Tualatin, Oregon 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

624
FXUS66 KPQR 040934
AFDPQR

Area Forecast Discussion
National Weather Service Portland OR
234 AM PDT Fri Apr 4 2025

.SYNOPSIS...Warm and dry weather expected through Saturday with
high pressure over the region. Cooler and wetter weather returns
Sunday into early next week. No significant weather concerns
within the next seven days.

&&

.DISCUSSION...Satellite imagery reveals clear skies over the
region early Friday morning, which has allowed temperatures to
drop into the 30s overnight across the interior valleys of
northwest Oregon and southwest Washington. A Frost Advisory
remains in effect until 9 AM this morning for most of these
locations as temperatures bottom out in the low to mid 30s
around sunrise. The exception will be the coast and the
Portland/Vancouver metro where temperatures will stay a bit
warmer in the upper 30s to low 40s. After the chilly start
today, temperatures will warm well into the 60s across most of
the area this afternoon as a highly amplified upper level ridge
builds over the region from offshore. NBM probabilistic
guidance continues to give the Portland area around a 50/50
chance to reach 70 degrees this afternoon, with closer to a
10-20% chance elsewhere in the Willamette Valley. Do not
anticipate any further frost concerns tonight as overnight lows
increase into the 40s across most of the area. Saturday remains
on track to be the warmest day of the week as the ridge axis
moves directly overhead, with most interior valley locations
likely to reach 70 degrees (70-90% chance). The warmth will not
extend to the coast as continued marine layer influence keeps
those locations more mild into the weekend.

The warm and dry stretch comes to an end on Sunday as the ridge
shifts east of the Cascades and allows the next front to move
into the region, dropping temperatures back into the low to mid
60s and bringing the next round of widespread rain to the area
beginning Sunday afternoon. Expect seasonably mild and wetter
weather to then persist through the middle of next week as
ensemble clusters indicate upper level troughing over the NE
Pacific and Pacific NW. NBM guidance depicts a 15-20% chance of
thunderstorms across much of the area on Monday as colder air
arrives over the region in association with the upper level
trough. Otherwise, expect mostly benign weather through the end
of the period as daytime highs hover close to seasonal norms in
the upper 50s and precipitation remains sporadic and light
enough to minimize any hydro concerns. /CB

&&

.AVIATION...A ridge of high pressure building over the Pacific
Northwest will maintain predominately VFR thresholds under mostly
clear skies for all terminals through the TAF period. Clear skies,
calm winds, and a moist surface will favor areas of frost
development across the central and southern Willamette Valley
between 12-16z Fri. Exposed, elevated metal surfaces are more
likely to develop frost. There is also a 15-25% chance that fog
develops rather than frost in the central and southern Willamette
Valley, which would lead to LIFR VIS/CIGs. Any frost or fog that
develops this morning should dissipate after 16-18z Fri with
daytime heating. Expect easterly to northeasterly winds around
5-10 kt across all terminals today.

The KAST anemometer remains inoperative. Therefore, KAST TAF
amendments are limited to CIG and VIS.

PDX AND APPROACHES...VFR thresholds under mostly clear skies
through the TAF period with easterly winds around 10 kt or less
today. Frost and/or fog development is unlikely this morning as
conditions in the eastern Portland Metro are slightly warmer and
drier than the rest of the Willamette Valley. -Alviz

&&

.MARINE...High pressure building over the Pacific Northwest will
maintain benign marine conditions today into Saturday. With higher
pressure inland and lower pressure offshore, expect easterly to
northeasterly winds around 5 to 10 kt today. Seas remain around 3
to 5 ft at 8 seconds through Saturday.

Winds will shift southerly around 10 to 15 kt Saturday morning
ahead of the next approaching front. This front will push through
Saturday night into Sunday, strengthening southerly winds. There
is a 30 to 50 percent probability for Small Craft level wind gusts
up to 25 kt with the frontal passage Saturday night into Sunday
morning. A west-southwesterly swell will also push through the
waters during this time, building seas to 6 to 8 ft at 10 seconds
by late Saturday night and 11 to 13 ft at 17 seconds by Sunday
afternoon. This swell will increase the threat for sneaker waves
on Sunday.

Active weather continues early next week with a stronger front
forecast late Monday night into early Tuesday morning. Guidance
currently suggests a 40 to 60 percent probability for Gale force
wind gusts up to 35 kt with this stronger front. -Alviz

&&

.PQR WATCHES/WARNINGS/ADVISORIES...
OR...Frost Advisory until 9 AM PDT this morning for ORZ104-105-109-
     113>118-121-123>125.
WA...Frost Advisory until 9 AM PDT this morning for WAZ205-208.
PZ...None.

&&

$$

www.weather.gov/portland

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