303
FXUS66 KPDT 222259
AFDPDT

Area Forecast Discussion
National Weather Service Pendleton OR
359 PM PDT Tue Sep 22 2026

.KEY MESSAGES...
- Windy conditions this afternoon across the Columbia Gorge and
  the foothills.

- Showers and isolated thunderstorms this afternoon across the
  Eastern Mountains.

- Gusty winds potentially approaching wind advisory criteria on
  Friday with widespread showers.

&&

.DISCUSSION...
Quiet weather earlier today is starting to turn more active with
showers starting to develop across the Blue Mountains. Current
satellite depicts partly cloudy skies across much of the region this
afternoon with cumulus and a few towering cumulus developing across
the Wallowa and Blue Mountains. Latest radar imagery shows that a
few showers have developed over the John Day Highlands stretching
into the Blue Mountains. As additional destabilization occurs
this afternoon, with latest model guidance suggesting around
200-400 MUCAPE developing this afternoon, an isolated
thunderstorm may develop (10-20% chance) across the Blue and
Wallowa Mountains.

Of additional note this afternoon, windier conditions are
starting to develop in areas with channeling effects (ie the
foothills, Columbia River Gorge, and the Kittitas Valley).
Latest observations depict winds are currently around 15-20 mph
with gusts around 20-30 mph. Latest model guidance suggests that
these winds remain around 20-25 mph with gusts up to around 35
mph in the aforementioned areas this afternoon. In addition,
models suggest RH values will be between 20-30% this afternoon
in lower elevations.

Looking past this afternoon, LREF clusters are in relatively good
agreement about the upper-air pattern through Saturday as a
negatively tilted trough moves through the region on Friday. This
system will bring widespread showers to the area with the NBM and
LREF clusters suggesting around a 70-90% chance of seeing at least
measurable rain (>0.01 in) Friday across the region. The best
chances for higher rain totals look to be in the Cascade Mountains.
Model guidance is also highlighting the potential for gusty westerly
winds Friday afternoon through the Cascade Gaps and the foothills
with winds of 15-30 mph and gusts of 35-50 mph (Confidence
70-80%). Additionally, the LREF and NBM suggest around a 25-45%
chance of wind gusts meeting wind advisory criteria (wind gusts
>45 mph). Probabilities of wind gusts meeting wind advisory
criteria have been increasing with model runs yesterday
suggesting a lower 10-20% chance.

After Friday, model spread increases substantially but are in
general agreement about second trough approaching the PacNW late in
the weekend but there is a lot of uncertainty regarding timing and
potential impacts. But there is relatively agreement on below
average temperatures this weekend (50-60%). Garty/26

&&

.AVIATION /00Z TAFS THROUGH 00Z THURSDAY/...

No risk of ceilings or visibility restrictions for local
terminals over the TAF period. DLS will remain the most
windy/gusty over the next few hours before a significant
decrease in the winds is noticed after sunset. YKM could see a
brief uptick in winds during the evening and all other terminals
are expected to remain below 12 knots.

&&

.Preliminary Point Temps/PoPs...
PDT  45  74  46  77 /   0   0   0   0
ALW  51  75  52  78 /   0   0   0   0
PSC  49  77  48  78 /   0   0   0   0
YKM  48  74  49  74 /   0   0   0   0
HRI  49  77  48  78 /   0   0   0   0
ELN  44  69  44  69 /   0   0   0   0
RDM  38  74  40  80 /   0   0   0   0
LGD  44  77  47  85 /   0   0   0   0
GCD  44  80  48  87 /   0   0   0   0
DLS  50  77  52  78 /   0   0   0   0

&&

.PDT WATCHES/WARNINGS/ADVISORIES...
WA...None.
OR...None.

&&

$$

DISCUSSION...26
AVIATION...71