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325
FXUS66 KSEW 080329
AFDSEW

Area Forecast Discussion
National Weather Service Seattle WA
829 PM PDT Mon Oct 7 2024

.UPDATE...
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Increasing clouds this evening will continue into early
Tuesday as a weak frontal system moves into the area. A brief
period of locally breezy southerly winds is expected into Tuesday
morning, mainly along the north coast and into portions of
northern Puget Sound, with gusts 20 to 30 MPH. No major forecast
updates this evening.
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&&

.SYNOPSIS...
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A cooler weather pattern settles into the Pacific
Northwest this week. A cold front will bring in cooler
temperatures, light precipitation, and brief breezy winds
overnight into Tuesday, with showers continuing through Wednesday.
High pressure will allow conditions to dry out on Thursday ahead
of another incoming system towards the end of the week.
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&&

.SHORT TERM /TONIGHT THROUGH THURSDAY/...Clear skies across much
of western Washington this afternoon is allowing temperatures to
climb into the 70s across much of the lowlands, with highs on
track to peak roughly 10 to 15 degrees above normal. Today will
likely be the warmest day of the week before troughing settles
into the Pacific Northwest, bringing in cooler temperatures and
periods of rain showers.

A cold front stemming from an upper level trough in the Gulf of
Alaska will continue to approach the coast throughout the
afternoon, bringing light showers over the northwestern Olympic
Peninsula. The cold front will slowly shift eastward later this
evening and into Tuesday morning, with light shower activity
spreading inland overnight and through the morning. Breezy
conditions will accompany the cold front Tuesday morning, with
occasional gusts of 20 mph to 30 mph. The area may see some sun
breaks Tuesday afternoon, but highs will return into the mid 60s
across the lowlands. Another front stemming from the parent low
in the Gulf of Alaska will swing across western Washington on
Wednesday, maintaining scattered shower activity and causing
temperatures to lower a few degrees. Rainfall amounts through
Wednesday will be fairly light, with up to 0.25" in the lowlands
and generally up to 0.50" over higher terrain. Snow levels
between 5000-6000 ft will also allow for a dusting of snowfall
over higher peaks in the Cascades.

As a trough drops over northern California on Thursday, ridging
will amplify over the Pacific Northwest. Conditions will dry out
and warm up a few degrees, with near normal temperatures in the
low to mid 60s.

.LONG TERM /FRIDAY THROUGH MONDAY/...Forecast confidence
decreases heading into the weekend, with ensembles favoring a
wetter solution while the latest deterministic models trend drier.
Upper level troughing is favored along the Pacific Northwest
coast, with any precipitation across western Washington highly
dependent on the track of this storm system. Ensemble members show
a broad range of solutions through early next week, maintaining a
chance of precipitation and cooler temperatures through the
period.

Lindeman

&&

.AVIATION...
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Southwesterly flow aloft will extend into Tuesday. At
low levels light and variable winds will increase somewhat and
become more southerly ahead of the approaching weak front. Low level
winds this evening 4 to 8 kts will become more gusty for many areas
15 to 20 kts from 10z through 15z as the front moves through Western
Washington. Increasing high clouds this afternoon with increasing
low level clouds and light rain along the coast around 08Z spreading
inland through 15-18Z. MVFR ceilings 1500 to 2500 feet with the
front will lower through mid morning to 500 to 1500 ft for many
locations.

KSEA...VFR conditions with increasing high clouds through the
evening. Light surface winds will veer to the S/SW during the
remainder of the evening and strengthen -  becoming gusty ahead of
and with the front after 08Z. HREF continues to highlight 70-80%
probability of ceilings below 3000 feet and 40% chance below 1000
ft.
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&&

.MARINE...
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Southerly winds will continue over the coastal waters in
advance of an approaching front. HREF continues to show less than a
20% chance of sustained winds greater than 21 kts as the front moves
through area waters overnight into Tuesday morning. Having said that
periods of gusty winds possible especially just ahead of and with
the front. Winds will veer more westerly Tuesday. Another system on
tap for Wednesday...with winds more westerly...but speeds will be
lower with minimal SCA concerns. Another system is progged for the
weekend.

Seas generally 5 to 7 feet will build to 7 to 9 ft especially over
the outer coastal waters Tuesday, then easing to 6 to 8 ft
through Thursday.
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&&

.SEW WATCHES/WARNINGS/ADVISORIES...
WA...None.
PZ...None.
&&

$$