Blachly, Oregon Weather Forecast Discussion

022
FXUS66 KPQR 172300
AFDPQR
Area Forecast Discussion
National Weather Service Portland OR
400 PM PDT Wed Sep 17 2025
.SYNOPSIS...Onshore flow and seasonable temperatures are
expected through Saturday. A larger trough digging southeast
from the Gulf of Alaska this weekend will bring a more
noticeable cool- down and higher rain chances, especially for
the coast and southwest Washington Saturday night through
Sunday.
&&
.SHORT TERM...Now through Saturday...Seasonable temperatures and
tranquil conditions are expected through Saturday. A weak cold
front passing through the area brought little in the form of
precipitation, a few light sprinkles along the coast where
clouds haven`t dissipated are possible. Onshore flow behind the
front is expected to persist through the remainder of the work
week as high pressure offshore builds towards the coast. Highs
on Thursday are expected to be tad cooler, topping out in the
mid to upper 70s inland and low to mid 60s along the coast and
higher terrain. Friday and Saturday will be slightly warmer,
closer to the 80 mark as a weak upper level short wave ridge
passes overhead. -Batz
.LONG TERM...Saturday night through Tuesday night...Dry
conditions will come to an end Saturday night as a strong short
waver trough drops southeast along the British Columbia coast.
A cold front will approach the WA and OR coasts Saturday night
into Sunday. Probabilities for measurable rain will range from
20-60% for most of northwest Oregon, with lower chances (as low
as 15%) in the southern Willamette Valley and into the Lane/Linn
County Cascades and foothills. Higher chances of 50-80% are
expected north and west of a line from the Willapa Hills down to
Tillamook, including the southwest Washington coast and around
Astoria. Temperatures trend cooler for Sunday, generally into
the low 70s inland and 60s along the coast as cloud cover
increases.
Looking into early next week, highs remain seasonable in the
mid to upper 70s inland, with continued cool conditions along
the coast. Tuesday into Wednesday, a low pressure system off the
coast of northern California rides up a trough over the
northeast Pacific and into Oregon. Guidance currently suggests
widespread 20-30% probabilities for precipitation, though
details such as timing remains uncertain. -Batz/Hall
&&
.AVIATION...The upper level ridge is moving east, but the region
is still maintaining a generally warm and dry air mass. VFR with
mostly sunny skies continues this evening across Willamette
Valley terminals. MVFR CIGs along the coast are beginning to
scatter out and/or lift to VFR, and should predominately be VFR
after 02-03z Thu. Expect northerly to northwesterly winds this
afternoon around 5-10 kt inland and 10-15 kt along the coast with
gusts up to 20 kt, strongest in the afternoon.
Moistening conditions overnight will favor marine stratus
developing again along the coast after 10-12z Thu, however,
currently have moderate confidence for this. Guidance suggests a
40-60% chance for IFR/MVFR CIGs returning to KONP and KAST. Higher
confidence (60-80% chance) for MVFR stratus development across
the far eastern Portland/Vancouver Metro Area after 10-12z Thu.
KPDX AND APPROACHES...VFR with mostly clear skies this evening.
Northwest winds around 7-10 kt this afternoon. 30-40% chance for
MVFR CIGs after 10-12z Thu as morning stratus develops in the far
eastern Metro.      -Alviz
&&
.MARINE...As of 3 PM Wednesday, buoy observations are now showing
winds across the waters turning northerly to northwesterly. Expect
these winds to gradually increase through this afternoon as high
pressure strengthens. Small Craft Advisories remain in effect
across the waters through Thursday evening for northerly winds
15-20 kt with gusts up to 25 kt. Seas are also expected to build
to around. Seas are also expected to build to around 8 to 10 ft
with a period of around 10-11 seconds during this time.
High pressure shifts south and eases on Friday, weakening
northerly winds across the waters. A frontal system arrives this
weekend from the north, returning southerly winds. No substantial
impacts expected for now, with guidance suggesting a 15-30% chance
for southerly wind gusts of 21 kt or greater (small craft
conditions).      -Alviz/DH
&&
.PQR WATCHES/WARNINGS/ADVISORIES...
OR...None.
WA...None.
PZ...Small Craft Advisory from 3 PM this afternoon to 5 AM PDT
     Thursday for PZZ210.
Small Craft Advisory from 3 PM this afternoon to 11 PM PDT
     Thursday for PZZ251>253-271>273.
&&
$$
www.weather.gov/portland
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NWS PQR Office Area Forecast Discussion