Wilsonville, Oregon 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

175
FXUS66 KPQR 200420
AFDPQR

Area Forecast Discussion
National Weather Service Portland OR
920 PM PDT Sat Jul 19 2025

Updated aviation discussion.

&&

.SYNOPSIS...Expect near average temperatures for this time of
the year the next couple of days with a small chance (10-25%) of
showers Sunday night into Monday before a return to warmer
temperatures during the middle of next week.

&&

.SHORT TERM...Now through Monday...Water vapor satellite
imagery reveals a low amplitude shortwave trough over the
Pacific Northwest this afternoon. This is bringing near zonal
upper level flow over the region. Ensembles are in good
agreement 500mb heights will gradually lower over the next 24
hours as the aforementioned upper level trough sags southward
over the Pacific Northwest. This should act to deepen the marine
layer and may aid in more low clouds spreading inland tonight
into Sunday morning relative to this morning. Admittedly, HREF
guidance is certainly not sold on this idea, though and suggests
some inland locations that saw clouds this morning will not do
so Sunday morning.

Ensembles are coming into agreement an upper level low pressure
will close off over the Pacific Northwest late Sunday into early
Tuesday. This will keep temperatures near average through
Monday. Depending on how close the upper level low tracks to the
region, will result in whether or not we remain dry or see at
least some isolated to scattered showers develop Monday. The
highest chances for showers appear to be across the Cascades.
NBM PoPs look on track given most ensemble members from the
GEFS, GEPS and EPS keep the area dry.


.LONG TERM...Tuesday through Friday...WPC clusters suggest
global ensemble guidance is in relatively good agreement 500mb
heights will build across the Pacific Northwest Tuesday into
Wednesday. This will result in warming temperatures with a 90%
chance that temperatures reach at least 86F at KPDX and 88F at
KEUG by Wednesday with the most likely scenario being
temperatures in the 89-95F range by Wednesday in the Willamette
Valley. Onshore flow would keep the coast with near average
temperatures during this time. There is a substantial set of
ensemble guidance that closes off a piece of the early week
shortwave trough off the California coast Tuesday into Wednesday
and then ejects it northeastward close enough to the region to
bring a risk for thunderstorms Thursday and/or Friday. At this
point, the probability of thunderstorms occurring at some point
during that 48-hour timeframe is ~10-30% across the Cascades.
The highest probability is near the Cascade crest in Lane and
Linn Counties. The lowest probabilities are farther north and
west of that region. Because our forecast highlights 12-hour
thunder probabilities, which are substantially lower due to
timing uncertainty (i.e. Thursday vs. Thursday night vs.
Friday), it is not in the official forecast at this time.

&&

.AVIATION...Mainly VFR conditions across NW Oregon and SW
Washington through the TAF period with the exception being the
area along the coast. Conditions are mostly clear currently but
marine stratus is expected to build back in late this evening.
Additionally, there`s a 60-80% chance of MVFR/IFR marine stratus
forming again along the coast south of KAST after 06-08z Sun.
Latest guidance indicates the potential for stratus to move inland
along the Columbia River once again, with a 10-20% chance of it
reaching the Portland/Vancouver Metro area terminals between
10-17z Sun. Any MVFR ceilings could clear by 18-20z Sun with
daytime heating. Winds remain from the north to northwest
generally less than 10 kts.

PDX AND APPROACHES...VFR conditions expected through the TAF
period with some high clouds, though there`s a 10-20% chance of
brief MVFR ceilings between 14-17z Sun. Expect northwesterly
winds 5-10 kt. -Batz/HEC


&&

.MARINE...Benign weather expected across the waters this
weekend into early next week. High pressure will maintain north
to northwesterly winds, generally less than 10 kts. Wave heights
of 3-5 ft are expected to lower to 2-4 feet this evening. These
wind and wave conditions are forecast to continue through at
least mid-week. -HEC

&&

.PQR WATCHES/WARNINGS/ADVISORIES...

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

&&

$$

www.weather.gov/portland

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