361
FXUS66 KPQR 261816 AAA
AFDPQR

Area Forecast Discussion...UPDATED
National Weather Service Portland OR
1016 AM PST Wed Nov 26 2025

Updated aviation discussion.

&&

.SYNOPSIS...Showers continue across the region today with a
brief break for most areas late this afternoon into this
evening. The next frontal system impacts the region overnight
tonight through Thursday night, bringing another round of
widespread rain and breezy winds. Conditions gradually trend
drier Friday into Saturday with lingering showers largely pinned
to higher terrain features. Snow levels drop to the passes by
late Friday and Saturday but limited accumulation expected due
to the showery nature. A cooling trend impacts the region Sunday
into early next week.

&&

.DISCUSSION...Wednesday Morning through Tuesday...As expected,
the band of rain showers slowly moved south and stalled
overnight along a weak frontal boundary over northern Oregon,
with current radar imagery show it located generally from
Newport through the Cascades north of Lane County between the
Portland area and Eugene, though drizzle and occasional showers
continue to occur outside of the main band. The moisture
associated with the showers has been on the lower side, with
less than 0.15 inch observed in the lowlands and anywhere from
0.3-0.75 inches along the coast, Coast Range, and Cascades since
8 PM Tuesday night. This band is expected to remain fairly
stationary or maybe moving south a little bit more through
around 7-10 AM before another low pressure system developing
over the eastern Pacific begins moving towards the coast and
pushing the rain back to the north through the afternoon and
early evening hours. Rain intensity could increase again this
morning as another pulse of warm Pacific moisture is fed into
the front from the incoming low pressure system. Between 4 AM
and 10 PM today, an additional 0.1-0.5 inch of rain is forecast
in the lowlands and 0.25-0.75 inch along the coast, Coast
Range, and Cascades, except for only up to 0.15 inch in the Lane
County Cascades.

Confidence is increasing in a bit of a break in the rain after
the current band of rain moves north into Washington and the
next front ushers in another round of widespread rain. Ensemble
and deterministic guidance continues to indicate that the low
pressure system currently developing over the eastern Pacific
will move east through the day on Wednesday and making landfall
somewhere along the Washington or northern Oregon coast late
Thursday. Uncertainty still remains in the exact placement of
where the low will move inland, but the timing has come into
much better agreement. The cold front associated with this low
will approach the coast early Thursday morning and move inland
through the day, bringing another round of widespread rain with
scattered showers continuing into Friday morning. Rain amounts
with this system are expected to be similar to the previous
front with 0.1-0.40 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 0.75-2
inches for the north Oregon and SW Washington Cascades. Snow
levels will remain above pass level with this warm system.

Winds will also increase as the front and low pressure center
move inland. Expect winds along the coast to begin increasing
late Thursday morning or early afternoon, then transitioning
inland late Thursday afternoon into Thursday night as the low
finally moves inland. Ensemble guidance indicates peak gusts up
to 30-35 mph along the coast and Cascades and up to 20-25 mph
for inland valleys. However, there`s a 40-60% chance of peak
gusts of at least 30 mph for inland valleys and 40 mph along the
coast and Cascades. Probabilities of peak gusts of at least 50
mph are around 10-30% along the beaches and headlands of coast,
highest between Seaside and Lincoln City. These probabilities
are near zero for inland valleys.

Weather on Friday into Saturday looks pretty benign other than
slight 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 continue to suggest a weak shortwave will move along the
flow over the PacNW Saturday, which is what is causing the
slight rain chances. Then this wave is expected to deepen as it
moves south as the ridge continues amplifying over the far
eastern Pacific, which will allow colder arctic air to funnel
into the region. 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 cold
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. This is
due to an increase in onshore flow that will allow for warmer
easterly winds through the Columbia River Gorge combined with
the urban heat island effect to keep temperatures above
freezing, though still likely to fall into the 30s. 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 Willamette Valley mentioned
earlier has around a 15-30% chance.

By Tuesday, ensembles are in agreement that a 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. -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 1-2 kft along the coast and
around the Portland Metro. Sites in the southern and central
Willamette Valley have started to improve to MVFR/VFR as the front
lifts northward. CIGs around 3-5 kft are expected to slowly spread
northward through the afternoon. Low end VFR to high end MVFR
conditions are expected for inland terminals after 03-06z this
evening. Coastal sites are expected to remain MVFR or lower
through the period.

The next frontal system approaches 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
20-25 kts.

KPDX AND APPROACHES...Sub-VFR conditions expected through the
afternoon. Conditions trend toward VFR late this between 03-06z as
the warm front lifts. A short lull is expected overnight before
the next system brings another round of rain and sub-VFR
conditions. /19

&&

.MARINE...Winds and seas have decreased this morning in a brief
break between frontal systems. Generally north winds less than
15 kts with seas around 7-8 ft at 8-10 seconds are being
observed. Winds will shift easterly to southerly as a warm front
moves through the waters today, though gusts should remain
below 15 kts. 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, though hourly probabilities
drop to 10-20%, indicating widespread gale force wind gusts are
unlikely to occur. Seas will rise Thursday, as well, peaking
around 15-18 ft at 12-13 seconds late Thursday afternoon through
Thursday evening, though there is a 5-10% chance seas peak as
high as 20-22 ft. The uncertainty in exact peak wind gusts and
seas is due to some lingering uncertainty regarding the exact
strength and track of the closed surface low and the frontal
system accompanying the low. Regardless of the outcome for this
system, winds and seas will lower significantly on Friday. Winds
and seas over the upcoming weekend are currently forecast to
stay below small craft advisory thresholds with a period of
offshore flow. -03/23

&&

.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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