019
FXUS66 KPQR 021015
AFDPQR

Area Forecast Discussion
National Weather Service Portland OR
315 AM PDT Wed Jul 2 2025

.SYNOPSIS...Onshore flow returns today which will bring in
cooler and more moist air. Stronger westerly flow will cause
winds to increase in the Columbia River Gorge and Upper Hood
River Valley through today.

&&

.SHORT TERM...Now through Friday...The upper level ridge which
brought high temperatures into the 90s is beginning to decay.
This will initiation the return of onshore flow and cooling
temperatures through the rest of the week. Overall, 850 mb
temperatures will fall to around 10 degrees C each day. There
will be a drastic drop in temperature today with highs only
forecast to reach 80 degrees in the Greater Portland-Vancouver
Metro 80-85 degrees in the southern Willamette Valley from
Corvallis South, in the low 80s through the Gorge, and 60s along
the coast. For those still dreaming of temperatures in the 90s,
you better head to the east as there is less than a 5% chance
anywhere in the forecast area.

On Thursday into Friday a weak shortwave aloft will move over
the area. This will increase some convective behavior though
thunderstorms are not necessarily expected. However, some
showers are possible over the Lane County Cascades. As it passes
could see an increase of westerly winds through the passes,
though not expected to be impactful.

For those wanting to enjoy outdoor activities on the 4th,
prepare for seasonable temperatures, mostly clear skies, and no
rain. -Muessle

.LONG TERM...Friday Night through Tuesday...The trough continues
to push inland through the weekend and ridging builds in behind
it. Will see a return of warmer conditions though flow will
continue to be onshore aloft. Therefore, conditions not expected
to be exceptionally warm until late in the forecast on Monday or
Tuesday. As we round out the weekend, flow will shift to the
north-northeast ushering in much drier and warmer air to the
region. A weak thermal trough will begin to form on Sunday
afternoon. At this point, the pressure gradient, combined with
the temperature gradient across the Cascades, will intensify.
Westerly winds will ramp up late Sunday afternoon.

500 mb height ensembles are in fairly good agreement moving
forward with the ridge intensifying. Temperatures will rise by
around 5 degrees each day on Monday and Tuesday with around a
50% chance of exceeding 90 degrees on Monday through the
Willamette Valley, and 75% or more on Tuesday. -Muessle


&&

.AVIATION...Marine stratus continues to support mixed IFR/low-
end MVFR cigs and occasionally restricted vis within mist at
coastal terminals including KONP/KTMK/KAST. The stratus deck has
also pushed inland along the Lower Columbia as far as KKLS early
this morning, suggesting higher (50-60%) chances of MVFR stratus
reaching Portland-area terminals including KPDX/KVUO/KTTD/KHIO by
12-15z Wed than predicted in numerical or statistical guidance.
Stratus will then slowly erode inland through the morning while
remaining more entrenched with persistent MVFR/IFR cigs along the
coast. Otherwise, sct-bkn cirrus at 20-25 kft leftover from
earlier convection along and east of the Cascades will trend
clearer by 15-18z Wed, yielding continued VFR conditions. Diurnal
NW winds reaching 10-15 kt with gusts to 20 kt return after
18-22z Wed, easing below 10 kt again by 03-06z Thu.

PDX AND APPROACHES...Ongoing VFR under bkn high cirrus deck may
continue beyond 12z Wed, with increasing likelihood of marine
stratus pushing inland along the Columbia River by 15z Wed
resulting in MVFR cigs around 1500 ft. Any stratus will be favored
to mix out by 17-18z Wed, with VFR conditions otherwise expected
throughout the period. Diurnal NW winds around 5 kt will increase
to 10-15 kt by 21-24z Wed with gusts as high as 18-20 kt through
the afternoon, easing to less than 10 kt after 04-06z Thu. -Picard

&&

.MARINE...Persistent surface high pressure offshore will result in
continued north to northwesterly winds across the waters. Diurnal
gusts will reach 10-15 kt north of Cape Falcon and 15-20 kt from
Cape Falcon to Florence each afternoon, easing to around 10 kt
overnight. Seas will continue at 3-6 ft through the weekend.
Strengthening surface high pressure will then see winds and seas
build Sunday into next week. -Picard

&&

.PQR WATCHES/WARNINGS/ADVISORIES...
OR...None.
WA...None.
PZ...None.
&&

$$

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