729
FXUS66 KPQR 211759 AAA
AFDPQR

Area Forecast Discussion...UPDATED
National Weather Service Portland OR
1059 AM PDT Thu May 21 2026

...Updated aviation discussion...

.SYNOPSIS...Dry and warm weather is expected across the region
through the weekend with high pressure over the NE Pacific spreading
east over the Pacific NW. Rain and cooler temperatures return to the
area late Sunday into early next week, which could impact any
outdoor Memorial Day plans.

&&

.DISCUSSION...Today through Wednesday...The upper level ridge that
has been persistent over the NE Pacific will slide across the
Pacific NW today as shortwave trough over the Gulf of Alaska sends a
weak impulse toward the region. 850 mb temps rise to around 12-13C
this afternoon while a weak surface thermal trough pushing into the
Willamette Valley this morning shifts over the Cascades. With drier,
offshore flow in the foothills, there are lower chances for morning
stratus developing. This should allow mostly sunny skies to help
warm surface temperatures into at least the lower 80s for inland
areas today, which is around 10-15 degrees above normal for today.
Record high temps are generally in the upper 80s to mid-90s through
the Memorial Day Weekend, so we are not expecting any record high
temps to be broken at this time.

Conditions are expected to remain dry through the end of the week
and into the weekend as high pressure continues across the region.
The upper level ridge re-amplifies over the NE Pacific tonight and
sags back over the PacNW region on Friday. Broad upper level ridging
on Friday becomes more zonal aloft Saturday into Sunday. Expect a
slight cooling trend in temperatures through the weekend, but still
likely to remain above seasonable averages. Coastal locations will
experience a brief warmup today into the 60s to lower 70s before
onshore flow brings typical temperatures there.

There remains good agreement that Sunday will remain mainly dry and
warm, though could begin to see increasing cloud cover ahead of an
approaching weather system. About 90% of ensemble members indicate a
frontal system will push into the PacNW sometime late Sunday night
into Monday, with chances of rain increasing for Monday, followed by
showers into Tuesday. Some uncertainty still remains in the general
timing of rain as well as rain totals, but latest consensus is that
rain will hold off until at least late Sunday night along the far N
OR and SW WA coast, then spread southeast Monday morning.
Temperatures will also drop substantially Monday and Tuesday with
high temperatures in the lower to mid 60s for the interior lowlands.
Conditions are likely to rebound back to seasonable norms by the
middle of next week, though some uncertainty remains due to low
chances of precipitation.   DH/03

&&

.AVIATION...High pressure over the area will maintain VFR
conditions with clear skies for Willamette Valley terminals through
the entire TAF period. Along the coast, marine stratus has burned
off and will briefly maintain VFR conditions with clear skies
through this evening. Tonight, marine stratus re-develops along the
coast and will lead to a 40-60% chance for IFR/MVFR CIGs or lower at
any given hour for KAST/KONP between 09-17z Fri. Northerly to
northwesterly winds today with gusts up to 20-25 kt along the coast
and central/southern Willamette Valley. Elsewhere, winds generally
under 10 kt. Winds weaken overnight as pressure gradients ease.

KPDX AND APPROACHES...VFR with clear skies through the TAF period.
Northwesterly winds 5-10 kt. No impacts expected.      -10

&&

.MARINE...High pressure offshore will maintain breezy northerly
winds through the end of the week. The strongest winds are
expected during the afternoon and evening periods as the surface
thermal trough strengthens over the northern CA/southern OR coast.
Small Craft Advisories remain in effect for the waters south of
Cape Falcon through tonight for northerly wind gusts up to 25 kt.
Will note that there may be a brief lull in the winds between
5-11 AM Thursday for the inner water and northern outer water
zones before increasing again this afternoon. Gusty northerlies
are again likely south of Cape Falcon on Friday. Seas 6 to 9 feet
are expected across all waters through this weekend. The summer-
like pattern is expected to break down Sunday night as a front
approaches the waters and returns southwesterly winds by Monday.
                                                -10/DH

&&

.PQR WATCHES/WARNINGS/ADVISORIES...

OR...None.
WA...None.
PZ...Small Craft Advisory from 7 AM this morning to noon PDT today
     for PZZ210.

     Small Craft Advisory until 5 AM PDT Friday for PZZ252-253-
     271>273.

&&

$$

www.weather.gov/portland

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