259
FXUS66 KPQR 151016
AFDPQR

Area Forecast Discussion
National Weather Service Portland OR
316 AM PDT Tue Jul 15 2025

.SYNOPSIS...Hot and dry conditions today through Wednesday with
daytime highs 90 to 100 degrees and overnight low temperatures
65 and 70 degrees for inland locations. A Heat Advisory remains
in effect for this afternoon through Wednesday evening. Cooler
temperatures expected along the coast. A slow cooling trend
begins Thursday with temperatures reaching near seasonal
normals (low to mid 80s for inland areas) by Saturday.

&&

.SHORT TERM...Tuesday through Thursday...A quick-moving upper
trough is currently grazing western WA and OR as it drops
southeast from Canada through far northeastern WA into ID early
Tuesday morning. This is allowing cooler temperatures this
morning with lows in the low to mid 50s for most of the region.
Temperatures will quickly rise today as high pressure over the
eastern Pacific builds east by this afternoon in the wake of the
trough. High temperatures this afternoon are expected to peak in
the low to mid 90s inland, which will be roughly 5-15 degrees
warmer than Monday`s high temperatures for most inland locations
north of the southern Willamette valley. High pressure continues
building into Wednesday, bringing warm overnight temperatures
and hotter daytime temperatures. Low temperatures Wednesday
morning will only fall to the mid to upper 60s for locations
near and north of Salem. NBM indicates a 15-25% chance of low
temperatures not falling below 70 degrees for certain urban
areas such as the Portland/Vancouver metro, Salem, and
Corvallis. Daytime temperatures are forecast to peak around
97-100 degrees across the entire Willamette Valley, with a
50-80% probability of temperatures exceeding 100 degrees.
However, there`s less than 5% chance of temperatures reaching
105 degrees except for a 15-25% chance for a small area between
Salem and Canby. These temperatures will produce Moderate to
Major HeatRisk (risk level 3 and 4 out of 5) across the region,
which means most of the general population could be susceptible
to heat-related illness, though those without access to adequate
cooling resources Tuesday night into Wednesday will be most at
risk. A Heat Advisory remains in effect from noon today through
Wednesday evening.

This pattern will also produce offshore (west to northwesterly)
flow over the PacNW. Northerly winds are forecast to increase
again in the Willamette Valley today in the afternoon and
evening hours, and downslope winds will increase along the
Cascade foothills Tuesday night into early Wednesday, with
gusts up to 20-25 mph at times in both areas. With the warming
conditions, relative humidities are expected to drop rapidly
today into tomorrow, enough to cause elevated fire weather
concerns but not for Red Flag Warnings. It is important to
always practice fire safety during hot and dry days.
Additionally, guidance indicates the offshore winds will push
wildfire smoke from fires in eastern WA and OR west of the
Cascades today into Wednesday. The HRRR indicates the majority
of smoke will remain aloft, which could cause hazy skies and
maybe an occasional smell of smoke. Depending on how thick the
smoke is aloft, this could affect how high daytime temperatures
could reach, but it could also keep overnight temperatures
warmer. Will definitely have to keep monitoring.

Ensemble guidance has come into much better agreement for
the pattern on Thursday. The majority of ensemble members
indicate another upper trough pushing southeast into
northeastern WA, very similar to the current trough, late
Wednesday into Thursday, which will break down the high
pressure over western WA and OR. Overnight temperatures will
once again be able to fall to the 50s to low 60s, providing
relief from Wednesday`s heat, with high temperatures on Thursday
in the upper 80s to right around 90 degrees. There`s still
around a 40-80% chance of temperatures exceeding 90 degrees, but
only a 15-30% chance of temperatures reaching 95 degrees, mainly
for a small area from Salem to Tigard. -HEC

.LONG TERM...Friday through Monday...Ensemble guidance remains
in agreement that troughing will remain the general pattern
Friday through early next week, with high confidence in a
cooling trend bringing temperatures back to near seasonal
normals for mid July (low to mid 80s for inland areas) by
Saturday, continuing into Monday. No precipitation is expected,
but this pattern will bring the return of onshore (west to
northwest) flow, which should push any wildfire smoke east of
the Cascades. Additionally, expect the return of marine stratus
to the coast in the evening through morning hours most days as
well as lighter winds across the region, except for the central
Columbia River Gorge which could see breezy westerly winds in
the afternoon and evening hours. -HEC

&&

.AVIATION...Satellite imagery as of early Tuesday morning depicts
MVFR marine stratus along the coast and VFR conditions inland with
clear skies. As of 10z Tue, some light offshore winds are pushing
marine stratus away from some parts of the coast including the
KONP area. Could see CIGs fluctuate between MVFR and VFR along
the coast this morning as variable wind directions bring
intermittent clearing or a marine stratus push. Guidance also
suggests a 20-30% chance of IFR/MVFR stratus across the Willamette
Valley between 12-16z Tue, however confidence is low due to the
overall dry air mass.

Marine stratus should clear out by 17-19z Tue as high pressure
builds and daytime heating progresses, returning VFR conditions
along the coast. Sunny skies prevail inland. Expect breezy
northerly to northeasterly winds today, strongest in the afternoon
with gusts to 20-25 kt at any given terminal.

PDX AND APPROACHES...Predominately VFR with clear skies through
the TAF period. Northerly to northeasterly winds increase this
afternoon with gusts up to 20 kt.        -Alviz

&&

.MARINE...High pressure over the Pacific will maintain northerly
winds through the week. A thermal trough developing inland today
will help tighten pressure gradients and strengthen winds. The
current Small Craft Advisory for the outer waters (10-60 NM out)
has been extended to Wednesday morning for the combination of
breezy northerly winds with gusts up to 25 kt and choppy seas of
7-9 ft at 8-9 seconds. The advisory was also expanded into
portions of the inner waters (out 10 NM), mainly from Cape Falcon
southward to Florence from 1700 Tuesday to 0800 Wednesday. Winds
weaken and seas subside in the latter half of the week and into
the weekend. -Alviz

&&

.PQR WATCHES/WARNINGS/ADVISORIES...

OR...Heat Advisory from noon today to 10 PM PDT Wednesday for
     ORZ108>122.

WA...Heat Advisory from noon today to 10 PM PDT Wednesday for
     WAZ204>207-209-210.

PZ...Small Craft Advisory from 5 PM this afternoon to 8 AM PDT
     Wednesday for PZZ252-253.

     Small Craft Advisory until 8 AM PDT Wednesday for PZZ271>273.
&&

$$

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