Aloha, Oregon 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

829
FXUS66 KPQR 051026
AFDPQR

Area Forecast Discussion
National Weather Service Portland OR
325 AM PDT Sun Apr 5 2026

.SYNOPSIS...Dry conditions will persist through Friday aside from a
15-30% chance of showers over the Oregon Cascades in Lane and Linn
counties Wednesday afternoon through Thursday evening and Friday
afternoon/evening. High pressure will maintain well above normal
temperatures for this time of year through Monday. Onshore flow
returns Tuesday and Wednesday, bringing relatively cooler
temperatures. Trending a bit warmer again Thursday into Friday with
light offshore flow developing.

&&

.DISCUSSION...Sunday through Saturday night...High pressure and
low-level offshore flow remains in place today with scattered to
broken high clouds and light winds, aside from the western Columbia
River Gorge and the Troutdale, Washougal and Camas area where
easterly winds are a bit breezy with gusts up to 15-25 mph. Expect
easterly winds to ease late in the day as low-level offshore flow
weakens. Despite the aforementioned high clouds in place today,
temperatures are still on track to warm well into the mid to upper
70s across the interior lowlands and upper 60s to lower 70s at the
coast. Most locations within the Willamette Valley and greater
Portland/Vancouver metro have anywhere from a 10-30% chance of
reaching 80 degrees or warmer this afternoon, which would likely only
occur if high clouds are thin enough during peak heating. Although
high pressure weakens a bit tomorrow with 850 mb temperatures cooling
slightly, high clouds will be dissipating. Given a full day of sun,
Monday is on track to be just as warm as Sunday with similar
probabilities of reaching 80 degrees. The only exception is at the
coast where the return of onshore flow will bring relatively cooler
temperatures compared to Sunday with highs near 60 degrees. A few
record high temperatures may be tied or broken both Sunday and
Monday. It is not recommended to cool off in local lakes and rivers
as water temperatures are currently frigid enough to result in cold
water shock, which can become life threatening.

Models and their ensembles continue to suggest temperatures will
trend cooler Tuesday and Wednesday with dry northwest flow aloft and
relatively stronger low-level onshore flow. The NBM depicts low model
spread for temperatures both days, suggesting highs will likely wind
up in the low to mid 60s, except 55-60 degrees at the coast. Note dry
weather will persist both days, with one potential exception over the
Oregon Cascades in Lane and Linn counties beginning Wednesday
afternoon and continuing through Thursday evening. This is when there
is a 15-30% chance of light showers due to wrap-around moisture from
the south associated with an upper level low off the California
coast. It is also worth mentioning that areas of morning frost are
still possible on Wednesday and Thursday, mainly away from the
Portland metro where morning lows will be coolest. That said,
probabilities for lows of 36 degrees or colder have decreased
slightly from previous cycles of the NBM. Probabilities now range
between 10-25% over the interior lowlands and inland coastal
communities, except 1-5% in the Portland metro to the east of the
West Hills and 40-75% in the Upper Hood River Valley from Odell to
Parkdale. Anyone with sensitive outdoor vegetation that is
susceptible to frost damage should stay up-to-date on the temperature
forecast over the coming days and monitor for potential Frost
Advisories.

Model guidance is now trending warmer Thursday afternoon through
Friday compared to previous cycles due to potential shortwave ridging
on the northeast periphery of the aforementioned upper low. As such,
the deterministic NBM is now suggesting highs in the upper 60s to
around 70 degrees over the interior lowlands both days. However,
there is still some uncertainty regarding how amplified the
shortwave ridge will become, and there is a 25% chance highs wind up
in the mid 60s or cooler. Chances for rain finally return next
weekend (25-50% chance), however guidance suggests rain amounts will
most likely be light and non-impactful (80-90% chance total rain
amounts will be under 0.25 inches from 5am Saturday through 5am
Sunday, April 11-12).
-23

&&

.AVIATION...Widespread VFR flight conditions will continue across
northwest OR and southwest WA through Sunday night with scattered
to broken high clouds above 20 kft. Light offshore winds at the
coast should be enough to prevent fog or low clouds from
developing at KAST and KONP based on the latest trends. Localized
fog has developed in the Creswell area this morning but is not
expected to expand into KEUG. Breezy easterly winds continue at
KTTD with gusts up to 19-21 kt, but should weaken Sunday evening.

KPDX AND APPROACHES...Expect VFR flight conditions to continue
through 12z Monday with scattered to broken high clouds above 20
kft. Light and variable winds less than 5 kt should become
easterly sometime between 17-19z Sunday, sustained between 6-10
kt. -23

&&

.MARINE...High pressure remains anchored over the waters and is
resulting in rather benign conditions. Seas early Sunday morning
were around 4 to 7 feet and are expected to remain within that
range through at least Thursday morning. Northerly winds have
decreased to below 15-20 kt over the waters early Sunday morning,
bringing an end to Small Craft Advisory conditions. Winds will
turn more offshore and weaken later Sunday morning before
temporarily becoming southerly late Sunday into Monday morning as
a thermal trough along the coast moves offshore. Winds are still
on track to become northwesterly by Monday afternoon, and will
then remain out of the north to northwest through the remainder of
the week.

Seas are expected to build slightly to 7 to 9 ft late in the week
in response to increasing northerly winds (up to 20-25 kt) and a
fresh northwesterly swell that will impact the waters. This will
likely result in another round of marginal Small Craft Advisory
conditions. -23

&&

.PQR WATCHES/WARNINGS/ADVISORIES...

OR...None.
WA...None.
PZ...None.

&&

$$

www.weather.gov/portland

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