018
FXUS66 KPQR 102249
AFDPQR

Area Forecast Discussion
National Weather Service Portland OR
249 PM PST Wed Dec 10 2025

.SYNOPSIS...Heavy rain from the atmospheric river has now
shifted northward into northwest Washington. Light to moderate
rain continues across southwest Washington and the north Oregon
Coast Range, maintaining elevated river levels. Flood Warnings
remain in effect for several rivers through the end of the week.
Drier weather returns Friday to Saturday, with more rain and
breezy winds returning by late weekend into early next week.

&&

.SHORT TERM...Now through Tuesday...The atmospheric river that
brought heavy rain and flooding impacts across northwest Oregon
and southwest Washington the last couple days has now shifted
northward. Most of the heavy rain is now falling over northwest
Washington; however, we will continue to see light to moderate
rain showers across southwest Washington and the north Oregon
coast and Coast Range through Thursday. Observations as of early
Wednesday afternoon showed rainfall rates of 0.10-0.25" per
hour over the Willapa Hills and parts of Cowlitz County. Based
on REFS guidance, there is high confidence (60-80% chance) that
rainfall rates across southwest Washington and far northwest
Oregon remain around 0.10" per hour or less through tomorrow,
but there is still a 20-30% chance that rainfall rates of 0.25"
per hour or greater occur over high terrain. If higher rainfall
rates occur, creeks and rivers will be slower to subside.

Elsewhere, most areas across northwest Oregon remain overcast
and mostly dry with some isolated to scattered rain showers
through Thursday. Snow levels still remain above 7000-8000 ft,
so any precipitation in the Cascades should fall as rain except
for the volcano peaks. Breezy south-southwesterly winds continue
through this evening with gusts up to 20-30 mph for most areas.
An exception would be for higher terrain and south Washington
and north Oregon coasts where gusts could reach 30-40 mph, with
a 30-50% chance that gusts exceed 40 mph through 10 PM. Winds
will weaken overnight as pressure gradients gradually ease.

Shower activity decreases Thursday night into Friday as an
upper level ridge builds over the Pacific Northwest. This will
bring a decent break from the rain with dry weather heading into
the weekend. Some locations may start to see cloud breaks as
early as Friday, but more widespread cloud breaks will occur on
Saturday as the upper level ridge moves overhead. Will note that
if any locations clear out of the clouds Friday night, there
could be some morning fog or low stratus development Saturday
morning. However, that should burn off by the late morning and
early afternoon, making way for some brief sun! Wow, sun? What`s
that!? Don`t know her. Emphasis on `brief` though.

Saturday night into Sunday, the next frontal system will move
into the Pacific Northwest, returning clouds and chances for
rain. Snow levels briefly fall to 6000-7000 feet, so it`s still
looking like rain will be falling at pass-level with this
system. This upcoming front doesn`t look too impactful and
ensemble guidance keeps rain amounts generally light. NBM
chances for 0.25" or rain or more in 24 hours ending 4 PM Sunday
are 40-60% along the coast, Coast Range, and southwest
Washington, and 10-25% across the Willamette Valley and north
Oregon Cascades.

Ensemble guidance is in agreement that a more impactful system
will follow Monday to Tuesday, potentially bringing heavier rain
and breezy winds. This is a warm system, so snow level will rise
again above 7000-8000 feet. There is still some uncertainty
with exactly how much rain we`ll get, but current guidance
suggests that the chances for 2" or more in 48 hours from 4 AM
Monday to 4 AM Wednesday are around 10-20% for interior lowland
valleys and 40-70% across the Coast Range, Willapa Hills, and
Cascades, with the highest chances north of Lane County. Chances
for maximum wind gusts of 45 mph or greater are also around
50-60% along the coast and 10-20% for interior lowland valleys.
Considering how saturated our soils are, wind gusts of this
magnitude along with additional rain would make trees more
susceptible to falling. Local rivers and creeks will also have
to be monitored closely with the upcoming rain given that we are
just coming out of an atmospheric river that brought many
rivers to flood stage.      -10

&&

.AVIATION...Steady rain remains north of the area today however
persistent low clouds and drizzle/light rain will continue to
fall along the coast due to moist upslope flow, including KAST
and KONP. Expect LIFR to IFR cigs cigs and/or visibilities to
continue at the coast through 18z Thursday with continued
drizzle/rain. Inland TAF sites will see a mix of MVFR/VFR cigs,
with MVFR cigs being most predominant. Latest hi-res models
indicate -shra to sag southward into the Portland area 05-06z
and central Willamette 10-12z Thursday. Gusty south to southwest
winds will continue through 09-11z Thursday with wind gusts up
to 20-30 kts.

KPDX AND APPROACHES...The KPDX terminal will see a mix of MVFR to
VFR cigs through 20z Thursday, with MVFR cigs being most
predominant. Probabilities for cigs to become broken increase
from 55% to 75% during this time. 30% chance for showers to return
to the KPDX terminal 06-09z increasing to 70% 10-11z. Gusty
south to southwest winds around 15 kts with gusts up to around
25 kts will continue through 11z Thursday then decreasing
15-18kts and below 15kts after 16z.       -nws spokane

&&

.MARINE...Seas remain around 10 to 12 ft at 12 to 13 seconds
Wednesday afternoon, with southerly to southwesterly winds
gusting up to 20-30 kt, except up to 35 kt over the inner waters
to the north of Cape Foulweather, including the Columbia River
Bar. These gales will diminish by late this evening as winds
decrease significantly overnight.

However, seas remain hazardous to smaller crafts into early
Thursday as a steep swell remains in the waters. The sea state
will improve by Thursday evening as the westerly swell drops
below 10 feet.

The next concern will be Monday when a cold front traverses 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 30-40% chance
storm force wind gusts over 48 kt occur with this frontal
system, especially closer to shore. 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/Smith

&&

.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

&&

.HYDROLOGY...Rain continues to persist across southwest
Washington and the north Oregon Coast Range as of Wednesday
afternoon and will continue through Thursday. This will maintain
river flooding concerns as runoff from previous rainfall
continues to work through the system.

Flood Warnings remain in effect for four rivers: the Grays
River at Covered Bridge near Rosburg, WA, the Cowlitz River at
Kelso, WA, the Luckiamute River near Suver, OR, and the Pudding
River at Aurora, OR. The Grays River remains at Moderate flood
stage and the latest observations show the river level
plateauing, which makes sense given that rain hasn`t ended yet
in that area. The Cowlitz River at Kelso is currently in Minor
flood stage, but that is forecast to fall into Action stage
this evening. The Luckiamute River is also in Minor flood stage,
but continues to rise and hasn`t crested yet. Meanwhile, the
Pudding River is just now reaching Action stage and has not
flooded yet. This river in particular is slower to respond in
nature but is still forecast to reach Minor flood stage on
Thursday.

Hydrologic concerns will persist even as the weather begins to
improve later today and Thursday, with several rivers remaining
elevated late into the week given the amount of rain we`ve
received the last few days. However, the threat of urban
flooding is now over since rainfall rates have decreased across
the area.     -10

&&

.PQR WATCHES/WARNINGS/ADVISORIES...

OR...None.
WA...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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