721
FXUS66 KPQR 160450
AFDPQR

Area Forecast Discussion
National Weather Service Portland OR
950 PM PDT Sun Jun 15 2025

Updated Hazards and Aviation discussion.

.SYNOPSIS...Onshore flow will maintain seasonable temperatures
through much of the coming week. Chances for light rain return
to the coast Monday night into Tuesday and inland Tuesday night
into Wednesday, with very little to no measurable rain expected
for most inland locations. Transitioning to a cool and showery
weather pattern Friday into Saturday as a closed upper level low
settles over the region and brings more substantial rain
amounts to the area.

&&

.DISCUSSION...Visible satellite shows clear skies across
northwest Oregon and southwest Washington this afternoon as
morning stratus was much quicker to burn off than the past few
days. This will help temperatures reach well into the 70s across
most inland locations today, with marine influences keeping
coastal areas closer to the upper 50s or low 60s. Little change
is expected in the sensible weather over the next few days as
deep upper level troughing over the NE Pacific maintains a
broad onshore flow regime across the Pacific Northwest. This
will equate to seasonable temperatures in the upper 70s in the
inland valleys through Wednesday, with onshore flow keeping
coastal communities cooler and cloudier. Tuesday has the
potential to be the warmest day of the week, with the
probability to surpass 80 degrees ranging from 60-80% from the
Portland Vancouver Metro through the rest of the Willamette
Valley on Tuesday afternoon.

Rain chances continue to look rather minimal and mostly
confined to the coast through Wednesday as a pair of week fronts
traverse the area. The first of these fronts approaches late
Monday into Tuesday, but looks to fall apart offshore. Can`t
rule out a few sprinkles along the coast late Monday night into
early Tuesday, but expect the rest of the area to remain dry.
The somewhat better chance for some light rain will come with
the second weak front Tuesday night into early Wednesday,
however, model QPF values remain on the meager side as coastal
areas from about Tillamook County northward still only have a
30-40% chance to reach a tenth of an inch. Meanwhile, amounts
have continued to dwindle further inland as the Portland area
now only has about a 5% chance to even see a tenth of an inch
through Wednesday morning. Will most likely see only a trace to
a couple hundredths in the Portland Metro, with areas to the
south from Salem to Eugene likely to stay dry.

After another dry and seasonable day on Thursday, chances for
more substantial rainfall continue to increase Friday into
Saturday as the deep upper level trough moves directly overhead.
Nearly all ensemble members now depict at least some measurable
rain for locations in the Willamette Valley, with the chance to
receive a wetting rain of a quarter inch increasing to around
40% in the Portland Metro and 20% from Salem to Eugene. Coastal
areas and the higher terrain of the Cascades have the best
chances for a wetting rain, with probabilities ranging from
50-60% in those areas. Regardless of exact amounts, confidence
continues to increase in a wetter pattern with widespread
showers likely across the area towards the end of the week,
Can`t rule out a few thunderstorms Friday into Saturday as
cooling aloft yields steeper mid level lapse rates, but opted
not include thunderstorms in the forecast at this time as the
NBM currently only depicts around a 10% chance across the area.
Thunderstorm potential will likely ultimately depend on any
breaks in the cloud cover which can help to generate surface
based instability. It is worth noting that any thunderstorms
would likely be accompanied by locally heavy rainfall given the
abundant moisture which will be in place. /CB

&&

.AVIATION...Along the coast, marine stratus will redevelop
tonight, yielding MVFR/IFR cigs at AST/ONP after 10-12Z Mon with
chances for IFR conditions increasing to the north. Restricted
cigs should mix out by 18-20Z Mon, before further stratus is
expected again after 03-06Z Tue. Northwest winds will remain below
5 kt through the overnight period, and increase to 5-10 kt out of
the west to northwest by Monday afternoon.

Inland, VFR conditions are likely to persist throughout the
period, although few-sct stratus at 2-3 kft is expected to build
westward from the Cascades overnight. There remains a 15-25%
chance of coverage increasing enough to result in MVFR cigs, most
likely at TTD. Cloud bases will lift as mixing deepens by 20-21Z
Mon. Winds below 5 kt overnight will increase out of the west to
northwest at 5-10 kt by Monday afternoon.

*KTTD ASOS is currently INOP except for altimeter and will be AMD
 NOT SKED.

PDX AND APPROACHES...VFR flying conditions expected throughout the
period. Sct stratus coverage at 2-3 kft is again expected to
encroach from the west after 10-12Z Mon, with around a 10% chance
of MVFR cigs if stratus coverage is higher than anticipated. Skies
will trend clearer and cloud bases lift above 3-4 kft by Monday
afternoon as mixing increases. Northwest winds around 5 kt
overnight increase to 5-10 kt by Monday afternoon. -Picard

&&

.MARINE...North/northwesterly flow continues, with diurnally
driven peaks in the afternoon. Winds 15-20 kt with gusts to
around 25 kt continue south of Cape Falcon to Florence through
this evening. As a result, the Small Craft Advisory from Cape
Falcon OR to Florence OR will remain in effect until 11 PM Sunday.

A weak disturbance is expected to cross the region on Monday,
supporting southerly winds late Monday and through Tuesday. A
westerly swell is also expected to move into the waters late
Monday, generally around 5 ft at 10 seconds. Combined seas still
look to remain 7 ft or less through next week. -Batz

&&

.PQR WATCHES/WARNINGS/ADVISORIES...

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

&&

$$

www.weather.gov/portland

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