490
FXUS66 KPQR 062254
AFDPQR

Area Forecast Discussion
National Weather Service Portland OR
352 PM PDT Sat Jun 6 2026

.SYNOPSIS...Numerous showers and isolated thunderstorms Saturday
afternoon will quickly dissipate from west to east Saturday evening.
Weak high pressure will bring mainly dry conditions Saturday night
through at least Sunday afternoon. Scattered light showers return
late Sunday evening/night before widespread steady rain arrives on
Monday (85-95% chance). Steady rain will then transition to
off-and-on showers Monday evening and continue through Wednesday,
maintaining cooler than average temperatures. Trending much warmer
and drier June 11-15 with increasing heat concerns next weekend,
especially for inland valleys.

&&

.DISCUSSION...Saturday afternoon through Friday night...Radar,
satellite, and surface weather observations from Saturday afternoon
showed numerous heavy showers and isolated thunderstorms over
southwest WA and northwest OR. The strongest showers and storms are
producing brief heavy downpours, small hail up to the size of peas,
and gusty outflow winds up to around 30-35 mph. Cloud to ground
lightning will also pose a safety hazard for any thunderstorm that
develops. Areas that have observed repeated heavier showers or storms
have picked up another from 0.2-0.9 inches of rain over the past 6-12
hours. Despite the heavy rain rates with the strongest cells, these
showers and storms are moving too fast to warrant a threat of
flooding as heavier bursts of rain are typically only lasting
anywhere from 5-15 minutes. However, ponding of water on roads and
reduced visibilities during heavier showers will be hazardous to
motorists. The latest suite of CAM guidance remains in agreement for
an abrupt end to the ongoing convection after 6 PM west of the
Cascade foothills and after 10 PM for the Cascades and Cascade
foothills. This timing seems reasonable given high pressure will be
building into the area this evening while peak daytime heating wanes.

Weak high pressure will then remain in place tonight through at least
Sunday afternoon, bringing a brief break from precipitation. However,
cloud cover will be on the increase ahead of the next weather system,
resulting in the continuation of below average high temperatures in
the 60s. Model ensemble guidance has come into better agreement on
the arrival time of rain with the aforementioned weather system. It
now appears a steady stratiform rain will arrive Monday morning into
the early afternoon (85-95% chance) before transitioning to
off-and-on post-frontal showers Monday evening. We will then remain
in a cool and showery onshore flow regime through Wednesday. There is
also a 10-20% chance of short-lived thunderstorms Tuesday afternoon,
however these would be sub-severe and isolated due to limited
instability. The latest NBM 48-hr probabilities for rain amounts over
0.50" now peaks between 5 AM PDT Monday and 5 AM PDT Wednesday,
showing anywhere from a 60-80% chance for most locations in southwest
WA and northwest OR, except an 80-95% chance in the Cascades, Cascade
foothills, and Coast Range.

Conditions should dry out with temperatures trending towards seasonal
normals on Thursday as high pressure builds into the area. Our focus
then shifts to a significant warming and drying trend late next week
through next weekend. Cluster analysis for June 11-15 for 500 mb
heights generally suggest upper level ridging will gradually develop
over the region. This will bring a prolonged stretch of dry weather,
with temperatures likely warming each day. However, there is still
considerable uncertainty in regards to exactly how warm temperatures
will get, which could wind up anywhere in the 80s, 90s, or even lower
100s for inland valleys. That said, confidence has increased for high
temperatures of at least 90 degrees or warmer by June 13-15. By June
15, probabilities for highs above 90 degrees peak near 55-75% for
inland valleys per the latest NBM guidance, and less than 10% at the
coast. With the increase in temperatures, there is a 25-45% chance
for a moderate HeatRisk or higher over inland valleys on June 12, a
50-75% chance on June 13, a 65-85% chance on June 14, and a 70-90%
chance on June 15. There is a 5-20% chance for a major HeatRisk or
higher on June 13, a 15-35% chance on June 14, and a 20-40% chance on
June 15. Those who plan on swimming in lakes or rivers to cool down
should be mindful of the dangers that come with cold water
temperatures and/or swift currents. Anyone who is sensitive to heat
and/or has outdoor plans June 12-15 should pay attention to the
forecast over the coming days. -23

&&

.AVIATION...Largely VFR flying conditions expected through the
period with brief periods of MVFR/IFR restrictions as rain
showers and thunderstorms track eastward across the airspace.
Shower coverage is highest to the north of US-20 and east of I-5,
but is expected to quickly wane through the coming few hours.
While a heavy shower may reduce cigs/vis, the primary aviation
concern will be continued 25-45% chances for thunder. Where
thunder is ongoing, the placement of potential thunder remains
difficult to anticipate, and AMDs will be issued as needed for
TSRA/VCTS when radar and lightning observations depict storms
headed for terminals. Rain will end and skies will clear by
sunset. VFR conditions then prevail through the remainder of the
period, although a wet ground surface followed by clear skies may
allow for some low cloud or fog development in sheltered locales
late in the period. West winds of 8-12 kt at all terminals with
occasional gusts of 15-20 kt most likely at the coast will ease
below 5 kt after by 06z Sun and begin to turn out of the south
after sunrise on Sunday.

KPDX AND APPROACHES...VFR conditions most likely to prevail
through the period. Scattered rain showers and 30-40% chances for
thunder will quickly diminish after 00z Sun, with any storm
capable of brief restricted vis/cigs during heavy rain. Lingering
showers will dissipate by 03-04z Sun. West winds of 8-10 kt
continue through this evening with thunderstorms generating
locally gusty and erratic winds, becoming light and variable
tonight, then rising out of the south Sunday morning. -36

&&

.MARINE...An active weather pattern continues through midweek with
repeated frontal systems bringing periods of rain and increased
winds. Isolated rain showers this afternoon will rapidly decrease
in coverage in the hours before sunset while west-northwest winds
of 10-15 kt ease to around 5 kt and turn out of the south tonight.
A brief dry break from Sunday into Monday as a shortwave ridge
passes overhead will see southerly winds build to 15-20 kt with
gusts up to 25 kt, peaking early Monday morning. Small Craft
Advisories may be needed if confidence increases in the duration
of wind gusts greater than 21 kt. Seas of 4-8 ft at 8-9 seconds
continues with a dominant westerly swell. This next, more robust
frontal system will arrive Monday night into Tuesday with
additional rain and winds again turning west-northwesterly behind
the boundary.

Beyond midweek, there is high confidence that high pressure will
build offshore, turning winds northerly over the coastal waters.
Diurnal winds will peak in the afternoon and evening, reaching
15-25 kt with wind gusts near 30 kt. Seas of 6-8 ft at 10 seconds
with a dominant westerly swell look to continue. -36

&&

.PQR WATCHES/WARNINGS/ADVISORIES...

OR...None.
WA...None.
PZ...None.

&&

$$

www.weather.gov/portland

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