087
FXUS66 KPQR 212238
AFDPQR

Area Forecast Discussion
National Weather Service Portland OR
238 PM PST Fri Nov 21 2025

.SYNOPSIS...Dry weather under higher pressure continues through
late Saturday with another round of fog and frost development
expected tonight into Saturday morning. A pattern shift early
next week will favor a wet week for the upcoming holiday.

&&

.DISCUSSION...Friday afternoon through Thursday...Visible
satellite imagery as of 2 PM PST Friday shows mostly clear skies
across NW Oregon and SW Washington except for much of the
central and southern Willamette valley where stratus lingers.
Temperature observations under the stratus deck and over the
higher terrain remain in the 40s, but elsewhere temperatures
have risen into the low to mid 50s. Minimum temperatures this
morning were in the 30s across the board except for 40s along
the coast and 20s over the Cascades. Tonight into Saturday is
expected to be mostly a rinse and repeat of the 24 hours
previous. Model guidance has high confidence in widespread fog
and low stratus forming in the inland valleys tonight,
remaining until the late morning to early afternoon hours on
Saturday. Expect cool overnight temperatures with frosty
conditions warming into the upper 40s to low 50s for the high
temperature.

A weather system slowly approaches the region Saturday causing
precipitation chances to increase along the north Oregon and SW
Washington coast through the day. As the frontal system reaches
the coast, a widespread band of precipitation will spread
inland late Saturday night through Sunday, turning to showers
late Sunday and continuing through Monday afternoon. Rain
amounts with this system will be on the lower side with 0.15-0.5
inches for the inland valleys, 0.5-1 inch along the coast and
Coast Range, and 0.5-1.5 inches over the Cascades. Snow levels
will remain above Cascade pass level through Sunday, then they
will begin falling Sunday night behind the cold front, falling
to 2500-3000 ft by Monday morning. However, as conditions will
be showery by this point, limited snow accumulation is expected
at pass level, generally less than 2 inches. Winds are not
expected to increase much with this system with gusts up to
20-30 mph along the coast Sunday during the day and over the
Cascades Sunday night, remaining less than 20 mph for inland
valleys.

Temperatures Sunday night into Monday morning are once again
expected to be on the cooler side despite overhead clouds due to
colder air behind the frontal passage. Monday night into early
Tuesday is expected to be dry with another night of colder
temperatures in the 30s across the interior lowlands. By midday
Tuesday, widespread precipitation chances increase again as
ensemble members indicate the first in a series of back to back
frontal systems could move through the region. Ensemble guidance
indicates another frontal system will follow quickly behind
Wednesday into Thursday, bringing widespread rain chances
Tuesday through the Thanksgiving holiday. Timing details remain
uncertain this far out, but limited impacts are expected with
these systems. Probability for 3 inches of rain in the 72 hour
period from 4 AM Tuesday to 4 AM Friday are less than 10% for
inland lowlands, 10-20% chance south of Highway 20 in Oregon,
and 20-45% chance north of Highway 20. Winds are not expected to
be much of an impact either with a 20-40% chance of gusts
exceeding 30 mph along the coast and 5-20% chance for inland
lowlands Wednesday and Thursday. These will be warm Pacific
weather systems, so snow levels will rise above pass level.
Looking beyond Thursday, ensembles indicate yet another weather
system could bring additional rain on Friday into Saturday. Keep
an eye on the forecast if you have holiday travel plans! -03

&&

.AVIATION...High pressure over the area will lead to a mixture of
VFR and IFR conditions over the next 24 hours. Skies have finally
begun to clear is some of our fog prone areas but dense IFR CIGs
remain within the Willamette Valley via satellite imagery. There
is a weak band from a front to the north that sits draped over the
northwestern portion of the forecast area, but ultimately it is
having minimal impact as they are fairly thin. A light wind around
KONP is bringing in a little mist from the ocean and causing VIS
to drop to MVFR levels. This is not going to be pervasive so have
omitted from the TAF.

These conditions will be short lived as the high pressure will
lead to yet another round of fog late tonight into early Saturday.
There is high confidence in widespread dense fog with VIS less
than 1/4 SM throughout the Willamette Valley and coastal
gaps.Based on high resolution guidance there is a 30% chance of
LIFR VIS forming by 03Z Sat around KEUG, and a 60% chance by 06Z
Sat. Those areas north of KSLE will be slightly more delayed with
a 30-50% chance of fog forming as early as 08Z Sat. The big
concern that would inhibit fog formation will be any kind of
easterly flow. The challenge in the back half of the forecast is
dissipation time of the fog. Areas from KUAO southward will
maintain dense fog through at least 16Z Sat but there is a 20%
chance that it could persist until 18Z in the southern portions.
The area most at risk for maintaining it longer will be around the
central Willamette Valley and around KCVO.

KPDX AND APPROACHES..VFR conditions but will once again fall
overnight. There is a 40-50% chance of IFR VIS returning again
tonight after 08Z Sat, and a 20-30% chance of LIFR VIS. Similar
probability for CIGs. Temperatures will lower tonight once again
but freezing is not expected. -27

&&

.MARINE...High pressure over the area is maintaining fairly stable
conditions with minimal change through the next few days. Very
few fluctuations in overall sea state and winds through Monday.
Seas currently range from 8-11 ft at 14 seconds, but are
unexpectedly easing below small craft advisory criteria for some
buoys. However, in generally looking to see seas right around the
threshold. Tonight, a fresh swell will surge in causing a brief
increase in significant wave heights up to 16 ft at 15 seconds.
Because of the short duration, have not issued a Hazardous Seas
Warning but cannot rule out a more prolonged period if the
background swell too increases. These seas will mainly impact the
outer waters. By the evening, seas will return to a height of 10
ft at 14 seconds.

On Sunday a frontal system will make it`s way over the waters
causing winds to increase from the south. The low will move inland
late Sunday into Monday and winds will shift to the northwest.
When southerly, gusts up to 25 kt will be observed with a
partially heightened wind wave. Seas fall below 10 ft on Monday.
-27

&&

.BEACH HAZARDS...An energetic westerly swell is expected along
the northwestern Oregon and southwestern Washington coasts through
Monday. Seas 9-14 ft at 12-16 seconds are forecast through the
the weekend. 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 5 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. -27/42

&&

.PQR WATCHES/WARNINGS/ADVISORIES...

OR...None.
WA...None.
PZ...Small Craft Advisory until 4 AM PST Monday for PZZ210-251>253-
     271>273.
&&


$$

www.weather.gov/portland

Interact with us via social media:
www.facebook.com/NWSPortland
x.com/NWSPortland