Hillsboro, Oregon 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

351
FXUS66 KPQR 150351 AAA
AFDPQR

Area Forecast Discussion
National Weather Service Portland OR
850 PM PDT Thu Aug 14 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 from tonight
through Saturday morning. The system exits late Saturday,
giving way to drying through Sunday. Onshore flow remains in
place early next week, keeping temperatures below seasonal norms
with areas of morning cloud cover.

&&

.SHORT TERM...Now through Sunday...We are looking at a notable
late-summer weather system for the next 36 to 48 hours. Light
showers are expected to develop tonight along higher terrain and
coastal areas, gradually becoming more widespread across the
region by Friday morning. By Friday afternoon, a strong cold
front will move in from the Pacific, tapping into unusually high
atmospheric moisture - precipitable water values near 1.8
inches, which is near record territory for mid-August.

As this front pushes through Friday evening into early Saturday,
widespread moderate to locally heavy rainfall is anticipated.
Current projections give most locations at least a 0.25 inch
total (80-90% probability, a bit lower in Lane County). Many
areas from the coast to the Cascades should see over 0.5 inches,
such as all of southwest Washington, Portland/Vancouver metro,
and elevated terrain in northwest Oregon. Locations with best
chances for totals above 1 inch would be the Portland/Vancouver
metro, Columbia Gorge, Coast Range, and Cascades. A few west-
facing Cascade slopes in southwest Washington could approach 2
inches, but flooding concerns are low. Southerly winds will
increase Friday night, with gusts of 20-25 mph possible along
exposed areas. Following the front, rain will taper back to
intermittent showers Saturday morning before drying spreads from
west to east by late Saturday night. Outdoor plans will be
impacted, especially Friday evening.

.LONG TERM...Sunday through Wednesday night...High pressure
will not fully reestablish, but a quieter pattern is expected
into early next week. Persistent onshore flow under southwest
aloft will keep temperatures running cooler than average - mid
to upper 70s inland, mid to upper 60s along the coast - along
with daily morning cloud cover.

There remains a slight chance (15-30%) of afternoon
thunderstorms over the Oregon Cascades, mainly south of Santiam
Pass, on both Saturday and Sunday (highest chances on Sunday).
Most of this activity will remain east of the crest given
prevailing southwest flow.
~Hall

&&

.AVIATION...Moist, westerly flow aloft will continue through
the period, while a warm front brings lowering ceilings across
the area along with light rain to the coast and inland areas
north of KSLE through Friday afternoon. As of 03z, CIGs have
fallen to MVFR along the coast. Expect conditions there to
continue to deteriorate overnight to IFR, likely persisting
through much of the day on Friday. Chances for CIGs inland
lowering to MVFR increase to around 50-60% by 10-12z Fri, with
conditions very likely to return to predominately VFR by Friday
afternoon.

A cold front will approach the coast late Friday afternoon and
evening as south wind increase with gusts up to 25-30 kt,
strongest along the north Oregon coast. Heavier rain will be
possible as the frontal band moves across the region Friday night.

PDX AND APPROACHES...Increasing clouds as moist, westerly flow
moves across the area tonight through Friday. Conditions likely to
remain predominately VFR tonight with CIGs around FL040-060.
Chances for CIGs lowering to MVFR increase to around 50-60% after
12z Friday. Light rain possible through Friday afternoon, before a
frontal band brings likely heavier rain late Friday. Northwest
winds less than 10 kt expected to become more southerly after
midnight. /DH

&&

.MARINE...South winds across the waters this evening ahead of a
weak warm front, which will move across the waters tonight. An
early season cold front will approach Friday increasing the south
winds. Stronger winds are expected with the frontal passage Friday
afternoon and evening, especially near the south Washington and
extreme north Oregon coasts. Have issued a Gale Watch for marine
zone 251 and the Columbia River Bar as NBM 5.0 shows a 60% chance
for wind gusts above 34 kt. Seas will respond to the increase of
winds becoming steep and choppy Friday and Friday night. The
available water content is high with this front, and the rain will
be heavy at times and briefly reduce visibilities. Winds decrease
significantly Saturday night and Sunday as the waters are in a
barometric col (lower pressure to the north and higher pressure to
the south, aka saddle point). ~TJ

&&

.PQR WATCHES/WARNINGS/ADVISORIES...

OR...None.
WA...None.
PZ...Small Craft Advisory from 8 AM to 1 PM PDT Friday for PZZ210-251.

     Gale Watch from Friday afternoon through late Friday night for
     PZZ210-251.

     Small Craft Advisory from 8 AM Friday to 5 AM PDT Saturday for
     PZZ252-271-272.

     Small Craft Advisory from 2 PM Friday to 5 AM PDT Saturday for
     PZZ253-273.
&&

$$

www.weather.gov/portland

Interact with us via social media:
www.facebook.com/NWSPortland
x.com/NWSPortland