644
FXUS66 KPQR 052205
AFDPQR

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

.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...Satellite imagery as of 21z Fri depicts VFR conditions
with mostly sunny skies across northwest Oregon. High pressure
will maintain dry weather and clear skies for inland terminals
through the TAF period. Meanwhile, marine stratus continue to
linger offshore. This is resulting in IFR/MVFR CIGs with
intermittent VFR clearing for coastal terminals. Guidance
continues to suggest the north Oregon coast (KAST) will clear out
for several hours this afternoon to VFR. However, the central
Oregon coast (KONP) will likely remain under LIFR/IFR marine
stratus through the rest of the evening. There is a 40-60% chance
that IFR/MVFR stratus returns to KAST tonight, however, there is
model disagreement on the timing. Some suggest marine stratus
returning as early as 02-04z Fri, or as late as 10-12z Fri. Will
continue to monitor the progression of the marine stratus tonight.

North-northwesterly winds across the region will generally be
around 10 kt or less through this evening, except along the coast
and southern Willamette Valley where tighter pressure gradients
will lead to 10-15 kt winds with gusts up to 20 kt. Winds weaken
overnight.

PDX AND APPROACHES...VFR through the TAF period. Northwest winds
around 10 kt or less through this evening, weakening overnight.
                                                    -Alviz

&&

.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

Interact with us via social media:
www.facebook.com/NWSPortland
x.com/NWSPortland