331
FXUS66 KPDT 100826
AFDPDT

Area Forecast Discussion
National Weather Service Pendleton OR
126 AM PDT Fri Oct 10 2025

.DISCUSSION...Overnight water vapor imagery reveals a clearly
defined low pressure system centered just off the coast of the
PacNW. This low will be slow to push onshore, but once it does,
expect a nice dose of gusty winds and mountain precip as the region
gets its first real taste of an autumnal weather system.

The S/SW winds aloft leading this low have introduced intermittent
rain showers across the Cascades and east slopes over the past day,
and this will continue into today as models generally keep this low
stationary until around Friday evening. Winds will pick up as an
upper-level jet moves in overhead, with scattered shower chances
spreading east of the Cascades heading into the Friday
night/Saturday morning time frame. Mid-level winds generally depict
a moisture advection profile that mostly favors areas west of the
Cascades, so while the mountains stand to see good chances at
wetting precip, NBM probabilistic guidance depicts more modest
amounts of QPF for the lower elevations. Overall, for Friday through
Monday morning, expect a >90% chance for QPF of at least a quarter
of an inch across our mountain zones, 20-35% chance across the Basin
and Yakima/Kittitas Valleys, and a 40-60% chance elsewhere. Expect
our mountaintops to start whitening from snow as well, with snow
levels dropping to around 3500 ft for the WA Cascades and 4500 ft
elsewhere by Sunday.

Winds will become an issue with the aforementioned jet, followed by
the center of the low itself passing over the forecast area over the
weekend. Adjusted winds up for Friday afternoon, as the jet is
causing 850mb wind readings up to 40 kts over the Basin, favorable
for some strong gusts to mix down to the surface. Wind gusts will be
stronger through the Cascade Gaps Saturday night into Sunday as the
center of the low moves through, hence the Wind Advisory issued for
the Gorge and simcoe Highlands. These winds will unfortunately not
play well with the ongoing wildfire activity across the WA Cascades,
but fortunately, due to the track of the low, the strongest winds
look to be well south of the active fires. Still, here`s hoping that
the precip that falls outweighs any wind concerns over the weekend.

Ensembles generally keep the region under a trough pattern through
early next week, going so far as to split off another low from this
parent trough during the day Monday. While the center of both lows
will be overhead, limiting precip concerns after Sunday, expect cool
conditions to dominate next week, as temps start to really read more
fall-like numbers with highs in the 50s and lows in the 30s.
Overnight freezes may become a concern across the Basin next week as
well. 74

&&

.AVIATION...12z TAFs...A weather system will circulate scattered
rain showers into the forecast area today, mainly for sites along
the Cascades. DLS, BDN, and RDM are expected to receive at least
light showers on and off during the day today, drying out in the
evening, while YKM and sites to the west remain mostly dry. Cigs
will start bkn-ovc in the morning, with some clearing for the
eastern sites during the afternoon, before clouds build back in
during the evening/overnight hours heading into Saturday. Winds will
be breezy as well, gusting up to 20-25 kts for most sites at times
during the afternoon, mainly out of the west. 74

&&

.PRELIMINARY POINT TEMPS/POPS...
PDT  71  43  61  42 /  10  50  40  70
ALW  73  48  60  46 /  20  50  50  80
PSC  73  44  64  44 /  10  30  30  40
YKM  71  41  62  38 /  30  30  40  20
HRI  71  44  62  44 /  10  40  30  40
ELN  67  38  58  36 /  40  40  30  40
RDM  61  30  55  31 /  70  70  50  50
LGD  76  40  56  39 /  20  50  60  80
GCD  71  39  56  38 /  10  40  40  60
DLS  67  45  62  47 /  60  50  70  60

&&

.PDT WATCHES/WARNINGS/ADVISORIES...
OR...Wind Advisory from 11 PM Saturday to 5 AM PDT Sunday for ORZ041.

WA...Wind Advisory from 11 PM Saturday to 5 AM PDT Sunday for WAZ024-
     521.

&&

$$

SHORT TERM...74
LONG TERM....74
AVIATION...74