246
FXUS66 KPQR 220545
AFDPQR

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

.UPDATED AVIATION DISCUSSION.

&&

.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...The influence of high pressure aloft continues
tonight with fog already in place across much of the Willamette
Valley and portions of SW Washington leading to fairly prolific
LIFR CIGs/VIS. These conditions will eventually progress into the
Portland metro area the latter half of the night into the sunrise
hours, primarily at KHIO and KPDX, with the latest 00z high
resolution guidance giving those sites a ~70% chance for 0.5 mile
VIS or less by 12z Sat. Tougher call at KTTD where much like last
night weak east flow through the Gorge may spare them the worst of
the impacts; 25-40% chance for IFR/LIFR conditions between
~13-17z. The most challenge aspect of the forecast, however, is
midday Saturday through the afternoon in timing the dissipation
of the fog. Areas from KUAO southward through the Willamette
Valley will maintain LIFR conditions through at least 20-21Z but
wouldn`t be surprised if much like Friday a lingering low stratus
layer fails to completely clear south of KSLE through KEUG. Winds
stay light through the forecast period, generally less than 5-8
knots.

KPDX AND APPROACHES..MVFR conditions are in place late this
evening but fog is lurking to the south and just to the WNW of the
terminal. As the night goes on expected this fog layer to expand
into PDX, most likely around ~08-09z Sat. That said, there is a
layer of high clouds passing overhead which adds a slight bit more
uncertainty to this timing than if it was otherwise clear - these
high clouds have the potential to push LIFR CIGs/VIS back to 12z
but given how close the fog layer already is to KPDX it won`t take
much growth to degrade conditions. Expecting conditions to
improve around 18z Sat with a return to VFR conditions 19-20z
although confidence in that exact timing is only moderate at this
time. -99

&&

.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...Dense Fog Advisory until 11 AM PST Saturday for ORZ116>118.
WA...None.
PZ...Small Craft Advisory until 4 AM PST Monday for PZZ210-251>253-
     271>273.
&&

$$

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