909
FXUS66 KPQR 100420 AAA
AFDPQR

Area Forecast Discussion...UPDATED
National Weather Service Portland OR
920 PM PDT Mon Jun 9 2025

Updated aviation discussion and climate section.

.SYNOPSIS...High pressure aloft will begin to weaken today, but
not before supporting one final day of hazardous heat across
inland areas while the coast begins to cool. Increasing onshore
flow will see a cooling trend continue through the workweek.

&&

.SHORT TERM...Now through Tuesday Night...Ridge axis has already
passed east of the area, and one more day or potentially hazardous
heat is expected the rest of this afternoon. Temperatures as of 2pm
Monday are around 90 degrees for most of the Willamette Valley, with
high temperatures this afternoon expected to settle around the mid
90s. The hottest temperatures are again likely from the
Portland/Vancouver Metro east through the Columbia River Gorge to
Hood River. The Heat Advisory currently in place continues through
10pm tonight as a result. Those sensitive to heat, and especially
those without effective cooling and/or adequate hydration, may feel
impacts from this level of heat. Those seeking relief in area lakes
and rivers should also be aware that water temperatures are still
very cold and hypothermia can occur despite the hot air temperatures.
The coast sees cooler temperatures today, with an expected high
between 65-70 degrees. Overnight temperatures tonight will be
significantly cooler than last night as the ridge breaks down, with
inland low temperatures in the mid 50s expected.

Heading into Tuesday, increasing onshore flow and the ridge moving
out of the area allows for a slightly cooler conditions during
daytime hours. The Willamette Valley only sees a 0-10% chance of high
temperatures exceeding 90 Tuesday afternoon, with expected values in
the mid-80s. The coast looks even cooler, with a high around 60
degrees. The trend of cooling temperatures continues through the rest
of the workweek as onshore northwesterly flow continues, bringing
cooler air into the region. /JLiu

.LONG TERM...Wednesday through Sunday...Ensemble guidance
remains in good agreement that upper-level ridging will be
replaced by weak troughing in the Pacific Northwest through the
latter half of the week. Increased onshore flow will continue to
see temperatures cool toward seasonal norms, with increasing
confidence in highs in the 70s along I-5 & I-84 by Friday and
Saturday while coastal areas see highs in the 50s to 60s. There
is growing consensus that a closed upper low will track to the
southeast from south-central Alaska toward the Haida Gwaii,
while repeated shortwave impulses on its southern flank may
bring chances for rainfall to the region by Friday or the
weekend. At this lead time, global ensemble members suggest only
very light potential rainfall amounts with any disturbance that
does affect the region. -Picard

&&

.CLIMATE...

Multiple official record high temperatures were set on June 9, 2025:

- A record high temperature of 96 degrees was set at Salem, OR, which
ties the old record of 96 degrees set in 1955.

- A record high temperature of 96 degrees was set at Eugene, OR,
which breaks the old record of 91 degrees set in 2015.

- A record high temperature of 95 degrees was set at Hillsboro, OR,
which ties the old record of 95 degrees set in 1955.

&&

.AVIATION...Strong high pressure continues to support clear skies
and VFR conditions across most of the region through the TAF
period. The exception will be at the coast where IFR cigs are
likely to redevelop between 06-10z Tuesday before scattering out
around 18-19z Tuesday. Light winds around 5 kt or less will
increase to 5-10 kt out of the north to northwest towards 23z
Tuesday-00z Wednesday as a diurnal sea breeze pushes inland.

PDX AND APPROACHES...VFR under clear skies through the period.
Light northwest winds around 5 kt or less will increase close to
10 kt with gusts up to 15 kt towards 00z Wed as a diurnal sea
breeze pushes inland. -TK

&&

.MARINE...Little change in the forecast as surface high pressure
centered well offshore maintains a northerly wind regime through
the end of the week. Current observations show winds gusting to
20-25 kt over the coastal waters, with seas running 8-9 ft due to
a combination of short period wind waves and building northwest
swell. These conditions will maintain Small Craft Advisories
through Tuesday and possibly beyond as combined seas generally
remain in the 7-9 ft range for the next several days. /CB

&&

.PQR WATCHES/WARNINGS/ADVISORIES...

OR...Heat Advisory until 10 PM PDT this evening for ORZ108>125.

WA...Heat Advisory until 10 PM PDT this evening for WAZ204>210.

PZ...Small Craft Advisory until 6 PM PDT Tuesday for PZZ251>253-
     271>273.
&&

$$

www.weather.gov/portland

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