3 inches on the Klondike Highway.

Through Tuesday the parent low will track southeast and this will
draw the precip along with it. A high pressure ridge from the
surface and aloft will assist with the brief drying trend. Northerly
outflow of moderate speeds will form through Lynn Canal late Tuesday
night because of the Yukon high and the low moving to Haida Gwaii.

.LONG TERM.../Wednesday through Sunday night/...As of Saturday
evening. By Wednesday morning, any remaining shower activity will
move inland in advance of the next approaching front. Model guidance
for winds associated with this mid-week front is quite divergent,
ranging from small craft winds to solid storm force, so current
confidence in this aspect of the forecast is definitely below
average. Associated precipitation should arrive over the northeast
Gulf coast by Wednesday afternoon as rain. Overnight lows will
likely result in a transition to snow over more inland northerly
locations, but the outer coast and southern Panhandle will likely
remain in rain through the night.

By Thursday evening as we leave the more deterministic portion of
the forecast for the more probabilistic section, model agreement
diminishes significantly. However, GFS and ECMWF are currently in
extremely good agreement on another powerful and moisture laden
front affecting Southeast Alaska Saturday through Sunday night.
GFS and the Canadian NH are also in good agreement on this weekend
storm being a high end gale event. If model agreement continues
to be this good on the wind field, look for subsequent forecasts
to reflect this with increased weekend winds over the eastern
Gulf.

&&

.AJK WATCHES/WARNINGS/ADVISORIES...
PUBLIC...Strong Wind from Monday morning through Monday afternoon for
     AKZ023-027.
     Winter Weather Advisory from 9 AM to 9 PM AKST Monday for AKZ019.
MARINE...Storm Warning for PKZ043-051-052.
     Gale Warning for PKZ034-036-041-042.
     Small Craft Advisory for PKZ012-013-021-022-031>033-035-053.

&&

Bezenek/Fritsch

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