834
FXUS66 KPDT 270452
AFDPDT

Area Forecast Discussion
National Weather Service Pendleton OR
952 PM PDT Sat Sep 26 2026

.KEY MESSAGES...
- Light mountain showers Tuesday, with some uncertainty in the
  pattern going through the midweek.

- Dry conditions with light winds through tomorrow, with breezy
  winds developing Tuesday.

- Near to below normal temperatures through the period with
  freezing temperatures possible in lower valleys.

&&

.DISCUSSION...
The trough that brought windy and rainy conditions yesterday has
moved off to the northeast into Canada. Guidance advertises that
a second trough will draw onshore more towards Northern
California, allowing split flow to take effect in the area. The
trough will dig south enough (75-85% chance) that most of the
impacts will stay in the mountain areas with light mountain
showers (20-30% chance). Higher chances (50-70% chance) develop
across the Cascades with wetting rains possible near Snoqualmie
(50-70% chance). At the same time, the split flow aloft will
allow calmer weather conditions with lights winds and slightly
cooler than average temperatures. Freezing temperatures is
possible tonight in parts of lower valley`s in the Blues and
Wallowa`s, but confidence is low (10-30% chance) that freezing
temperatures will be prolong due to expected cloud cover coming
through overnight that will level out temperatures by the late
evening to early morning hours.

Uncertainty with the pattern starts Wednesday/Thursday, with
guidance not in agreement how it wants to handle the system
with strength and timing. Guidance is split almost three evenly
ways if by the time Thursday that a ridge, trough, or zonal flow
will be aloft. This will either allow mountain showers in the
Cascades to continue (32% of members) or dry out as the ridge
axis takes overhead. Either way, not expecting anything too
impactful other than some light to moderate precipitation in the
mountain regions. Will need to continue monitoring to have a
good picture of the week ahead.

&&

.AVIATION /06Z TAFS THROUGH 06Z MONDAY/...

Light winds under 12 knots and VFR conditions will prevail
through the TAF period.

&&

.Preliminary Point Temps/PoPs...
PDT  43  63  37  70 /   0   0   0   0
ALW  42  64  43  71 /   0   0   0   0
PSC  46  71  39  74 /   0   0   0   0
YKM  44  67  41  72 /   0   0   0   0
HRI  43  68  38  74 /   0   0   0   0
ELN  42  63  36  67 /   0   0   0   0
RDM  39  63  31  70 /   0   0   0   0
LGD  41  66  37  70 /   0   0   0   0
GCD  44  70  37  71 /   0   0   0   0
DLS  47  71  44  74 /   0   0   0   0

&&

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

&&

$$

DISCUSSION...95
AVIATION...71