Lake Oswego, Oregon 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

364
FXUS66 KPQR 061804
AFDPQR

Area Forecast Discussion
National Weather Service Portland OR
1104 AM PDT Tue Oct 6 2026

Updated aviation discussion.

&&

.SYNOPSIS...Unseasonably warm and dry weather persists through
Thursday with areas of early morning valley and coastal fog.
Weak offshore flow will bring slightly warmer temperatures
Wednesday and Thursday, before a trough brings a return to
cooler temperatures with chances for light rain Friday into
Saturday. Cool nights will bring chances for morning frost in
rural valleys away from urban cores this weekend into next week.

&&

.SHORT TERM...Now through Thursday Night...The recent stagnant
pattern will continue to bring similar weather to the region
through much of the workweek. A broad but low amplitude upper
ridge will steadily build over the West Coast, supporting the
development of weak thermal troughing along the coast. This
pattern will see temperatures steadily rise through the week to
afternoon highs in the upper 70s to mid 80s in interior valleys
on Thursday. Daily records on Thursday at most climate sites
appear to be out of reach with a 5% chance or less of tying or
surpassing existing record values, except for slightly higher
chances of 15-20% at Salem and Eugene. See the Climate section
below for a full list of record temperatures for October 8.

Periods of early morning valley fog or low stratus will also
likely reoccur in the coming days west of the Cascades as
conditions remain ideal for efficient radiative cooling during
increasingly long nights while high pressure aloft compresses
the surface layer, pushing cloud bases down to near the surface.
Morning commuters - whether traveling by car, bike or foot -
should expect to encounter rapidly changing visibility and
should take actions to improve their visibility to others.

The offshore-oriented pressure gradient has trended weaker in
recent forecast updates, with short-range ensembles favoring
a difference of only -1 to -2 mb between Portland and The
Dalles, although a handful of members still highlight a chance
for a stronger gradient up to -4 mb. In the mean case near -1.5
mb, east winds tonight and Wednesday night in the Cascades and
foothills would be light, with peak wind gusts of only 15-20 mph
in the western Columbia River Gorge and nearby terrain. -36


.LONG TERM...Friday through Monday...A strong ensemble
consensus continues to support upper-level troughing returning
to the region from Friday through this weekend. The large
majority of members bring rain into the Oregon and Washington
coasts late Friday morning or early Friday afternoon, reaching
inland to the I-5 corridor by Friday mid- afternoon. Chances for
light rain showers persist into Saturday as the trough
elongates and ultimately looks to pinch off into a closed low
which drifts south over California. Mean 48-hour rainfall totals
from Friday through Saturday night are generally less than 0.1
inches, higher to the north and on western slopes of terrain,
and lower to the south and on eastern slopes. There is a 10%
chance of up to 0.2-0.4 inches of rain at low elevations, and
higher amounts in excess of 0.5 inches in areas of terrain.

As the core of cold air within the upper trough moves overhead
this weekend, temperatures will fall to much more seasonable
levels with afternoon highs largely in the 60s. Morning lows
will similarly cool, yielding increasing chances for frosty
temperatures in the low to mid 30s from Friday night through
Monday night. Frost may occur as early as Friday night in the
Upper Hood River Valley, with 30-40% chances of falling to 36F
or lower near Parkdale and Dee. Saturday and Sunday nights look
to be the coldest, with nearly 10% chances for frost in Hood
River proper, 50% near Odell, and 90% in Parkdale and Dee.
Elsewhere, frost chances reach 15-35% in north Oregon Coast
Range valleys, the central and southern Willamette Valley away
from urban cores, and the Cascade foothills from Cowlitz County
south to Lane County on Sunday night. Chances for a true freeze
peak Sunday night at 50-60% near Parkdale and Dee and 15-20%
near Odell in the Upper Hood River Valley, and at 20-35% along
the OR-58 corridor between Eugene and Oakridge. Those with
agricultural interests or home growers with sensitive outdoor
plants should continue to monitor the forecast this week.

As the closed upper low then drifts to the south, rising
heights aloft in the Pacific Northwest could again favor a
drying and warming trend early next week. -36

&&

.AVIATION...Through 18z Wednesday...The widespread stratus that
formed through inland valleys and along the coast Tuesday morning is
beginning to dissipate fairly rapidly as of 1745z Tue. Most inland
and coastal terminals with MVFR/IFR/LIFR conditions are expected to
improve to VFR by 18-20z. Winds increase and turn north to
northwesterly this afternoon, up to 5-10 kts inland and 10-15 kts
along the coast with gusts up to 20 kts. Winds decrease by 03-06z
Wed, turning more east to northeasterly along the western Cascades,
Coast Range, and into the coast into Wednesday morning. These
easterly winds should limit the amount of marine air able to
infiltrate the coast and inland, likely preventing another round of
widespread stratus and fog Wednesday morning. There are pockets of
10-20% chances of MVFR/IFR conditions along the coast near KNOP and
in the Portland metro area, with 20-40% chances in the SW Washington
lowlands including KSPB, mainly after 13z Wed for inland areas.

KPDX AND APPROACHES...VFR conditions have returned and are expected
to prevail through the TAF period. There`s a low (10-20%) chance of
stratus returning MVFR conditions 13-18z Wed. Northwest winds 5-7
kts today, becoming light after 03z Wed. -03

&&

.MARINE...High pressure offshore will continue to maintain
diurnal northerly winds through the week with peak afternoon and
evening wind gusts of 20-25 kt today through Thursday. Small
Craft Advisories are now in effect across the waters from 2 PM
PDT this afternoon into tonight. Expect largely wind-driven seas
around 4-6 ft through midweek, with a west-northwest swell of
3-4 ft at 10-12 seconds. High pressure aloft will also support
areas of dense fog developing nightly through the morning hours
as cloud bases are compressed down to the surface. Dense Fog
Advisories for visibility of 1 NM or less also remain in effect
across the waters until noon PDT today.

More active marine conditions are likely in the latter half of
the week as troughing over the Gulf of Alaska generates a
building northwest swell. Seas will increase to 7-10 ft
Wednesday into Thursday, with the longer-period swell also
supporting a moderate risk for sneaker waves at the coast.
Chances for rain return to the region Friday into the weekend,
though rain amounts are not expected to be impactful. -36/03

&&

.CLIMATE...
Daily record high temperatures for October 8

LocationValue (Year)

Astoria81 (1951, 1971)
Portland Int`l87 (2022)
Vancouver, WA89 (1891)
Hillsboro89 (2022)
McMinnville88 (2022)
Salem84 (1971, 2022)
Eugene83 (1934, 1943)

&&

.PQR WATCHES/WARNINGS/ADVISORIES...

OR...None.

WA...None.

PZ...Dense Fog Advisory until noon PDT today for PZZ210-251>253-
271>273.

     Small Craft Advisory from 2 PM this afternoon to 2 AM PDT
     Wednesday for PZZ210.

     Small Craft Advisory until 2 AM PDT Wednesday for PZZ251>253.

     Small Craft Advisory until 5 AM PDT Wednesday for PZZ271>273.

&&

$$

www.weather.gov/portland

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