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000
FXAK67 PAJK 262303
AFDAJK

Southeast Alaska Forecast Discussion
National Weather Service Juneau AK
303 PM AKDT Mon Oct 26 2020

.SHORT TERM...Main moisture band of heavy rain continues to lowly
slide south the southern third of the panhandle. Most the
locations will have the rain rates less to about .15 to .25 in
three hours by mid evening. and then lighter by Tuesday morning.

A surface low near northern gulf remains in place weakening.
Onshore flow remains to keep lighter rain showers into Wednesday.
Overcast conditions will continue through the time frame as well.
Some snow for White Pass as the temperatures cool down slightly
however shower activity there will be lessening.

Gusty winds through Lynn Canal this evening with gusts to 40 to 45
kt this evening. The winds will weaken through overnight and then
should stay 20 kt or less for the marine areas.


.LONG TERM...Wednesday, broad troughing in the long-wave pattern
across Mainland Alaska will result in surface low pressure
persisting across the northern gulf. With cool Bering Sea air
migrating into the Gulf of Alaska, we expect cool, moist onshore
flow across the Panhandle with the northern and central Panhandle
experiencing the greatest amount of lift through Thursday.
Temperatures at 850 mb will hover between -3 C and -5 C, and thus
for the most part, we think showers will mainly be rain. The two
areas we will have to monitor though will be the highways of
Upper Lynn Canal and Hyder. Winds will largely blow westerly and
southerly, but at this point, gradients look mild and thus winds
will be light.

Later in the week, the Arctic jet and Pacific jet look to lock in
phase across the western gulf. Because of this, we expect a
baroclinic zone to set up across the North Pacific and the eastern
gulf. Solutions then rightfully develop a storm and draw it into
Southeast Alaska maybe Friday into Saturday. Cold air will filter
behind the system to the west, but it is just as likely that the
cold air filters in just as precipitation ends. But all the same,
we hold off on mention of snow until this weekend, when there is
far more agreement for genuine cold air with 850 temperatures of
-8 C or colder air. We have nudged temperatures cooler, but as of
yet have not pulled temperatures all the way down towards the
majority of guidance. There should be no surprise that a lot of
volatility in the extended forecast speaks to our low confidence
for stark changes.

Confidence in the synoptic pattern is good through Thursday, and
then slides from Friday into the weekend.

&&

.AJK WATCHES/WARNINGS/ADVISORIES...
PUBLIC...Strong Wind until 10 PM AKDT this evening for AKZ018.
MARINE...Gale Warning for PKZ012-052.
     Small Craft Advisory for PKZ011-013-021-022-031-036-041>043-051-
     053.

&&

$$

Bezenek/JWA

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