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FXAK67 PAJK 101445

Southeast Alaska Forecast Discussion
National Weather Service Juneau AK
545 AM AKST Mon Dec 10 2018

.SHORT TERM.../Through Tuesday night/ Active weather pattern
continues with our next storm system starting to affect the
panhandle right now. Precipitation has started up again for many
areas and winds have starting to increase again early this
morning. Precip mainly rain, but snow has crept into some areas
around the northern gulf coast as some cooler air ahead of the
system moved through. Yakutat was one such area. A burst of
heavier precip rates cooled the surface temps enough to change the
rain to snow for two hours, yielding around a half inch of snow
accumulation before temps warmed up again.

For the next 48 hours a series of troughs and fronts will be
taking aim at the panhandle bringing an extended period of rain
and winds. The highest winds are expected today into tonight as a
strong trough moves through. Widespread gusts to 40 or 50 mph are
expected with gale force winds across many marine areas. The
strong winds will also bring in more warm air keeping the ptype
rain in many areas. The main exception is the higher elevations
of the Klondike Highway where a winter storm warning for up to 20
inches of snow remains through 5 am Tuesday. Forecast confidence
remains relatively high for this scenario with decent agreement
from forecast models.

One last trough expected to move through Tuesday afternoon and
evening, but it will be somewhat weak compared to the previous
waves. Highest winds (just reaching gale force) expected out in
the gulf and along the outer coast. Also expect another round of
rain. Once this feature moves through there is some notably
cooler air behind it that will start moving in Tue night. Expect
snow levels to start dropping late Tue night as it does so.
Forecast confidence moderate due to decent model agreement but
high complexity of the forecast throughout the short range period.

.LONG TERM/Wednesday through the weekend/...The long range
forecast remains very active with multiple strong low pressure
systems expected to enter the gulf.

Wednesday begins with a strong upper level trough pushing
northeast over the northern Pacific. A well developed surface low
pressure system will be present as well, and continue to
intensify as it pushes northeast into the south central gulf of
Alaska Wednesday. While the low intensifies, a substantial low
level just will develop on the south side of the low, with some
hints of nearly 100 knot winds in the lowest 2000 ft of the
atmosphere. There is potential for winds to develop to hurricane
force strength at the surface; however, with the uncertainty in
the track and ultimate intensity winds remain limited to strong
gales. These will likely see increases as the final path and
strength of the low becomes more certain. The current forecast
carries this low toward northern Baranof and Chichagof Island by
late Wednesday night. Additionally this storm may support snow
across the northern Panhandle and heavy precipitation rates will
accompany the low due to its convective nature.

Another strong upper level low pressure system will push across
the Pacific later this week and bring another strong low pressure
system into the gulf Saturday. This low looks to be yet another
strong one with a band of storm force winds likely to accompany

Favored the 00Z NAM and 18Z GFS to handle the low development on
Wednesday. While not incorporated into the decision making
process, the 00Z GFS remained in good agreement with its 18Z run
and 00Z ECMWF trended toward the stronger solutions held within
the NAM and GFS. For Friday through the rest of the period the
forecast remained unchanged with newest WPC guidance remaining in
good agreement with the existing forecast. Overall forecast
confidence is average in the long term.


.AJK Watches/Warnings/Advisories...
PUBLIC...Strong Wind through this evening for AKZ025>027.
     Strong Wind from 9 AM AKST this morning through this evening for
     Strong Wind from 9 AM this morning to 3 PM AKST this afternoon
     for AKZ022.
     Strong Wind through this evening for AKZ019-021-023.
     Strong Wind from 9 AM AKST this morning through this evening for
     Winter Storm Warning until 5 AM AKST Tuesday for AKZ018.
     Strong Wind from 9 AM AKST this morning through this afternoon
     for AKZ017.
MARINE...Storm Warning for PKZ041-042.
     Gale Warning for PKZ012-013-021-022-031>036-043-051.
     Small Craft Advisory for PKZ011-052-053.




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