Valley River Center, Oregon Weather Forecast Discussion

543
FXUS66 KPQR 191054
AFDPQR
Area Forecast Discussion
National Weather Service Portland OR
354 AM PDT Fri Sep 19 2025
.SYNOPSIS...
Onshore flow will persist through the weekend and into early
next week, maintaining seasonable conditions. A deeper trough
moving in from the Gulf of Alaska will bring a cool-down and
increasing rain chances late in the weekend. The most impactful
system arrives Sunday with widespread precipitation, including a
period of elevated chance of wetting rain (CWR), and there
remains a low potential for isolated thunderstorms in the
Lane/Linn County Cascades on Friday and a bit more widespread on
Sunday. A weaker, less certain system could bring additional
precipitation midweek.
&&
.SHORT TERM...Now through Saturday...Tranquil weather will
dominate most of the area during the short term period. High
pressure offshore will maintain mostly clear skies through
today, though some clouds may drift into eastern Lane/Linn
Counties tonight as a weak surface low over northern California
shifts northward. Overnight lows will be near average, in the
upper 40s along the coast and lower 50s inland.
Temperatures today will rise into the 80s inland, with only a
10-20% chance of exceeding 85 degrees. Coastal highs remain in
the 60s. A narrow 5-10% chance of a shower or isolated
thunderstorm remains over the Lane/Linn County Cascades Friday
afternoon and evening, but the rest of the area is expected to
remain dry. Saturday will see slightly cooler conditions, but
highs should still reach the low 80s inland and 60s along the
coast. Winds will shift westerly and eventually southwesterly
late Saturday night as a strong front approaches the coast.
.LONG TERM...Saturday Night through Thursday...Rain chances
increase late Saturday into Sunday as a strong shortwave trough
digs southeast from the Gulf of Alaska. The associated cold
front is expected to reach the coast around midnight Saturday
night, then progress inland near daybreak Sunday (~5 AM). that
said, confidence in exact timing remains low at this time.
Probabilities for precipitation increase to around 40% across
much of northwest Oregon and southwest Washington, with
localized values up to 80% as the front moves through.
Chance of wetting rain (CWR) rises to 30-60% through Sunday
during the frontal passage, mainly along the coast and across
southwest Washington. A low-end chance (~10%) for isolated
convection lingers into Sunday morning across southwest
Washington and northwest Oregon. Temperatures Sunday will cool
noticeably under cloud cover and frontal passage, generally
topping out in the low 70s inland and 60s along the coast.
Early next week, temperatures moderate back to seasonable levels
with inland highs in the mid to upper 70s and 60s along the
coast. There is a 20-40% chance for inland highs to reach 85
again on Tuesday. Precipitation potential has shifted later in
the period, with only 20-40% of ensemble clusters now suggesting
measurable precipitation by midweek. For now, a 10-20% chance of
showers is maintained from Wednesday through at least Thursday,
though details remain uncertain.
~Hall
&&
.AVIATION...VFR conditions expected to prevail across the area as
high pressure builds over the region. Skies remain mostly clear
through this evening, except for some high clouds to the south due
to an area of low pressure off the northern California coast.
Also, there remains a 20-40% chance of IFR CIGs developing at the
coast between 10-18z this morning, highest at KONP. Northwest
winds increase again during the afternoon and evening hours.
KPDX AND APPROACHES...VFR conditions with mostly clear skies
through the TAF period. Expect northwest winds around 5-10 kt
during the afternoon and evening hours. /DH
&&
.MARINE...Northerly winds will gradually ease today as pressure
gradients weaken, with gusts falling below 20 kt. Seas will also
gradually subside to around 5 to 7 ft at 9-10 seconds by Friday
afternoon. The next frontal system arrives this weekend from the
north, returning southerly winds by Saturday afternoon. The front
is expected to push through Saturday night into Sunday,
potentially leading to a brief coastal jet across the Columbia
River Bar and inner waters north of Cape Falcon. Guidance suggests
around a 50% chance for southerly wind gusts greater than 21 kt
for these locations late Saturday night, while chances are around
5-10% or less everywhere else. High pressure returns with winds
turning northwesterly postfrontal on Sunday. Northerly winds
likely to persist into early next week. DH/Alviz
&&
.PQR WATCHES/WARNINGS/ADVISORIES...
OR...None.
WA...None.
PZ...Small Craft Advisory until 5 AM PDT early this morning for
     PZZ251>253-271.
Small Craft Advisory until 11 AM PDT this morning for PZZ272-273.
&&
$$
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NWS PQR Office Area Forecast Discussion