125
FXUS66 KPQR 060501
AFDPQR

Area Forecast Discussion
National Weather Service Portland OR
1001 PM PDT Thu Jun 5 2025

.UPDATED AVIATION DISCUSSION...

&&

.SYNOPSIS...A stretch of warm, dry weather will continue across the
Pacific Northwest through early next week as high pressure
remains the dominant feature. Inland temperatures will steadily
rise, climbing into the low 80s for today, mid 80s by Friday,
upper 80s to low 90s by Saturday, then low to mid 90s by Sunday.
Saturday, Sunday, and Monday have a moderate Heat Risk for
interior valleys. Coastal areas will stay cooler, but may still
warm slightly over the weekend depending on wind direction.
Breezy afternoon winds each day may offer modest, localized
relief from the heat.

&&

.DISCUSSION...Now through Wednesday...Temperatures will continue
to trend upwards through the weekend and into early next week.
The eastern edge of an upper level trough is positioned over the
PacNW, supporting dry conditions and temps rising into the
uppers 70s to around 80 inland and into the 60s along the coast.
The ridge centered over the northeastern Pacific will gradually
shift eastward as a trough digs into the western edge of the
ridge. Friday will see temps rise into the mid 80s inland and
mid to upper 60s along the coast. Friday afternoon will also see
the development of a weak thermal low west of the Cascade crest
which will help aid weak easterly downslope flow into the
Willamette Valley. NBM probs for Friday highs reaching 85 or
greater throughout the Willamette Valley range from 40-80%, so
likely some lower elevations will eclipse that mark.

Temps will continue to rise Saturday and Sunday, with the
warmest temps of the year so far expected across southwest WA
and northwest WA. The center of the ridge will continue eastward
with the center almost directly overhead on Sunday. Thermal low
pressure is expected to develop west of the Cascades both days
as well, helping support at minimum, weak easterly downslope
flow. Saturday highs are expected to reach into the upper 80s,
possibly low 90s while the coast remains in the upper 60s to low
70s. Probs for highs inland reaching 85 or greater range from
60-90%, with the higher end around the Portland/Vancouver metro.
Probs for 90 degrees drop off significantly to around 20-30%,
slightly higher around 50-60% around the metro. Sunday will be
even warmer with inland temps likely surpassing 90, possibly 95
degrees. Probs to reach 90 degrees are 80 to nearly 100% and
40-70% to reach 95 around the metro, slightly lower around 20%
for the rest of the Willamette Valley.

Overnight lows will stay in the 50s for most locations, but
Saturday and Sunday nights could remain in the low 60s,
particularly in urban areas. These warmer overnight
temperatures, combined with persistent daytime heat, contribute
to a moderate HeatRisk for much of the interior Saturday through
Monday. While not extreme, the prolonged heat may still pose
health risks to sensitive populations. Coastal areas will remain
cooler with highs mostly in the low to mid 70s, though some
locations could briefly reach the upper 70s depending on wind
direction. Breezy afternoon winds are expected daily,
occasionally gusting to 15-20 mph in the valleys. These winds
could provide modest, localized relief from the heat but will
not significantly affect overall warming.

Model agreement begins to degrade into Monday but it is
possible Monday turns out to be another warm day. Currently,
models depict the ridge shifting farther inland but still
influencing the PacNW, supporting highs into the low to mid 90s.
Others depict a transition to more zonal flow and an embedded
short wave trough coming up from northern CA. Regardless, temps
are expected to remain well above seasonal norms through
Tuesday. -Batz


&&

.AVIATION...High pressure will maintain dry weather for inland
terminals through the TAF period. Meanwhile, marine stratus
continues to thicken along the coastline late this evening with
widespread IFR to LIFR CIGs/VIS already in place. Expect these
conditions to persist through the night, slowly lifting back to
IFR/MVFR Friday afternoon. There`s a decent chance KAST sees a
brief period of VFR in the 20-00z Fri too as the stratus pulls
westward, although confidence in the exact timing/length of this
significant improvement is low to moderate at this time. It`s also
worth noting we`ll have to watch for patchy low cloud cover
developing along the west coast of the Cascades near sunrise
Friday morning, added a SCT010 to KTTD as they have the best
chance 30-40% to be impacted by this cloud cover as it slowly
meanders westward while dissipating mid-morning. Otherwise high
confidence in prevailing VFR conditions for inland terminals.

PDX AND APPROACHES...VFR through the TAF period. Still, will need
to watch 12-17z for off chance(10-20%) to a drop to 1kft CIGs as
patchy low clouds drift westward off the Cascades. Winds generally
stay less than 5-10 knots through the period out of the N-NW.
-Schuldt


&&

.MARINE...Minimal changes to the forecast. High pressure
offshore will maintain breezy northerly winds across the waters
through early next week. A Small Craft Advisory remains in
effect for most coastal waters except the inner-northern waters
(PZZ251) and Columbia River Bar. Within the advisory, expect
northerly winds of 15-20 kt with gusts to 25-30 kt. The
strongest gusts are expected across the central and southern
outer waters (PZZ272 and PZZ273), where pressure gradients are
tighter. Seas remain dominated by northerly wind waves and
northwesterly swell through the weekend, with significant wave
heights of 5 to 8 ft at 8 to 10 seconds. Expect steep and choppy
seas when winds are strongest. -Alviz

&&

.PQR WATCHES/WARNINGS/ADVISORIES...
OR...None.
WA...None.
PZ...Small Craft Advisory until 11 PM PDT Friday for PZZ252-253-
     271>273.
&&

$$

www.weather.gov/portland

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