Gale Warning 298, NWS Juneau, AK

Southeast Alaska Forecast Discussion
National Weather Service Juneau AK
610 AM AKST Wed Dec 12 2018

.SHORT TERM...Surface analysis and satellite imagery show
showers activity continues over the gulf and SE AK early this
morning. Another low is evident near 52N/150W. This storm force
low will move into the S central gulf today and drift NE while
weakening before moving into Baranof Island Thu morning. Model
solutions in good agreement with the track and trend, but continue
to differ on which circulation within this low complex will
dominate. This system will push another gale force front into the
S panhandle later this morning/afternoon. This will bring a
period of strong wind to the S panhandle and outer coast coast
later this morning and expand Nwd through the afternoon with a
brief period of strong winds ahead of the front. Models show the
strongest gradient behind the low, so expect winds over the S to
ease briefly this afternoon/early evening before picking back up
this evening and overnight. Widespread to numerous rain and snow
showers across the region will lead to isolated accumulations of
up to 3 inches mainly over central/northern inner channels. Gales
will develop over the S gulf and S inner channels this morning and
expand N into Cross Sound and PKZ043 this afternoon with SCA
expected over the rest of the inner channels. Instability indices
near the upper low support mention of TS and lighting has been
detected with this low attm so, included mention over the SE gulf
and S panhandle this afternoon and evening. Main forecast
challenge will be which circulation in this Fujiwara low will
dominate. A more dominant E circulation would bring stronger winds
to the S panhandle while one further W would result in less winds.
Models have struggled and shown poor run to run consistency
determining the dominant circulation but the the overall trend of
filling as it moves NE persists. Overall, forecast confidence
is about average.

.LONG TERM.../Friday through Tuesday/...Active and generally
stormy weather pattern for the long term period. Deep long wave
trough will exist at the start of the period over the eastern gulf
with a strong closed low likely existing to our south. Models are
struggling a bit with interaction between northern and southern
stream on Friday and thus with how far north precipitation from
this system will get. Thus elected to make minimal changes to
Friday at this time. Should the US models be correct, it will
likely be more clear and dry than our forecast currently depicts
with deep northerly flow promoting some outflow over the inside
waters.

Any clearing on Friday into Friday night will be short lived as
all guidance indicates the reinforcement of the deep long wave
trough over the Gulf through early next week. This will lead to
the return of southerly flow over the Panhandle and warmer,
wetter conditions. This pattern will also likely spawn one or two
deep surface lows lifting northward into the Gulf bringing more
strong winds and heavier precipitation. Some over-running snow
will be possible ahead of the first system on Saturday, however
with ridging building again in BC, there will be no mechanism to
keep continental air in place once the residual cooler, drier air
gets mixed out. Thus by Sunday into early next week, expect any
snow to be confined to the far north.

&&

.AJK Watches/Warnings/Advisories...
PUBLIC...Strong Wind from 9 AM AKST this morning through this afternoon
     for AKZ027.
     Strong Wind late tonight for AKZ027.
     Strong Wind from 3 PM AKST this afternoon through this afternoon
     for AKZ025.
     Strong Wind from noon today to 3 PM AKST this afternoon for
     AKZ022.
     Strong Wind from 9 AM this morning to 3 PM AKST this afternoon
     for AKZ023.
     Strong Wind from noon AKST today through this afternoon for
     AKZ028.
     Strong Wind until 9 AM AKST this morning for AKZ018.
MARINE...Gale Warning for PKZ022-035-036-041>043.
     Small Craft Advisory for PKZ012-013-021-031>034-051>053.

&&

BC/DEL

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