768
FXUS66 KPQR 261031
AFDPQR

Area Forecast Discussion
National Weather Service Portland OR
331 AM PDT Sat Jul 26 2025

.SYNOPSIS...Benign onshore flow keeps temperatures near
seasonal norms through this weekend. Temperatures trend warmer
again during the first half of next week, with thunderstorms
looking increasingly possible along the Cascades each afternoon
and evening.

&&

.SHORT TERM...Now through Sunday Night...The upper level
pattern this morning features persistent troughing extending
southwestward from British Columbia, maintaining robust onshore
flow across the Pacific Northwest. Satellite imagery again shows
abundant marine stratus locked in along the coast and into the
Coast Range gaps, although cloud cover has not made as much of
an inland push as at the same time yesterday. Still expect some
intrusion into the interior valleys later this morning as HREF
guidance depicts a 50-60% chance for stratus to reach the Eugene
area and a 40-50% chance for the Portland Metro after daybreak.
Expect similar temperatures as yesterday across the area this
afternoon, with highs again running near seasonal norms in the
low 80s in the interior valleys. Sunday will bring more of the
same, with afternoon highs perhaps running 2-3 degrees warmer in
some locations as transient shortwave ridging passes overhead.
/CB

.LONG TERM...Monday through Friday...Little change in thinking
in the long term as guidance continues to point to another
stretch of warmer weather along with increased thunderstorm
chances through much of next week. Temperatures will climb back
into the upper 80s in the interior valleys by Monday as a stout
upper level ridge begins to build over the western CONUS, with
temperatures looking to peak in the low 90s Tuesday into
Wednesday. Although hotter temperatures are expected, a more
significant heat event continues to look unlikely as the
forecast envelope remains rather tightly clustered in the low
90s while HeatRisk largely remains in the minor category with a
few patches of moderate in the interior valleys. This is
underscored by NBM probabilistic guidance which continues to
keep chances to reach 95 degrees near or under 20% for the most
part. Guidance then suggests temperatures will begin to moderate
back towards seasonal norms late in the week as the ridge axis
begins to shift further east.

The amplification of the upper level pattern during the first
half of next week will also feature the development of an
unseasonably deep upper low in the vicinity of the Gulf of
Alaska. This will establish southerly flow over the Pacific
Northwest between the two features, creating a pattern
conducive to thunderstorms along the Cascades and perhaps into
the interior valleys at times through much of next week as rich
mid level moisture is drawn northward into the region. The NBM
forecast has latched onto this potential relatively well with
regards to precipitation chances as it maintains chance to
slight chance PoPs along the Cascades each afternoon and
evening. Will continue to advertise corresponding thunderstorm
chances in the 15-20% range for each of these periods given the
favorable synoptic setup. Wednesday into Thursday is shaping up
to be a period to watch particularly closely in terms of
thunderstorm coverage as models are depicting an embedded piece
of shortwave energy lifting northward from California and
enhancing forcing for ascent. Will continue to closely monitor
thunderstorm potential throughout the coming week as these
details begin to come into better focus. /CB

&&

.AVIATION...Currently as of 10Z Saturday, VFR conditions inland
and MVFR condition along the coast. Satellite currently shows
stratus pushed into coastal areas, up the Columbia River to KKLS
and KSPB, as well as somewhat through the Coast Range gaps to the
south around KCVO and KEUG. Expect MVFR conditions to persist
at coastal terminals until around 20-23Z Sunday, then improving to
VFR. Additionally, there is a 10-30% chance for conditions to
briefly deteriorate to IFR during the aforementioned time range.
Inland terminals will see VFR conditions through most of the TAF
period, with the exception being coastal stratus pushing inland
and potentially (10-30% chance) ushering MVFR conditions between
12-17Z Saturday. Otherwise, expect light winds this morning to
become northwest at 5-10 kt this afternoon.

PDX AND APPROACHES...VFR conditions through most of the TAF
period. There is a 10-30% chance for conditions to deteriorate to
MVFR between 12-17Z Saturday. Expect light winds this morning to
become northwest at 5-10 kt this afternoon.
~Hall

&&

.MARINE...Fairly benign conditions are expected through the
weekend into early next week as high pressure near the surface
persists overhead. This will keep winds predominately out of the
north to northwest with afternoon/evening gusts around 10-15 knots
through Sunday before increasing a touch into the 15-20 knot
range by the middle of next week. Background swells remain
unimpressive through the weekend into the middle of next week as
well. The likelihood for Small Craft advisory conditions going
forward is low. There will be some strong ebb currents through
the Columbia River bar at times this morning and Sunday morning
which may lead to locally choppy seas. ~Hall/Schuldt

&&

.PQR WATCHES/WARNINGS/ADVISORIES...
OR...None.
WA...None.
PZ...None.

&&

$$

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