753
FXUS66 KPQR 222251
AFDPQR

Area Forecast Discussion
National Weather Service Portland OR
251 PM PST Sat Nov 22 2025

.SYNOPSIS...Cool temperatures and low stratus clouds continue
across the Willamette Valley this afternoon. The next system
arrives tonight into Sunday morning, returning light rain across
northwest OR and southwest WA. Temperatures cool down behind
this system, dropping snow levels below 4000 ft Sunday night,
resulting in light snow through the Cascade passes. Expect a
chilly Monday and Tuesday morning. The next system arrives
Tuesday night into Wednesday, with wet weather continuing
through the end of the week.

&&

.SHORT TERM...Now through Monday Night...Satellite imagery as of
early Saturday afternoon depicts widespread low stratus across
the Willamette Valley and southwest Washington lowlands. There
is some clearing occurring in the south Valley in the Eugene
area, however, it`s unlikely that areas north of Eugene will
clear out this afternoon. Pilot reports this morning were
observing a pretty deep stratus deck (~1200 ft thick), and high
pressure aloft is prevent this stratus from mixing out. Plus
with the sun angle being lower this time of year, we won`t have
enough heating/time to burn out the stratus. As a result, went
ahead and increased the sky cover forecast and decreased the
high temperature forecast today across the Willamette Valley and
southwest WA lowlands below 1000 ft. Areas under this stratus
deck will struggle to hit 50 today, and will likely peak in the
mid to upper 40s.

The next frontal system will approach the region tonight into
Sunday, returning widespread light rain. High resolution
guidance suggests that the cold front will swing through late
tonight into early Sunday morning, with light rain reaching the
south WA and north OR coast by around 11 PM Sat - 2 AM Sun, and
spreading into the central OR coast and interior lowland
valleys by 5-8 AM Sun. 24 hour rainfall totals from 4 AM Sun to
4 AM Mon are forecast around 0.30-0.60" along the coast (highest
along the north OR and south WA coast), 0.25-0.75" along the
Coast Range and Willapa Hills (highest amounts north of Highway
20), 0.20-0.40" across the Willamette Valley and southwest
Washington lowlands, and 0.50-1" across the Cascades. Winds turn
more southerly as the system approaches the region, but
generally remain light and non-impactful. Behind the front,
winds turn more westerly late Sunday night and become breezy
across the high Cascades and eastern Columbia River Gorge with
gusts up to 25-30 mph (30-50% chance gusts exceed 30 mph).

Will note that there is also still a decent spread in forecast
precipitation amounts among models, especially when comparing
the "wettest" and "driest" scenarios. Based on the NBM 10th
percentile guidance (driest scenario), there is a 10% chance
that rainfall totals remain less than 0.20" along the coast and
interior valleys. Based on the NBM 90th percentile guidance
(wettest scenario), there is a 10% chance that rainfall amounts
exceed 1-1.25" along the coast and Cascades and 0.50-0.75"
across the Willamette Valley and southwest WA lowlands.
Precipitation may fall as stratiform rain along the coast
initially, but become more showery as the front progresses
inland, hence the varying precipitation amounts. It will also
depend on how strong the front is as it makes landfall.

Shower activity gradually decreases Sunday night into Monday
morning as the system weakens and exits the region. Temperatures
will also cool down behind this system, making for a chillier
Monday morning across interior valleys with snow levels dropping
below pass-level. Remaining showers in the Cascades Sunday night
into Monday would fall as snow, with snow amounts forecast
around 0.5-2" through the passes, highest along Highway 26.
There is currently a 15-30% chance that snow amounts exceed 2",
with the highest chances along Santiam Pass and Highway 26.
Drier conditions return by Monday afternoon and evening as a
brief shortwave ridge builds over the Pacific Northwest ahead of
the next system.       -10

&&

.LONG TERM...Tuesday through Friday...Tuesday morning will be
the chilliest night of the week, with low temperatures forecast
to drop into the low to mid 30s across interior lowland
valleys. With moist surface conditions, there will be potential
for frost development early Tuesday morning especially on
grasses and elevated metal surfaces. By late Tuesday afternoon
and evening, the majority of ensemble members suggest upper
level ridging will build over the U.S. West Coast, however, the
Pacific Northwest appears to be right at the top of the ridge.
While 500 mb heights will climb and bring relatively warmer
temperatures, we will be far from dry.

