176
FXAK67 PAJK 222355
AFDAJK

Southeast Alaska Forecast Discussion
National Weather Service Juneau AK
355 PM AKDT Wed May 22 2024

.SHORT TERM...Widespread rain will return to SE AK through the
overnight hours as a developing wave races up into the panhandle,
setting the stage for a series of systems to move through the
area, though a brief break may be possible on Friday.

As of the time of writing a weak front is attempting to push
through the panhandle, bringing with it chances of rain. The front
itself is disintegrating as it moves further away from its source
point - an occluding low in the vicinity of Nunivak Island. As
the closed low becomes a negatively tilted open trough across the
Gulf of AK, cyclogenesis will occur along a wave racing out of the
SW Gulf. This intensifying wave will reach the panhandle through
late Wednesday night into Thursday morning, bringing with it a
surge of rainfall. Anticipate moderate to heavy rain at times for
some locations, along with breezy conditions. Rain will begin to
diminish through the latter half of Thursday as the synoptic
level flow pattern shifts more to the NW. This will result in the
remaining moisture being increasingly concentrated around interior
locations along the Coast Mountain Range further away from the
Gulf Coast. A ridge will build in beginning late Thursday and into
Friday, which could lead to some more substantial clearing skies.

Primary changes to the forecast were to broadly increase QPF
totals with the upcoming system as well as the PoPs for the latter
half of Thursday. Also adjusted temperatures to better reflect
the impact of the associated cloud deck. Made some minor
adjustments to wind directions and speeds, but maintained the
general pattern.


.LONG TERM.../ Friday through Monday night / Once the rain moves
through and accompanying low diminishes into a weak broad open
trough, skies are set to progressively clear out by Friday morning.
This will allow for potential fog development in areas which can see
maximized radiational cooling in the overnight hours along with
light winds. Clearing skies on Friday also means warmer temperatures
once more, with daytime highs rebounding back to upper 50s and near
60 for the majority of the panhandle. Temperatures are not expected
to go any higher than this despite clearer conditions due to
unseasonably cold air aloft at 850 mb.

Unfortunately unsettled weather combined with the cooler air aloft
will lead to a rather wet and cool holiday weekend overall. An upper
level low is set to drift over the northern gulf with an
accompanying surface low, which will stagnate and continue to throw
light precipitation towards SE AK starting late Friday night into
Saturday, continuing into the start of next week. Overall this
system is not expected to have strong winds associated with it,
though expect some localized gusty winds near ocean entrances and
the potential for winds up to 25 kt along the NE gulf coast Saturday
afternoon/night.

&&

.AVIATION.../Through Wednesday night/...Rain had arrived as far
east as Gustavus by early afternoon and had been falling in
Yakutat since early morning. Radar imagery suggests that it should
have begun already at Sitka, but nothing as of 1:30pm. Still the
front is approaching and VFR conditions will deteriorate through
the night to less than 1000/3 across most of SEAK by morning.
Better conditions expected over the far northern inner channels
(Haines & Skagway) as well as the Misty Fjord area. Although
conditions there will be "better", expect mountain obscuration due
to lower CIGs and reduced VSBY in precipitation. Some turbulence
at and below ridge tops will be associated with the front, but did
not see enough to warrant LLWS in the TAFs. But as always, if it
gets reported in PIREPS, the affected TAFs will get amended.

&&

.AJK WATCHES/WARNINGS/ADVISORIES...
PUBLIC...None.
MARINE...Small Craft Advisory for PKZ641>644-651-652-661>664-671-672.

&&

$$

SHORT TERM...GFS
LONG TERM....STJ
AVIATION...Fritsch

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