624
FXUS66 KPDT 222229
AFDPDT

Area Forecast Discussion
National Weather Service Pendleton OR
229 PM PST Sat Nov 22 2025

.DISCUSSION...Low stratus continues to blanket much of the lower
Columbia Basin, Yakima and Walla Walla, and Wallowa valleys.
Elsewhere, skies are mostly clear to partly cloudy as we await the
arrival of a Pacific cold front Sunday. Have included a mention of
patchy fog in the forecast overnight into Sunday morning for the
aforementioned areas as confidence is high (80 percent) that the
inversion will persist.

Snow levels will drop Sunday afternoon through Sunday night as the
cold front sweeps across the region. No winter highlights are in
effect, but do have medium-high confidence (60-80 percent) in
one-half inch to two inches of snow for mountain passes in the
Cascades and northern Blue Mountains.

Breezy westerly winds of 10-20 mph accompanied by gusts of 20-35
mph are forecast late Sunday afternoon through Monday.

Tuesday afternoon through Thursday, uncertainty in forecast
details is still present as ensemble guidance struggles to resolve
features of a progressive weather pattern, including the
magnitude and axis of moisture transport into the Pacific
Northwest, focusing mechanisms for precipitation (fronts, surface
lows, etc.), and any wintry precipitation. Will note the NBM
suggests a low probability (5-20 percent) of 1 inch or greater
snowfall for the 48-hr period ending 4 PM PST Thursday for the
Yakima, Kittitas, and Grande Ronde valleys. In the eastern half of
the Columbia Basin and farther south into central Oregon,
guidance is more confident in a warmer air mass, resulting in very
low probabilities of measurable snowfall (less than 5 percent).
While probabilities are still quite low (up to 10 percent), the
synoptic pattern does support some potential for measurable
freezing rain Tuesday night and Wednesday in sheltered valleys
along the east side of the Washington Cascades as warm air
overrides colder air at the surface.

&&

.AVIATION...00Z TAFs...LIFR to IFR stratus remains stubbornly
entrenched in the Columbia Basin, including surrounding low-
lying areas such as the Yakima and Walla Walla valleys. In the
eastern Columbia River Gorge, stratus has dissipated except in the
immediate vicinity of DLS. Elsewhere, mostly clear skies are
present at RDM/BDN/PDT. Anticipating stratus will break at DLS
this afternoon, but confidence is now low (30 percent) that
stratus will dissipate at YKM/PSC.

Mid- to high-level cloud cover will become more BKN-OVC tonight
through Sunday as a Pacific cold front approaches the region.
Confidence in the return of widespread fog and stratus is low-
medium (20-50 percent, varying by site) for Basin sites as
forecast soundings show the temperature inversion persisting.

Sustained winds of 10 kts or less are forecast for all sites
through the next 24 hours, albeit some afternoon gusts of 15-20
kts are likely (70 percent confidence) at DLS/PSC with lower
confidence (50 percent) in gusts at PDT/ALW.

Low (10-20 percent) chances of rain overnight into early Sunday
morning (roughly 12Z-18Z) at DLS/YKM/PSC/ALW were not mentioned in
the 00Z TAFs. Best rain chances (20-40 percent) will be at
ALW/PDT/PSC by 21Z Sunday to 00Z Monday.

&&

.PRELIMINARY POINT TEMPS/POPS...
PDT  35  53  32  47 /   0  20  70  10
ALW  39  52  35  46 /   0  40  80  20
PSC  34  54  32  50 /   0  20  40   0
YKM  35  53  27  49 /  10  30  20   0
HRI  34  53  33  49 /   0  20  50   0
ELN  34  49  29  44 /  20  50  30  10
RDM  27  54  24  45 /   0  20  40   0
LGD  34  53  30  43 /   0  20  90  20
GCD  31  55  29  44 /   0  10  60  10
DLS  40  52  37  50 /  10  60  50  20

&&

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

$$

DISCUSSION...86
AVIATION...86