The next system will ride the periphery of the ridge and enter
the Pacific Northwest, returning widespread rain chances Tuesday
night into Wednesday. Since this would be a warmer system, snow
levels will climb above 6000 ft and result in rain through the
Cascade passes. Conditions remain showery through Thursday as
this system moves through the region. Chances for 48-hour
liquid precipitation exceeding 1" from 4 AM Wed to 4 AM Fri are
around 45-65% along the coast, Coast Range, Willapa Hills, and
Cascades, 15-30% across the Willamette Valley and Upper Hood
River Valley, and 30-50% across the southwest WA lowlands.

The vast majority of ensemble members suggests that we will
maintain wet weather through the end of the week, however,
there is uncertainty with exactly how much we will end up with.
Ensemble guidance shows another system potentially arriving on
Friday; however, the exact track and magnitude of this system is
uncertain. About 55% of members suggest some sort of troughing
in the NE Pacific or Pacific Northwest that would lower 500 mb
heights and thus lower temperatures, and bring another round of
at least 0.25-0.50" of liquid precipitation.        -10

&&

.AVIATION...High pressure will remain in place through at least
12z Sunday, resulting in calm winds and an expansive/persistent low
stratus deck with cigs in the 200-700 foot range across the
entire Willamette Valley. With high clouds moving in from the west
over the top of this stratus deck, combined with a low sun angle
this time of year and little to no mixing, this stratus deck will
remain in place through tonight with no significant clearing. The
exception is at KEUG where low clouds have temporarily scattered
out. However, expect low stratus to fill back in at KEUG shortly
after sunset. Cigs in the mid to late afternoon will most likely
range between 400-700 ft, before lowering back to 200-300 ft
towards 03z Sunday. This is also when surface visibilities will
likely lower to 1/4 to 3/4 SM at all inland terminals, aside from
KTTD which may see relatively higher surface visibilities. In
summary, expect LIFR to IFR flight conditions for all inland
terminals through at least 12z Sunday. After 12-15z Sunday, a
front will begin moving inland, bringing light rain and increased
mixing to the area. This will eventually help lift fog and cigs,
with flight conditions improving to IFR or MVFR. That said,
confidence is low regarding the exact timing cigs/visibilities
will lift Sunday morning. Meanwhile, coastal terminals will most
likely experience a mix of IFR/MVFR cigs throughout the TAF period
with relatively higher surface visibilities.

KPDX AND APPROACHES...Expect low stratus to remain in place
through at least 12-15z Sunday, with cigs hovering between 200-700
ft (highest from 21z Saturday-01z Sunday, lowest from 02-12z
Sunday). By 03-06z Sunday, fog will likely redevelop with surface
visibilities lowering to 1/2 SM or lower. There is a 20-30%
chance surface visibilities will fall to 1/4 SM or lower. By 15z
Sunday, an incoming front will bring light rain and increased
mixing. This should help scour out fog and allow cigs to lift to
IFR or low-end MVFR thresholds, however the exact timing this will
occur is uncertain.       -23

&&

.MARINE...High pressure over the area is maintaining fairly stable
conditions with minimal change expected through Sunday. Seas will
remain around 10 to 13 ft through the weekend before falling to 8
to 9 ft on Monday and then 6 to 8 ft on Tuesday. A weak cold
front will move over the waters Sunday morning, bringing southerly
wind gusts up to 20-25 kt. A relatively stronger front arrives
Tuesday night into Wednesday, bringing wind gusts up to at least
25-30 kt with a 30-50% chance for gale force wind gusts up to 35
kt. Confidence in gale force wind gusts materializing is not high
enough to issue a Gale Watch at this time.       -23

&&

.BEACH HAZARDS...An energetic westerly swell is expected along
the northwestern Oregon and southwestern Washington coasts through
Monday. Seas 10-14 ft at 14-16 seconds are forecast through the
the weekend, resulting in a high sneaker wave threat. These
energetic waves can run significantly farther up a beach than
normal, including over rocks and jetties, creating potentially
life-threatening conditions in the surf zone when beachgoers can
be unexpectedly knocked off their feet and pulled out into cold
ocean waters.

A Beach Hazards Statement has therefore been issued through 10 AM
Monday. Caution should be used when in or near the water, and
beachgoers with children should be especially watchful. Never turn
your back on the ocean, and be sure to keep an eye on the waves.
Those participating in razor clam digs should additionally
exercise caution.       /42

&&

.PQR WATCHES/WARNINGS/ADVISORIES...

OR...None.
WA...None.
PZ...Small Craft Advisory until 10 AM PST Monday for PZZ210-251>253-
     271>273.
&&

$$

www.weather.gov/portland

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