390
FXUS66 KPQR 101222
AFDPQR

Area Forecast Discussion
National Weather Service Portland OR
422 AM PST Wed Dec 10 2025

.SYNOPSIS...
An atmospheric river remains draped across the Pacific
Northwest, of which has shifted more north, offering some relief
to northwest Oregon and continued impacts for southwest
Washington. Today will have continued periods of rain, breezy
winds, and notable hydrologic concerns, primarily in elevated
terrain in southwest Washington and the northern portion of
northwest Oregon. Although the moisture plume is beginning a
gradual decline in strength, runoff from recent heavy rainfall
will keep rivers elevated through the day. Winds remain locally
gusty, especially across higher terrain, where saturated soils
may contribute to tree damage. A shift toward lighter, more
intermittent precipitation begins later today and persists into
Thursday as the moisture transport diminishes.

&&

.DISCUSSION...Now through Monday...The atmospheric river that
has dominated the region continues to influence conditions early
this morning, though less widespread and impactful due to its
pivot to the north into Washington. The most persistent rain
through the morning hours will be mainly focused over the
Willapa Hills and south Washington Cascades. Additional rainfall
amounts in these areas until 4 AM Thursday are expected to
range from roughly 1.5 to 3.5 inches in the south Washington
Cascades and Willapa Hills, and 1 to 3 inches in the north
Oregon Cascades and North Oregon Coast Range. The interior
valleys will see much less, generally 0.05 to 0.15 inches at
McMinnville and northward. The real edge of the heavier
precipitation from the atmospheric river will likely be located
around Longview, where 0.50 to 0.75 inches of additional rain is
possible. Note, the threat of urban flooding is now over due to
the atmospheric river shifting more north, ushering lighter
rain.

Snow levels remain high (near or above 8000 ft) through today,
ensuring rain continues across the Cascades and sustaining
runoff into downstream rivers. A slow downward trend is
anticipated tonight into Thursday as colder air gradually
filters in behind the weakening plume.

Winds will remain a secondary but meaningful hazard today.
Southwesterly gusts will commonly reach 25 to 30 mph within
interior valleys, while gusts of 35 to 45 mph are likely across
higher terrain including the Coast Range, Willapa Hills, and
Cascade ridges. Even where gusts are not particularly strong,
soil saturation increases the potential for tree falls and
localized power outages. A Wind Advisory continues until 10 PM
today for portions of northwest Oregon where the combination of
wind and compromised soil stability is most concerning.

As the atmospheric river breaks down later today, precipitation
rates will diminish, with showers becoming more scattered
overnight and into Thursday. Terrain-focused showers are
expected to persist longest across southwest Washington and the
north Oregon Coast Range. A more substantial drying trend is
anticipated Friday into Saturday as high pressure begins to
build offshore. Despite improving weather, rivers may remain
elevated for some time due to the slow response of several
basins and continuing saturation of soils across the Coast Range
and Cascades. Soils will remain saturated, particularly across
the Coast Range and Cascades, leaving the region sensitive to
additional rainfall. A frontal system looks to arrive early next
week, with potential for another round of notable rain amounts.
~12

&&

.HYDROLOGY...
River flooding remains a prominent concern this morning as
runoff from earlier rainfall continues to work through the
system. Additional precipitation through today, though lighter
than previous surges, will sustain elevated flows across
southwest Washington and far northwest Oregon. Note rain today
will be mainly limited to southwest WA and the coast. Multiple
rivers remain in or near flood stage, including the Grays,
Cowlitz, Nehalem, Wilson, and Siletz. The Pudding River, in
particular, is not near action or minor flood stage due to its
slower to respond nature but is still forecasted to reach flood
stage this morning before peaking later today. All of these
river stretches have Flood Warnings in effect.

Flood Advisories remain posted for portions of southwest
Washington and the north Oregon Coast where widespread ponding,
smaller stream rises, and localized flooding impacts are
ongoing. Although rainfall rates are not expected to be as
intense as earlier in the event, saturated soils continue to
pose a risk for landslides and debris flows, especially across
steep terrain and near recent burn scars. People, structures,
and roads located below steep slopes, in canyons, and near the
mouths of canyons may be at serious risk from rapidly moving
landslides.

