Lake Oswego, Oregon 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

203
FXUS66 KPQR 252120
AFDPQR

Area Forecast Discussion
National Weather Service Portland OR
220 PM PDT Sat Jul 25 2026


.SYNOPSIS...Onshore flow will bring near average temperatures
with varying degrees of morning clouds and afternoon sunshine
for much of the next week. A series of weak fronts will bring
notable chances for light rain and drizzle to portions of the
north coast this afternoon and evening, Sunday and then again on
Tuesday.


&&


.DISCUSSION...Now through Saturday...Visible satellite imagery
reveals a small low pressure moving north-northeastward
off the Washington coast. Marine clouds have pushed across much
of the region except across the Cascades south of Mt Hood.
Doppler radar indicates light returns (rain) spreading onto the
north coast this afternoon. While rain reaching the ground has
been limited so far, we are expecting at least a few locations,
particularly across the higher terrain of Tillamook northward to
Pacific Counties to wring out a couple hundredths of an inch of
rain by later tonight. While not terribly impactful, south to
southwesterly winds will be the most unusual aspect of this
storm system with winds currently gusting near 30-35 mph along
portions of the coast and between 15-30 mph in the Willamette
Valley. Winds should subside this evening as the lower
atmosphere stabilizes and the wind field aloft weakens.

A secondary stronger front is currently out near 130W off the
Pacific Northwest coast. Models are in good agreement it will
shift towards the region, but there remains quite a bit of
uncertainty in how much it will hold together as it moves
towards the region, and more importantly, whether or not it
will push into our northwestern zones or stall offshore. At this
point, there is a sharp gradient in rain chances between even
northern Pacific County and southern Clatsop County on Sunday.

Height fields build a touch going into Monday, which will reduce
rain chances and allow for high temperatures to climb more
solidly into the 80s for inland valleys. Another weak front is
slated to clip the Pacific Northwest Tuesday as a shortwave
trough lifts northeastward into British Columbia. Rain chances
will once again most likely be limited to the far north Oregon
and Washington coast, but there is a 30% chance at least some
light rain reaches the Kelso/Longview area. There is a just a
10% chance that rain reaches the Portland/Vancouver area on
Tuesday with rain probabilities decreasing even more towards
Salem and Eugene. Regardless, this passing storm system will
reinforce marine clouds and cooler temperatures with high
temperatures likely falling several degrees on Tuesday relative
to Monday.

In general, ensembles are in general agreement that our 500 mb
height field will increase midweek with the end result being a
warming trend late in the work week. Around 30-40% of the
global ensemble guidance suggests a shortwave trough will dampen
the weak ridging in place late in the week and allow another
weak front to graze our northwestern coastal zones around next
Saturday. /Neuman


&&


.AVIATION...Through 18z Sunday...An area of low pressure offshore
will lift to the north-northeast through the period. This will place
the region under moist south-southwesterly flow with lots of marine
clouds spreading across the region. This will result in
predominantly a mix of IFR and MVFR conditions along the coast with
a high probability that KONP drops into an extended period of
LIFR/IFR conditions later this afternoon and evening. Farther
inland, marine stratus appears most likely to end up just above MVFR
thresholds. Nonetheless, there is a 20-30% chance at most inland
terminals of ceilings lowering into high end MVFR thresholds
overnight, primarily after 09z Sunday. It should be noted that gusty
south-southwest winds will abruptly appear at many sites over the
next 1-2 hours with gusts to around 15 kt for inland sites and to
near 25 kt for coastal sites. Winds should ease around 00-03z
Sunday.

KPDX AND APPROACHES...Moist onshore flow will produce plenty of
ceilings, but conditions should generally remain VFR through at
least 09z Sunday. Thereafter, there is a 20-30% chance for MVFR
ceilings at any given hour as marine clouds lower and/or spread
inland. Gusty south to southwest winds up to 15-20 kt will primarily
occur between now and 00z Sunday before subsiding this evening.
/Neuman


&&


.MARINE...A weak low pressure is lifting north-northeastward
off the Washington coast this afternoon. This storm system has
resulted in Small Craft Advisory level wind gusts of 25 kt and
steep seas across portions of the water so far today. There
remains about a 10% chance of wind gusts rising briefly into the
30-35 kt range within 20 NM of the coast, but this appears less
and less likely based on the latest observations and trends.
Expect winds to drop below advisory level thresholds upon
frontal passage. This appears most likely to occur between 4-8pm
Saturday. Seas will take several hours thereafter to subside,
though.

Another weak front will approach the waters late Sunday into
early Monday with just a 30-40% chance that the far outer
waters beyond 40 NM north of Cape Falcon will see southerly wind
gusts at least briefly rise into the 22-25 kt range. Another
front will push towards the waters late Monday into Tuesday.
While this front stands a better chance (~50-60%) of bringing
southerly 22-25 kt wind gusts to all of the waters north of Cape
Falcon, the probability those winds extend as far south as Cape
Foulweather is just 10-20%.

Winds appear likely to return to a more typical Summertime
northerly wind pattern during the latter half of next week.
There is a 30-40% chance another weak front moves towards the
Pacific Northwest and turns winds southerly next Saturday-ish.
Once we get past the steep seas of today, seas will generally be
in the 3-5 ft range for much of the next week unless some of
the stronger wind scenarios mentioned above come to fruition.
/Neuman


&&


.PQR WATCHES/WARNINGS/ADVISORIES...
OR...None.
WA...None.
PZ...Small Craft Advisory until 8 PM PDT this evening for PZZ210-
     251>253-271>273.
&&


$$

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