422
FXUS66 KPQR 290412 AAA
AFDPQR

Area Forecast Discussion...UPDATED
National Weather Service Portland OR
912 PM PDT Thu Aug 28 2025

Updated aviation discussion.

.SYNOPSIS...Warm and dry weather through Friday before inland
temperatures cool to the low to mid 80s for the weekend into
Monday. Temperatures could warm back up again to around 90
degrees for Tuesday into midweek. Onshore flow expected the next
week could push marine stratus inland along the Columbia River
and through Coast Range gaps, especially over the weekend.

&&

.SHORT TERM...Thursday afternoon through Sunday...Satellite
imagery early Thursday afternoon depicts mostly clear skies
across NW Oregon and partly cloudy skies across SW Washington
with marine stratus socked in along the coast. A low pressure
system is situated over the Eastern Pacific while the meso-low
that caused showers and thunderstorms the past couple of days
slowly moves north through Washington today into tomorrow. This
is allowing weak high pressure to build over Oregon and SW
Washington, and daytime temperatures are expected to warm to the
upper 80s to around 90 degrees today and tomorrow.

Ensemble guidance is in good agreement that the low pressure
system is expected to remain spinning over the Eastern Pacific
into early next week. It will move closer to the coast this
weekend, pushing high pressure to the east and allowing inland
temperatures to cool to the low to mid 80s for Saturday and
Sunday. Stronger onshore flow under this pattern will keep
marine stratus along the coast, with it likely pushing inland
along the Columbia River and through Coast Range gaps. Could see
westerly wind gusts up to 20-25 mph through the central Columbia
River Gorge and over Cascade ridgetops in the afternoon and
evening hours, as well. -HEC

.LONG TERM...Monday through Wednesday...On Monday, ensembles
indicate the low pressure system begins moving northwest away
from the coast, with temperatures rising a few degrees to the
mid to upper 80s inland, though onshore flow will continue with
marine stratus along the coast keeping coastal temperatures in
the 60s.

There is significant uncertainty in the weather pattern Tuesday
and especially Wednesday, mainly due to ensemble guidance
struggling to resolve the tropical disturbances that are
currently located SW of Mexico. In general, the majority of
ensemble members indicate high pressure will build back to the
west over Oregon and Washington, which would cause temperatures
to rise again. However, the details of this high pressure, such
as how strong it builds and exact location, remain uncertain
amongst members, which will influence just how much warming will
happen. The NBM`s temperature spread (10th to 90th percentile)
for inland locations ranges from the mid 80s to the upper 90s on
Tuesday and mid 80s to around 105 degrees on Wednesday. At this
point, NBM deterministic forecast suggests temperatures warming
back to the low 90s, but with such a wide spread, expect changes
to future forecasts as the models continue to try to resolve the
pattern. -HEC

&&

.AVIATION...Expect VFR conditions and mostly clear skies for
inland terminals through the TAF period. That said, there is a
20-25% chance for MVFR cigs below 3000 ft at KEUG and KSLE between
12-18z Friday. There is also a 25-35% chance for MVFR cigs at
KHIO, KPDX, KUAO and KTTD during that same time period. These
probabilities are not high enough to reflect MVFR cigs in the
TAFs, however amendments may be needed if observations begin to
suggest stratus will push far enough inland. Coastal terminals
will see much different conditions, but similar to the last few
days. LIFR/IFR cigs at the coast have lifted to low-end MVFR as of
21z Thursday, however LIFR/IFR cigs are likely to return to the
north Oregon coast by 06-09z Friday and by 03z Friday for the
central Oregon coast (>80% chance). West to northwest surface
winds between 5-10 kt or less will continue through this evening
before becoming light and variable less than 5 mph overnight.

PDX AND APPROACHES...VFR conditions will continue with mostly
clear skies and light northwesterly winds through the TAF period.
-TK

&&

.MARINE...Benign conditions will continue over the coastal waters
through the upcoming weekend as winds remain around 10 kt or less
and seas hover between 2 and 4 ft, resulting in conditions that
are favorable for small craft. A more typical summertime pattern
returns on Monday and likely continues through at least Wednesday
of next week, bringing persistent northerly winds that are
strongest during the afternoon and evening hours each day,
especially to the south of Cape Falcon. That being said, the
probability of reaching small craft advisory level wind gusts of
21 kt or stronger is only around 5-10% each day due to a
relatively weak surface pressure gradient in place. Seas should
remain less than 5 ft on Monday before increasing to 5 to 7 ft
late Tuesday into Wednesday. -TK

&&

.PQR WATCHES/WARNINGS/ADVISORIES...
OR...None.
WA...None.
PZ...None.

&&

$$

www.weather.gov/portland

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