483
FXUS66 KPQR 022156
AFDPQR

Area Forecast Discussion
National Weather Service Portland OR
256 PM PDT Thu Oct 2 2025

.SYNOPSIS...Dry and seasonable on Friday with northerly flow aloft.
Light rain showers likely on Saturday, especially in the morning.
Low-level offshore flow develops Sunday and continues through at
least Tuesday, bringing an extended period of dry weather with
daytime high temperatures in the 70s across the lowlands.

&&

.DISCUSSION...Thursday night through Wednesday night...Scattered rain
showers continue to be observed across northwest Oregon and southwest
Washington, but will begin dissipating after sunset. Dry northerly
flow aloft and high pressure at the surface develops on Friday,
bringing dry weather with seasonable high temperatures in the 60s.
Winds look fairly light on Friday, around 5-10 mph or less.

Chances for rain have increased considerably on Saturday, with
probabilities now peaking between 50-80%. This is in response to a
series of two upper level impulses embedded in northerly to
northwesterly flow aloft that will move southward over the forecast
area. The first impulse moves through during the early morning,
bringing a brief period of light rain to most locations. The second
impulse moves through during the afternoon and early evening,
resulting in isolated light rain showers. Although PoPs are high,
forecast rain amounts are low, ranging from a trace to a few
hundredths of an inch.

The forecast remains dry Sunday through Wednesday in response to a
prolonged period of offshore flow. This pattern change will result in
mostly sunny and breezy conditions with temperatures becoming
noticeably warmer. Expect highs temperatures in the 70s each day
across the lowlands. Even the coast will likely warm into the 70s on
Monday and Tuesday due to easterly winds downsloping on the lee side
of the coastal mountains, resulting in compressional warming and a
lack of cloud cover. Tuesday is shaping up to be the warmest day of
the week with highs well into the 70s. Probabilities for highs of 80
degrees or warmer are low, ranging between 5-10%.

Lastly, overnight lows in the Upper Hood River Valley near Parkdale
will likely fall into the upper 30s on Friday morning. Cannot
completely rule out patchy frost Friday morning given the clear skies
and light winds in place, however the probability for this to occur
is at 10-30% across the Upper Hood River Valley, except 50% in
Parkdale. Given the marginal temperatures in place and the fact that
temperatures will most likely stay above 36-37 degrees, have decided
not to issue a Frost Advisory. However, given that it is now October,
the climatological likelihood of frost developing is increasing. -59

&&

.AVIATION...Radar imagery shows showers throughout the area. These
showers are causing CIGs to vary between MVFR and VFR, especially
within the Willamette Valley from KUAO and KSLE. However, showers
are beginning to dissipate and CIGs should begin to lift and clear
to most predominately VFR conditions. This trend will continue
through the evening with high probabilities of VFR conditions.
Exceptions will be along the coast, and some locations within the
Willamette Valley. Coastal terminals will see a southerly wind
which will usher in cooler and moist air (especially with the
residual moisture from the rain). Due to clear conditions there,
there will be a potential for fog and low stratus to form. There
is around a 60% chance of MVFR CIGS/VIS, with some models
suggesting a 20% chance of IFR conditions. These probabilities
will generally persist between 09-16Z Friday.

Inland sites will be less prone due to more persistent cloud
cover which will insulate and prevent radiational cooling.
Overall, conditions inland will be a bit more variable but staying
VFR. There is around a 10-15% chance of MVFR categories.

KPDX AND APPROACHES...VFR conditions through the TAF period. Less
than a 10% chance of MVFR CIGS/VIS, but will greatly depend on
clearing in the afternoon. Current cloud cover, if it were to
persist, will be enough to inhibit fog or low stratus. -27

&&

.MARINE...The frontal bands that brought elevated seas, gale force
winds, and choppy conditions has shifted inland and the area over
the waters has become post-frontal. With that, winds have begun to
ease with speeds around 10-15kt with gusts up to 20 kt. Some
isolated gusts up to 25 kt are still possible, but will not be
widespread. This downward trend is supported by outer water buoys
like 46089 where wind gusts are around 10 kt. In regards to seas,
heights and periods have been a bit more stubborn to decrease and
models have not projected well. Currently most of the waters are
experiencing seas of 8-11 ft at 12 seconds. Decided to extend the
Small Craft Advisory a few more hours in order to compensate for
the model uncertainty. Will see a slow easing of wind and seas
through Friday.

On Saturday winds will begin to shift to the west before becoming
northerly in the afternoon as another weak front moves into the
area. Winds will increase through Sunday with a high probability
(greater than 50% chance) of Small Craft Advisory winds in the
outer waters late into Monday morning. Ridging follows. -27


&&

.PQR WATCHES/WARNINGS/ADVISORIES...

OR...None.
WA...None.
PZ...Small Craft Advisory until 11 PM PDT this evening for PZZ210-
     251>253-271>273.
&&

$$

www.weather.gov/portland

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