Orcas, Washington Weather Forecast Discussion

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FXUS66 KSEW 200949
AFDSEW
Area Forecast Discussion
National Weather Service Seattle WA
249 AM PDT Sat Sep 20 2025
.SYNOPSIS...Mostly dry and mild conditions continue today before a
frontal system move through the area late tonight into Sunday
morning, bringing widespread rain, breezy winds, and cooler
temperatures. High pressure will return Monday for a return to
sunny skies and warmer conditions through at least the first half
of the week.
&&
.SHORT TERM /TODAY THROUGH MONDAY/...Skies remain mostly clear
across much of western Washington, though marine stratus is
developing along the coast and will push inland a little bit
tonight. The Puget Sound area and the metro should remain under
clear skies. Lows will be again be cool for this time of year, in
the low 40s to low 50s. Stratus should quickly retreat, allowing
the sun to warm us back up into upper 60s on the coast, with low
to mid 70s for the interior.
Smoke from fires on the Olympic Peninsula will continue to
degrade air quality through today, through this incoming system
tonight into tomorrow should help to clear some of it out and
improve air quality.
Clouds will start to increase in the evening as the frontal
system approaches the area. Rain will first reach the coast late
this evening, moving across the interior early Sunday morning. The
heaviest rain will be before sunrise but showers may stick around
into Sunday morning. Additionally, a convergence zone may keep
some showers going over the metro area and towards the passes into
Sunday afternoon. With the trough axis directly overhead by
Sunday afternoon, there may be just enough instability for a
lightning strike or two, but overall the probability is low
(10-15%). Through Sunday afternoon, 0.5-1" will be possible across
the mountains and the Pacific coast, with the interior receiving
around 0.25-0.5" with this system. Definitely not a fire season-
ender, but should bring a temporary reprieve for the active fires
in the area. As the rain moves through overnight, low temperatures
will be warmer, in the mid 50s, though Sunday`s high temperatures
will remain quite cool, in the mid to upper 60s. Decreasing
clouds Sunday night should allow lows to once again cool quite
effectively, in the 40s to near 50 in the metro. Areas of fog will
be expected Monday morning. Upper level ridging will quickly
build over the area behind the trough Monday morning, allowing for
a rapid return to mostly clear skies and more seasonable
temperatures, with highs a few degrees on either side of 70 on
Monday.
.LONG TERM /TUESDAY THROUGH FRIDAY/... Upper level ridging looks
to remain in place into Tuesday and Wednesday, allowing for a
gradual warm-up, back into the mid to upper 70s. Lows remain in
the 50s. The ridge looks to flatten around mid-week, which may
allow systems to move through and reach the area by late week into
next weekend and bring temperatures back close to/slightly below
normal, however there is considerable uncertainty as to how
quickly that occurs and whether or not incoming waves are able to
sustain themselves to reach the Pacific Northwest. That being
said, ensembles keep the area dry through Friday.
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&&
.AVIATION...Southwest flow aloft will increase over Western
Washington today as an upper ridge shifts eastward and a trough and
associated frontal system approach the region. The low level flow is
light onshore. Shallow LIFR stratus along the coast will spread
inland this morning reaching portions of Puget Sound before receding
back toward the coast. Reduced visibility in smoke and haze will
continue to affect areas downwind of the Bear Gulch
Fire...especially south portions of Puget Sound eastward. High and
mid level clouds will increase late this afternoon and tonight. MVFR
ceilings in rain will develop along the coast late this evening with
said conditions spreading to interior areas overnight.
KSEA...High level smoke and haze will persist across the area
through much of the day, but LIFR stratus is expected to remain
south and west of terminal this morning. High and mid level clouds
ahead of an approaching front will increase this afternoon and
evening with ceilings lowering to MVFR in rain near or after 08Z
tonight. Surface winds light and variable early will turn S/SW and
rise to 7 to 10 knots this afternoon and evening. Winds will become
gusty for a period with and behind the front early Sunday morning.
27
&&
.MARINE...A weak surface ridge over the waters will give way to
a weak trough and associated frontal system tonight into early
Sunday. High pressure will rebuild over the waters later Sunday into
Monday. Another thermal trough expanding northward along the Oregon
coast early next week will turn the flow more northerly or weakly
offshore. Onshore flow will resume around midweek as another frontal
system moving into British Columbia passes mostly north of the area.
27
&&
.SEW WATCHES/WARNINGS/ADVISORIES...
WA...None.
PZ...Small Craft Advisory from 11 PM this evening to 1 PM PDT Sunday
     for Central U.S. Waters Strait Of Juan De Fuca-East
     Entrance U.S. Waters Strait Of Juan De Fuca.
Small Craft Advisory from 1 AM to 9 AM PDT Sunday for Puget
     Sound and Hood Canal.
Small Craft Advisory from 2 PM this afternoon to 2 AM PDT Sunday
     for Coastal Waters From Cape Flattery To James Island 10 To
     60 Nm-Coastal Waters From Cape Flattery To James Island Out
     10 Nm-Coastal Waters From James Island To Point Grenville
     10 To 60 Nm-Coastal Waters From James Island To Point
     Grenville Out 10 Nm-Coastal Waters From Point Grenville To
     Cape Shoalwater 10 To 60 Nm-Coastal Waters From Point
     Grenville To Cape Shoalwater Out 10 Nm.
&&
$$

NWS sew Office Area Forecast Discussion