804
FXUS66 KPDT 101005
AFDPDT

Area Forecast Discussion
National Weather Service Pendleton OR
305 AM PDT Mon Aug 10 2026

.KEY MESSAGES...

- Dry and warm with diurnal breezes through Wednesday.

- An upper level trough will then move in followed by a return
  to southwesterly flow. Then there will be opportunities for
  mountain showers and thunderstorms for the end of the week.

&&

.DISCUSSION...
Dry westerly flow will continue over the Pacific Northwest for
the next several days. Breezy diurnal winds are anticipated,
with the Simcoe Highlands, Columbia Basin, Gorge and Kittitas
Valley having afternoon wind gusts in the 20 to 30 mph range,
possibly as high as 35 mph today and Tuesday, then decreasing a
bit on Wednesday.

NBM probabilities of wind gusts >=25 mph are >80 percent in
these areas today, and similar on Tuesday, though with slightly
less areal coverage. NBM probabilities of wind gusts >=39 mph
are 70-90 percent in the Kittitas Valley and generally less than
50 percent everywhere else.

High temperatures today will be similar to yesterday, perhaps a
degree or two cooler in some locations. Tuesday will be about
the same as today and Wednesday will be a couple of degrees
cooler. With the slightly lower temperatures by midweek, RH
values will increase a couple of percentage points today and a
few more going into Wednesday. This will help with fire weather
conditions, though they will still remain elevated.

By midweek, low pressure in British Columbia will move south and
push a trough into the Pacific Northwest. This low could
potentially trigger some light showers over the Washington
Cascades Wednesday, but not much more than that.

By Thursday, southwest flow will develop behind the departing
low and will strengthen into the weekend. There will also be
increasing monsoonal moisture specially Friday onward.

While it is too early to tell exactly how things will develop
this far out, there is definitely some potential (15-30%) for
mainly mountain showers and thunderstorms over central and
eastern Oregon.

&&

.AVIATION /06Z TAFS THROUGH 06Z TUESDAY/...
VFR conditions are generally expected through the TAF period.
The only current exception is RDM where MVFR is occurring due to
smoke. BDN now has some smoke that has moved in with IFR
conditions. Not sure how long this will last. RDM may improve
later this afternoon, as winds increases but confidence is
marginal at best.

Winds have remained gusty at DLS to around 20 kts and are
expected to increase this afternoon to around 30 kts. Winds are
expected to gust at PDT, BDN, RDM and YKM to around 20 kts this
afternoon, before all sites return to 10 kts or less this
evening. ALW and PSC will remain 10 kts or less through the
period.


&&

.Preliminary Point Temps/PoPs...
PDT  88  53  88  57 /   0   0   0   0
ALW  89  60  89  62 /   0   0   0   0
PSC  92  57  91  58 /   0   0   0   0
YKM  92  58  92  59 /   0   0   0   0
HRI  91  58  90  59 /   0   0   0   0
ELN  85  56  86  56 /   0   0   0   0
RDM  89  47  89  47 /   0   0   0   0
LGD  90  53  90  53 /   0   0   0   0
GCD  91  53  92  53 /   0   0   0   0
DLS  89  61  89  62 /   0   0   0   0

&&

.PDT WATCHES/WARNINGS/ADVISORIES...
WA...Air Quality Alert until 5 AM PDT Tuesday for WAZ024-026>030-
     521>523.
OR...Air Quality Alert until noon PDT today for ORZ041-044-049-050-
     502-503-505>511.

&&

$$

DISCUSSION...77
AVIATION...77