748
FXUS66 KPDT 041135
AFDPDT

Area Forecast Discussion
National Weather Service Pendleton OR
335 AM PST Thu Dec 4 2025

.DISCUSSION...Fog still lingers throughout parts of the Foothills
of the Blues and Kittitas Valley through the rest of the morning.
Precaution should be given in areas of very dense fog and freezing
fog. Even given the stratus cloud cover, temperatures will
efficiently cool enough, thanks to light winds, to bring
saturation in many areas, especially the lower valleys, plumes of
fog through the night. We`ll continue to see temperatures drop
region wide to below freezing, with lower valleys have a bit
shorter on the confidence side that they`ll drop below freezing
and instead hover around the low to mid 30s (40-60% chance for
Valleys staying above freezing, and >85% chance for higher
elevations dropping below freezing). Otherwise, upper level dry
northwest winds will keep conditions dry for the rest of the
night. Unsettled weather continues later in the late morning hours
to early afternoon when a trough deepens in central Canada,
allowing shortwaves to form valley rain and snow/wintry mix in the
higher elevations.

We`ll have a constant stream of instability with surface southwest
flow, allowing a continuous stream of wetter/warmer weather
through the beginning of next week. Heaviest QPF amounts will be
located in the mountains, with three day totaling up to 3 inches
in the highest elevations (50-70 percent chance) with the lower
elevations that include the Basin, Central Oregon, and the
Kittitas Valleys seeing up to a quarter of an inch of rain, more
so than where the heaviest rain bands occur (40-60 percent
chance). A warm trend will begin on Friday with high temperatures
rising to low to mid 50s and continue on through next week as
well. This will cause some hydro and river level concerns going
through Wednesday with the snow falling between now and then,
although guidance at this time does not have some rivers going
beyond `Action` stage, it is something to keep an eye for the next
couple of days.

Breezy to windy conditions will be observed with the upcoming
system, with the strongest winds occurring between Friday night
and Saturday morning. Parts of the Columbia Basin, Foothills, and
other lower elevation areas will see gusts up to 30 to 40 mph for
much of the time. NBM advertising 40 to 60 percent chances of wind
advisory conditions over the weekend, with 10 to 30 percent
chances of gusts 57 mph or greater. No wind highlights expected
yet, but confidence is increasing slightly for Wind Advisory
thresholds, the question will be if they mix down enough to the
surface to exceed advisory thresholds.

&&

.AVIATION...06Z TAFs...Thanks to the low stratus layer, this will
drop KDLS/KPSC to MVFR with KYKM at IFR and KPDT/KALW to LIFR
conditions. KDLS/KPSC may briefly see patchy fog overnight into
early Thursday morning (35% confidence), but dense fog could
redevelop for KYKM/KALW while continuing for KPDT thus dropping
VSBYs to 1/2sm or less. The fog should then dissipate around 12Z
for KDLS/KPSC and later in the afternoon for KYKM/KALW. KPDT may
have lingering fog/mist through the day Thursday (40-50%
confidence). In addition to the fog and low cloud decks, a weak
system will begin approaching early Thursday morning with light
rain starting KDLS first before other sites. KRDM/KBDN will be VFR
with light rain Thursday morning until MVFR conditions return
early Thursday evening when low clouds redevelop. Winds will
remain less than 10kts. Feaster/97


&&

.PRELIMINARY POINT TEMPS/POPS...
PDT  42  37  54  41 /  90  80  90  50
ALW  41  38  51  42 /  90  90 100  70
PSC  40  33  53  41 /  80  70  70  20
YKM  41  30  51  39 /  50  50  70  50
HRI  41  36  55  43 /  90  70  80  30
ELN  41  33  46  35 /  60  60  80  60
RDM  46  35  56  34 /  50  50  70  30
LGD  40  35  49  39 /  90  90 100  80
GCD  42  37  48  36 /  80  90  90  50
DLS  46  42  56  47 /  80  80  90  80

&&

.PDT WATCHES/WARNINGS/ADVISORIES...
OR...Dense Fog Advisory until 11 AM PST this morning for ORZ507.

WA...Dense Fog Advisory until 11 AM PST this morning for WAZ029.

     Freezing Fog Advisory until 11 AM PST this morning for WAZ026-
     027.

&&

$$

SHORT TERM...95
LONG TERM....95
AVIATION...97