452
FXAK67 PAJK 112314
AFDAJK

Southeast Alaska Forecast Discussion
National Weather Service Juneau AK
314 PM AKDT Sun Aug 11 2024

.SHORT TERM...Rain returns to the panhandle as another system
moves through the area alongside breezy conditions for some
locations. The rain and wind will diminish on Monday, though some
chances of showers will linger through the remainder of the time
frame.

Satellite and radar imagery shows that rainfall has begun to spread
across the panhandle. Surface observations indicate that parts of
the northern panhandle have already begun to report precip, and
the remainder of the northern panhandle will see rain arrive
through the afternoon or early evening time frame. The source of
the rain is a system moving E out of the Northern Gulf. The
system`s corresponding upper level reflection
- a weakening trough, will still be sufficiently strong enough to
eject the ridge which had been rebuilding across the area
previously.

As the system moves through, breezy conditions are expected for some
locations, especially in the northern half of the panhandle and the
Icy Strait Corridor. Winds will increase through the afternoon
and evening hours on Sunday, and could reach as high as 15 to 20
kt sustained in some parts of Juneau, with stronger winds
possible for parts of the far northern panhandle. These winds will
be diminishing by late Sunday night, and the system itself will
have largely departed the panhandle by the late afternoon.
Although chances of rain are also in the forecast for much the
southern panhandle, precipitation totals there will be
considerably lower ( with maximum totals of up to 0.2 inches, as
compared to 0.4 - 0.8 inches for the northern panhandle) given the
system`s continued weakening.

Improving conditions are expected through Monday, with only
residual showers by late Monday afternoon. The synoptic scale
flow from the WNW is one that is less than favorable for
continuing shower activity, and so anticipate that despite the
lingering chances of precip, many areas will likely see a dry
second half of the day. Clearing skies in the wake of the
departing system will help set the stage for the arrival of fog
across much of the area Monday night into early Tuesday morning.

Given the clearing skies on Monday, expect that temperatures in
some areas will reach as warm as the upper 60s, though lower 850
mb temperatures will help put a cap on any truly warm weather for
the immediate future. Low temperatures will largely stay in the
50s across many areas near sea level Sunday night, but could drop
into the 40s for some locations Monday night as clearing skies
enable more radiational cooling.

The forecast generally remains largely on track. Increased winds
across Cross Sound and Icy Strait given the anticipated system
track, and made some minor adjustments to temperatures given
anticipated cloud cover. Also accelerated the forecast departure
of the system across the northern panhandle, given slightly faster
than previously progged system motion.

.LONG TERM.../Tuesday to Friday/...
Quick hits for next week:
-Rainy start for some in the mid-range. Dry weather late week for
 all.
-Moderate chances (40-70%) of rain linger into Tuesday with PoPS
 decreasing Wednesday, leaving Thursday and Friday dry.
-Marine winds will be strongest in the Lynn Canal area, at around
 10 to 20 knots at times with some evidence showing near 25 knot
 wind speeds possible. The rest of the inner channels look to have
 wind speeds around 5 to 15 knots.
-Daytime temps will be near normal with a warming trend for the
 second half of the week.
-Nighttime temps will be cooler than normal with morning lows in
 the 40s for much of the central panhandle.


Details for next week:
On the heels of an exiting trough, a 500mb low will move towards the
northern Gulf, keeping chances for rain in the forecast for mainly
the northern panhandle. The southern panhandle may end up being on
just enough of a ridge that would keep the bulk of the rain at bay.
Wednesday into the weekend, 500mb ridging sets up, giving the
panhandle another few days of dry weather.

Inner channel marine winds look to be around 5 to 15 knots for most
of the area. The main exception is Lynn Canal, where stronger winds
may end up setting up. The NBM is hinting at wind speeds around 10
to 15 knots, which usually translates to winds around 20 to 25
knots. So while the marine forecast for Lynn Canal is set to 15 to
20 knots, the confidence is low and may need to be increased as we
get closer.

For temperatures, according to the EURO Ensemble and GEFS 850mb
temps, it could be a chilly morning Wednesday. 850mb temps could dip
to near 2 to 3C, which is cooler than normal for mid-August. So went
with temps in the low to mid 40s for parts of the central and
northern panhandle. Temps in the mid 40s aren`t hugely impactful but
it`s a gentle reminder of the cooler temps on the way.

&&

.AVIATION...Aviation conditions along the NE outer coast are
already starting to degrade as a new front moves in from the west
this afternoon. Yakutat and Elfin Cove are reporting IFR
conditions with ceilings as low as 700 ft and 1 1/2 mile vis.
There are also some breezy conditions with the front with Yakutat
gusting to 20 kt currently. That is going to spread inland this
evening and overnight with the northern half of the panhandle
seeing the brunt of it. Expect IFR conditions overnight and
possibly tomorrow morning before conditions gradually improve into
Monday. Some breezy conditions likely in the north tonight as
well, but nothing greater then 20 kt. Exception is Skagway and
upper Lynn Canal where winds are gusting to 35 kt this afternoon.
Those winds will mostly persist overnight before diminishing
tomorrow morning.


&&

.MARINE...Elevated winds will persist across the outer coastal
waters and inner channels through the remainder of Sunday, with
wind speeds increasing through Sunday evening in the inner
channels as a system moves into the panhandle. Winds will diminish
across most of the inner channels through the latter half of
Monday as the system departs, though northern Lynn Canal will
prove to be the exception. Small craft conditions are anticipated
for many of the outer coastal waters and near some of the ocean
entrances and Lynn Canal. Some gale force conditions are expected
through the early evening hours on Sunday for parts of the
northern gulf.

&&

.AJK WATCHES/WARNINGS/ADVISORIES...
PUBLIC...Strong Wind until 4 PM AKDT this afternoon for AKZ318.
MARINE...Gale Warning for PKZ651.
     Small Craft Advisory for PKZ012-053-643-644-652-661>664-671-672.

&&

$$

SHORT TERM...GFS
LONG TERM....GJS
AVIATION...EAL

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