Hydrologic concerns will persist even as the weather begins to
improve later today and Thursday, with several rivers expected
to remain elevated late into the week. Meanwhile, the threat of
urban flooding is now over with given the light rain rates in
place.

&&

.AVIATION...Rain associated with an atmospheric river has finally
shifted northward into northwest Washington, bringing an end to
precipitation at all TAF sites. The exception is at the coast
where moist upslope flow is maintaining persistent drizzle and
light rain, including at KAST and KONP. Expect LIFR to IFR cigs
cigs and/or visibilities to continue at the coast through 12z
Thursday with continued rain much of the time. Inland TAF sites
will see a mix of MVFR/VFR cigs, with MVFR cigs being most
predominant. Towards 11-12z Thursday, light rain will most likely
spread inland again and begin impacting locations north of KEUG
and KSLE. Gusty south to southwest winds will continue through the
TAF period with wind gusts up to 20-30 kt.

KPDX AND APPROACHES...The KPDX terminal will see a mix of MVFR to
VFR cigs through 12z Thursday, with MVFR cigs being most
predominant. Light rain returns to the KPDX terminal around 11z
Thursday. Gusty south to southwest winds around 15 kt with gusts
up to around 25 kt will continue through 12z Thursday. -23

&&

.MARINE...Seas were hovering around 10 to 12 ft at 12 to 13
seconds early Wednesday morning, with southerly to southwesterly
winds gusting up to 25-30 kt, except up to 35 kt over the inner
waters to the north of Cape Foulweather, including the Columbia
River Bar. These windier marine zones have a Gale Warning in
effect, while the outer waters and central inner waters from Cape
Foulweather to Florence have Small Craft Advisories in effect for
a combination of steep seas and wind gusts over 21 kt. Expect wind
gusts to fall below 30 kt over the inner waters by late Wednesday
evening, at which point the Gale Warning that is currently in
effect for the aforementioned marine zones ramps down to a Small
Craft Advisory.

Seas should fall below 10 ft by Thursday night and remain below
10 ft through the weekend. Next chance for strong winds and
hazardous seas will be late Sunday night into Monday when a strong
frontal system is set to move over the coastal waters. The
current forecast suggests wind gusts will peak between 35-40 kt,
which seems reasonable given there is a 80-90% chance for gale
force wind gusts over 34 kt during that time. While confidence is
high gale force wind gusts or stronger will materialize, there is
some uncertainty regarding how strong wind speeds will get.
Currently there is a 30% chance storm force wind gusts over 48 kt
occur with this frontal system. This means there is also
uncertainty regarding how high wind waves will build, which will
impact significant wave heights. There is currently a 50% chance
seas will peak around 13-15 ft late Monday, and a 10% chance seas
will peak near 20 ft. Suspect seas will peak closer to 15 ft if
gale force wind gusts materialize, and close to 20 ft or higher if
storm force wind gusts materialize. -23

&&

.BEACH HAZARDS...A Coastal Flood Advisory for tidal overflow is
now in effect for the south WA coast through 7 PM PST Wednesday to
cover high tide early Wednesday morning and high tide Wednesday
afternoon. The tidal gauge in Toke Point, WA shows the forecast
total tide peaking near 9.5 ft at high tide early Wednesday morning,
and again at high tide Wednesday afternoon. The Willapa River has
fallen below 80% of flood flow, thus limiting the tidal overflow
flooding threat where the Willapa River drains into the Willapa
Bay. However, river levels remain near 80% of flood flow on the
Naselle River near Naselle. This means the threat for tidal overflow
flooding around high tide will be highest where the Naselle River
drains into the Willapa Bay.

In additional to the tidal overflow flood threat along the south
WA coast, there remains an elevated threat for sneaker waves late
Wednesday 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. 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

&&

.PQR WATCHES/WARNINGS/ADVISORIES...

OR...Wind Advisory until 10 PM PST this evening for ORZ104>115-123.

WA...Wind Advisory until 10 PM PST this evening for WAZ202>208.

     Coastal Flood Advisory until 7 PM PST this evening for WAZ201.

PZ...Gale Warning until 10 PM PST this evening for PZZ210-251-252.

     Small Craft Advisory from 10 PM this evening to 1 PM PST
     Thursday for PZZ210-251-252.

     Small Craft Advisory until 1 PM PST Thursday for PZZ253-271>273.
&&

$$

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