316
FXUS66 KPQR 161720
AFDPQR

Area Forecast Discussion
National Weather Service Portland OR
1020 AM PDT Sun Aug 16 2026

Updated aviation discussion.

&&

.SYNOPSIS...Seasonably warm and dry conditions expected through
much of the week with morning clouds and afternoon clearing.
Winds generally out of the west/northwest, strongest in the
afternoon and along the Central Columbia River Gorge and Upper
Hood River Valley. Chances for precipitation return at the end
of the week, but uncertainty remains with exactly how much
precipitation we would receive.

&&

.DISCUSSION...Today through Saturday...Seasonably dry and warm
conditions continue through the week with minimal weather
impacts. The large-scale pattern remains fairly stagnant through
the period, with broad and relatively flat upper-level ridging
over the majority of CONUS and a weak, positively-tilted upper-
level troughing over the northeast Pacific. This pattern will
support continued onshore flow, maintaining near-normal daily
high temperatures in the 80s within inland valleys and 60s along
the coast, and overnight lows in the 50s across the region. Each
morning will be characterized by morning clouds (at least along
the coast) which clear up in the afternoon. Expect mostly light
winds from the west/northwest across the region this week,
strongest each afternoon and along the Central Columbia River
Gorge and Upper Hood River Valley.

The majority of ensemble members are in agreement that upper-
level ridging over the Rockies and Great Basin will build late
in the workweek, which would favor a brief warm-up on Thursday.
However, ensemble guidance shows the broad upper-level trough
over the northeast Pacific progressing toward the Pacific
Northwest by Friday into the weekend, resulting in slightly
cooler temperatures and winds coming from the west/southwest.
Chances for precipitation also increase to 10-30% across the
region during this time, however, there is still high
uncertainty with how much precipitation we would receive and the
exact timing. If the a potential front at the end of the week is
too weak, it will have a hard time counteracting the overall dry
airmass and make it unlikely for us to receive substantial
rainfall. -10/36

&&

.AVIATION...Through 18z Monday...Nocturnal marine stratus has
begun to erode, leading to mixed MVFR/low-end VFR flying
conditions inland as cloud bases lift above 3 kft, and
widespread MVFR at terminals along the coast and lower
Columbia River. Faster and more widespread clearing is expected
today than yesterday, with high confidence (>90% chance) of
widespread VFR conditions after 20-21z Sun inland and moderate
to high confidence (70% chance) of widespread VFR conditions
after 21-22z Sun at coastal terminals. Resurgent marine stratus
tonight may yield further MVFR cigs after 03-09z Mon, most
likely along the coast and with lower confidence inland. Light
northwest to north winds this morning will build to 5-10 kt at
inland terminals and 10-15 kt with gusts to 20 kt along the
coast, before easing below 5 kt after 06z Mon.

KPDX AND APPROACHES...Low-end VFR cigs persist through 20z Sun
as cloud bases lift and skies trend clearer, leading to high
confidence in continued VFR through much of the period. Moderate
(30-50%) chances for MVFR cigs after 06-09z Mon as marine
stratus again pushes inland. Diurnal northwest winds will rise
to 6-8 kt this afternoon, then ease to 3-4 kt this evening. -36

&&

.MARINE...A largely stagnant pattern continues through much of
the week with high pressure offshore supporting northerly to
northwesterly winds of 8-15 kt and gusts up to 20 kt. Friday
into the weekend, weak low pressure over the northeast Pacific
will shift winds more westerly/southwesterly across the waters,
but chances for small craft wind gusts exceeding 21 kt remain
5-10%. Benign seas of 3-6 ft persist through the period. -10/36

&&

.PQR WATCHES/WARNINGS/ADVISORIES...

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

&&

$$

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