Area Forecast Discussion
Issued by NWS Juneau, AK

Current Version | Previous Version | Text Only | Print | Product List | Glossary Off
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14

FXAK67 PAJK 072218

Southeast Alaska Forecast Discussion
National Weather Service Juneau AK
218 PM AKDT Wed Jun 7 2023

.SHORT TERM.../Through Thu night/ Another mostly quiet day across
the panhandle as a ridge over the panhandle keeps a front in the
gulf nearly stationary. Main difference between today and
yesterday is the large area of partly cloudy to clear skies that
has opened up from Chatham Strait eastward. Warmer temperatures
this afternoon as well with Wrangell, Klawock, and Hyder already
nearing 70 as of 1 pm.

Weather pattern into Thu night remains relatively the same with
the front in the gulf staying mostly where it is due to the ridge
over the panhandle. E to SE winds of 25 to 30 kt will be common in
the northern and central gulf from this front (a brief period of
min gale force likely near Cape Suckling tonight). Rainfall from
this front will mainly affect the area from Yakutat westward, but
there is the chance (around 30 percent) of some light rain for the
area west of Chatham Strait Thu into Thu night.

Farther east low to mid level offshore flow will keep the skies
mostly blue through Thu morning. Flow then starts to turn more
onshore southerly again by Thu afternoon which will allow clouds
to start to return. Still enough sunshine should linger combined
with the warmer airmass that has been advected into the area over
the last two days that high temperatures are expected to reach
near 70 Thu afternoon for the eastern half of the panhandle. This
is dependent on cloud cover however and too much cloud cover
could curtail high temperatures down to near 60 instead.

.LONG TERM.../Friday through Monday night/...Dominant features in
this extended range forecast period continue to be a very large
upper level low over the central Aleutians and a relatively weak
southerly upper level jet over the far eastern Gulf of Alaska. The
jet will shift east as a result of an upper level trough that
will rotate about the low. The jet will impinge upon an upper high
centered over the Alberta, Saskatchewan, Montana border and gain
strength as a result. The upper trough will amplify and become
situated over Southeast Alaska by Saturday. Meanwhile, the upper
low will not have moved much at all. The upper trough lifts to the
east and a stronger southwesterly upper level jet will begin
moving out of the north Pacific and into the Gulf of Alaska by the
end of this extended range forecast. As of today`s model runs, the
core of the jet is forecasted to stay south of the forecast area. At
the surface, a weakening front in the eastern gulf falls apart as
it works into the Panhandle Friday. Brief ridging builds again
Saturday and Sunday with the next, more robust warm front
impacting the Panhandle Sunday afternoon. The cold front and
trough swing through the Panhandle on Monday.

As far as sensible weather, expect showers on Friday with the
weakening front, mainly for the northern Panhandle, steadiest and
heaviest for Yakutat and points west. Light showers continue into
Saturday before diminishing Saturday night into Sunday morning
with the ridge building. Rain returns Sunday mid-late day as the
warm front starts impacting the Panhandle, starting along the
outer coast and moving across the rest of the area and continuing
into Monday. As far as precipitation amounts, the EC ensemble EFI
shows a shift of tails for QPF over the central Panhandle and the
EC ensemble SAT for precipitable water shows mean values of 1-1.25
inches which is in the 95-99th percentile for this time of year.
NAEFS PW isn`t as aggressive with amounts 0.5-0.75 inches. Either
case, although robust for June, is not impactful for SE AK
standards and there are no hydrologic concerns at this time. Small
craft advisories with the front are likely for the outside
waters. Ensemble guidance does show a possibility of gales for
the outside waters west of Yakutat to Cape Suckling, so increased
the forecast wind speeds to 30kt to trend that direction, with
further forecast cycles to refine as necessary. For the inside
waters, expect a wind shift from easterly to westerly in the E-W
oriented channels on Monday as the trough moves through and an
increase in speed to 15kt. After Thursday`s warm weather,
temperatures are expected to decline gradually and steadily
through Monday.


.AVIATION...Widespread VFR conditions this afternoon as a ridge
builds over the inner channels. Afternoon sea breezes have started
to kick in with the clear skies and warming temperatures. Expect
similar conditions Thursday as the ridge remains overhead. The
northeast gulf coast is an exception though where VFR conditions
are expected to lower to MVFR as a front pushes through Yakutat
this evening through Thursday morning.


MARINE...Gale Warning for PKZ672.
     Small Craft Advisory for PKZ644-652-662>664-671.




Visit us at is the U.S. government's official web portal to all federal, state and local government web resources and services.