174
FXUS66 KPDT 072316
AFDPDT

Area Forecast Discussion
National Weather Service Pendleton OR
416 PM PDT Mon Sep 7 2026

.KEY MESSAGES...
- Low chance (<=30 percent) of showers this afternoon and
  evening mainly over far eastern Oregon.

- Breezy winds this afternoon and evening over the Columbia
  Basin, Cascade Gaps, Kittitas Valley and Simcoe Highlands.

- Dry and warmer Tuesday through Thursday, then breezy Thursday
  in as a weak trough moves through in advance of the next
  upper low which will bring the potential for more unsettled
  weather to the mountains over the weekend.

&&

.DISCUSSION...
The persistent upper low that had been over the Pacific
Northwest has moved eastward out of the region. However,
lingering troughing remains and a secondary low/short wave will
move though this evening. This short wave energy could touch of
some showers and possibly a thunderstorm mainly over far
eastern Oregon, though some activity has developed over
Washington it has not been long lasting.

Breezy conditions are also expected this afternoon through the
evening across the Cascade Gaps, Columbia Basin of Oregon,
Columbia Gorge, Simcoe Highlands and Kittitas Valley. Winds
should gust in the 25 to 30 mph range, with gusts as high as 35
mph.

However, the rest of the area will remain dry. By Tuesday, a
split flow regime will develop over the area, which will become
more westerly by Wednesday. Temperatures will warm to seasonal
values for much of the week, after being below normal for the
last several days. By the weekend, temperatures return to below
normal with the trough moving through. Highs will be mainly in
the 70s at that time which is about 10 degrees below normal. The
EFI indicate the 60th t0 70th percentile below normal at that
time.

On Thursday, some short wave energy and a weak trough will move
through the flow and increase the winds, and the flow will
become more northwesterly. Wind gusts will be in the 25 to 30
mph range, with gusts as high as 35 mph in the same areas as
today even going into central Oregon and the foothills of the
Blue Mountains. Wind gusts >=25 mph are >=70 percent in these
areas. Wind gusts >=39 mph are ars high as 60 to 90 percent
across portions of the Columbia Basin and Kittitas Valley and
lower elsewhere.

The flow returns to westerly again on Friday, then southwest in
advance of an upper low that will move across the region
Saturday into Sunday, bringing precipitation chances back to
the mountains. There is still some uncertainty as to the
evolution of the low next weekend, but the system does appear
to be progressive, but there will be at least some precipitation
in the mountains, an potentially in the lower elevations, but
the lower elevation rain chances appear low at this time.

&&

.AVIATION /00Z TAFS THROUGH 00Z WEDNESDAY/...
VFR conditions with breezy winds in the DLS that will decrease
as we go into the later afternoon to early evening hours. Not
expecting and CIG or VIS issues through the TAF period.

&&

.Preliminary Point Temps/PoPs...
PDT  44  77  46  82 /   0   0   0   0
ALW  51  78  52  83 /   0   0   0   0
PSC  48  80  49  85 /   0   0   0   0
YKM  51  79  52  84 /   0   0   0   0
HRI  47  80  48  85 /   0   0   0   0
ELN  46  77  48  82 /   0   0   0   0
RDM  38  76  41  85 /   0   0   0   0
LGD  43  75  46  83 /  10   0   0   0
GCD  43  77  46  86 /   0   0   0   0
DLS  52  81  55  86 /   0   0   0   0

&&

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

&&

$$

DISCUSSION...77
AVIATION...95