Oregon City, Oregon 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

783
FXUS66 KPQR 250455 AAA
AFDPQR

Area Forecast Discussion...UPDATED
National Weather Service Portland OR
954 PM PDT Sun May 24 2026

Updated aviation discussion.

.SYNOPSIS...High pressure continues to linger over the region
through the evening, but confidence remains high that a significant
pattern change is on deck starting tonight. The cause of this
cooler and wetter pattern is a Gulf of Alaska low that looks to
bring widespread rain, breezy winds, and much cooler temperatures
across the area. Showers linger into Tuesday along with a
slight chance (10-20%) for thunderstorms. Conditions trend
warmer and drier through the middle of the week and into next
weekend.

&&

.DISCUSSION...Now through Saturday...Clear skies this evening
will soon be replaced by widespread cloud cover starting
tonight. GOES full disk, satellite observations shows a broad
upper level low covering a vast area of the northeastern
Pacific Ocean. Putting the satellite on a loop, this low is
moving eastward which will result in a cold front being pushed
across the Pac NW. This front will bring widespread rain and
thick cloud cover across our CWA. Rain should begin along the
coast around 5AM-7AM Monday morning, with rain starting to
impact inland locations around 12PM-2PM Monday. Recent guidance
supports 24 hour rainfall totals (roughly 5 AM Monday to 5 AM
Tuesday) in the 0.15"-0.80", with the greatest totals along the
coast and Coast Range. Probabilities for at least 0.25 inch are
generally 35-75% for the Willamette Valley and 60-95% for the
coast, Coast Range, and Cascades. Probabilities for 0.50 inch
or more are generally 5-30% for the Willamette Valley and 60-95%
for the coast and Coast Range, and generally 15-45% for the
Cascades. A corridor from Florence OR north toward Seaside OR
continues to show the best chances, around 20-40% for 1.0" or
more.

Winds will also pick up early Monday as the front moves
through. Currently probabilities strongly favor gusts exceeding
25 mph across much of the area (around 80-99%). Gusts over 30
mph are more likely along the coast (60-90%) than inland
(25-60%). Higher-end gusts around 35 mph or greater remain a
lower-probability outcome for inland locations (5-15%) but are
more favored along the coast (30-50%). Even without advisory-
level winds expected inland, these speeds can still impact
tents, canopies, and other unsecured items.

By Tuesday, the low shifts southeastward with showers lingering
and a more southerly flow developing. That setup is more
supportive of thunderstorms, which is resulting in a 10-20%
chance for the Willamette Valley and Cascades by late Tuesday
morning through late Tuesday evening.

From midweek through next weekend, guidance trends toward a
warming and drying pattern as weaker high pressure/zonal flow
returning. For reference, daytime highs will likely (70-85%)
remain slightly cooler than this weekend. While confidence
remains low, ensemble guidance suggests that the weak high
pressure ridge will weaken Friday as a broad trough over the
Northeast Pacific nears the Pacific Northwest. /42~12

On a slightly personal note, with Monday being Memorial Day, it
is time to remember those who served that are no longer with
us. I want to remind everyone that if you are a fellow veteran
or know a veteran that needs help, you can always call the VA
Crisis Line by dialing 988 and pressing 1 or text 838255
24/7/365. We must take care of and look out those who stood
besides us, who came before us and who will follow in our
footsteps. Semper Fi. /42

&&

.AVIATION...A frontal system remains just offshore this evening
which will be the weather maker over the next 24 hours. Most
locations remain VFR except a few isolated areas along the central
Oregon coast. A layer of marine stratus is working it`s way
northward and should impact KONP in the next few hours. 50% chance
of IFR conditions and greater than an 80% chance of MVFR along
coastal terminals. The north coast though will likely stay out of
a bulk of that stratus due to mixing from the frontal passage
after 12Z Mon. Winds will continue to shift through the period
becoming southwesterly in the afternoon with the front. As they
do, expect gusty winds with many airports seeing gusts in excess
of 20 kt. Some areas within the Columbia River Gorge will be even
windier with some models suggesting as high as 30 kt at 3000 ft.

Rain expected over the region with a 15-30% chance of
thunderstorms after 18Z Mon. Trending on the lower end of that
range, but cannot rule out an isolated thunderstorm or two -
though confidence is much lower than in previous forecasts. Have
included PROB30 in the TAF for KAST, KONP, KHIO, KPDX, and KTTD.
This is not looking like a widespread thunderstorm system but
rather a few one-hit-wonders.

KPDX AND APPROACHES...Predominately VFR conditions through the
TAF period with increasing SCT/BKN high clouds ahead of the next
system. After 13-15z Mon, southerly winds increase with gusts up
to 20 kt as the front approaches. CIGs also gradually fall to low-
end VFR after 19Z Mon with around a 15% chance of MVFR CIGs.
Rain in the area with gusty winds may temporarily reduce VIS at
times. PROB30 included late in the forecast for thunderstorms but
confidence is low. At this point, there is a high level of
uncertainty in regards to whether or not we will see any kind of
thunderstorm activity so those probs could be removed in later
forecasts. -27

&&

.MARINE...Northerly winds will gradually turn more southerly this
afternoon and evening ahead of the next frontal system. Tonight,
southerly winds increase with widespread gusts up to 30 kt across
all waters as the next front moves through. Peak winds are
expected between 5-11 AM Monday with a 50-70% chance for isolated
Gale force gusts up to 35 kt for the inner waters (from shore to
10 NM out) north of Cape Foulweather. After 11 AM Monday, winds
turn more west-southwesterly behind the front with gusts up to 25
kt. Small Craft Advisories are in effect from 11 PM Sunday
through 5 PM Monday for all waters including the Columbia River
Bar. Seas around 6 to 8 ft through early Monday morning.

Following the frontal passage, a westerly swell will move in a
build seas above 13 ft (>90% chance). There is also a 5-10% chance
for seas exceeding 20 ft Monday night into Tuesday morning, with
the highest chances for the outer waters beyond 30 NM offshore.
Given the potential for seas between 15-20 ft, there remains a
Hazardous Seas Watch for all waters including the Columbia River
Bar between 5 PM Monday to 11 AM Tuesday. Seas subside to 10-12
ft by Tuesday evening and gradually subside into Wednesday. Will
also note that there is a 10-20% chance for thunderstorms across
the waters Monday night. Any passing thunderstorms may produce
lightning, brief heavy downpours that reduce visibility, erratic
winds, and/or small hail.      -10

&&

.PQR WATCHES/WARNINGS/ADVISORIES...

OR...None.
WA...None.
PZ...Small Craft Advisory from 11 PM this evening to 5 PM PDT Monday
     for PZZ210-251>253-271>273.

     Hazardous Seas Watch from Monday afternoon through Tuesday
     morning for PZZ210-251>253-271>273.

&&

$$

www.weather.gov/portland

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