261
FXUS66 KPQR 222224
AFDPQR

Area Forecast Discussion
National Weather Service Portland OR
324 PM PDT Wed Jul 22 2026

.SYNOPSIS...Showers and storm chances continue through the
evening and into the overnight hours. Frequent lightning and
gusty winds are possible with any storm that develops.
Temperatures Thursday and Friday will remain warm but not as
warm as the previous few days. A cooler and drier trend expected
this weekend with temperatures closer to normal.

&&

.SHORT TERM...Now through Thursday...Hot conditions and
thunderstorms continue to be the two main threats for today.
Temperatures range from the mid 90s around the Portland metro
and northern lowland locations while temperatures in the upper
70s to mid 80s are common across the Willamette Valley where
cloud cover and precipitation have been more prevalent. Dew
points across the area are in the upper 50s to mid 60s which is
contributing to the unpleasant, muggy conditions. A Heat
Advisory remains in effect until 11 PM for the
Portland/Vancouver metro, Columbia River Gorge, northern
Willamette Valley, and the Lower Columbia and Cowlitz Valleys
into the southwest Washington Foothills. Luckily, today is the
last of the temperatures in the 90s, at least for the near
future.

An upper level closed low remains offshore over the far northeast
Pacific and is slowly drifting northwest. This is supporting
south to southeast flow in the midlevels which is increasing
monsoonal moisture across the area. Hi-res models depict an
environment conducive to elevated convection with little
surface CAPE but MUCAPE of 500-1000 j/kg west of the Cascades
and slightly higher up to 1500 j/kg across the higher terrain.
This indicates that the CAPE is elevated and will generally need
a forcing mechanism that`s not surface heating for convective
initiation. In this scenario, south to southeast flow over the
area will produce orographic lift over the higher terrain. PWAT
values over the area range from 1.0-1.5 inches but model
soundings indicate dry air at the low levels. Given these two
variable are at odds, there is both potential for decent local
rainfall but also a chance for dry convection. SPC has also
added a marginal risk for severe thunderstorms over the central
ORegon Cascades for damaging wind potential. DCAPE values over
the area are around 700-900 j/kg with an inverted-V sounding
which indicated wind potential. Showers and storms will be
possible through the evening, decreasing overnight from south to
north. The areas including the Portland metro northward hang
onto a low (10- 15%) chance into Thursday morning.

Conditions trend cooler and less active on Thursday as the upper
level ridge weakens a bit. Highs will still be toasty on Thursday
with mid to upper 80s expected across the interior lowlands and 60s
along the coast. Precipitation chances decrease as available
moisture decreases though convection could graze right along
the Cascade crest in Lane and Linn counties during the
afternoon.
-19

.LONG TERM...Thursday Night through Wednesday...Temperatures on
Friday are expected to be similar to Thursday as the upper
level pattern remains largely unchanged. Heading into the
weekend, a pattern change is expected with a trough dropping
south from the Gulf of Alaska on Saturday. This will allow
onshore flow to re- establish itself and bring a more noticeable
cooling trend late this week, along with a return to more
marine influence and night/morning cloud cover. This will also
support a trend toward more normal temperatures in the upper 70s
to low 80s inland along with overnight lows in the 50s. There
is no notable precipitation signal outside of low potential for
light showers along the coast on Saturday. -19

&&

.AVIATION...Through 18Z Thursday...Showers and isolated
thunderstorms have developed across central and northern Oregon
and will track northward through the afternoon and evening hours.
Chances will decrease by 00-03z Thu south of KSLE then by 09-12z
Thu south of KPDX. All shower and thunderstorm activity should end
by 18z Thu. Confidence in the occurrence of thunder is too low at
any one terminal to include in TAFs at this time, but heavy
showers may briefly result in MVFR/IFR vis if they pass over a
terminal. Showers may also produce gusty or erratic winds nearby.

Winds have shifted westerly. Along the coast, expect winds up to
10-15 kts with gusts up to 20-25 kts. Winds inland increase to
8-10 kts after 23z Wed, decreasing around 06z Thu. Outside of
showers, VFR conditions continue at most terminals with some haze
from wildfire smoke. The exception is KONP where there is a 60-75%
chance of marine stratus continuing IFR/LIFR conditions through
the TAF period. Stratus is forecast to return to the general coast
by 00-03z Thu with a 50-75% chance of IFR/LIFR conditions
continuing through the TAF period. The west winds will allow for
an inland push of marine air, producing a 50-70% chance of MVFR
ceilings developing along the Columbia River south into the
Portland metro area and around KEUG between 11-15z Thu. There`s a
25-40% chance elsewhere in the Willamette Valley.

Afternoon temperatures are forecast to approach 100 degrees at
many inland terminals this afternoon; be aware of high density
altitude which may reduce aircraft performance.

KPDX AND APPROACHES...Chances for showers or an isolated
thunderstorm begin around 21z, increasing after 00z Thu. The most
likely terminal impacts are frequent lightning, gusty/erratic
winds, and locally heavy downpours which may briefly restrict vis
to IFR/MVFR levels. Otherwise, VFR conditions persist with hazy
conditions from smoke. There`s a 50-70% chance of MVFR ceilings in
marine stratus developing after 11z Thu. West winds around 8-10
kts, decreasing by 04-06z Thu. -03

&&

.MARINE...North to northwest winds over the coastal waters are
shifting to south to southwesterly winds this afternoon as weak
low pressure remains over the waters. Winds will remain light
less than 10-15 kts. Seas will be 3-6 ft at 8-9 seconds. These
conditions will continue through the weekend.

Showers and thunderstorms continue across the central and northern
waters into the overnight hours. Showers and thunderstorms could
redevelop Thursday morning. There could be frequent lightning and
gusty and erratic winds with any thunderstorm that forms. -03

CLIMATE...

Daily record high minimum temperatures for July 22
Astoria 62 (2007)
Vancouver, WA 74 (2006)
Portland Int`l 74 (2006)
Hillsboro 73 (2006)
McMinnville 73 (2006)
Salem 74 (2006)
Eugene  71 (2006)

Daily record high maximum temperatures for July 22
Astoria 88 (1891)
Vancouver, WA 98 (1928)
Portland Int`l 98 (1978, 2004)
Hillsboro103 (1938)
McMinnville102 (1928)
Salem102 (1928, 1978)
Eugene101 (2006)

&&

.PQR WATCHES/WARNINGS/ADVISORIES...

OR...Heat Advisory until 11 PM PDT this evening for ORZ108>115-
     120>122.

WA...Heat Advisory until 11 PM PDT this evening for WAZ204>210.

PZ...None.

&&

$$

www.weather.gov/portland

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