200
FXUS66 KPQR 262227
AFDPQR

Area Forecast Discussion
National Weather Service Portland OR
227 PM PST Wed Nov 26 2025

.SYNOPSIS...Wet conditions continue through Thanksgiving as
another frontal system impacts the region bringing additional
widespread rain and breezy winds. Conditions gradually trend
drier Friday into Saturday with showers largely pinned to higher
terrain features. Snow levels drop to the passes by Saturday
but limited accumulation is anticipated. A cooling trend impacts
the region Sunday into early next week with additional chances
for precipitation arriving on Tuesday.

&&

.DISCUSSION...Now through Tuesday night...Current radar and
satellite observations show our current swath of rainfall
slowly shifting northward late this afternoon with the south
Willamette valley beginning to see a break from the rainfall.
This northward trend in the precipitation continues into the
evening/overnight hours, and confidence is high we`ll
experience a region wide lull in the rainfall until the next
frontal system arrives from the west Thursday morning. Both
ensemble and deterministic guidance continue to indicate that
the center of this low pressure system likely makes landfall
somewhere just north of Astoria, OR along the Washington
coastline Thursday evening. Rain amounts with this system are
expected to somewhat similar to the previous front with 0.2-0.45
inch for the central and southern Willamette Valley, 0.4-0.75
for the northern Willamette Valley into the SW Washington
lowlands, 0.5-1.5 inches along the coast and Coast Range, and
Oregon Cascades south of Clackamas County, and 0.8-2 inches for
the north Oregon and SW Washington Cascades. Snow levels will
remain just above pass level with this second system as well.

Winds are also expected to increase as the front and low
pressure center move inland. Expect winds along the coast to
begin increasing Thursday morning, then inland areas Thursday
afternoon as the aforementioned low finally onshore tightening
pressure gradients near the surface. There are some
discrepancies between the various sets of guidance as to just
how breezy winds will get with the NBM markedly lower than high
resolution ensembles like the HREF and REFS. Given that winds
aloft are expected to be elevated (~40-50 knots at 850 mb) with
neutral to slightly unstable conditions present in the boundary
layer to facilitate vertical mixing Thursday afternoon, nudged
wind/wind gust values towards the high resolution ensemble
means. With this in mind expect peak gusts of 35-45 mph along
the coast and Cascades crests, and up to 25-38 mph for inland
valleys (highest Salem to Portland). However, it`s worth
highlighting there is a 15-25% chance for peak gusts to exceed
45 mph in the north Willamette Valley into the
Portland/Vancouver Thursday late afternoon and evening which
would cause additional impacts. We`ll need to watch the
progression of this low pressure closely. High confidence winds
decrease Thursday night into Friday.

The weather on Friday into Saturday looks pretty benign other
than shower chances continuing. Ensemble guidance is in good
agreement of a strong upper ridge beginning to build in the
eastern Pacific through the weekend. A good number of ensemble
members and their deterministic counterparts continue to
suggest a weak shortwave will move along the flow aloft over
the PacNW on Saturday, which is stretching out the chances for
precipitation. However, there still remains decent uncertainty
in the exact location of the shortwave, whether it will move
over western WA and OR, or more to the east in eastern WA, OR,
and into Idaho. This will affect exactly how much cooler air
will funnel into NW Oregon and SW Washington. If the wave is
more to the west, more colder air will move into NW Oregon and
SW Washington. If the wave is more to the east, the coldest air
will remain east of the Cascades. Latest NBM guidance indicates
cooling Sunday morning with Monday morning being the coldest.
Sunday morning has a 20-50% chance of low temperatures falling
below 32 degrees with probabilities increasing to 40-80% for
Monday morning. The highest probabilities are in typical colder
spots outside of urban areas, especially in the Willamette
Valley between Corvallis and Eugene. One thing to note is
probabilities of sub-freezing temperatures around the Portland
metro area are only around 10-25% for each day. When looking at
the probability of temperatures falling to 25 degrees (Cold
Weather Advisory criteria), most lowland locations are below
10%, though the cold pocked in the central/south Willamette
Valley mentioned earlier has around a 15-25% chance.

By Tuesday, ensembles are in agreement that a slightly stronger
shortwave and associated frontal system will slide south from
western Canada into the PacNW, breaking down the high pressure
over the region and returning precipitation chances over the
area. Quite a bit of uncertainty exists in the strength of this
system and the impacts associated with it, though cold weather
could stick around in the wake of it. -99/03

&&

.AVIATION...Thick cloud cover and light rain cover the area as a
warm front lifts northward through the region. Conditions are
mainly sub-VFR with CIGs between 1-3 kft along the coast and
around the Portland Metro. Rain is expected to continue through
the early evening as the front lifts northward. Sub-VFR CIGs are
expected for most of the period though clouds may break up a bit
in the southern Willamette Valley and Cascades this evening.
Surface low and cold front approach the coast around 12-15z Thu,
bringing another round of widespread precipitation and sub- VFR
conditions. Winds along the coast could increase as early as 10z
Thu, but more likely after 12z Thu, with south gusts up to 25-30
kts. Inland winds will be gusty in the afternoon with gusts 20-25
kts expected.

KPDX AND APPROACHES...Sub-VFR conditions expected through the
period. A short lull in precipitation is expected overnight
before the next system brings another round of rain and sub-VFR
conditions. /19


&&

.MARINE...A warm front lifting through the area has increased shifted
winds at buoy 46050 to the south while winds at buoy 46029 are
are easterly due to the front sitting to the south. South winds
begin increasing tonight into Thursday morning as the cold
front and surface low pressure system approach the waters.
Expecting strongest winds with widespread gusts up to 30 kts
between 2 AM to 5 PM Thursday. During this time, there`s a
70-85% chance for maximum wind gusts to peak around 35 kt for
all marine zones. However, hourly probabilities drop to 10-20%,
indicating widespread gale force wind gusts are unlikely to
occur. Seas will rise Thursday, peaking around 15-18 ft at
11-13 seconds late Thursday afternoon through Thursday evening,
though there is a less than 10% chance seas peak as high as 20
ft. Small craft advisories are in place for all waters late this
evening and transition into hazardous seas to cover the large
swell that will move into the waters tomorrow. Conditions relax
late Thursday night into Friday with no hazardous conditions
expected through the weekend. -19/03

&&

.PQR WATCHES/WARNINGS/ADVISORIES...
OR...None.
WA...None.
PZ...Small Craft Advisory from 1 AM to 4 PM PST Thursday for PZZ210-
     251>253.
     Hazardous Seas Warning from 4 PM Thursday to 2 AM PST Friday
     for PZZ210-251>253.
     Small Craft Advisory from 9 PM this evening to 10 AM PST
     Thursday for PZZ271>273.
     Hazardous Seas Warning from 10 AM Thursday to 2 AM PST Friday
     for PZZ271>273.
&&

$$

www.weather.gov/portland

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