609 
FXAK67 PAJK 291217
AFDAJK

Southeast Alaska Forecast Discussion
National Weather Service Juneau AK
417 AM AKDT Sat Sep 29 2018

.SHORT TERM...Expect a dry and sunny weekend across Southeast AK 
with breezy winds in a few places as some early Fall outflow winds
set up. Satellite imagery early Saturday morning shows a band of 
mid level clouds over the outer coast moving away as the flow 
aloft becomes NE'ly. The upper ridge now extends north of mainland
AK, and WV imagery also indicates a dry upper shortwave moving 
south along the Alaska/Yukon border. This shortwave vort feature 
will help to enhance winds Saturday as it drops across the 
panhandle.

The main weather feature this weekend will be the wind. According
to surface analysis Saturday morning, a 1040 MB high is centered
in NW Canada and low pressure extending off the Washington state 
coast into the southern panhandle. Offshore flow will bring drier
air and some warmth to downsloping areas. Outflow winds will set 
up with tightening of the pressure gradient, especially over the 
northern inner channels. Expect N'ly winds to increase to gale
across Lynn Canal Saturday lasting into Sunday morning possibly.
Downtown Juneau and Douglas will also likely see strong winds 
with gusts to 45 mph. Winds should begin diminishing through 
Sunday as the pressure gradient slackens. Only slight changes were
needed from the inherited forecast as confidence remains above 
average in the short term.

.LONG TERM.../Monday to Saturday/ Monday can best be characterized
by a northerly outflow pattern. The surface high over the Yukon
(present this weekend) will begin a southward progression into 
British Columbia Monday. This will promote some potentially strong
winds over the northern Panhandle. Additionally, as the synoptic 
pattern shifts to the south, winds will increase over the 
southern Panhandle; strong gusts are not expected at this time; 
however, dependent upon the development this weekend, the areas 
around Wrangell may warrant additional attention. This pattern 
will continue to promote dry weather through the early part of the
week.

Toward the middle of the week a low pressure system looks to
develop over the Gulf. This low will draw upon tropical moisture 
and may develop into one of the stronger lows of the season thus 
far. While the low track remains uncertain, it will likely produce
heavy rain in some locations and develop strong small craft or 
gale force winds as it pushes toward the coastline.

Changes to the extended forecast were focused on an increase in
winds Monday, during the northerly outflow, and an increase in 
wind and PoPs between Thursday and Friday, as the low approaches.
The GFS was favored early in the extended forecast with influence
from the NBM and WPC being drawn into the later part of the week.
Forecast confidence is average early in the extended, but lower 
as the weekend approaches due to poor run to run consistency 
between models on both timing and placement of the low.

&&

.AJK Watches/Warnings/Advisories...
PUBLIC...Strong Wind through late tonight for AKZ025.
MARINE...Gale Warning for PKZ012-013. 
     Small Craft Advisory for PKZ022-031-041>043. 
     Small Craft Advisory due to Seas for PKZ051-052. 

&&

$$

DDH/JB

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