Gresham, Oregon 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

180
FXUS66 KPQR 252150
AFDPQR

Area Forecast Discussion
National Weather Service Portland OR
250 PM PDT Wed Jun 25 2025

.SYNOPSIS...Onshore flow will maintain cloudier weather and more
seasonable to slightly below normal temperatures through Friday.
Areas of light drizzle are expected tonight into tomorrow for most
locations, aside from the southern Willamette Valley and adjacent
Cascade foothills. Warm and dry conditions are expected this weekend
into early next week with inland high temperatures approaching or
exceeding 90 degrees by Sunday or Monday.

&&

.SHORT TERM...Now through Friday Night...The short term forecast is
highlighted by slightly cooler than average temperatures for this
time of year and chances for light drizzle Wednesday night into
Thursday. The cooler weather pattern is in response to a broad upper
level trough focused over the Gulf of Alaska and British Columbia.
With this set-up in place, the marine layer has already deepened
significantly, resulting in extensive cloud cover and areas of light
drizzle during the overnight/morning hours. While the marine stratus
deck that was in place over the area earlier today is beginning to
scatter out to the south of the Portland/Vancouver metro, expect low
clouds to quickly redevelop tonight and fill in across all of
northwest and southwest WA from the coast to the Cascades. Tomorrow
will be similar to today with cloudy conditions much of the day and
areas of light drizzle in the morning. Expect high temperatures in
the upper 60s to around 70 degrees, except in the southern Willamette
Valley where highs will likely warm to 70-75 degrees.

Not much change to the pattern on Friday, aside from morning cloud
cover scattering out a bit earlier in the afternoon. This will allow
temperatures to warm a bit more with widespread highs in the mid 70s
likely over the interior lowlands and 60s at the coast. A more
significant warming trend develops this weekend into early next week;
this is discussed below in the long term discussion. -TK


.LONG TERM...Saturday through Tuesday...The long term forecast is
highlighted by a warmer and drier weather pattern with above average
temperatures. Saturday looks to be a transition day with temperatures
beginning to warm more noticeably, but still fairly seasonable for
this time of year with highs in the upper 70s to lower 80s, except
65-70 degrees at the coast. Models and their ensembles remain in
excellent agreement Saturday will be a dry day with breezy north to
northwest winds in the afternoon and evening.

Temperatures are expected to peak Sunday and Monday with highs most
likely in the upper 80s to lower 90s for inland areas and upper 60s
to lower 70s at the coast. That said, cannot completely rule out high
temps in the mid to upper 90s on Monday. This is when the NBM is
showing a 30-50% chance for high temperatures above 95 degrees over
the Willamette Valley, Columbia River Gorge and Upper Hood River
Valley. Probabilities are lower along the Cowlitz Valley at 10-20%,
and less than 5% along the lower Columbia. Remaining warm on Tuesday,
however confidence is low regarding exact high temperatures that far
out in time due to an increase in overall model spread. Some guidance
maintains highs in the 90s, while some lowers temperatures back into
the low to mid 80s. There is currently around a 50/50 chance high
temps will be in the 80s versus the 90s over the Willamette Valley
and Portland/Vancouver metro on Tuesday.

Also worth noting is a 15-30% chance of showers and thunderstorms
over the Oregon Cascades on Monday, decreasing to a 10-20% chance on
Tuesday. It is unclear exactly where a closed upper level low
centered somewhere over California will set-up, and for how long this
low will persist. If this low moves over central or northern
California, conditions will become favorable for Cascade
thunderstorms due to a southeasterly flow regime aloft advecting in
monsoonal moisture from the Desert Southwest region and increasing
instability. This type of pattern can also result in thunderstorms
over the Cascades drifting northwestward over portions of the
Willamette Valley and Coast Range, however ensemble guidance for QPF
and NBM PoPs do not support this scenario at this time. Will need to
watch the set-up closely over the coming days and monitor
probabilities for thunderstorms. -TK

&&

.AVIATION...Onshore flow has been stronger than previously
expected with marine stratus still spread along most of the
terminals north and west of KSLE. MVFR CIGs continue to dominate
the region, but satellite shows them thinning this afternoon. Will
still see around a 40% chance of VFR CIGs within the Willamette
Valley after 00Z Thu though confidence is low. If CIGs do lift,
it will be to around 3000-5000 ft MSL. Coastal terminals are
bouncing between IFR, MVFR, and VFR CIGs.

Drizzle will return overnight as the cooling causes the lower
atmosphere to saturate and redevelop that deep marine layer.

PDX AND APPROACHES...Models show MVFR CIGs which will begin to
erode right around 00Z Thu. East approaches could see more dense
cloud cover due to packing against the terrain. Overall, light
westerly flow over the next 24 hours. Marine stratus will once
again develop overnight with a slight chance (<10%) for drizzle.
-Muessle

&&

.MARINE...A series of weak fronts will pass over the waters
through the remainder of the week maintaining steady conditions of
westerly winds and seas less than 6 ft. The pattern will begin to
shift over the weekend as high pressure begins to develop. Will
see a northerly wind shift as is typical with our summer time
patterns. Winds will begin to ramp up with a high probability of
Small Craft Winds along the waters. Seas too will respond, but the
background swell remains around 4-6 ft at 10 ft. Will continue to
monitor overall significant wave heights due to the addition of
the northerly wind wave - especially on Sunday and Monday. -Muessle

&&

.PQR WATCHES/WARNINGS/ADVISORIES...

OR...None.
WA...None.
PZ...None.

&&

$$

www.weather.gov/portland

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