Small Craft Advisory 154, NWS Juneau, AK

Southeast Alaska Forecast Discussion
National Weather Service Juneau AK
615 AM AKDT Sun Mar 12 2017

.SHORT and LONG TERM...As the low pressure system moves
northward, low level southerly winds will develop across much of
the Panhandle starting from the south. One of the main
uncertainties is the trajectory of the low. While the NAM and
ECMWF indicate the low will move inland late Sunday night, the GFS
and Canadian models keep the low just offshore. This will have an
impact on the intensity and direction of winds in local gaps,
with the low offshore favoring a more offshore component.

The surface low as it develops will move north past Baranof and
Chichagof Islands Sunday night into Monday. Moisture and frontal
band with warm air will spread north over southeast Alaska
changing the snow to a mix as far north as Frederick sound by late
Sunday night and then should edge northward into Admiralty Island
to south of Taku Inlet. A mix of rain just north of that line
into Monday is possible but as the front move east the atmosphere
cools a little and should see the central shift back to a snow
type precipitation.

Snowfalls totals with the warning ranging from 8 to 14 inches
depending on locations. Most of the heavy snows in the northern
panhandle should be tapering during Monday especially across the
northern panhandle.

Models indicate in the long term that a broad low pressure will
remain in the Gulf of Alaska, broad southerly flow will persist
across the Panhandle over the long term. Models indicate a new low
will approach the Panhandle late Monday night. Currently it
appears that the low will favor an inland track, supporting mainly
southerly flow. For the second trailing low it is expected to be
unstable enough to have the precipitation as locally heavy
showers. Not sure if instability is sufficient for thunder but
will need to watch.

&&

.AVIATION...Moderate gusts will continue along the mountains today
in persistent offshore flow. While conditions will begin as VFR,
conditions will quickly change this morning as snow forms ahead
of a front. Expect light snow in the morning hours, with ceilings
and visibilities lowering this afternoon.

&&

.MARINE...Moderate gusts will continue out of bays and passes as a
front approaches from the south today. With temperatures warming
gradually today, freezing spray will be a lower risk. However,
Heavy freezing spray will still occur at Glacier Bay, Lynn Canal,
and Yakutat Bay today. Snow will develop from south to north
today.

&&

.AJK Watches/Warnings/Advisories...
PUBLIC...Winter Storm Warning from 1 PM this afternoon to 1 AM AKDT
     Monday for AKZ026.
     Winter Storm Warning from 4 PM this afternoon to 1 PM AKDT
     Monday for AKZ021-024-025.
     Strong Wind until 4 PM AKDT this afternoon for AKZ025.
     Winter Storm Warning from 7 PM this evening to 10 AM AKDT Monday
     for AKZ020-022.
     Winter Weather Advisory until 1 PM AKDT Monday for AKZ023.
     Winter Weather Advisory until 4 PM AKDT this afternoon for
     AKZ028.
     Winter Storm Warning until 1 PM AKDT Monday for AKZ029.
     Winter Storm Warning from 10 PM this evening to 1 PM AKDT Monday
     for AKZ019.
     Winter Weather Advisory from 10 PM this evening to 1 PM AKDT
     Monday for AKZ018.
     Wind Chill Advisory until 9 AM AKDT this morning for AKZ018.
MARINE...Heavy Freezing Spray Warning for PKZ011>013-031-053.
     Gale Warning for PKZ011>013-022-036.
     Small Craft Advisory for PKZ021-031>035-041>043-051.
&&

EN/Bezenek

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