Ketchum Reservoir Oregon Weather Forecast Discussion

273
FXUS66 KPDT 111736
AFDPDT
Area Forecast Discussion
National Weather Service Pendleton OR
1036 AM PDT Sat Oct 11 2025
.Updated for Aviation
.AVIATION...
18Z TAFS...VFR conditions are expected through the TAF period.
Most sites will become gusty in the 20 to 25 kts later today
through this evening, with some lingering winds at KPDT into
Sunday. RA is expected to develop at PDT/ALW this evening into
tonight and DLS on Sunday with lower chances elsewhere, so they
were not included but most areas have at least 20-30 percent
chances of seeing some RA through the period.
&&
.PREV DISCUSSION... /issued 432 AM PDT Sat Oct 11 2025/
Updated Aviation Discussion.
DISCUSSION...Scattered showers are moving through the forecast area
early this morning as the center of a deep trough moves through the
PacNW. Expect breezy and wet conditions to prevail across the CWA as
a result, with the mountains potentially seeing a dose of snow,
especially above 4500 ft. Next week then turns a little chilly as
models generally keep us under a generally cold and progressive
synoptic pattern.
No major changes in forecast messaging thus far. This first round of
showers is associated with the arrival of the cold front linked to
this trough, ahead of which saw an outflow boundary that brought
gusty and dusty conditions to the Basin. The rain along this front
has been relatively light across the lower elevations, which isn`t
surprising given the dry center of this low is essentially tracking
right over the Basin. Not expecting much QPF for the Basin as a
result, with the bulk of moisture coming in the form of
intermittent, broken shower activity across the mountains. Winds
will pick up behind the front as well, especially through the
Cascade Gaps and the base of the Cascades. The ongoing Wind Advisory
for the Simcoe Highlands and Gorge remains in effect, although it
will admittedly be borderline, as pressure gradient guidance only
reads about 4-5 mb through the Cascades, and 850 mb winds sit right
round 35-40 kts according to the NAM. The rest of the forecast area
should expect to see gusts in the 25-35 mph range, especially
Saturday night into Sunday, ahead of a secondary shortwave moving in
from the northwest.
The parent trough circulating this next wave in will bring with it
colder air and thus the better chances for mountain snow between the
two waves, with snow levels dropping down to around 3500 ft Sunday
night for the central WA Cascades, and 4500 ft elsewhere. Given that
it`s still mid-October, am a bit skeptical at the efficiency of
snowfall accumulations suggested by the NBM, although it is possible
(confidence 20-30%) that White and Santiam Pass receive an inch or
two of snow from this system. Otherwise, impacts from round two will
consist of more widespread shower chances given the more favorable
moisture advection profile of this shortwave, although expectation
is that the Basin and central Oregon will struggle to see a wetting
rain this weekend (25-35%). Probabilities have gone up for the
Yakima/Kittitas Valleys, however, given the northerly track of this
secondary wave (60-70% chance).
Ensemble guidance generally leans toward keeping this parent trough
centered over the Four Corners region once it shifts down and out of
the PacNW, leaving us with a cool N/NW flow aloft. This will result
in some low-end chances for mountain showers (20%) as well as the
possibility of overnight freezes for the Basin and adjacent valleys,
especially Tuesday and Wednesday morning. Highs will be a crisp 50s-
60s for most of the forecast area next work week. 74
AVIATION...12Z TAFS...VFR conditions currently across all sites,
which will stay the course through the period. KDLS will be the only
exception as MVFR conditions are expected to occur late this morning
and extend through the afternoon with reduced ceilings of 3kft.
Elsewhere, ceilings will hover between 5-8kft with light rain across
KPDT/KALW late in the evening as a reinforcing wave brings enough
moisture to allow for upslope showers. Breezy winds are also
anticipated at KPSC/KDLS/KPDT/KRDM/KBDN through the morning and
afternoon with gusts of between 18-25kts. 75
&&
.PRELIMINARY POINT TEMPS/POPS...
PDT  61  42  55  40 /  50  70  70  70
ALW  61  45  55  43 /  60  80  80  80
PSC  65  44  58  42 /  30  30  50  70
YKM  63  39  57  39 /  40  20  60  90
HRI  63  45  58  42 /  30  40  50  70
ELN  58  37  51  33 /  40  40  60  90
RDM  54  32  52  33 /  30  30  50  80
LGD  55  38  50  37 /  70  90  70  70
GCD  55  37  51  37 /  50  60  30  70
DLS  62  47  58  44 /  60  50  90  90
&&
.PDT WATCHES/WARNINGS/ADVISORIES...
OR...Wind Advisory from 11 PM this evening to 5 AM PDT Sunday for
     ORZ041.
WA...Wind Advisory from 11 PM this evening to 5 AM PDT Sunday for
     WAZ024-521.
&&
$$
SHORT TERM...74
LONG TERM....74
AVIATION...77

NWS PDT Office Area Forecast Discussion