775
FXUS66 KPQR 262047
AFDPQR

Area Forecast Discussion
National Weather Service Portland OR
147 PM PDT Sat Sep 26 2026

.SYNOPSIS...Cool and generally dry weather will continue
through Monday as temperatures gradually moderate. The next
chance for rain arrives Tuesday into early Wednesday, with the
best chances along the coast, Coast Range, and northern Cascades
while most inland valleys likely remain dry. Forecast
uncertainty increases toward the latter half of next week.

&&

.DISCUSSION...Now through Friday...A weak ridge and surface
high pressure are settling over the region, resulting in a quiet
and dry remainder of the weekend. Temperatures will gradually
recover from the chilly conditions of the past few days, with
highs generally in the upper 60s to low 70s Sunday and Monday
across the interior lowlands. Despite the slight warm up,
temperatures will remain below seasonal average through the
weekend.

Clear skies and light winds will promote efficient cooling
tonight and again Sunday night, particularly across sheltered
valleys. The Upper Hood River Valley remains the primary area of
concern for frost, especially Sunday and Monday morning as
temperatures could again fall into the 30s. However, chances are
much less, with only a 5-15% chance of temperatures dropping to
36 degrees or below Sunday and Monday morning. Patchy fog is
also possible during the morning hours where low-level moisture
and favorable radiational cooling overlap, with the central and
southern Willamette Valley, Coast Range valleys, and Cascade
valleys among the more favored locations. Any fog should be
localized and dissipate with daytime mixing.

The next meaningful change arrives Tuesday as a weak upper-
level trough and associated frontal boundary move into the
region. The highest confidence for measurable precipitation
remains along the north Oregon coast and Coast Range into
southwest Washington, where precipitation probabilities increase
to around 50-75% Tuesday morning and then decrease Tuesday night
into Wednesday morning. Some precipitation may extend into the
northern Oregon Cascades as well. Farther inland, the signal is
much weaker, with only around 15-35% of ensemble members
indicating more than a trace of precipitation in the Portland
metro and Willamette Valley Tuesday afternoon through Wednesday
morning. Most inland locations therefore remain more likely to
stay dry.

The front and associated trough weaken as they move through
Wednesday, with dry conditions expected to return by Wednesday
afternoon into Thursday. Ensemble guidance becomes increasingly
spread out late next week as the larger-scale flow remains
fairly progressive. Some solutions favor another weak trough and
cooler conditions with a few light rain chances along the coast
on Thursday, while others maintain zonal flow or weak ridging
and generally dry weather. Specifically, current ensemble
clusters are as such: 25% weak troughing, 25% weak ridging, and
50% roughly zonal. There is not yet enough agreement to favor a
specific outcome of ridging or troughing, but the overall
pattern remains relatively cool compared to seasonal averages.
~12


&&

.AVIATION...Through 00Z Monday...Primarily VFR conditions
expected through the TAF period. A broken mid to high level cloud
deck will spread across the region through this afternoon and
evening, remaining through most of the overnight hours. This is
expected to clear over the area sometime on Sunday morning.
Similar to this morning, if it clears by 10-13z Sun, patchy
fog/low stratus could quickly develop again by 12-15z with
MVFR/IFR/LIFR conditions. There`s around a 15-25% chance of this
occurring at any terminal. If any fog/low stratus does occur,
expect it to dissipate by 17-19z Sun. North winds today 10-15 kt
at the coast and across the central and southern Willamette Valley
with gusts up to 20-25 mph, decreasing after 03-06z Sun. North
winds increase again along the coast to 10-15 kt by 19-21z Sun,
though they remain generally less than 10 kts inland.

KPDX AND APPROACHES...Predominately VFR conditions expected
through the TAF period. There`s a 10-15% chance of MVFR/IFR low
fog/stratus returning after 10-12z Sun if the high cloud deck that
moves in tonight dissipates early enough Sunday morning. North to
northwest winds increase to around 8-10 kt after 21z, decreasing
after 02-05z Sun. -03

&&

.MARINE...Weak high pressure continues over the waters through
Sunday. Northerly winds increase this afternoon and evening and
remain elevated through Sunday evening with gusts up to 20-25 kts.
There could be a short lull in wind gusts Sunday morning before
they increase again Sunday afternoon/evening. Small Craft
Advisories remain in effect through 11 PM PT Sunday, except
through 5 AM PT Sunday for the Columbia River Bar. Wave heights
will remain around 4-6 ft at 8-10 seconds through Sunday night.

A weak front approaches the waters Monday, shifting winds more
westerly then southerly as the front moves through the waters on
Tuesday. There are high chances (70-90%) of wind gusts exceeding
21 kts, Small Craft Advisory criteria late Monday into Tuesday for
the coastal waters north of Cape Falcon, with gusts most likely
peaking around 25-30 kts. A longer period west to northwesterly
swell of 5-8 ft at 12-16 seconds will also move into the coastal
waters late Monday into Wednesday, resulting in a moderate
sneaker wave threat and increasing seas to 6-8 ft. -03

&&

.PQR WATCHES/WARNINGS/ADVISORIES...

OR...None.
WA...None.
PZ...Small Craft Advisory from 5 PM this afternoon to 5 AM PDT Sunday
     for PZZ210.

     Small Craft Advisory from 5 PM this afternoon to 11 PM PDT
     Sunday for PZZ251-271.

     Small Craft Advisory until 11 PM PDT Sunday for PZZ252-253-272-
     273.
&&

$$

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