993
FXUS66 KPQR 242155
AFDPQR

Area Forecast Discussion
National Weather Service Portland OR
155 PM PST Sat Jan 24 2026

.SYNOPSIS...Dry weather continues through the weekend as high
pressure remains over the region. Cold overnight lows in the
low to mid 20s through Saturday night/Sunday morning in the
lowlands. Clear skies and light winds will result in frost
formation for the interior lowland valleys and coast range
Valleys. Chances for precipitation return Tuesday/Wednesday,
but some uncertainty remains with the exact timing and
precipitation totals.

&&

.SHORT TERM...Now through Sunday Night...Benign weather
continues for the region as high pressure persists over the
Pacific NW and NE Pacific Ocean. Clear skies will bring efficient
cooling across the region and result in cold overnight conditions
returning tonight and Sunday night/Monday morning. Expect
overnight lows tonight in the low to mid 20s for most locations
west of the Cascades. Therefore, have issued another Cold
Weather Advisory starting tonight through late Sunday morning.
Conditions will also be cold in the Cascades but Cold Weather
Advisory criteria is colder than lower elevations and is not
expected to be met. Probabilities for temperatures to drop to
or below 25 degrees are highest in the central and southern
Willamette Valley at 65-85% while the northern Willamette
Valley is only 40-50%. The Portland/Vancouver metro is even
lower at 15-20% except for the more rural locations that range
from 60-80%. Sunday night into Monday morning looks unfavorable
for advisory criteria cold as cloud cover increases and winds
decrease leading to only a 10-20% chance of reaching 25 degrees
in the southern Willamette Valley, Clark county lowlands, and
the Coast Range valleys.

A weak frontal passage is expected late Sunday/Monday which will
bring a 15-30% probability of precipitation for the Coast, Coast
Range and Cascades. While little to no precipitation is expected
with this system as the atmosphere is very dry. It will help to
keep the atmosphere mixed as well as bring some slightly warmer
air into the region.

Another Air Stagnation Advisory may be warranted, mainly for
the Willamette Valley as transport winds do decrease through the
weekend. However, the weak frontal passage, mentioned above
looks to keep the atmosphere mixed enough to mitigate any
potential Air Stagnation concerns. Still, we will continue to
monitor the situation and adjust the forecast as needed. /42/19

.LONG TERM...Monday through Friday...Models and their associated
ensembles continue to support a pattern shift starting
Tuesday/Wednesday as Pacific low digs across the Pacific. This
looks to weaken the anchored ridge enough to finally see a
substantial change in the overall forecast. While exact details
remain unclear at this time, ensemble guidance is pointing
towards a moderate PoP (35-60% chance) with relatively
low/moderate QPF totals of 0.15-1.00 inches from Tuesday through
Friday, with most of the precipitation being rain rather than
snow or a wintery mix as snow levels are forecasted to rise
towards 4500-5000 feet by Wednesday and 6000 ft or higher by
Thursday. At this point, there are no major impacts expected
with this weather system, and if precipitation does occur, it
would be more beneficial than impactful. /42/19

&&

.AVIATION...High pressure will maintain VFR conditions with clear
skies through this evening. Tighter pressure gradients between
KTTD and KDLS will lead to breezy easterly winds through the
Columbia River Gorge and far east Portland Metro (KTTD) with gusts
up to 25 kt. Offshore winds continue along the coast with light
northerly winds across the Willamette Valley.

Tonight into early Sunday, the highest chances for LIFR
conditions due to fog are around 15-25% across the southern
Valley, mainly between 12-18z Sunday. Low confidence for fog as
Sunday morning low temperatures across the Willamette Valley are
forecast to fall to the upper 20s again. This will lead to another
round of widespread frost, especially over metal surfaces. Will
see high clouds gradually increase over the area after 18z Sunday
ahead of a weak system, but conditions will remain dry.

KPDX AND APPROACHES...VFR through the TAF period with clear skies
through this evening. Variable winds around 5 kt or less. Expect
another round of frost overnight.       -10

&&

.MARINE...A weak thermal trough along the coast will continue
easterly to northeasterly winds under 10 kt across the waters
through Sunday. Winds turn more southerly Sunday night into Monday
as a weak system moves in, however chances for widespread and
frequent wind gusts exceeding 21 kt (small craft wind gusts) are
only 10-20%. Seas remain around 4-5 ft at 11-12 sec through Monday
night.

The next frontal system approaches the waters on Tuesday, bringing
breezier southerly winds and building seas. Chances for frequent
and widespread southerly wind gusts of 21 kt or greater are around
50-70%, mainly for the waters beyond 30 NM offshore. A west-
southwesterly swell will also move in by Wednesday and build seas
to 10-13 ft (60-80% chance), with a 20-30% chance for seas
exceeding 15 feet as early as Wednesday evening.      -10

&&

.PQR WATCHES/WARNINGS/ADVISORIES...

OR...Cold Weather Advisory from 10 PM this evening to 11 AM PST
     Sunday for ORZ104-105-108>110-114>118.

WA...Cold Weather Advisory from 10 PM this evening to 11 AM PST
     Sunday for WAZ204>206-208.

PZ...None.

&&

$$

www.weather.gov/portland

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