692
FXUS66 KPQR 111139
AFDPQR

Area Forecast Discussion
National Weather Service Portland OR
339 AM PST Thu Dec 11 2025

.SYNOPSIS...
Light to moderate rain persists across southwest Washington and
the north Oregon Coast Range early this morning, keeping several
rivers elevated as runoff continues to work through the system.
A gradual improvement in conditions is expected later today into
Friday as an upper ridge begins to build. A quieter stretch of
weather follows Friday and Saturday before the next organized
frontal system approaches late Saturday night into Sunday. A
stronger and wetter system is then anticipated early next week.

&&

.DISCUSSION...Now through Tuesday...Lingering moisture on the
southern flank of the weakening atmospheric river continues to
support areas of light to moderate rainfall across southwest
Washington and portions of the north Oregon Coast Range.
Expected precipitation rates generally remain at or below one
tenth of an inch per hour, though there is still a modest chance
for brief increased rates over higher terrain. While these
rates are not expected to produce new flooding concerns, they
will delay recession on rivers that remain high from earlier
rainfall. Farther south, conditions across northwest Oregon are
mostly quiet aside from patchy showers and persistent cloud
cover. Snow levels remain high, around 7500 to 8500 feet,
keeping the Cascades predominantly in rain except at the highest
volcanic summits. Winds are gradually diminishing early this
morning following a breezy period, with gusts now mostly below
advisory levels for all but the Columbia River Gorge and a few
exposed ridgetops.

A more notable improvement in weather is expected later today
into Friday as an upper ridge strengthens over the region.
Shower coverage will steadily decline, and many locations will
see extended breaks from precipitation beginning Friday. Partial
clearing is possible by Friday morning, which may support areas
of fog or low stratus through the day and into Saturday
morning. Better clearing is anticipated Saturday afternoon as
the ridge shifts overhead.

The next frontal system approaches the region Saturday night
into Sunday, bringing increasing cloud cover and renewed chances
for rain. Current ensemble guidance suggests modest
precipitation amounts with this initial front, with the higher
totals most likely along the coast, Coast Range, and southwest
Washington (24 hour rain totals from 10 PM Sat to 10 PM Sun:
0.3-0.5 inch around the coast, Coast Range, and southwest
Washington and under 0.2 inch elsewhere). Snow levels briefly
dip to around 6000 to 7000 feet, keeping pass-level
precipitation as rain.

A more robust and wetter system follows early next week, around
Monday. Confidence is increasing that this system will produce
heavier rainfall across southwest Washington, the Coast Range,
Willapa Hills, and the Cascades, with lower amounts extending
into the interior lowlands. Given how saturated the soils are at
the moment, even moderate additional rainfall may lead to
renewed sensitivity of rivers and streams. Breezy winds are also
likely with this system, particularly along the coast. Current
guidance suggests wind gusts around 30 to 35 mph inland and 45
to 50 mph at the coast on Friday. Worst case scenario (10%
chance of occurring), winds could gust up to 40 to 45 mph inland
and 55 to 60 mph along the coast. Given the spread, details
regarding magnitude and timing of winds remains uncertain and
warrants monitoring as early next week nears. ~12

&&

.HYDROLOGY...
Rivers across southwest Washington and the north Oregon Coast
Range remain elevated early this morning due to ongoing light
rainfall and continued runoff from earlier precipitation. Flood
Warnings remain in effect for the Grays River near Rosburg, the
Cowlitz River at Kelso, and the Luckiamute River near Suver.
While the Pudding River near Aurora is not forecasted to reach
minor flood stage, it remains in action stage early this
morning, very close to minor flooding. As a result, we will
continue to closely monitor the Pudding River, especially as
as runoff continues to drain into this river. Each river is
responding at a different rate, with some having crested and
others still rising or leveling off, but all are expected to
remain elevated into the latter half of the week.

