Cedar Mill, Oregon 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

625
FXUS66 KPQR 261045
AFDPQR

Area Forecast Discussion
National Weather Service Portland OR
345 AM PDT Tue May 26 2026

.SYNOPSIS...A showery, cool pattern continues today as
yesterdays front gives way to an upper-level low over the
Oregon coastal waters. Scattered thunderstorms remain possible
this afternoon (10-20%), with the best window late morning
through the afternoon. Drier and warmer weather returns
Wednesday into Thursday as high pressure rebuilds, but wrap-
around moisture may keep shower chances going over the Cascades
late week. Another cool-down is possible heading into Friday and
through the weekend. Ridging and much warmer temperatures may
return at the start of next week.

&&

.DISCUSSION...Today through Monday...Early this Tuesday
morning, the region sits in the wake of Mondays cold frontal
passage with an upper-level trough becoming a closed low over
the Oregon coastal waters. As a result, expect a classic post-
frontal day: variable clouds, scattered showers, and cool
temperatures for late May. Any shower activity will be
intermittent rather than organized, but brief heavier bursts are
possible under stronger cells.

The potential for thunderstorms persists today, although
instability remains modest. Latest guidance suggests CAPE
generally around 100-200 J/kg by midday/afternoon, supporting a
10-20% chance of thunderstorms, most favored from late morning
into the afternoon (roughly 11 AM to 5 PM). Compared with
Monday, the better thunder potential today shifts more into the
interior (including portions of the I-5 corridor), generally
from Eugene to the Portland/Vancouver metro. Any thunderstorms
that develop could produce lightning, brief downpours, small
hail, and locally gusty/erratic winds.

By Wednesday and Thursday, confidence increases in a transition
back toward a warmer and drier regime as the upper low drops
into the Great Basin and 500 mb heights rise over the Pacific
Northwest. High temperatures should rebound to near or slightly
above normal, with the warmest outcomes favored across the
Portland/Vancouver metro, Salem, and southwest Washington
lowlands. Current probabilities for 80 degrees have increased:
about 50-70% in the Portland/Vancouver metro Wednesday,
increasing to 60-80% Thursday. Elsewhere across interior
valleys, chances for 80 degrees are around 30-50% on Wednesday
and Thursday (highest chances on Thursday).

One possible scenario late week is wrap-around moisture
rotating back north on the east side of the departing low. This
keeps a 50-80% chance for showers over the Cascades on
Thursday, along with a 15-30% chance of thunderstorms (highest
chances in the Marion, Linn, and Lane County Cascades). West of
the Cascades, most locations stay dry, though a stray shower
cant be ruled out if moisture wraps farther west than currently
expected. Additionally, more extensive cloud cover would also
limit highs (more lower 70s versus upper 70s/low 80s).

Friday into the weekend, ensembles suggest another trough
approaching from the northeast Pacific, bringing cooler
temperatures again. Lingering wrap-around moisture could
maintain some shower chances into Friday (with current
forecasted chances around 40-60% in the Oregon Cascades), while
the weekend currently trends toward drier weather overall given
limited moisture with the broader troughing. Saturday into
Sunday, the trough digs south rather than shifting east towards
the region, allowing for high pressure to build into the
beginning of next week. Uncertainty in temperatures drastically
increase for early next week, with ensemble guidance suggesting
the possibility of an afternoon high temperature anywhere
between 73 and 93 degrees on Monday. We will continue to monitor
this range of values as ensemble guidance hones in on the
potential outcomes of this late weekend into early next week
ridge. ~12


&&

.AVIATION...Currently a mix bag of MVFR and VFR CIGs as of 11Z
Tue. Showery activity continues to dwindle throughout the
airspace, with rain expected to end by 13-15Z Tue and any
deteriorated conditions improved back to VFR by 15-18Z Tue. In
the meantime, some inland terminals may lower to MVFR CIGs (if
not currently MVFR) as partial clearing skies improve
radiational cooling early this morning. Conditions will likely
stay VFR between 18Z Tue and 06Z Wed (70-90% chance of VFR
conditions at the coast; greater than 90% inland), then
potentially lower back to MVFR thereafter (40-60% chance of MVFR
CIGs at the coast; 20-40% inland).

Winds will shift to the north around 17-19Z Tue as the low
pressure system moves southward along the coast. All terminals
could see some increased winds with gusts up to 20 kt possible
between 21Z Tue and 03Z Wed.

There remains a 15% chance of thunderstorms today between 17Z
Tue and 00Z Wed, with much less confidence for thunderstorm
development due to the dry air present within the vicinity.

KPDX AND APPROACHES...Currently VFR with showers bringing
occasional MVFR VIS. Rain showers continue to dwindle early this
morning, expected to completely clear by 15Z Tue. Expect any
deteriorated conditions to end and improve back to VFR by 18Z
Tue. There is a 10-20% chance for MVFR CIGs to return after 06Z
Wed. Winds shift northerly in the afternoon 18-21Z Tue which
may produce gusts as high as 20 kt until 03Z Wed. Speeds are not
nearly enough for any kind of LLWS, though those landing on E-W
runways may experience localized weak LLWS of +/- 5 kt.
~12

&&

.MARINE...
A westerly swell continues to push seas into the mid teens
at around 14 to 16 seconds. Winds have weakened over the waters
as of 4 AM this morning but expect another increase to around
20 to 25 kt gusts in the waters by this afternoon. A Hazardous
Seas Warning continues for all the waters until 11 AM today. A
Small Craft Advisory will follow, coming into effect from 11 AM
today to 11 PM tonight. Seas subside to 10 to 12 ft by this
evening and gradually subside into Wednesday. Seas will remain
around 8 to 11 feet through Thursday, then dropping well below
10 ft Friday into the weekend. Winds will remain gusty around
20 to 25 kt mostly in the outer waters through Thursday,
although gusts up to 30 kt is possible Wednesday afternoon for
the outer waters south of Cape Falcon.
~12

&&

.PQR WATCHES/WARNINGS/ADVISORIES...
OR...None.
WA...None.
PZ...Hazardous Seas Warning until 11 AM PDT this morning for PZZ210-
     251>253-271>273.
     Small Craft Advisory from 11 AM this morning to 11 PM PDT this
     evening for PZZ210-251>253-271>273.
&&

$$

www.weather.gov/portland

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