Corvallis, Oregon 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

347
FXUS66 KPQR 140925
AFDPQR

Area Forecast Discussion
National Weather Service Portland OR
225 AM PDT Mon Jul 14 2025

.SYNOPSIS...Expect sunny skies across the area with morning
marine stratus/fog along the coast. Temperatures drop slightly
on today, but still remain warm and dry. A Heat Advisory
has been issued for some interior valley locations from Tuesday
to Wednesday, as afternoon temperatures between 90 to 100
degrees and low temperatures between 65 and 70 degrees.
Uncertainty increases late week into the weekend.

&&

.SHORT TERM...Now through Wednesday Night...A brief break from
the hot conditions today with closer to normal but still above
average temperatures expected. The ridge over the northeast
Pacific will shift slightly west, reducing it`s influence on
the PacNW briefly as a short wave trough drops southeast from
central British Columbia toward Washington and northern Idaho.
The trough axis will extend southwest into Oregon, bringing
westerly flow aloft and a drop in 850 mb temperatures into the
15-18 C range. This will translate to high temperatures this
afternoon around 8-12 degrees cooler for most locations
generally low to mid 80s around the Portland/Vancouver Metro to
upper 80s in the southern Willamette Valley. Coastal
temperatures drop a few degrees topping out in the low to mid
60s. North/northwest winds will again increase during the
afternoon as surface high pressure offshore and low pressure
east of the Cascades increases the pressure gradient. Expect
wind gusts up to 15-20 mph through inland valleys, 25-35 mph
through the Columbia River Gorge, and gusts up to 25 mph will be
possible along the central Oregon coast.

Conditions heat back up for Tuesday and Wednesday as the short
wave trough moves east and 500 mb heights rebound. The high over
the northeast Pacific will broaden, extending eastward back
into the PacNW. 850 mb temperatures increase on Tuesday to
around 18-20 C and on Wednesday to 20-23 C. This will lead to
temps in the low to mid 90s inland on Tuesday and mid to upper
90s with a few triple digits possible on Wednesday. Temperatures
along the coast expected to top out in the mid 60s to mid 70s
both days.

Probabilities for reaching 100 on Tuesday are minimal, topping
out around 10% across the central and southern Willamette
Valley. Probabilities are much higher on Wednesday at 30-70%.
On top of the hot conditions during the day, overnight lows
Tuesday night into Wednesday morning are expected to remain
mild in the mid 60s to around 70, giving little reprieve from
the heat. Probabilities for inland locations to remain at 65 or
above are 40-70%. Given the forecast temperatures and the
potential for even warmer temperatures, a Heat Advisory has
been issued for the Portland/Vancouver Metro, Willamette Valley,
Lower Columbia and Cowlitz Valleys, and the Columbia River
Gorge from noon Tuesday through 10 pm Wednesday. -Batz


.LONG TERM...Thursday through Saturday...Model agreement remains
poor as we enter the latter half of the week and into next
weekend with a general trend back toward average temperatures,
however, there is a good amount of uncertainty. Thursday is
forecast to remain warm with highs in the low 90s throughout the
inland valleys. However, there is a large spread between the
10-90th percentiles, generally mid 80s to upper 90s. If
temperatures trend toward the warmer end, heat headlines may
need to be extended through Thursday. Cluster analysis continues
to lean towards a series of weak troughs traversing the area
which would help keep temperatures at least closer to average
foe mid July in the low 80s inland by the weekend. Moisture
associated with these disturbances looks meager at best and the
dry conditions are likely to persist. -Batz

&&

.AVIATION...High pressure maintains VFR conditions with clear
skies inland and LIFR/IFR marine stratus and fog along the coast.
Between 14-17z Mon, guidance suggests a 15-30% chance for MVFR
stratus developing around the Portland/Vancouver Metro Area,
including KPDX, KTTD, and KHIO. Any morning stratus inland should
scatter out by 17-19z Mon as daytime heating progresses. VFR
conditions with mostly sunny skies prevail inland through the rest
of the TAF period. A shortwave trough will also move over the
region Monday, allowing marine stratus along the coast to lift to
more IFR/MVFR thresholds by 18-21z Mon, possibly clearing for a
few hours before stratus settles back in. No precipitation is
expected with this shortwave. Expect breezy northerly to
northwesterly winds across the area with gusts up to 25-30 kt
along the coast and 20-25 kt inland, strongest in the afternoon.

PDX AND APPROACHES...Predominately VFR through the TAF period
with mostly clear skies. Guidance suggests a 15-30% chance for
MVFR CIGs between 14-17z Mon. Stratus will be difficult to form
given the overall drier air mass, so if it does form it would be
short-lived. Light northwesterly winds under 10 kt increasing
after 21z Monday with gusts up to 20 kt. -Alviz/HEC

&&

.MARINE...Upwelling along the coastline is producing low cloud
cover and fog in the inner waters and the Columbia River Bar. A
Dense Fog Advisory remains in effect through this morning.

A broad area of high pressure over the Pacific will continue
through the week. A weak disturbance will move over the region
this afternoon and evening, which will briefly break down the
persistent thermal trough inland. Will see cooler temperatures,
decreasing northwesterly flow, and building seas. Winds remain
elevated through early this morning before easing, and a fresh
northwesterly swell moves in. Seas will rise to 7-10 ft at 9-10
seconds by this evening. The Small Craft Advisory currently
in effect for winds will transition to a wave based advisory late
today, lasting into early Tuesday.

A thermal trough rebuilds inland Tuesday into midweek, which
combined with the high pressure over the Pacific will bring the
return of increased north winds. -HEC/Muessle

&&

.PQR WATCHES/WARNINGS/ADVISORIES...

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

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

PZ...Dense Fog Advisory until 2 PM PDT this afternoon for PZZ210-
     251>253.

     Small Craft Advisory until 11 PM PDT this evening for PZZ251>253.

     Small Craft Advisory until 5 AM PDT Tuesday for PZZ271>273.
&&

$$

www.weather.gov/portland

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