224
FXUS66 KPQR 291612
AFDPQR

Area Forecast Discussion
National Weather Service Portland OR
912 AM PDT Sun Jun 29 2025

.UPDATED AVIATION DISCUSSION...


&&

.SYNOPSIS...
Warm and dry weather will persist through the remainder of the
weekend, with temperatures continuing to rise into early next
week. The hottest day is expected to be Monday, with widespread
highs in the low to mid 90s across interior valleys. Slight
cooling follows midweek, but temperatures will remain above
seasonal norms. There is also a low-end potential for isolated
thunderstorms over the central Oregon Cascades Monday and
Tuesday.

&&

.SHORT TERM...Now through Monday...The region remains under the
influence of dry and warming conditions this morning, with
temperatures on track to climb further through Monday. A broad
zonal flow pattern across the Pacific Northwest is evolving into
a more amplified regime as a ridge of high pressure - rooted
over the Desert Southwest - builds northward along its western
edge. This will reinforce warming across the area, particularly
for inland valleys.

High temperatures today will reach the upper 80s to near 90
across the interior lowlands. Meanwhile, cooler marine influence
and persistent onshore flow will keep coastal zones and higher
elevations in the upper 60s to mid 70s, offering more
comfortable conditions.

Monday will likely be the hottest day of the period. Inland
valleys are forecast to see highs in the low to mid 90s, with
localized downslope easterly flow enhancing warmth on the
western slopes of the Cascades. However, this downslope
influence should remain shallow and not significantly impact
coastal temperatures, which are expected to hold in the low to
mid 70s. Current probabilistic guidance indicates a 40-70%
chance for temperatures exceeding 95 degrees in the Willamette
Valley, particularly south of Portland. Similarly, there is
about a 50-70% chance that the Upper Hood River Valley will also
reach 95 degrees on Monday. Although this heat event is brief
and does not currently meet criteria for excessive heat
headlines, sensitive populations - especially those without
access to cooling - may experience discomfort.

There is also a slight chance (15-25%) of isolated
thunderstorms Monday afternoon and evening across the Oregon
Cascades, mainly from Lane County southward. A weak disturbance
off the northern California coast is helping to advect mid-level
moisture into the region. Combined with modest instability -
most notable over the central Oregon Cascades - this may be
sufficient for thunderstorm initiation over higher terrain.
Should moisture trends shift northward, isolated storm activity
could approach areas closer to Mount Hood, though confidence
remains rather low at this time.  -Hall


.LONG TERM...Tuesday through Saturday...A similar pattern holds for
Tuesday, though storm coverage and organization appear to
diminish somewhat. With southwesterly upper level flow expected,
confidence for thunderstorm development is much lower as the
flow will likely keep thunderstorms to the east of the Cascades.

Temperatures will moderate slightly beginning Tuesday, though
still remaining above normal. Highs through midweek should
settle into the low to mid 80s across the Willamette Valley,
with overnight lows generally in the 50s. Ensemble guidance
continues to support a warm and dry pattern through at least
Saturday, with little signal for significant cooling during
that time frame. -Hall


&&

.AVIATION...VFR through the next 24 hours. Light northwesterly
flow around KONP is pushing mist into the terminal causing
visibility to decrease. Once winds rise above 5 kt though that
will improve. High pressure will cause winds to increase from the
north. Coastal terminals will see the bulk of the wind with gusts
up to 30 kt possible around KONP. Elsewhere in N-S aligned
terrain, expect gusts up to 25 kt.

PDX AND APPROACHES...VFR with northerly winds. For approaches,
gusts up to 25 kt from 1500-3000 ft AGL after 02Z Mon.
-Muessle


&&

.MARINE...
High pressure over the Pacific will maintain northerly
winds across all waters through the week. Today, winds will
gradually strengthen from south to north as pressure gradients
tighten. Expect northerly winds around 15-20 kt with gusts to
up to 30 kt, through at least early Monday morning. Breezy
northerly winds are expected to persist given the overall pattern
is not expected to change much. Therefore, have extended the
current suite of Small Craft Advisories through at least Monday
morning.

Seas 5 to 8 ft at 9 to 10 seconds through Tuesday. Given that
seas will mainly be wind-driven, combining that with westerly
swells, expect conditions to be steep and choppy at times. Overall
conditions expected to slowly subside through the middle of the
week as the aforementioned high pressure is pushed eastward. -42

&&

.PQR WATCHES/WARNINGS/ADVISORIES...
OR...None.
WA...None.
PZ...Small Craft Advisory from 2 PM this afternoon to 11 AM PDT
     Monday for PZZ210.
     Small Craft Advisory until 11 AM PDT Monday for PZZ251>253-
     271>273.
&&

$$

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