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FXAK67 PAJK 251546
AFDAJK

Southeast Alaska Forecast Discussion
National Weather Service Juneau AK
629 AM AKDT Thu May 25 2017

.SYNOPSIS...A ridge of high pressure persists over the eastern gulf
through Friday. A weak weather front moves eastward and
dissipates across the northern panhandle through Thursday night.

&&

.SHORT TERM.../Thursday through Friday/ Conditions across the
panhandle vary widely in the short term. Currently, a weak front is
moving east across the northern panhandle. However, it is trying to
fight its way through a surface ridge of high pressure located over
the eastern gulf. The hardest element of the forecast is how quickly
rain dissipates today as the front moves eastward. There is very
light rain and drizzle associated with this front. Rain is most
likely early in the day with the chance of rain diminishing through
this evening as the front dissipates.

The forecast for the southern panhandle is much different where
dry conditions remain in place today. Cloud cover decreases
through this afternoon with partly cloudy to mostly clear
conditions expected inland this afternoon.

Tomorrow`s weather as a whole will be much more pleasant than today
with drier and warmer conditions expected across the panhandle.
Cloudiest areas will be along the outer coast and partly cloudy
skies are expected inland. Significant winds are not expected
tomorrow, however winds will be strongest during the afternoon with
some thermal enhancement expected.

Used the NAM and GFS for input where needed and adjusted all
precipitation intensity to be light through the period.

.LONG TERM.../Friday night through Wednesday/ As of 10 pm
Wednesday. A short wave digging south out of the eastern Bering
Sea deepens the upper trough near 160W Friday night through
Saturday night, while an upper ridge builds along the western US
coast and over British Columbia. The corresponding surface ridge
is positioned over the eastern half of the gulf with a complex
pattern of low pressure south of the Alaska Peninsula and the
Aleutians.

The ridge position should be far enough west to keep the panhandle
region on the dry side into the start of the next week. For the
early part of next week (Mon-Wed) there are model differences that
are positioning the ridge axis more to the east which will allow a
better chance for rain to try and ride over the western side of the
ridge.

With a persistent ridge over the eastern gulf for several days, will
need to watch for the development/continuation of widespread low
marine stratus deck out over the gulf and how far it will try and
penetrate into the southeast panhandle. Have kept the mostly cloudy
skies in the forecast, though if the low clouds and fog develop then
that will be under forecast.

For Friday night to Saturday, used the GFS and then tried to
blend back to the WPC solution where possible. Forecast confidence
is average through the extended part of the forecast.

&&

.MARINE...A few small craft advisories remain in the forecast today.
Northern Lynn Canal, Cross Sound, near Cape Decision and Dixon
Entrance will be the windiest. Marine winds tomorrow are expected to
be weaker than today, but still exhibit a diurnal pattern of
weakening during the overnight period and increasing during the late
afternoon/early evenings.

&&

.AVIATION...Low clouds and drizzle will prevail over the northern
panhandle and Yakutat through Thursday morning. Some improvement
from MVMC to VMC is expected over the inner channels through the
afternoon, however the outer coast areas including Yakutat and Sitka
will remain IMC the longest. The southern outer coast is affected by
the marine layer and MVMC CIGs early this morning, but are expected
to break up fairly early on.

.AJK Watches/Warnings/Advisories...
PUBLIC...None.
MARINE...Small Craft Advisory for PKZ012-022-041.
     Small Craft Advisory due to Seas for PKZ052.

&&

$$

Byrd/Bezenek

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