Lake Oswego, Oregon 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

683
FXUS66 KPQR 190014 AAA
AFDPQR

Area Forecast Discussion...UPDATED
National Weather Service Portland OR
514 PM PDT Thu Jun 18 2026

Updated aviation discussion.

.SYNOPSIS...Warmer than normal and dry conditions expected to
continue through the middle of next week. Confidence is
increasing that hot temperatures peaking Monday and Tuesday will
support Moderate to Major HeatRisk, however there remains
uncertainty in the temperature forecast at this time.

&&

.DISCUSSION...Tonight through Wednesday...There has been very
little change in the forecast since the last package. An upper-
level ridge axis currently centered over the northeastern
Pacific will shift eastward and inland through Saturday
bringing warmer temperatures with a typical summertime northerly
wind pattern. Temperatures peak on Friday for inland locations
as troughing aloft supports a return to stronger onshore flow
Friday into Saturday. As daytime highs reach to near 70 degrees
on the coast and 80s to near 90 degrees on Friday, this will
result in Minor HeatRisk for most areas within our CWA and
locally Moderate HeatRisk from Salem, OR northward towards
Kelso/Longview, WA and across the greater Portland/Vancouver
Metro area. Aforementioned troughing and onshore flow will yield
cooler temperatures near 60 degrees for Friday along the coast,
with persistent onshore flow will help to cool inland locations
down, which will bring daytime highs into the upper 70s to low
80s on Saturday.

Ensemble guidance remains in good agreement that renewed ridging
will develop from Sunday into early next week, raising the
chances for another period of hot temperatures for the start of
next week with the warmest days looking to be Monday and
Tuesday. Uncertainty in the position and amplitude of the ridge
axis remain, leading to uncertainty in the temperature
forecast, but given the model consensus, there is 85-95%
probability for daytime highs to exceed 90 degrees F throughout
inland valleys Monday and Tuesday. The chances to exceed 95
degrees similarly peak at generally around 40-85% chance Monday
and Tuesday, while the chances to reach 100 degrees reach 25-40%
only from Salem, OR north to Vancouver, WA on Monday and 20-40%
from Corvallis, OR north to Kelso/Longview, WA.

These daytime temperatures combined with overnight lows in the
upper 50s to low 60s support widespread Moderate HeatRisk inland
both Monday and Tuesday, with the coverage of Major HeatRisk
largely dependent on the occurrence of overnight low temperatures
falling into the mid 60s. Looking beyond, towards the middle of
next week. Long-range guidance is favoring a cooling trend beginning
Tuesday night and continuing into later next week, but there`s
still a 30-50% chance for temperatures above 90 degrees to
persist on Wednesday. It should also be noted that there are no
strong signals for any precipitation through the entire
forecast. -42/03

&&

.AVIATION...Dry with widespread VFR conditions over the next 24
hours. Northerly winds transition to the west-northwest after 10Z
Fri. Clouds will be minimal inland, but along the coast, the
addition of westerly flow will cause CIGs to drop to MVFR levels.
There is a 40% chance of IFR conditions along the coast from KTMK
southward, and some hints of lower clouds are already starting to
develop around KONP though have been bouncing between BKN and SCT.


KPDX AND APPROACHES...VFR with northerly winds. Periods of gusty
winds up to 20 kt until 04Z Fri then will become light overnight.
-27

&&

.MARINE...High pressure offshore will maintain a summertime
pattern through the remainder of the week. Diurnally driven
northerlies are expected to peak each afternoon and evening
through at least Friday but there will be a slightly more
westerly wind pattern in the inner waters. Winds are expected
to peak each afternoon and evening with gusts to 25-30 kts,
decreasing a bit in the late overnight to morning hours. Winds
will likely ease over the weekend as high pressure weakens and
low pressure moves into northwest WA, turning winds more
northwesterly on Saturday.

Seas around 9 to 11 ft at 9-10 seconds persists into early
Saturday as a fresh northwesterly swell persists across the
coastal waters. For those traveling across the Columbia River
Bar, strong ebbs are expected around sunrise Friday morning. Seas
are expected to subside later Saturday into Sunday. -27/03

&&

.PQR WATCHES/WARNINGS/ADVISORIES...
OR...None.
WA...None.
PZ...Small Craft Advisory from 5 AM to 10 AM PDT Friday for PZZ210.
     Small Craft Advisory until 5 AM PDT Friday for PZZ251>253.
     Small Craft Advisory until 5 AM PDT Saturday for PZZ271>273.
&&

$$

www.weather.gov/portland

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