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421
FXAK67 PAJK 191231
AFDAJK

Southeast Alaska Forecast Discussion
National Weather Service Juneau AK
431 AM AKDT Sat Oct 19 2019

.SHORT TERM.../Through Sunday night/ Upper trof over the gulf
will drift onshore this afternoon, then lift N across the area
tonight. A shortwave trof will move E across the far southern gulf
tonight into Sun morning, then head inland across BC Sun afternoon
and evening. At the sfc, a weakening low will drift WSW across the
gulf through tonight. another low will move E across the far
southern gulf tonight and Sun, then weaken to a trof and lift NE across
the far SE gulf Sun night. Models were still struggling a bit
with this system though, so we used a middle ground compromise on
it by blending the 06z NAM and NAMnest.

As upper trof moves onshore, a more organized band of showers will
move with it along the associated sfc trof today. This band will
weaken tonight into Sun morning as offshore low level flow
increases ahead of the low moving across the southern gulf. Expect
some steadier precip to reach the far southern area late tonight,
then hang up there and gradually decrease Sun afternoon. However,
as low weakens to a trof and lifts NE Sun night, precip threat
across the far S should increase again. Meanwhile, the precip
threat across the N will decrease Sun with offshore flow
increasing, and there may be significant breaks in the clouds by
afternoon across the far N. One aspect of the forecast that later
shifts may need to monitor is potential for fog tonight in some
areas. This will depend on how quickly the clouds break later
tonight into Sun morning.

.LONG TERM.../Monday through Saturday as of 10 pm Friday/ Minimal
impactful wx expected early next week as highly zonal flow across
the gulf maintains active wx pattern across the panhandle. A
weakening crossing Dixon Entrance will exit the region with deep
onshore flow maintaining precip chances across the region. By mid
week more impactful weather is expected to develop across the
region as a long wave trough moves towards the W gulf. This
pattern is favorable for heavy precip across SE AK. Operational
guidance continues to show run to run discrepancies with ensemble
means more stable but wash out stronger features. The biggest
challenge with eventual migration of this pattern is the potential
phasing with northern stream. Given the uncertainty, maintained
forecast with gales expected over the gulf as the first in a
series of fronts impacts the region. This wet pattern for the
latter half of next week will see widespread precip likely heavy
at times for portions of the panhandle. Temps will remain near to
slightly above normal so not anticipating precip type issues.
Overall forecast confidence in synoptic pattern remains about
average.

&&

.AJK Watches/Warnings/Advisories...
PUBLIC...None.
MARINE...Small Craft Advisory for PKZ022-041>043-051>053.

&&

$$

RWT/BC

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