Winter Storm Warning 16, NWS Juneau, AK

Southeast Alaska Forecast Discussion...CORRECTED
National Weather Service Juneau AK
1137 PM AKST Sat Dec 28 2019

.SHORT TERM...Rain showers will becoming more numerous this
evening as a trough passes over the region from south to north.
Just about every part of the panhandle should see a period of
showers with some gusty winds as this feature moves through. The
trough extends from a small/tightly wrapped low over the western
gulf and has multiple small vorticies along it. Have included a
slight chance of thunderstorms over the gulf, extending into
Yakutat late tonight with the trough. On either side of the
trough, showers will be fairly scattered and could be mixed with
snow at times over portions of the northern panhandle, but with
less than 2 inches along the northern borders.

Scattered showers continue on Sunday, then another gale force
front moves into the area from the west. Expect rain to become
heavy at times along with gusts to 40 mph overnight. Rain will be
the predominate p-type as temperatures remain steady or warm
through Monday morning. The exception is snow at the upper
elevations of the Klondike Highway. Have a Winter Storm Watch in
effect for the White Pass area and elevations above 2000 ft on the
highway for 6-10 inches. Some blowing and drifting snow is also
possible.

The front will still be causing moderate to heavy rain Monday
morning, especially over the southern panhandle. 1-2 inches of
rain is likely from this front.

.LONG TERM.../ Monday to Saturday as of 9 pm Friday / Southwest
flow persists into the panhandle area aloft into Tuesday while
and upper level low and trough organizes near Bristol Bay Tuesday.
A short wave diving into the Bristol Bay low shoots around it
from the north and pulls part of the energy into the northern gulf
for that last half of the week.

Monday a mid tropical source low will move quickly through the
gulf and into the panhandle. The expected rainfall is well above
average for this time of year with expected accumulation of 1.5 to
2.5 inches in the short duration the front passes through the
panhandle and southward. The Monday front looks like the
associated winds should be around gale force.

Small trough will continue Tuesday to Wednesday over the panhandle
with rain/showers continuing. When the short wave rounds its way
about the Bristol Bay area, there will be a serious batch of cold
air behind the low diving south through the Bering and then moving
over the gulf to the panhandle late Wednesday to Thursday. Even
with this long track and moderating influence of the warmer gulf
water temperatures, expect to see 850 mb temperatures lower 7 to
10 degrees Celsius ( 15 to 20 F) from Monday to late Thursday.
The much longer portions of the forecast push the very cold core
from the interior of Alaska to Northwest Canada the following
weekend.

So it looks like there will be an airmass change over the forecast
area at the end of the week. How low it will persist will be the
question most winter weather enthusiasts will be asking.

Forecast wise the GFS solution was used sparingly as some
timeframes fell more into an outlier pattern, and the forecast
stayed more along the lines of the consensus.

&&

.AJK Watches/Warnings/Advisories...
PUBLIC...Winter Storm Watch from Sunday evening through Monday morning
     for AKZ018.
MARINE...Gale Warning for PKZ052.
     Small Craft Advisory for PKZ011>013-022-035-036-041>043-051-053.

&&

Ferrin/Bezenek

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