766
FXUS66 KPQR 282254
AFDPQR

Area Forecast Discussion
National Weather Service Portland OR
254 PM PST Fri Nov 28 2025

.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...Flying conditions are expected to continue improving
toward VFR across the region through this evening as high pressure
begins to build inland. Areas of mist or lingering light rain
showers with vis/cigs restricted to IFR have been observed early
this afternoon, however the drying trend should see even these
areas improve by 06z Sat. Elsewhere inland, there is only a 10-20%
chance MVFR conditions continue beyond 02-03z Sat, with VFR cigs
otherwise favored. Aforementioned high pressure building inland
will see generally light winds turn offshore through tonight.
Terminals downwind of terrain gaps will be the most likely to see
stronger east flow, most notably at KTTD where sustained winds of
15-20 kt may gust over 30 kt tonight. Gusts in excess of 20 kt are
expected to reach as far west as KPDX, and even coastal terminals
including KAST/KONP may see east winds reach 10 kt. The only other
potential for flight impacts through the period are low chances,
10% or less, for fog development within the central and southern
Willamette Valley after 09-12z Sat. Persistent sky cover would
act to limit these chances, as would enough clearing and cooling
to support frost development. In either of these cases, chances
for fog would be minimal.

KPDX AND APPROACHES...Building high pressure inland will see MVFR
cigs continue improving to VFR in the next few hours while low
cloud cover lessens and cloud bases lift to 4-5 kft. East winds
will strengthen west of the Columbia River Gorge, reaching 10-15
kt with gusts of 20-25 kt at KPDX after 04-06z Sat and continuing
through tonight. Gusts may not ease below 15 kt until 18z Sat. -36

&&

.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.
&&

$$

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