420
FXUS66 KPQR 110437 AAA
AFDPQR

Area Forecast Discussion...UPDATED
National Weather Service Portland OR
937 PM PDT Mon Aug 10 2026

...Updated aviation discussion...

.SYNOPSIS...Warm and dry conditions continue through the
upcoming week as temperatures moderate towards August normals.
Onshore flow will keep smoke east of the Cascades, while
precipitation chances remain very low through the end of the
week. Temperatures trend slightly warmer towards the end of the
week as a ridge of high pressure develops offshore. Increasing
potential for afternoon convection over the central OR Cascades
Friday into the weekend.

&&

.DISCUSSION...Tonight through Sunday...Fairly typical summer
weather continues this week as near average temperatures are
expected through Tuesday. This is in part due to zonal flow
aloft and onshore flow in the lower levels. Shallow marine
stratus is expected to return overnight along the coast and push
inland along the Columbia River towards the Portland/Vancouver
Metro area. Clear and sunny skies are expected to return on
Tuesday, with a near repeat of Monday`s conditions.

For Wednesday, there is increasing confidence that an upper
level pattern change will occur as a broad upper level
trough will move southward out of British Columbia into
Washington and Oregon. Model forecast soundings are showing a
deepening of the marine layer which would allow for deeper
stratus to push into SW Washington and the northern Willamette
Valley, as well as the potential for some aggressive drizzle
along the coast. This would result in daytime highs for inland
valleys to warm into the upper 70s to low 80s, with highs in the
60s along the coast and the 70s for the Cascades.

Looking towards the latter part of this week, some uncertainty
within the models and their ensembles remain. Daytime high
temperature spread remains relatively large Thursday and
Friday as guidance is split between the mid-week trough
lingering or a return of zonal flow in the upper levels of the
atmosphere. If troughing were to linger, cooler (or near
average) temperatures would be more likely, but if the more
zonal flow pattern develops, a warming trend would be more
likely with highs returning into the mid to upper 80s, with at
least a 25% chance of reaching 90 degrees on Friday and
continuing through Sunday.

500 mb cluster analysis of the ensembles indicates the
potential for upper level ridging to build offshore with varying
degrees of troughing or upper level low pressure developing
near central California. This feature is also bringing the
potential (5-10% chance) for more convective weather developing
near the central OR Cascade crest both Friday and Saturday
afternoons with the northward push of some monsoonal moisture.
Temperatures are likely to persist near to slightly above normal
into next weekend, with warm and dry conditions likely. /42-DH

&&

.AVIATION...Through 06Z Wed...Satellite imagery as of late Monday
evening depicts marine stratus filling in along the coast, returning
low-end MVFR CIGs (1-2 kft) to KAST. Expect MVFR CIGs to gradually
make its way to KONP in the next hour or so. High confidence for
IFR/MVFR CIGs tonight along the coast as stratus holds. Increasing
onshore flow may also push stratus up the Lower Columbia River
Valley and could reach the Portland Metro Area later this morning.
The onshore push doesn`t look as strong as yesterday, but there is
still a 15-20% chance for MVFR CIGs at any given hour between 12-17z
Tue for eastern Portland Metro terminals. Otherwise, VFR conditions
with clear skies prevail for Willamette Valley terminals through the
TAF period. Variable winds under 5 kt tonight, becoming north-
northwesterly and increasing to 7-11 kt at any given terminal after
18-21z Tue.

KPDX AND APPROACHES...Predominately VFR with clear skies through the
TAF period. There is a 15-20% chance for MVFR CIGs at any given hour
between 12-17z Tue. Northwest winds 3-4 kt tonight increasing to 8-
10 kt after 18z Tue.    -10

&&

.MARINE...High pressure offshore will continue to support
northerly winds through much of the week. Surface pressure
gradients this afternoon may result in wind gusts up to 21 kt
south of Cape Foulweather through this evening. The Small Craft
Advisory remains in effect until 11 PM Mon. Winds will ease
on Tuesday with much lower chances (less than 10%) of wind gusts
exceeding 21 kt. Similar conditions persist through late in the
week. Wind driven seas are expected to remain around 3 to 6 ft
through the week.
~12/DH

&&

.PQR WATCHES/WARNINGS/ADVISORIES...

OR...None.
WA...None.
PZ...Small Craft Advisory until 11 PM PDT this evening for PZZ253.

 Small Craft Advisory until 11 PM PDT this evening for PZZ273.

&&

$$

www.weather.gov/portland

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