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FXAK67 PAJK 262250
AFDAJK

Southeast Alaska Forecast Discussion
National Weather Service Juneau AK
250 PM AKDT Sat May 26 2018

.SYNOPSIS...A gale force front will lift N across the northern
gulf and central and southern Panhandle Saturday evening and
dissipate. An associated gale force low in the central gulf will
track very slowly N Saturday night and stall Sunday. It will then
weaken as it crawls E into the Panhandle through Monday night.

&&

.SHORT TERM...Never allow a low to stand next to you to your left
(west). You may need a raincoat. One would be hard pressed to
conjure up a conceivable, more miserable weekend for outdoor
activities than this Memorial Day weekend for Southeast Alaska. If
you prefer dry holiday weekends, you need a low to your right
(east). Sadly, for many this is not the case.

With the front lifting northward across the area, rain has been
falling across most all of Southeast Alaska with the exception of
Yakutat. We fully expect this to continue with rain likely
reaching Yakutat later this evening. Wind, too has been inching
its way northward along with the front. Prince of Wales Island,
and the southern Inner Channels have felt it the strongest with
wind gusts of 45 to 55 mph at times. Port Alexander and Sitka may
experience strong gusts later this afternoon. Gales were just
recorded at Cape Spencer.

Tonight, showers will then spread behind the front with the
exception of the far southern Panhandle where rain will be
steadier, more persistent, and heavier. The more unstable air may
keep breezy conditions likely along the coast with Pelican and
Sitka receiving the highest gusts through early Sunday morning.
Tonight into Monday, a wave feature to ride northeast along the
baroclinic front draped just southeast of the US-Canadian marine
boundary, which earlier looked to threaten Metlakatla and possibly
Ketchikan with winds Sunday, now looks to remain to our south and
strike the north coast of BC instead. However, Ketchikan,
Metlakatla, and Hyder will likely experience heavier rain with
this system as it splashes its moisture north across Dixon
Entrance as it passes.

With the low`s very slow progress eastward Sunday night through
Monday night into the Panhandle, we have kept pops high across
much of the Panhandle, with the exception of the far north where
showers were allowed to scatter out. Temperatures will also be
kept chilly through the period with some possible inconsequential snow
at times below 3,000 feet including White Pass.

We used the NAMnest/NAM/ECMWF with some GFS toward late Tuesday.
We coordinated with AKPRFC to favor NAM/GFS for QPF for much of
the time period with late but now good solid agreement for this
low. Temperatures were cooled Monday to account for a persistent
wet chilly air mass. Forecast confidence is generally good.

.LONG TERM.../Tuesday through Saturday as of 10 PM Friday/ The
remaining showers will diminish through Tuesday. Then a surface
ridge of high pressure builds behind the low keeping conditions
dry in the middle of the week. This could allow temperatures to
warm depending on the length of the dry period. Late in the week
another surface low pressure system develops; however, the track
and timing of this system is too uncertain to place in the
forecast currently.

After Memorial Day newest guidance from WPC did not differ
significantly from the existing forecast so little change was
made.

&&

.AVIATION...As the front lifts north and weakens winds will be on
the diminishing trend for many locations this evening with the
possible exception of Sitka who could remain breezy from the south
or southeast through Sunday morning. Wind shear will likely remain
in the south and along the eastern gulf coast through Sunday. We
expect wet VMC conditions, however, some MVMC conditions for both
ceilings and visibility could develop at times in heavier
showers.


&&

.MARINE...Widespread gale warnings will afflict the gulf waters
first with the northern gulf front and then around the low itself
Inner Channel winds will peak at small craft, but as the second
wrap feature, pushes northward, offshore of Baranof Island, we
depict a core of small crafts Saturday night into Sunday morning
for the central Inner Channels. These winds will gradually lighten
through the weekend as the low and its associated gradients
weaken.


&&

.HYDROLOGY...We are not expecting any hydro concerns as the
different weather features will work in tandem to provide lighter
periods of precipitation for particular regions as others receive
more consistent rains. Totals from Saturday afternoon through
Monday night should range between 2 and 2.5 inches for the eastern
gulf coast and southern Inner Channels with lighter amounts of 1
to 2 inches in the interior central Panhandle and less than 1 inch
for the northern Panhandle. We will probably see some river rises
in the central and southern Panhandle, but nothing significant.

&&

.AJK Watches/Warnings/Advisories...
PUBLIC...Strong Wind until 4 PM AKDT this afternoon for AKZ023-027.
     Strong Wind until 6 PM AKDT this evening for AKZ028.
MARINE...Gale Warning for PKZ036-042-043-051.
     Small Craft Advisory for PKZ013-021-022-031>035-041-052.
     Small Craft Advisory due to Seas for PKZ053.

&&

$$

JWA/JB

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