West Linn, Oregon 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

235
FXUS66 KPQR 302144
AFDPQR

Area Forecast Discussion
National Weather Service Portland OR
244 PM PDT Sun Mar 30 2025

&&

.SYNOPSIS...Ridging builds into the area bringing a brief break
in precipitation as well as a slight warming trend today. This
will be short lived as a broad area of low pressure will bring
cool and wet conditions back to the region through the latter
part of the upcoming week. Another shortwave ridge looks to
develop Wednesday evening/Thursday which will bring warm and dry
conditions once again.

&&

.DISCUSSION...Today through Saturday...A pattern change is currently
occurring as troughing begins to build back into the region, and rain
is currently pushing into the region from the south. This marks the
beginning of a few cool and showery days as an offshore low spins a
few rounds of moisture between now and Thursday.

The initial wave of moisture is currently pushing into the area,
though QPF looks fairly low and rainfall will likely be
non-impactful. Between 5pm Sun to 5pm Monday, only around a 40-50%
chance of lowland rainfall in the Willamette Valley and SW Washington
lowlands to exceed 0.25 inches. At the coast and Coast Range,
slightly higher accumulations closer to 0.5-1.0 inches is expected
during this period. Snow levels are currently around 5000 feet, but
will be falling to around 2500-3000 ft by the end of Sunday night. As
such, Cascades snow accumulation can be expected with this initial
wave of moisture. That said, accumulations are expected to remain
below advisory level, though snow accumulations will continue in the
mountains throughout the week. Initial snow between now and 5pm
Monday looks to be only around 3-4 inches at the central Oregon
Cascades passes, even less at the northern Oregon Cascades.

Easterly gusts through the Columbia Gorge are currently around 30-35
kts, including the Portland metro area. These will continue to
decrease through this evening and tonight, shifting southerly with
gusts up to 10 kts by around midnight tonight. Afterwards winds
remain onshore and fairly weak through Thursday. Additionally, some
weak instability is expected at the coast beginning this evening,
enhanced in part due to orographic lift. This will produce a 10-15%
chance of some weak isolated thunderstorms tonight at the coast.
Monday sees showers continuing, with thunderstorms at the coast
remaining possible (10-15% chance) through evening hours.

Heading into Monday night, the main low passes south of the area
(near the OR/CA border). Tuesday and Wednesday see generally
unsettled conditions remaining, with weak showers at times.
Accumulations will be generally negligible. Daytime high temperatures
generally around the mid 50s for most inland locations, closer to the
low 50s at the coast.

Thursday through Saturday look to be very similar to each other
as a shortwave ridge builds across the region. Daytime highs
will starting the 50s on Thursday and warming around 5-7
degrees each day with daytime highs in the upper 60s to low 70s
expected by Saturday. /JLiu/42

&&

.AVIATION...Light rain is now in progress across much of the
region with mainly VFR conditions late this afternoon. As the bulk
of the stratiform rainfall moves through the next several hours
MVFR cigs/vis cannot be ruled, especially along the coast
including AST/ONP and in the southern Willamette Valley. Beyond
this points all sites could see brief MVFR cigs and vis in
heavier rain showers this evening through Monday. Expect easterly
winds, currently breezy (as of 22z) at some locations like KPDX,
and KTTD to turn more southerly by the evening after the south to
north frontal passage, although due to a persistent offshore
pressure gradient KTTD may see persistent easterly component.


PDX AND APPROACHES...VFR conditions generally prevail through
Monday. A frontal boundary has brought light rain to the terminal
expected to break to showers early this evening. But, low-end VFR
cigs at 4-7 kft and unrestricted vis are expected to hold through
the evening. Then we`ll see around 30% chance of MVFR cigs in
showers focused late tonight through Monday morning. Easterly
winds likely shift southerly around 00-03z this evening with
occasional gusts up to 15-25 knots decreasing tonight.
-Schuldt

&&

.MARINE...A frontal system is beginning to move across the
coastal waters this afternoon as winds turn from easterly to more
southerly and increase over the next several hours. The latest
high resolution guidance indicates a moderate to high chance
(60-80%) for low-end gale force wind gusts across the inner and
outer waters south of Ocean Park, WA, including the Columbia River
Bar through tonight. Thus, left the Gale Warning currently in
place across all the coastal waters even given the more marginal
nature of the set-up. Winds decrease somewhat by early Monday
morning, though remain elevated with gusts up to 30 kts through
Monday afternoon as another low pressure system approaches the
waters. The Small Craft Advisory was extended out through Monday
evening, and may need to be drawn out further for at least the
inner and outer waters south of Cape Falcon where higher seas and
winds may persist.

Expect seas will build again into the low teens late tonight
driven by the marginal gale force winds. These winds will remain
elevated through Monday into Tuesday as a fresh southwesterly
swell arrives, keeping seas up into the 9-14 ft range. Seas then
decrease late Tuesday into Wednesday, leveling out around 5 to 7
ft at 9 seconds by Wednesday afternoon, remaining there for the
middle to end of the week as north to northwesterly flow resides
aloft, keeping winds fairly low, and the prevailing swell low as
well.  -Schuldt/HEC

&&

.PQR WATCHES/WARNINGS/ADVISORIES...

OR...None.
WA...None.
PZ...Gale Warning until 2 AM PDT Monday for PZZ210-251-271.

     Small Craft Advisory from 2 AM to 11 PM PDT Monday for PZZ210-
     251>253-271>273.

     Gale Warning until 2 AM PDT Monday for PZZ252-253-272-273.
&&

$$

www.weather.gov/portland

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