Area Forecast Discussion
Issued by NWS Seattle/Tacoma, WA

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518
FXUS66 KSEW 162155
AFDSEW

Area Forecast Discussion
National Weather Service Seattle WA
255 PM PDT Thu Oct 16 2025

.SYNOPSIS...A weak frontal system will move across the area
tonight into Friday bringing light rain showers to the area. A
stronger, wetter system will follow Saturday evening into Sunday,
bringing gusty winds, lowland rain, and mountain snow to the
area. A brief drying trend is expected on Monday, before unsettled
conditions look to return Tuesday and continue through the rest of
the week.

&&

.SHORT TERM /TONIGHT THROUGH SUNDAY/...Recent satellite imagery
shows mid to high level clouds streaming in ahead of an
approaching system. This system is fairly weak and will spread
light rain showers across the area, with showers moving in
throughout the evening. QPF is pretty minimal so most areas may
not even see rain, with only a few hundredths of an inch rain
likely across the lowlands, which a quarter to a half an inch
expected for the mountains. Increasing onshore flow into Friday
will help develop a weak convergence zone across the Central and
South Sound early Friday morning with showers tapering off by the
afternoon for most of the area. High temperatures on Friday look
to remain in the upper 50s to low 60s.

A stronger and wetter system will cross over the region Saturday
evening into Sunday, with widespread rain, breezy conditions, and
mountain snow. Snow levels will rise upwards to 7000-9500 feet
late Saturday evening as widespread rain will spread across most
of the region. Winds will also become breezy, with gusts up to 20
to 30 mph at times throughout the overnight period. Winds will
continue to remain breezy Sunday morning with showers continuing
across most of the area - with areas along the Olympics and
Cascades getting the bulk of the precipitation. Snow levels will
fall back down towards 4500 feet in the wake of the front on
Sunday, likely bringing some snow to the higher elevations of the
mountains. The weekend system will bring QPF totals somewhere
around a half an inch to an inch of rain across the interior
lowlands, along with 1-3 inches along the coast and 2-4 inches for
the Olympic and the Cascades. Though this event will be a good
primer for area rivers, the antecedent dry conditions lend little
concern for any flooding at this time.

.LONG TERM /MONDAY THROUGH THURSDAY/...A transient upper ridge
looks to move over the area on Monday which will help dry
conditions out, with temperatures in the mid to upper 50s.
Low confidence in the forecast starting on Tuesday as ensemble
clusters still show a wide spread of solutions. A few weak systems
look to move across the area midweek which would allow for
showery and unsettled conditions. Will need to keep and eye on
the intensity and exact placement of a ridge which could keep
these systems away from western Washington, but for now, looks
like unsettled conditions will continue at the end of the long
term.

Mazurkiewicz

&&

.AVIATION...Mostly VFR this afternoon with areas of MVFR cigs
generally west of the Puget Sound with increasing high and mid level
clouds. Light showers will spread inland tonight as a weak frontal
system crosses the region. Areas east of the Olympics are likely to
be rain shadowed, while showers elsewhere will be light. Incoming
moisture paired with onshore flow will generate widespread low
stratus early Friday morning bringing most terminals to MVFR/IFR
with areas of patchy fog. Conditions will slowly improve throughout
the morning and afternoon Friday with the next system entering the
region Saturday. Surface winds will generally remain out of the S/SW
through the TAF period 5 to 12 kt.

KSEA...VFR this afternoon with increasing mid level clouds.
Conditions are favored to deteriorate early Friday morning, with a
moderate chance (30% to 40%) of IFR ceilings developing around 1500
feet between 12z and 18z. Conditions will improve to VFR by the
early afternoon Friday with mid level clouds. Surface winds will
generally stay out of the S/SW 4 to 9 kt through Friday afternoon,
before a brief switch to NE winds after roughly 19z.

15

&&

.MARINE...A weak frontal system will cross area waters tonight into
early Friday with weak high pressure building in thereafter through
Saturday morning. Post-frontal winds will increase through the
Central Strait of Juan de Fuca on Friday, reaching Small Craft
Advisory strength. A much stronger frontal system will move over
area waters Saturday into Sunday, with numerous headlines expected
across the outer and inner waters over the weekend. A series of
additional frontal systems will cross the region through next week.

Seas generally 4 to 6 feet will gradually build to 5 to 7 feet
through Friday morning, then increase to 9 to 12 feet by Friday
evening. Seas will remain elevated through the weekend, building as
high as 19 feet across the outermost outer waters and 15 feet along
the coastal waters on Sunday. Seas may be steep at times, especially
Saturday night into Sunday. Seas are expected to fall below 10 feet
briefly on Monday before building back to 10 to 16 feet through the
remainder of the week.

15

&&

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

$$