472
FXUS66 KPQR 160330 AAA
AFDPQR

Area Forecast Discussion...UPDATE
National Weather Service Portland OR
830 PM PDT Tue Jul 15 2025

Updated Avaition discussion

.SYNOPSIS...
Hot and dry conditions persist through Wednesday, with inland
highs reaching the 90s to near 100 degrees and overnight lows
staying warm, generally in the mid 60s to low 70s. A Heat
Advisory remains in effect through Wednesday evening for much of
northwest Oregon and southwest Washington. While coastal areas
stay cooler, a gradual cooling trend begins Thursday, leading to
more seasonal temperatures by the weekend.

&&

.SHORT TERM...Now through Thursday...A strong ridge of high
pressure continues to dominate the pattern across the Pacific
Northwest this afternoon. In the wake of a departing upper
trough early this morning, skies are mostly clear and
temperatures are climbing into the low to mid 90s across inland
valleys. Todays high will end up several degrees warmer than
Monday, particular for areas north of the southern Willamette
Valley. Overnight lows tonight will remain elevated, especially
in urban centers - due to a combination of residual warmth and
weak offshore flow. Temperatures are expected to dip only into
the mid to upper 60s across most inland areas, with a 15-25%
chance of staying above 70 degrees in parts of Portland,
Vancouver, Salem, and Corvallis.

The hottest day of the stretch will be Wednesday, when strong
ridging peaks directly overhead. Forecast highs in the
Willamette Valley are expected to reach 97-100 degrees, with
30-60% probabilities of exceeding the 100 degree mark. While
temperatures above 105 degrees remain unlikely, a small zone
between Salem and Canby carries a 15-25% chance of reaching that
level. This combination of heat and limited overnight relief is
pushing HeatRisk into the Moderate to Major range across the
region. These conditions will pose challenges not only for
sensitive groups, but also for the broad population - especially
those without adequate access to cooling tonight through
Wednesday. A Heat Advisory continues through Wednesday evening.

In addition to the heat, north to northwest surface winds will
strengthen again late this afternoon and evening, particularly
in the Willamette Valley and along the Cascade foothills. Gusts
could reach 20-25 mph in these areas. Relatively humidity is
also dropping off quickly this afternoon and is expected to
remain low into Wednesday, creating elevated fire weather
conditions. While Red Flag criteria are not currently
anticipated, continued vigilance around ignition sources is
essential. In response to expected conditions and in an effort
to improve awareness, have issued a Special Weather Statement
(SPS) for the Willamette Valley and Columbia River Gorge for
today.

Another concern will be transport of wildfire smoke from active
fires in eastern Oregon and Washington. HRRR smoke output
continues to suggest plumes pushing west of the Cascades later
today into Wednesday. Most of the smoke is expected to stay
elevated, contributing to hazy skies and the occasional smell
of smoke. The extent to which the smoke aloft impacts surface
temperatures or overnight lows will need to be monitored.

By Thursday, ensemble guidance shows good consensus on a second
shortwave trough sliding southeast through eastern Washington.
This should flatten the ridge and begin ushering in cooler
marine air. Overnight lows Thursday morning are expected to fall
back into the 50s and low 60s, offering some much-needed relief.
Highs Thursday will still be warm, likely topping out in the
upper 80s to near 90 degrees, with only a 15-30% chance of
readings reaching 95 degrees, mostly in the Salem-Tigard
corridor.
~Hall

.LONG TERM...Friday through Monday...Forecast confidence remains
high that broad upper-level troughing will dominate the region
from Friday into early next week. This will reinforce onshore
flow and continue the cooling trend, with inland highs returning
to the mid 80s - right around seasonal norms for mid-July.

While no rainfall is expected, this pattern shift should help
push any lingering smoke back east of the Cascade. It will also
support the reestablishment of marine stratus, especially along
the coast and possibly into interior valleys during the
overnight and morning hours. Winds overall will be light,
except in the Columbia River Gorge, where breezy westerly winds
are expected during the late afternoon and evening.
~Hall/HEC

&&

.AVIATION...High pressure ridge remains offshore with northwest
winds aloft. Expect prevailing VFR conditions with mostly clear
skies through the period. Main exception will likely be along the
central Oregon coast where haze or fog, along with the potential
for shallow marine stratus, may linger overnight into Wed morning.
Northerly winds become light overnight. Slightly offshore winds
early Wednesday, expected to become onshore again late Wed
afternoon.

PDX AND APPROACHES...VFR expected to prevail with mostly clear
skies. Northwest winds continue to ease to around 3-6 kt
overnight, potentially becoming more northeast by 16z Wed morning.
/DH


&&

.MARINE...High pressure over the Pacific will maintain northerly
winds through the week. A thermal trough developing inland today
will help tighten pressure gradients and strengthen winds. The
current Small Craft Advisory continues to demonstrate potential
for choppy swells through Wednesday night, and has been extended
to reflect this possibility. Northerly winds with gusts up to 25
kt and choppy seas of 7-9 ft at 8-9 seconds. Winds weaken and
seas subside in the latter half of the week and into the weekend.
-Alviz/JLiu

&&

.PQR WATCHES/WARNINGS/ADVISORIES...

OR...Heat Advisory until 10 PM PDT Wednesday for ORZ108>122.

WA...Heat Advisory until 10 PM PDT Wednesday for WAZ204>207-209-210.

PZ...Small Craft Advisory until 2 AM PDT Thursday for PZZ252-253-
     271>273.
&&

$$

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