&&

.AVIATION...An area of broken rainfall associated with an
atmospheric river north of the region in Washington is expected to
slowly sag southward Thursday morning, bringing increasing shower
chances to KPDX and KTTD. KHIO and KUAO may see a few stray
showers today as well. KSLE and KEUG should remain dry. However,
moist westerly flow along the coast will maintain light
rain/drizzle and LIFR to IFR CIGs throughout the TAF period for
KAST and KONP. Expect inland showers and coastal drizzle to begin
diminishing from south to north Thursday afternoon. Gusty south
to southwest winds up to 20-25 kt will continue through 16-20z
Thursday before winds weaken significantly Thursday afternoon and
evening.

High pressure develops Thursday evening/night, bringing calm
winds and some clearing Thursday night. This will set the stage
for widespread fog and low stratus develop across inland valleys,
including all inland TAF sites. Probabilities for surface
visibilities below 1 SM peak between 50-70% by 12z Friday, with
cigs likely falling below 500-1000 ft.

KPDX AND APPROACHES...Expect cigs to fluctuate between MVFR and
VFR thresholds Thursday morning, before trending towards MVFR most
of the time in the afternoon and evening. Fog and/or low clouds
will attempt developing over or near the terminal by 11-12z
Friday. This is when there is a 50% chance for surface
visibilities at or below 1/2 SM with cigs falling below 1000 ft.
-23

&&

.MARINE...Small craft advisories remain in effect through 1 PM
Thursday across the coastal waters, including the Columbia River
Bar. Although winds have fallen below 10-20 kt, seas remain
around 10-11 ft at 13 to 15 seconds and will be hazardous to small
craft. Seas are expected to fall below 10 ft by mid to late
Thursday afternoon and should then stay below 10 ft through
Sunday, marking a prolonged stretch of relatively benign
conditions. One exception is Saturday evening through Sunday
morning when marginal small craft advisory level wind gusts up to
25 kt have a 90% chance of occurring with a frontal passage.

This front will mark the beginning of a more active weather
pattern for the upcoming week. Main concerns begin early Monday
when a stronger front traverses the coastal waters, bringing
hazardous seas and increasing winds. There is high confidence for
southerly gale force wind gusts by Monday afternoon with this
front, as probabilities are near 90% for max wind gusts over 34 kt
between 10 Sunday and 10 PM Monday. Hourly probabilities are also
high, especially over the inner waters. Storm force wind gusts
over 48 kt cannot be ruled out either, as probabilities range from
around 20% over the outer waters and near 40% chance over the
inner waters. Probabilities are highest over the inner waters due
to the development of a potential coastal jet. Guidance suggests
seas will most likely peak somewhere between 15-20 ft Monday
afternoon and evening, however the outcome will be highly
dependent on wind speeds and how high wind waves are able to
build. While unlikely to occur, there is a 5% chance significant
wave heights will peak anywhere between 21-25 ft, which represents
the worst case scenario. Note seas and winds will remain elevated
Tuesday into Wednesday as well, albeit not quite as high as
Monday. -23

&&

.BEACH HAZARDS...There remains an elevated threat for sneaker
waves through Thursday along the entire coast. The swell period
increases to around 14-15 seconds with swell heights around 9-11
ft, with swell heights and swell periods decreasing late Thursday
night into Friday. This will create energetic waves that will
present a moderate to high risk for sneaker waves, which are waves
that can run significantly farther up a beach than normal,
including over rocks and jetties. Sneaker waves can suddenly knock
beachgoers off of their feet and quickly pull them into the
frigid ocean which may lead to serious injury or drowning. Caution
should be used when in or near the water. Always keep an eye on
the waves, and be especially watchful of children. -23/99

&&

.PQR WATCHES/WARNINGS/ADVISORIES...

OR...None.
WA...None.
PZ...Small Craft Advisory until 1 PM PST this afternoon for PZZ210-
     251>253-271>273.
&&


$$

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