649
FXUS66 KPDT 131223
AFDPDT

Area Forecast Discussion
National Weather Service Pendleton OR
423 AM PST Thu Nov 13 2025

.DISCUSSION...The forecast area finds itself caught between a
cutoff low to our south and an upper-level trough to our north
this morning, which will result in some moderately breezy
downslope winds and a round of light precipitation. Low ceilings
and even dense fog continue to persist for much of the Columbia
Basin and the Walla Walla Valley, respectively, as persistent cold
pooling from an otherwise stable synoptic pattern has allowed
these conditions to persist. The expectation is that we`ll see
some relief today, however, as even though the wind forecast
across guidance is subdued because of an overly stable environment
in the Basin, warm air advection brought about by the low to our
south and its subsequent downslope winds should provide enough of
a drying effect to at least partially lift ceilings, especially
along the foothills. So even though central Oregon and the
Foothills of the Blues will see gusts in the 20-30 mph range today
while the lower elevations continue to see light winds,
conditions are ripe for at least some scouring out of this pesky
fog and stratus.

With moisture advection lacking, however, precipitation impacts
are expected to be minimal with this system. CAMs generally
depict broken shower activity over the forecast area during much
of the day, with more persistent bands over primarily the
Cascades. But with snow levels well above 7000 ft, ptype will be
rain across all of our area`s mountain passes. Light shower
activity may persist across the mountains through Friday (30-40%
confidence), however the bulk of the moisture with this oncoming
system is expected to occur today, before transitory ridging
slides in late Friday into Saturday.

Widespread PoPs return on Sunday as global models generally depict
a weak shortwave clipping the forecast area to the east, but
again with only minimal precip impacts, concentrated mainly across
the eastern mountains where snow levels are generally expected to
be above the 6000-7000 ft range. Colder air then looks to intrude
on Monday as a more northwesterly trough moves in, but this
system looks to be relatively moisture-starved based on ensemble
QPF guidance. Better, more widespread PoPs materialize late
Tuesday into Wednesday as ensembles generally depict a more
organized trough moving into the PacNW. 74

.AVIATION...12Z TAFs...A variety of conditions ranging from VLIFR
to VFR are present and forecast across TAF sites. A break in mid-
to high cloud over the region has revealed low stratus and fog,
locally dense, in the lower Columbia Basin and Walla Walla Valley.
Sub-VFR CIGs/VSBYs are forecast at PSC/ALW/PDT into the early to
mid-morning hours. Showers will spread over the forecast area
today, with chances of precipitation at all sites. Winds will be
strongest at BDN/RDM, gusty out of the south, with winds remaining
lighter for Basin sites. Will note significant uncertainty in
30-40 kt south to southwest winds mixing down at PDT late morning
and afternoon; have advertised variable winds, though that is not
sufficient to describe the expectation that PDT will see highly
variable winds (magnitude and direction) as winds battle the
robust cold pool that is entrenched in the Columbia Basin. Have
opted to include WS at PDT due to the strong winds aloft. Overall,
forecast confidence in details at all sites is lower than average.

&&

.PRELIMINARY POINT TEMPS/POPS...
PDT  62  45  61  42 /  50  70  30  10
ALW  60  48  60  46 /  60  80  50  20
PSC  54  43  62  43 /  50  60  10  10
YKM  54  39  58  39 /  90  60  10  20
HRI  57  44  61  43 /  50  70  20  10
ELN  51  36  52  38 /  90  60  20  40
RDM  66  36  58  32 /  50  40  10   0
LGD  64  43  60  38 /  50  80  50  20
GCD  66  42  59  37 /  50  70  20   0
DLS  57  46  60  46 /  90  80  40  30

&&

.PDT WATCHES/WARNINGS/ADVISORIES...
OR...None.
WA...Dense Fog Advisory until 10 AM PST this morning for WAZ029.

&&

$$

DISCUSSION...74
AVIATION...86