Corvallis, Oregon Weather Forecast Discussion

387
FXUS66 KPQR 030947
AFDPQR
Area Forecast Discussion
National Weather Service Portland OR
247 AM PDT Fri Oct 3 2025
.SYNOPSIS...Seasonable temperatures on Friday with northerly
flow aloft. Very light rain showers likely Friday through
Saturday morning, with most areas likely not seeing any
precipitation. Low-level offshore flow develops Sunday and
continues through at least Tuesday, bringing an extended period
of dry weather with daytime high temperatures in the 70s across
the lowlands.
&&
.DISCUSSION...Friday through Thursday...Northerly flow aloft
and high pressure at the surface will result in relatively dry
weather with seasonable high temperatures in the upper 60s to
low 70s through Sunday. Models are showing a weak perturbation
within the upper level flow, which is resulting in a moderate to
high Pop/low QPF pattern which could result in some very light
showers through Friday evening. However, most locations will
likely not see any precipitation today. Winds also, look fairly
light with speeds less than 10 mph.
Chances for rain remain elevated on Saturday as a set of upper
level perturbations within the overall northerly flow will move
southward across the CWA. The first impulse moves through
during the early morning hours, while the second impulse moves
through during the afternoon and early evening. Both of these
impulses are showing high PoPs, but low QPF. So, don`t expect
much beyond a few hundredths of an inch.
As the weekend progresses, the forecast remains dry Sunday
through Wednesday in response to a building upper level
shortwave ridge combined with a prolonged period of offshore
flow. This pattern change will result in mostly sunny and breezy
conditions with temperatures becoming noticeably warmer. Expect
highs temperatures in the 70s each day across the lowlands, with
even the coast likely warming into the 70s on Monday and
Tuesday. Tuesday is still shaping up to be the warmest day of
the week with highs well into the 70s. Probabilities for highs
of 80 degrees or warmer are low, ranging between 5-10%. As the
latter part of next week approaches, the pattern becomes more
progressive. Looking at WPC 500 mb cluster, around 70% of the
models show a troughing pattern developing around the Pac NW,
while 20% of the models show a broad ridge over the western part
of CONUS and the remaining 10% have a more zonal regime setting
up. As a result, the multi-model ensemble is generally showing a
weak trough developing for the latter part of next week, which
would bring more seasonable conditions to the Pac NW. /42-59
&&
.AVIATION...As we enter a transitional period between two
significant systems, satellite and surface observations show a
mixture of all flight conditions for inland and coastal locations.
As the saturated airmass settles over the next few hours, most
locations will likely settle around IFR/LIFR and those conditions
look to persist through 18-20Z Friday, but some locations could
hold onto these lowered flight conditions through 22Z Friday.
Afterwards, conditions look to improve towards predominately
VFR, which is expected to persist through 04Z-06Z Saturday.
KPDX AND APPROACHES...Current IFR conditions are expected to
persist through around 19Z-21Z Friday. Could see some periods of
MIFG that could result in periods of LIFR condition at or near the
terminal through around 18Z Friday. Afterwards, conditions
expected to improve towards VFR through at least 05Z Saturday.
&&
.MARINE...A very weak frontal system will keep southerly winds
across all waters through this evening. Relatively benign
condition will slowly spread across all waters this weekend as
high pressure aloft slowly builds in. Saturday, expect
northwesterly winds as well as another weak front moves into the
area Saturday afternoon. Seas 5-7 ft by mid Friday and are
expected to persist through at least the start of next week.
As high pressure continue to develop on Sunday, expect more
northerly winds with a high probability (greater than 50% chance)
of Small Craft Advisory conditions developing. Timing, strength
and location are still uncertain so will refrain from issuing any
headlines at this time. As late Sunday/early Monday approaches,
expect winds to become slightly offshore before returning to an
onshore flow pattern by Tuesday. /42
&&
.PQR WATCHES/WARNINGS/ADVISORIES...
OR...None.
WA...None.
PZ...None.
&&
$$
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NWS PQR Office Area Forecast Discussion