926
FXUS66 KPQR 182208
AFDPQR

Area Forecast Discussion
National Weather Service Portland OR
308 PM PDT Fri Sep 18 2026

.SYNOPSIS...Temperatures warm up a few degrees this weekend as
an upper level shortwave ridge moves over the area. Trending a
bit cooler again next week as an upper level trough slowly drops
southward from the Gulf of Alaska. Dry conditions are heavily
favored through Thursday with a possible pattern shift toward
cooler and wetter conditions by next Friday, September 25th.

&&

.DISCUSSION..Now through next Friday...The latest satellite
imagery shows stratus still dissipating across the northern
portion of the Willamette Valley and around the Portland metro.
Stratus has stuck around much longer than originally expected
and has kept temperatures from increasing with observations
across the interior lowlands ranging from the low 60s to upper
60s where clouds have cleared. Stratus is expected to dissipate
over the next hour or so and will lead to mostly clear skies
through the evening and early overnight. Areas along the coast
likely remain socked in with low clouds which resurge back
through the coastal gaps later tonight.

The weekend looks like it will be quite pleasant with a slight
warming trend through Sunday as shortwave ridging persists across
the region. Each morning is expected to begin with stratus during
the morning hours but this stratus layer won`t be as thick moving
forward and should dissipate by mid to late morning inland. Highs
across the lowlands are expected to top out in the upper 70s on
Saturday and low 80s on Sunday but this will depend on how quickly
the stratus dissipates. There is high confidence that conditions
remain dry through the weekend.

The upper level pattern begins to shift next week as a large trough
over the Gulf of Alaska slowly progresses southeast through the
week. The eastern periphery of the trough will shift upper level flow
to the west/southwest. Temperatures will trend slightly cooler but
will generally peak in the mid to upper 70s across the interior
lowlands and 60s for the coast and higher terrain. The majority of
ensemble members show dry conditions through the middle of the week
with weak cold fronts losing steam before they reach the area. A
more substantial shortwave and associated cold front is possible
during the late Thursday into Friday timeframe which could finally
bring some rain to the area. Roughly 40-50% of ensemble members show
light rainfall by around this time. Uncertainty remains high during
this time frame as models differ in strength and timing this far in
advance. -19

&&

.AVIATION...Through 00Z Saturday...The stratus deck is dissipating
across inland areas as of 2130z Fri with any lingering stratus
likely dissipating by 22-23z, bringing a return to widespread VFR
conditions inland. Stratus continues along the coast with
conditions likely remaining MVFR ceilings through the period.
However, there`s a 40% chance terminals might briefly clear or
fluctuate between VFR and MVFR conditions through 01-04z Sat.
There`s a 50-70% chance that conditions deteriorate to IFR along
the coast after 04-06z Sat. Stratus is expected to form again
inland after 10-12z Sat likely becoming widespread once again.
Most inland terminals are expected to fall to at least MVFR cigs
around 1500-3000 ft by 12z Sat. Additionally, there`s a 40-60%
chance that all terminals fall to IFR cigs. Stratus is likely to
hang around through midday for inland terminals, clearing and
becoming VFR with daytime heating after 18-21z. Winds are
generally from the west and light less than 8 kts across the
area, becoming northerly after 00-03z Sat.

KPDX AND APPROACHES...MVFR cigs expected to scatter and improve to
VFR by 23z Fri. Stratus is expected to form again by 10-12z Sat,
returning MVFR cigs with a 40-60% chance of IFR cigs. Cigs once
again not expected to improve to VFR until after 18-21z Sat. Winds
are light and variable less than 5 kts, becoming northerly after
00-03z Sat. -03

&&

.MARINE...High pressure remains over the waters through the
weekend. Light winds will strengthen out of the north Saturday
afternoon and evening with gusts up to 15-20 kt, strongest over
the central and southern waters. Northerly winds peak in strength
Sunday afternoon and evening when there is a 50-90% chance for
maximum wind gusts of 21 kt or slightly stronger across the
waters, with the highest chances across the inner waters out to 10
NM offshore. Given wind gusts of this magnitude are not expected
to be frequent or widespread, Small Craft Advisories are not
anticipated at this time. Significant wave heights will remain
around 4 to 6 ft through the weekend, mainly driven by a
persistent northwesterly swell with a dominant wave period near
8 to 9 seconds.

Northerly winds are expected to linger Monday through Wednesday,
with wind gusts generally staying under 20 kt. A long period
west-northwesterly swell is set to arrive either Monday afternoon
or evening, pushing seas up by one or two feet. However, seas will
not be particularly steep as the dominant wave period with this
swell will be around 11-13 seconds. -23/03

&&

.PQR WATCHES/WARNINGS/ADVISORIES...

OR...None.
WA...None.
PZ...None.

&&

$$

www.weather.gov/portland

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