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000
FXAK67 PAJK 251527 CCA
AFDAJK

Southeast Alaska Forecast Discussion
National Weather Service Juneau AK
408 AM AKDT Thu Apr 25 2024

.SHORT TERM...High pressure expands over the AK Gulf and
Panhandle with the resulting blocking pattern providing more dry
weather, light and variable winds, and warm temperatures.
Residual rain showers over the southern panhandle end this
morning. the remaining moisture and clearing skies allowed for
some patchy fog formation. HiRes model boundary layer RH gave
indication of marine layer formation which match initially with
night time micro physics satellite imagery. However it wasn`t as
wide spread as indicated by airport observations. Keeping an eye
on if this stratus deck forms and possibly moves inland. Little
change made to previous forecast as models remained in line. Main
forecast question is if marine layer with form and how far inland
it would track.

.LONG TERM...Through the long term a Rossby wave will shift towards
the western seaboard carrying an open 500mb trough and associated
surface low into the Gulf. While Friday still looks quite agreeable,
light winds and warm temperatures, expect southeasterly winds to
increase 22-27 knots south of Cape Fairweather into Dixon Saturday
morning along with a southerly 8 to 12ft fresh swell. The highest of
these significant heights look to remain south of Cape Decision. For
this weekend, main areas of concern for mariners operating in
smaller vessels in our waters is Cross Sound south along the coast
of Prince of Wales, southern Chatham, and southern Clarence into
Dixon Entrance.

While the overall theme remains the same for this system, clusters
are starting to highlight an eastward shift of the surface low over
the weekend, with a slightly steeper pressure gradient stretching
into Haida Gwaii. These features in the ensembles could increase
southerly winds west of Haida Gwaii and in Hecate Strait, resulting
in an increase of the significant wave heights moving into Dixon and
southern Clarence; have adjusted the forecast accordingly.

Regarding precipitation and guidance analysis, we can take two
stances; one of the realistic optimist, while the other is the
defensive pessimist. Regarding the former, guidance from CW3E
Scripps highlights an uptick of IVT moving into Queen Charlotte
sound, with members starting to bring more moisture north into the
southern Panhandle. While amounts and rates still look abysmal, we
could see a bit more rain than our previous forecasts, perhaps 1 to
1.5 inches or so of light rain accumulation through the weekend into
Tuesday morning.

Switching to the defensive pessimist, while a few members of IVT
guidance are bringing rain north, the majority of solutions continue
to keep higher IVT values further south, with less than 1 inch of
total rainfall more likely into Monday. To put this pessimism into
context, precipitation sites in the south are reporting 2 to 4
inches of rainfall over the month, where April normals for Ketchikan
are around 10 inches. For now, the published forecast indicates less
than 1 inch totals over the weekend. No matter our attitudes on how
this metaphorical milk is spilled, the central and southern
Panhandle will likely finish the month far under normal precip
amounts.

&&

.AVIATION...Some MVFR conditions early this morning due to patchy
for formation, otherwise another day of VFR with some sea breeze
development in the late morning but no significant wind concerns.
Watching for marine layer formation under the gulf high pressure.
HiRes boundary layer indicates the low cloud deck moving inland
tonight, but it also has more low clouds early today, which were
not as wide spread.

&&

.AJK WATCHES/WARNINGS/ADVISORIES...
PUBLIC...None.
MARINE...None.

&&

$$

SHORT TERM...GFS
LONG TERM....AP
AVIATION...PRB

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