Wilsonville, Oregon 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

925
FXUS66 KPQR 102250
AFDPQR

Area Forecast Discussion
National Weather Service Portland OR
313 PM PDT Thu Apr 10 2025


.SYNOPSIS...A cool weather pattern will maintain itself across the
area through Saturday before the pendulum swings back to warm and dry
Sunday through at least early next week.


&&


.SHORT TERM...Through Saturday Night...A loop of radar and satellite
imagery this afternoon shows a front moving west to east across
northwest Oregon and southwest Washington. Rainfall amounts with the
front have generally been less than a quarter of an inch so far. High
resolution models and observations support that the bulk of the rain
will shift east of the region by 6-8pm. The main impact from this
front will be a return to cooler temperatures Friday and Saturday
with valley high temperatures struggling to reach 60F.

A reinforcing shortwave trough will clip the region Friday night.
While there is a decent chance (20-50%) that some lower elevations
get cold enough for frost Friday night, uncertainty surrounding the
extent of cloud cover makes confidence low in picking out which areas
will experience temperatures drop into the low to mid 30s at this
point. We may need Frost Advisories for some zones, but confidence is
not there yet.

Ensembles agree shortwave ridging will begin to build into the region
Saturday night. This should lead to clearing skies and decreasing
winds across the region. This will set the stage for colder overnight
low temperatures across the region with a 50-70% chance for
temperatures to drop into at least the mid 30s away from the coast
and inner Portland metro. Larger areas of frost appear much more
likely as a result. Meanwhile, the upper Hood River Valley appears to
have a very high chance (90%+) of experiencing freezing temperatures
Saturday night so went ahead and issue a Freeze Watch to cover this
hazard. /Neuman


.LONG TERM...Sunday through Wednesday...Ensembles are in good
agreement shortwave ridging will bring a warming trend Sunday into
Monday. While Willamette Valley locations stand a 50:50 chance of
hitting 70F Sunday, confidence is considerably higher for 70s to
materialize on Monday with the probability of them occurring at 90%
or higher at most sites in the Willamette Valley per the NBM.

Uncertainty in the extended forecast does begin to grow towards
Tuesday and Wednesday next week, but is still relatively limited.
Most of the global ensemble members suggest ridging temporarily
flattening and then returning with above average heights remaining
over the region through the middle of next week. While temperatures
appear most likely to cool Monday through Wednesday due to the
flattening ridge, temperatures should still remain above average.
With that said, there is ~10% of the global ensemble membership that
bring a deeper shortwave trough into the northern Pacific Northwest
that would result in a return to a cooler and wetter weather pattern.
Given well more than majority of ensemble members suggest dry weather
and mild temperatures continuing, kept the NBM forecast as is in the
extended which keeps temperatures well above average and keeps
mentionable (15% or higher) rain chances limited to our far northern
zones where the aforementioned shortwave trough is most likely to
clip. /Neuman


&&


.AVIATION...A cold front spreading eastward across northwest
Oregon and southwest Washington will continue to bring gusty
south to southwesterly winds and lowering ceilings for next the
next few hours. Expect a 2-4 hour period of steady rain
accompanied by IFR conditions along the coast and at least some
brief dips into MVFR thresholds for inland taf sites. Thereafter
conditions should settle more into VFR thresholds with only
occasional dips into MVFR thresholds. There is a 10-20% chance
that IFR conditions develop towards 12-15z Thursday as fog and low
clouds try and develop in the northern Willamette Valley. With
that said, it should be noted that the aforementioned front will
stall across southwest Oregon overnight. Lane County will be in
the northern periphery of this front and when coupled with light
northerly winds, there is a 40-50% at any given hour for MVFR
conditions to return to KEUG towards 12-18z Thursday.

PDX AND APPROACHES...A cold front crossing the region will bring a
2-4 hour period of steady rain and lower ceilings through
~02z Thursday. There is a 50-70% chance for at least brief MVFR
conditions through ~02z Thursday. Thereafter, conditions should
improve into VFR thresholds. There is a 10-20% chance that IFR
conditions develop towards 12-15z Thursday as light winds and
clearing skies lead to patches of fog and low clouds around the
region. /Neuman


&&


.MARINE...A cold front that pushed across the waters earlier this
afternoon is moving inland. The earlier Gale Force winds have
subsided with Small Craft Advisory level wind gusts to 25 kt
currently occurring across the waters. There is a good agreement
among the weather models winds will continue to decrease through the
evening hours as surface high pressure builds towards the waters.
Seas have climbed quickly to near 10 ft across the waters with
dominant periods of 6-7 seconds. While the decrease in winds will
allow seas to subside, seas will remain particularly steep through
the evening hours so will maintain a Small Craft Advisory to cover
this hazard.

A trailing westerly swell will push seas back up to near 10 ft
Friday, particularly across the northern waters. A much weaker
front will drop southeastward across the waters Friday night, but
the odds for wind gusts climbing up towards 21-25 kt is less than
10%.

There is high confidence high pressure will build over the Pacific
Northwest and thermally induced lower pressure will develop over
California and the southern Oregon coast late in the weekend. This
will lead to a Summer-like wind pattern with building northerly
winds across the waters during this time. Winds will generally be
strongest off the central coast of Oregon and weakest off the
south Washington coast during this time. Expect winds to peak
across the inner waters during the late afternoon and evening
hours, and gusty northerly winds to persist across the outer
waters during the overnight hours.

High pressure looks to gradually weaken next week, but there are
few signals among the weather models of any major fronts crossing
the waters that would produce Gale Force or higher winds. /Neuman


&&


.PQR WATCHES/WARNINGS/ADVISORIES...

OR...Freeze Watch from late Saturday night through Sunday morning for

     ORZ121.

WA...None.
PZ...Small Craft Advisory until 3 AM PDT Friday for PZZ210-251>253-
     271>273.
&&



$$

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