349
FXUS66 KPQR 290546 AAA
AFDPQR

Area Forecast Discussion...UPDATED
National Weather Service Portland OR
946 PM PST Fri Nov 28 2025

Updated aviation discussion.

.SYNOPSIS...A broad low pressure system is spinning off of the
Oregon and California border. This low is going to amplify high
pressure over the region and promote gusty winds overnight into
Saturday. Within the ridge, a weak shortwave will pass over late
Saturday into Sunday bringing a quick shot of rain. Dry and cold
conditions on Monday before additional rounds of rain on Tuesday
through the remainder of the week.

&&

.SHORT TERM...Now through Monday...Over the next several days
there are very few forecast changes and models appear to be in
fairly good agreement with the overall pattern. Currently, a low
pressure system is sitting over the Pacific with a weak
mesoscale low sitting nearly stationary over the
Oregon/Washington border. The position of this mesoscale low has
produced gusty easterly winds within the greater Portland-
Vancouver Metro area and the Columbia River Gorge. Based on
modeled pressure gradients, they will begin to intensify after
10 PM. They have come down slightly from previous forecast
gradients but they are still high enough to increase the threat
of potential impacts. Based on high resolution models there is
a 40% chance of meeting wind advisory criteria in eastern Clark
County and a 10-15% chance of meeting similar speeds in eastern
Multnomah County. However, some of the larger scale ensembles
are showing much lower probability for similar wind gust speeds.
At this point, the duration and the areal coverage is not
enough to warrant issuing any headlines. However, with recent
rain saturating soils and gusty winds, downed trees and
powerlines are not out of the question.

On Saturday a ridge will build keeping conditions mostly dry
through the morning. The shortwave trough will move through in
the afternoon and evening. High probability for rain returning
though accumulation not expected to be exceptional as it is
fairly quick moving. Some models are suggesting a slightly more
northerly track which would bring heavier rain to southwest
Washington and the Cascades, while others like the NAMNest are
slightly further south. With all that said, no major impacts
expected.

Rain dissipates on Sunday and skies clear. The clearing skies
combined with high pressure and weak easterly flow will create a
set up that would promote significant cooling. The coldest
areas will be in the rural portions of the lower inland
elevations like around Corvallis, Battle Ground, and Creswell.
The 25th to 75th percentile minimum temperature (most likely
range) is around 29-35 degrees F with the mean is 32 degrees F.
Now while this seems very cold, that is the minimum temperature
possible and likely just an instantaneous value instead of a
prolonged period of at or below freezing temperatures. Will note
though that the current forecast does have more widespread
areas of freezing temperatures. It is never a bad idea to be
prepared for these cooler end scenarios though. -27


.LONG TERM...Monday night through Friday...After the cooler air
mass, an inverted trough in the midlevels will bring in slightly
warmer air. This warmer airmass is associated with an incoming
warm front that arrives late Monday into Tuesday. A
strengthening jet streak is present at 250 mb (35,000 ft)
Tuesday morning and it is moving directly over the forecast
area. This amplified lift combined with warm air mass and
moisture will produce widespread rain. While initially it may
not be heavy, it will intensify though the afternoon and
evening. A concern that will have to be watched moving forward
though is the presence of a low level jet at 500 mb. This jet is
vertically oriented which could create breezy northerly winds
along the coast into Wednesday morning.

Weather will maintain a typical fall pattern through the end of
the week. -27

&&

.AVIATION...At 0530z Saturday, widespread VFR flight conditions
were being observed across northwest OR and southwest WA with
broken high clouds around 15-20 kft or higher. East winds have
strengthened to around 15 kt with gusts up to 25 kt at KTTD, and
may strengthen a few more knots between 06-09z Saturday before
gradually weakening between 12-18z Saturday. East winds will also
impact KPDX and KHIO at the same time, albeit weaker with gusts
up to around 15 kt. Winds are much weaker elsewhere.

In general, expect VFR flight conditions with broken high clouds
to continue through at least 00z Sunday at all terminals. Then,
chances for MVFR cigs begin to increase between 00-06z Sunday,
with probabilities reaching 30-50% by 06z, except around 75% at
KONP and around 5-10% at KTTD and KPDX. There are also increasing
chances for light rain showers or sprinkles from north to south
between 00-06z Sunday, mainly at the coast. Expect minimal impacts
from these showers.

While unlikely, will mention there is around a 10% chance or less
for fog development from KSLE to KEUG after 09-12z Saturday. The
reason probabilities are low is mainly due to persistent high
clouds helping to limit fog development. Nevertheless, a few
breaks in cloud cover later tonight, especially at KEUG, may
result in visibilities lowering to around 1-2 SM or lower at
times.

KPDX AND APPROACHES...Expect VFR flight conditions through at
least 00-03z Sunday with broken high clouds. Chances for MVFR cigs
below 3000 ft increase to 5-10% by 06z Sunday. East winds will
continue tonight around 5-10 kt with gusts up to 15 kt, before
weakening late Saturday morning. There is also a 20% chance of
light rain showers or sprinkles between 00-06z Sunday, however
these showers would result in little to no flight impacts. -23

&&

.MARINE...A weakening low pressure system continues to meander
westward away from the coast of northwestern Oregon early this
afternoon, yielding generally east winds at 5-15 kt to its north
and southwesterly to southerly winds at 5-10 kt to its south.
Winds will turn offshore across the waters tonight at around 10
kt, although areas immediately downwind of gaps in the coastal
terrain, including west of the mouth of the Columbia River, may
see locally stronger winds and gusts of 15-20 kt. Another weak low
moving over the waters on Saturday will yield variable winds and
seas of 4-7 ft before high pressure building offshore will see
largely northerly flow late Sunday into next week. A long-period
westerly swell will arrive late Monday into Tuesday, pushing seas
toward 10 ft before easing back to 5-7 ft by Wednesday. -36

&&

.BEACH HAZARDS...A long-period westerly swell is expected along
the northwestern Oregon and southwestern Washington coasts from
late Monday through Wednesday next week. Wave heights increasing
to 8 to 10 ft on Tuesday may not appear to present a safety risk
to those on area beaches, but these energetic waves will present a
moderate to high risk for sneaker waves, waves which can run
significantly farther up a beach than normal, including over rocks
and jetties. In addition, a period of perigean spring or "king"
tides means these waves will have an even easier time reaching
high up onto beaches, limiting the areas which may be safe from
wave action.

A Beach Hazards Statement has therefore been issued from 7 AM
Tuesday to 10 PM Wednesday. Sneaker waves can create potentially
life-threatening conditions in the surf zone when beachgoers can
be unexpectedly knocked off their feet and pulled out into cold
ocean waters. Caution should be used when in or near the water,
and those 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. -36

&&

.PQR WATCHES/WARNINGS/ADVISORIES...

OR...None.
WA...None.
PZ...None.

&&

$$

www.weather.gov/portland

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