934
FXUS66 KPDT 152302
AFDPDT

Area Forecast Discussion
National Weather Service Pendleton OR
402 PM PDT Wed Oct 15 2025

Updated Aviation Discussion

.AVIATION...00z TAFs...VFR conditions expected. Outside of some
light high clouds over the Cascades, all sites are expected to
remain clear through tomorrow morning, with light, terrain-driven
winds prevailing. A sct-bkn high cloud deck is then expected to
move in tomorrow afternoon as a weak weather system moves into the
region. 74

&&

.PREV DISCUSSION... /issued 259 PM PDT Wed Oct 15 2025/

DISCUSSION...Skies are clearing across the region as dry
northerly flow associated with a weak ridge of high pressure
infiltrates the region. The dry air mass coupled with clear skies
and mostly light winds will facilitate another night of efficient
radiational cooling. Most of our lower elevations observed a
season-ending freeze last night into this morning. Confidence in
widespread/zone-wide sub-freezing temperatures tonight into
Thursday morning is too low (<80%) to issue any Freeze Warnings
for remaining eligible zones (Columbia River Gorge of OR/WA and
the Lower Columbia Basin of OR). That said, areas of sub-freezing
temperatures for cold-prone locations are expected (90%
confidence) in the Lower Columbia Basin of OR overnight.

Late Thursday through Friday, a shortwave passing across the
northern Rockies will clip the region, bringing a chance (25-50%)
of light rain showers to the Cascade crest. The main weather
concern associated with the system will be breezy to locally windy
west to northwest winds as cross-Cascade pressure gradients
strengthen and isentropic descent to the lee of the Cascades
facilitates downward momentum transfer to the surface.
Additionally, while confidence is only medium (50%), localized Red
Flag conditions (overlap of wind/low RH) may develop Friday
afternoon through the Kittitas Valley and also limited areas of
the east slopes of the Washington Cascade and Columbia Basin;
forecast soundings from some CAMs indicate a layer of very dry air
aloft (approximately between 850 and 700 hPa) will reach the
surface.

Friday night into Saturday, confidence is very high (>90%) that a
temporary ridge of high pressure will move over the Pacific
Northwest.

The next chance of widespread precipitation will be associated
with a robust low-pressure system that is slated to arrive late
Saturday into the weekend. While ensemble clusters are in
excellent agreement (>90% of members) that some form of trough/low
will move over the Pacific Northwest through the weekend, they are
still unsure on the form (fast-moving trough vs slower-moving
closed low) and how much precipitation the region will get. The
faster-moving trough solution is becoming more likely (>70% of
ensemble members) compared to the slower-moving closed low (<30%
of members). The former scenario would lead to less precipitation,
especially for the lower elevations, and windier conditions
through the Cascade gaps and into the Columbia Basin.

&&

.PRELIMINARY POINT TEMPS/POPS...
PDT  34  62  40  64 /   0   0   0   0
ALW  37  62  45  63 /   0   0   0  10
PSC  32  64  39  66 /   0   0   0   0
YKM  34  64  39  65 /   0   0   0   0
HRI  33  63  42  65 /   0   0   0   0
ELN  31  62  39  59 /   0   0  10   0
RDM  27  63  33  64 /   0   0   0   0
LGD  29  61  36  62 /   0   0   0   0
GCD  29  61  35  64 /   0   0   0   0
DLS  40  66  47  66 /   0   0  10  10

&&

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

$$

SHORT TERM...86
LONG TERM....86
AVIATION...74