Cedar Mill, Oregon 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

177
FXUS66 KPQR 191013
AFDPQR

Area Forecast Discussion
National Weather Service Portland OR
313 AM PDT Thu Jun 19 2025

.SYNOPSIS...Dry weather today with seasonable temperatures and
northwesterly winds. Friday to Saturday, a low pressure system
will return widespread rain showers across northwest Oregon and
southwest Washington. This system will also lead to a 15-25%
chance for thunderstorms Friday afternoon/evening, which could
produce lightning, heavy downpours, gusty outflow winds, and/or
small hail. Drier and warmer weather returns Sunday into early
next week.

&&

.SHORT TERM...Now through Saturday Night...Expect dry weather
with seasonable temperatures today across northwest Oregon and
southwest Washington. We`ll see a bit of sun, but expect mid to
high level cloud cover to gradually increase today ahead of the
next system. Afternoon highs are forecast in the low to mid 70s
across interior lowland valleys and upper 50s to low 60s along
the coast. Surface high pressure will maintain northwesterly
winds across the area, generally around 5-10 mph. An exception
will be the eastern Columbia River Gorge and Upper Hood River
Valley, where breezy westerly winds are forecast to gust to
25-35 mph. Winds through the Gorge will peak in the
afternoon/evening when pressure gradients are tightest.

Much cooler and wetter weather returns Friday to Saturday as an
upper level trough dips into the Pacific Northwest from the
northeast Pacific. High temperatures on both days are forecast
well-below normal, peaking in the upper 50s to low 60s along
the coast and interior lowland valleys. Many locations will
likely receive a soaking rain with this system along with winds
turning more westerly to southwesterly. The initial surface
front associated with the upper trough will push through early
Friday morning, bringing widespread showers. A secondary
shortwave will then arrive on Saturday as the upper level trough
moves directly overhead, maintaining the wet weather.

Will note that there is a 15-25% chance for thunderstorms
Friday afternoon/evening. Cold air aloft from the trough will
increase atmospheric instability and steepen lapse rates.
Combined with abundant moisture and lift, this will be favorable
for the development of thunderstorms or heavy showers. Any
passing thunderstorms could produce lightning, downpours, or
gusty outflow winds. Can`t rule out some small hail either as
model soundings are showing CAPE/instability tapping into the
hail growth zone (-10 to -30 deg C layer). When thunder roars,
go indoors! Thunderstorm chances decrease on Saturday to around
5-10% across the area as the entire atmospheric profile cools
down and the cloud layer deepens.

The bulk of the precipitation is forecast from early Friday
morning to early Sunday morning. 48-hour probabilities for
0.50" of rain or more from 5 AM Friday to 5 AM Sunday has
increased to around 60-80% for most interior lowland valleys
and 80-90% along the coast and high terrain. For 1" or more of
rain in 48 hours during this same time period, probabilities are
around 15-25% for most interior lowland valleys and 50-70%
along the coast and high terrain. The current rain total
forecast calls for 0.70-1" across the Willamette Valley and
southwest Washington lowlands, 0.70-1.50" along the coast and
Coast Range, and 1-1.75" across the Cascades and foothills.
Given the showery nature of precipitation this weekend, some
locations may significantly overperform forecast rain amounts
while other locations underperform. Either way, these rain
amounts are pretty substantial for this time of year.    -Alviz

&&

.LONG TERM...Sunday through Wednesday...Shower chances linger
early Sunday morning, but conditions will gradually dry up
throughout the day as the upper level trough exits eastward.
High pressure will re-build, returning sunnier and warmer
conditions by Sunday afternoon with highs forecast to rebound
to the low 70s. Most ensemble members continue to suggest high
pressure building heading into early next week, leading to a
further warm-up. NBM guidance suggests a 70-90% chance that
temperatures exceed 80 degrees across the Willamette Valley
Monday to Wednesday.       -Alviz

&&

.AVIATION...Satellite imagery at 10z Thursday shows pockets of
stratus forming across NW Oregon and SW Washington. For inland
locations, current observations remain VFR, even in the forming
stratus deck, though there`s a 10-30% chance of occasional MVFR
ceilings through 16z Thursday. Along the coast, there`s a 60-80%
chance of MVFR ceilings from KTMK north, including KAST, and a
20-30% chance of occasional MVFR ceilings south of KTMK, including
KONP. Light north to northwest winds increase after 18-21z
Thursday to 10-15 kts with gusts to 20-25 kts, decreasing after
04-06z Friday. A frontal system begins approaching the region
after 06z Friday, bringing scattered showers to the coast by
08-12z Friday, lowering ceilings along the coast to MVFR/IFR, and
causing winds across the region to shift to west to southwest.

PDX AND APPROACHES...Predominately VFR conditions expected except
for a 10-20% chance of MVFR ceilings through 16z Thursday.
Northwesterly winds 5-8 kts increase after 21z Thursday to 10-15
kts with gusts 20-25 kts through 06z Friday.      -HEC

&&

.MARINE...Weak high pressure builds over the coastal waters today,
producing north to northwest winds 5-15 kts with occasional gusts
up to 20 kts this evening. A modest westerly swell will build
seas to 5-6 feet today. An unseasonably deep upper level low
pressure system will bring multiple surface frontal systems and
unsettled weather Friday into Saturday. Winds shift westerly
tonight ahead of the first frontal system on Friday, then increase
to near small craft criteria late Friday night into Saturday, and
waves build to 7-9 feet by Saturday. Additionally, there is a
chance of thunderstorms on Friday.      -HEC

&&

.PQR WATCHES/WARNINGS/ADVISORIES...

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

&&

$$

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