Canby, Oregon 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

176
FXUS66 KPQR 151755
AFDPQR

Area Forecast Discussion
National Weather Service Portland OR
1055 AM PDT Fri Aug 15 2025

Updated aviation discussion...

&&

.SYNOPSIS...A robust upper-level trough paired with a moisture-
laden Pacific front is set to bring an unseasonably strong round
of rainfall, breezy southerly winds, and cooler-than-average
temperatures across western Washington and northwest Oregon
today into tomorrow. The system exits late Saturday, giving way
to drying through Sunday. Onshore flow remains in place early
next week, keeping temperatures below seasonal normals with
areas of morning cloud cover.

&&

.SHORT TERM...Now through Sunday Night...We are looking at a
notable late-summer weather system for the next 24 to 36 hours,
which will bring widespread rain and breezy south winds to the
area late today into Saturday morning. Radar and surface weather
observations from early Friday morning depicted scattered rain
showers over southwest WA, the north OR coast, the Portland
metro and the northern/central Willamette Valley. Expect
occasional showers to continue today to the north of Eugene-
Springfield. The bulk of incoming precipitation arrives with a
strong cold front late Friday afternoon/early evening at the
coast before spreading inland Friday evening/night. This is when
off-and-on showers will transition to a persistent stratiform
rain, moderate to heavy at times, especially along west-facing
and southwest-facing slopes in the Cascades and coastal
mountains where favorable orographic lift will be in place. The
GEFS/GEPS/ENS ensemble means continue to show precipitable water
values peaking near 1.7-1.8 inches, suggesting the amount of
moisture in the atmosphere could reach record levels for this
time of year.

As such, confidence is high the most significant rain amounts of
the summer season thus far will occur across all of northwest
Oregon and southwest Washington. Still expecting 36-48 hour rain
amounts to top out between 0.5-1.0 inches for most inland
valley locations, except 0.25-0.40 inches for the western
Willamette Valley and eastern slopes of the coastal mountains
where some degree of rain shadowing is expected. The highest
rain amounts are forecast along the south WA/north OR coast,
Willapa Hills, and south WA Cascades/foothills where 1-2 inches
of rain is expected. Although this is an abnormally high amount
of rain for this time of year, river flooding is not a concern
as river levels leading into the event are very low. There will
be some rises on creeks and rivers, but do not expect flood
stage to be reached. In addition, the UWWRF and the HRRR suggest
hourly rain rates will generally stay under 0.25 inches/hr over
urban areas, which will limit the threat for urban flooding as
well. That said, will still see some ponding of water in low-
lying areas with poor drainage, and roads will become slick.
Also expect wind gusts up to 20-30 mph with the cold frontal
passage, except up to 35 mph at the coast. Be sure to secure any
loose outdoor items you may have. It is also a good idea to
make sure gutters and storm drains are cleared out.

Following the front, rain will taper back to intermittent
showers Saturday morning before drying spreads from west to
east Saturday evening. Outdoor plans will be impacted,
especially Friday evening through Saturday morning. Sunday looks
to be a mainly dry and mild day with high temperatures in the
mid to upper 70s, except 60s at the coast. There is also a
15-25% chance of showers and thunderstorms over the Lane County
Cascades Sunday afternoon, however it appears most of Sunday`s
convection will occur east of the Cascade crest due to
southwesterly flow aloft. -TK


.LONG TERM...Monday through Thursday night...Models and their
ensembles continue to show high confidence for a prolonged
period of southwest flow aloft and low-level onshore flow next
week. This pattern should keep temperatures near average to
slightly below average for this time of year with highs ranging
between 75-85 degrees for inland valleys each day and upper 60s
to lower 70s at the coast. Note Monday and Tuesday are trending
relatively cooler than Wednesday and Thursday, mainly due to
more morning cloud cover early in the week. Dry conditions are
also expected through the long term forecast, aside from a
10-15% chance of light rain or drizzle along the Long Beach
Peninsula Monday and Tuesday. -TK

&&

.AVIATION...Restricted vis/cigs expected at all terminals
through much of the period as a vigorous frontal system
approaches from the west through tonight. Ongoing light rain
showers will give way to steady light to moderate rain,
initially at KAST by 21-23z Fri, spreading to other coastal
terminals by 00-03z Sat, then inland to Willamette Valley
terminals by 03-06z Sat.

Along the coast, IFR vis/cigs are likely after 21-24z Fri, with
LIFR/VLIFR most likely at KONP after 00z Sat as steady rain
begins. Breezy south winds may gust to 20-30 kt, with the
highest gusts most likely near KAST ahead of the frontal
passage, before easing as flow shifts out of the southwest
behind the boundary by 09-12z Sat. Inland terminals are more
likely to see VFR or mixed VFR/high-end MVFR cigs through this
afternoon, before conditions degrade to widespread MVFR as
steady rain begins by 06z Sat. Southerly gusts ahead of the
frontal passage may reach 20 kt through this evening, before
easing as flow turns out of the southwest after 12z Sat.


PDX AND APPROACHES...VFR conditions favored to continue through
this evening with rain showers passing nearby. An occasional
shower may result in briefly restricted vis/cigs, but confidence
in timing of these showers remains low. Gusty southerly flow
continues ahead of the approaching frontal boundary, with gusts
to around 20 kt through this evening. Steady rain begins by
04-06z Sat, yielding MVFR vis/cigs through much of the overnight
period, before conditions slowly improve behind the boundary on
Saturday morning. -Picard

&&

.MARINE...
An unusually strong cold front for this time of year
will move over the coastal waters today, bringing increasing
southerly winds and rain, heavy at times with reduced
visibilities. A Dense Fog Advisory is in effect for the inner
waters and the Columbia River Bar through Friday afternoon for
visibilities of 1 NM or less.

Stronger winds are expected with the frontal passage Friday
afternoon and evening, especially near the south Washington and
extreme north Oregon coasts. Have upgraded the Gale Watch to a
Gale Warning for marine zone 251 and the Columbia River Bar as the
probability for marginal gale force wind gusts as high as 34-35
kt have increased to 60-90%. Note gale force wind gusts will most
likely only last for a two to four hour period, sometime between 1
and 6 PM today. The outer waters and the inner waters to the
south of Cape Falcon are only expected to see wind gusts as high
as 25-30 kt; a Small Craft Advisory remains in effect for these
marine zones. Seas will become steep and choppy in response to the
increasing winds, with significant wave heights most likely
reaching 6 to 8 ft with a dominant wave period between 6 and 8
seconds. Winds decrease significantly Saturday night and Sunday
with seas decreasing. -TK

&&

.PQR WATCHES/WARNINGS/ADVISORIES...

OR...None.

WA...None.

PZ...Dense Fog Advisory until 5 PM PDT this afternoon for PZZ210-
     251>253.
     Small Craft Advisory until 1 PM PDT this afternoon for PZZ210-
     251.
     Small Craft Advisory from 6 PM to 11 PM PDT this evening for
     PZZ210.
     Gale Warning until 6 PM PDT this evening for PZZ210-251.
     Small Craft Advisory from 6 PM this evening to 5 AM PDT
     Saturday for PZZ251.
     Small Craft Advisory until 5 AM PDT Saturday for PZZ252-271-
     272.
     Small Craft Advisory from 2 PM this afternoon to 5 AM PDT
     Saturday for PZZ253-273.

&&

$$

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