Area Forecast Discussion
Issued by NWS Juneau, AK

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FXAK67 PAJK 262203
AFDAJK

Southeast Alaska Forecast Discussion
National Weather Service Juneau AK
203 PM AKDT Mon Jul 26 2021

.SHORT TERM.../Through Tuesday night/...Areas of locally dense
fog over several of the inner channels and public zones dissipated
mostly as expected. The exception was Kake, where the fog
persisted until almost noon. Satellite imagery indicates a steady
flow of clouds north of the Icy Strait corridor as well as the
southern third of the Panhandle. Where the radar can see, shower
activity associated with the cloudiness to the south is obvious in
the composite reflectivity product. Over both the north and the
south, showers have been expected all day - both by the previous
shift as well as this day shift. Additionally, model guidance was
in very good agreement with this thinking and the 12Z sounding at
Annette indicated a nearly saturated air column extending up past
15 thousand feet. However, only Stewart (near Hyder) has reported
steady precipitation through the day and only trace amounts in
Ketchikan have been recorded. Undaunted by the present situation,
we still firmly believe that showers over the north and south will
develop this evening. Shower activity over the northeast gulf
coast is expected to train over the same area, but diminish
overnight. Showers to the south are forecast to migrate north
while while becoming more isolated overnight. Things begin to dry
out in earnest Tuesday night and the beginning of the extended
range period looks dry with a good change for partly cloudy skies
over the central and northern inner channels. The potential for
thunderstorms was considered, but modeled CAPE, instability, and
mid level lapse rates do not favor any meaningful threat of
thunder.

Winds will be unimpactful this short range forecast period and no
marine hazards were issued with the afternoon forecast. Overnight
lows will range from the upper 40s to the mid 50s. Daytime highs
will range from the lower to the upper 60s under mostly cloudy
skies through Tuesday afternoon and partly cloudy skies Tuesday
night.

.LONG TERM.../Wednesday through Monday as of 10 PM Sunday/...The
long range forecast has become rather consistent through next
week with uncertainty increasing significantly by the weekend.
Remnants of a low south of Haida Gwaii with high pressure over NW
Canada and Southern Alaska, which remains in the area through the
end of the week. More indications of a retrograding low tracking
from the NE Pacific back into the AK Gulf late Friday into
Saturday, then weakening as it tracks north. Beyond the weekend
large uncertainty remains on upstream wave development. Ensembles
still in general agreement with this pattern and deterministic
models starting to align on evolution of the ridging and even the
weekend low. As with most large ridging patterns, models diverge
rather significantly depicting the eventual break down. Kept with
WPC for any changes to the forecast, which were relatively few.

Expect drier weather to last through the end of the week as flow
becomes easterly and higher pressure builds over the region.
Increased pop with the development of the low moving back into the
Gulf for the weekend, but since confidence in the weather pattern
remains rather low with model run to run inconsistencies, still
kept pop at chance.

Winds through the period remain relatively light, with no major
systems approaching the area. Winds 15 kt or less expected
through next week. Expect afternoon sea breezes to develop from
Cape Spencer through Icy Strait and in Lynn Canal with winds
possibly upwards of 20 kt during peak heating of the day,
especially for Thursday.

Ensembles still indicate a warming trend in temperatures through
the week. With more sunshine plus slightly warmer 850mb temps and
downsloping should lead to highs in the mid 60s to low 70s for
most areas. Temps expected to cool again by the weekend due to the
advancing low and increased pop and cloud cover.

&&

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

&&

$$

Fritsch/PRB

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