899
FXUS66 KPDT 181657
AFDPDT

Area Forecast Discussion
National Weather Service Pendleton OR
957 AM PDT Tue Aug 18 2026

.KEY MESSAGES...
- Gusty west winds and low relative humidity will combine to
  create critical fire weather conditions This Afternoon,
  mainly across the Columbia Basin of Oregon.

- Another chance of showers and thunderstorms and gusty winds
  toward the of the week, associated with an upper low.

&&

.DISCUSSION...
An upper level split flow pattern in place Today will shift
over the next 24 hours to more upper southwest flow over the
western half of the region and ridging across the Interior
Northwest. Breezy winds across the Eastern Columbia River Gorge
Today will develop early as winds at DLS are already gusting to
around 15kts overnight. By Afternoon sustained winds will reach
around 20 mph with gusts to around 30 to 35 mph across the
Gorge, Oregon Columbia Basin, central Oregon and the Kittitas
Valley. Heat and Low relative humidity will be the maim impacts
from the daily strong surface heating across the lower
elevations. HeatRisk will be mainly in the minor category
(yellow), but the warmest day, Thursday, will bring pockets of
more elevated Heat Risk in the moderate category, across the
Columbia Basin, central Oregon and and the eastern Blue
Mountains. Mid level shortwave energy ahead of an advancing
coastal low on Friday into Saturday will drive breezy to windy
conditions again, with potential to enhance fire weather and
strong wind gusts though the Cascade Gaps even during the
overnight hours. Winds at this time look below advisory criteria
as NBM members suggest only about 10- 20% chances for sustained
winds exceeding 39 mph in the eastern Columbia River Gorge
Saturday.

&&

.AVIATION /18Z TAFS THROUGH 18Z WEDNESDAY/...
VFR conditions prevail for all TAF sites. Elevated smoke
prevails with a small chance (5 to 15 percent chance) that some
of the smoke will make its way down into the surface, bringing
temporary MVFR conditions. Otherwise, the main highlight will be
breezy winds developing this afternoon in DLS, RDM, and BDN
that will maintain through much of the afternoon and possibly
into the early evening hours.

&&

.FIRE WEATHER...
A cross barrier pressure gradient will lead to westerly winds
through the Cascade gaps Today. Red flag warnings remain in
place for the Lower Columbia Basin of Oregon from late this
morning through 10 PM This Evening for wind and low relative
humidity. Expect winds of 15 to 20 mph with frequent gusts in
the the 25 to 35 mph range, coupled with relative humidity in
the 15 to 20 percent range. West northwest winds with gusts
persisting through around 9 pm are expected to diminish
to around 10 mph by late evening through he overnight.

&&

.Preliminary Point Temps/PoPs...
PDT  91  54  90  56 /   0   0   0   0
ALW  92  62  92  63 /   0   0   0   0
PSC  95  57  92  56 /   0   0   0   0
YKM  95  59  92  61 /   0   0   0   0
HRI  93  59  92  59 /   0   0   0   0
ELN  87  59  88  59 /   0   0   0   0
RDM  91  47  91  50 /   0   0   0   0
LGD  92  53  93  56 /   0   0   0   0
GCD  93  55  95  57 /   0   0   0   0
DLS  90  60  91  61 /   0   0   0   0

&&

.PDT WATCHES/WARNINGS/ADVISORIES...
WA...None.
OR...Air Quality Alert until 1 PM PDT Wednesday for ORZ041-505-506-
     509>511.
     Red Flag Warning until 10 PM PDT this evening for ORZ691-701-
     703.

&&

$$

DISCUSSION...71
AVIATION...95
FIRE WEATHER...71