812
FXUS66 KPQR 250508 AAA
AFDPQR

Area Forecast Discussion...UPDATED
National Weather Service Portland OR
908 PM PST Sat Jan 24 2026


Updated aviation discussion


.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 over the area will keep skies clear and
temperatures to drop. Expecting VFR conditions through the next 24
hours. Offshore winds continue along the coast with light
northerly winds across the Willamette Valley. Tonight the highest
chances for IFR conditions due to fog is within the southern
Willamette Valley around KEUG. Probabilities have decreased though
with less than a 5% chance of LIFR VIS and a 10% chance of CIGs
less than 1000 ft AGL. However, because temperatures inland will
be below freezing we could see 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.
Variable winds around 5 kt or less. Expect another round of frost
overnight. The pressure gradient across the Cascades will
increase after 15Z Sunday through the Columbia River Gorge.
-27/10

&&

.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 until 11 AM PST Sunday for ORZ104-105-
     108>110-114>118.
WA...Cold Weather Advisory until 11 AM PST Sunday for WAZ204>206-
     208.
PZ...None.
&&

$$

www.weather.gov/portland

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