357
FXAK67 PAJK 111344
AFDAJK

Southeast Alaska Forecast Discussion
National Weather Service Juneau AK
544 AM AKDT Sun Aug 11 2024

.SHORT TERM...Cloud cover will rebuild on Sunday as another
system begins moving into the panhandle. Widespread rain will
reach Yakutat in the upcoming hours, and anticipate that rain
will reach Juneau through the afternoon, though a few showers
moving ahead of the system may bring some light rain to areas by
late Sunday morning. Yakutat will receive the greatest amount of
rainfall, but only hitting around a one year return interval for a
12 hour period. By Sunday evening, the rain will have spread
across the northern panhandle and the outer Gulf Coast, though
chances of rain will be lower for areas south of Sitka. Expect
areas on the west face of mountains to receive the greatest
rainfall, with Mendenhall Valley in particular having an increased
chance for moderate rainfall from 7 PM onwards through the night.
Through early Monday morning rain will attempt to spread into the
southern panhandle, though there will be significantly less
rainfall for this area than across the northern half of SE AK.
Expected rainfall totals of between 0.4 to 0.8 inches for the
northern panhandle down to Sitka, while the south will see upwards
of 0.2 inches. Winds across many land- based locations will
increase on Sunday as the system moves through the area, with
breezy conditions possible for some locations.

.LONG TERM...At the start of the week, a 500mb trough will finish
its trek through the area. So the day will start off with light
rain but as the day goes on, the rain will move east and out of
the area.

On the heels of that trough, another trough will dig in behind it on
Tuesday , keeping the 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 at times. 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 40s aren`t hugely impactful but
it`s a reminder than cooler temps are on the way.

&&

.AVIATION...Instrument conditions prevail along the immediate
outer coast from north of Kruzof Island all the way to Cape
Suckling beginning later this morning. Elsewhere...workable under
visual rules, but ridge tops will be obscured in places. Watch
out for LLWS and mod turbulence along the outer coast north of
Sitka with worst conditions north of Cape Spencer.


&&

.MARINE...Winds will increase across the inner channels and outer
coastal waters as the next system arrives. Gales are expected for
parts of the northern Gulf on Sunday extending down to Cape
Spencer due to barrier jet forcing. Elevated winds will enter the
inner channels through the latter half of Sunday, barring ocean
entrances, where strengthening winds will arrive sooner. Northern
Lynn Canal will remain at or near small craft wind speeds through
Sunday. Greatest areas of uncertainty are western Icy Strait and
Cross Sound, which could remain light to up to 10 knots from
perpendicular uniform S/SE flow aloft and out along the
coastline. Additionally, the Tarr Inlet in the far upper reaches
of Glacier Bay has the potential to blow up to 20 knots from a
tight gradient.

&&

.AJK WATCHES/WARNINGS/ADVISORIES...
PUBLIC...None.
MARINE...Gale Warning for PKZ651-652-672.
     Small Craft Advisory for PKZ012-053-643-644-663-664-671.

&&

$$

SHORT TERM...NC
LONG TERM....GJS
AVIATION...Fritsch

Visit us at http://www.weather.gov/Juneau