710
FXUS66 KPDT 211825
AFDPDT

Area Forecast Discussion
National Weather Service Pendleton OR
1025 AM PST Fri Nov 21 2025


.UPDATED AVIATION...18Z TAFs...As visibilities gradually improves,
low clouds continue to linger for the KDLS/KPSC, making them IFR
before clearing out later this morning. Afterwards, they will
return to VFR, joining in with the remaining sites. KDLS may
decrease to MVFR Saturday morning when low clouds return (>40%
confidence). Winds will be less than 10kts. Feaster/97


&&

.PREV DISCUSSION... /issued 737 AM PST Fri Nov 21 2025/

UPDATE...

Areas of Dense Freezing Fog are currently observed via visible
satellite imagery and webcams, which has warranted the issuance of
a Freezing Fog Advisory across the Lower Columbia Basin of Oregon
and Washington as visibilities as low as a quarter mile and
freezing temperatures are currently being observed. These
conditions are expected to dissipate around 10 AM, so use caution
if traveling in these areas this morning as you may encounter
reduced visibilities that may change quickly. 75


PREV DISCUSSION... /issued 153 AM PST Fri Nov 21 2025/

.DISCUSSION...Quiet weather is expected to prevail heading into
the weekend as a high pressure ridge settles over the PacNW. So
long as skies remain clear, however, conditions will be ripe with
overnight low stratus and fog development, which can already be
seen early this morning in central Oregon and along the Columbia
River. With high pressure in place, these low clouds will struggle
to lift as well, so many of our low-lying areas may see overcast
conditions persist well into the day once they form. Have already
issued a Dense Fog Advisory for central Oregon, and expectation is
that coverage will only spread over the coming days.

As far as precipitation chances are concerned, the ridge is broad
enough to welcome at least some moisture advection into the central
Washington Cascades, but should note that guidance has scaled back
PoPs quite a bit compared to previous runs, so current thinking is
that the next best chance for area-wide precip will arrive with a
cold front sometime around the Sunday afternoon and early evening
hours. Models are coming into better agreement with this system, but
still differ slightly on the attendant trough`s amplitude, so
confidence on QPF is only moderate (40-50%), but as of now, given
the quick-moving nature of the system, most impacts will be directed
to the Cascades and eastern mountains. Snow levels will fall as cold
air rushes in behind the front, down to 2500-3000 ft by early Monday
morning, so some accumulations are expected along our mountain
passes, albeit only a couple of inches at best for primarily the
Washington Cascade passes given the system`s speed and precip
transition from rain during the day to snow overnight into Monday.
Winds will be breezy as well, but are expected to remain below
advisory criteria at this time.

Ensembles are still not in great agreement beyond Monday, but do
favor some sort of ridging pattern through the midweek. Whether or
not the ridge axis will allow for moisture advection into the
forecast area is uncertain, however. Should note that by the end of
next week, both the deterministic GFS and ECMWF hint towards a cold
spell, but much could change across guidance between now and then.
74


&&

.PRELIMINARY POINT TEMPS/POPS...
PDT  50  31  51  34 /   0   0   0   0
ALW  49  36  51  38 /   0   0   0   0
PSC  49  29  47  32 /   0   0   0   0
YKM  48  29  49  34 /   0   0   0   0
HRI  49  29  48  33 /   0   0   0   0
ELN  48  30  48  34 /   0   0   0  10
RDM  51  24  58  28 /   0   0   0   0
LGD  51  30  53  34 /   0   0   0   0
GCD  50  29  56  31 /   0   0   0   0
DLS  51  35  51  39 /   0   0   0   0

&&

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

$$

MORNING UPDATE...75
SHORT TERM...74
LONG TERM....74
AVIATION...97