290
FXUS66 KPDT 031158
AFDPDT

Area Forecast Discussion
National Weather Service Pendleton OR
358 AM PST Tue Nov 3 2026

.KEY MESSAGES...

- Dense fog in the Grande Ronde Valley this morning, with patchy
  fog elsewhere.

- Near-normal temperatures and mostly dry conditions until late
  Wednesday.

- Periods of more active weather, breezy winds, and
  predominantly above-normal temperatures late week into next
  week.

&&

.DISCUSSION...
GOES-18 water vapor imagery shows ample moisture aloft spreading
across the region, north of a closed low-pressure system which
is located near 40N, 128.5W. Radar reveals some light returns
over the forecast area, but 00Z observed soundings upstream of
the forecast area at SLE and MFR showed a very dry sub-cloud
layer. Thus, little in the way of precipitation is anticipated
with this system; PoPs are generally 5-15% for our population
centers today.

At the surface, dense fog has been present in the Grande Ronde
Valley since late yesterday evening, and a Dense Fog Advisory
remains in effect this morning. Elsewhere, patchy fog has
developed in portions of the Columbia Basin, but has not yet
become widespread enough to warrant any headlines.

The aforementioned area of low pressure is expected (99%
confidence) to move inland over southern Oregon and northern
California by later today. Mostly dry conditions (PoPs of 20% or
less) are forecast to continue until late Wednesday. Ensemble
guidance is in very good agreement that a shortwave trough will
arrive from the Pacific late Wednesday, and subsequently track
inland through Thursday. Aside from some light precipitation and
locally breezy winds, little in the way of impactful weather is
anticipated with the shortwave. Near-normal temperatures are
expected to continue until late week.

Friday into early next week, ensemble guidance is showing likely
(80%) periods of wet weather for the Washington Cascades, with
significantly lower chances (10-30%) for wet weather east of the
Cascades. East of the Cascades, especially across eastern
Oregon and southeast Washington, above-normal temperatures and
periods of breezy southerly winds are expected (70% confidence).

&&

.AVIATION /12Z TAFS THROUGH 12Z WEDNESDAY/...
VFR conditions are forecast at most sites for the next 24 hours;
notable exceptions are at PDT/ALW (50-80% confidence), and
possibly PSC (30% confidence) where fog is developing or
anticipated to develop into the morning hours. Otherwise, A
low-pressure system tracking south of the forecast area will
bring ample cloud cover to the region today, and very low
(5-15%) chances of precipitation. Clearing skies are forecast by
later afternoon and evening. Winds of 12 kts or less are
forecast at all sites.

&&

.Preliminary Point Temps/PoPs...
PDT  50  29  54  36 /  10   0   0  40
ALW  50  33  53  39 /   0   0   0  20
PSC  53  29  55  34 /  10   0   0  40
YKM  56  31  55  36 /  10   0   0  30
HRI  52  28  55  35 /  10   0   0  50
ELN  52  26  53  29 /  10   0   0  50
RDM  51  20  57  30 /   0   0   0  40
LGD  56  29  57  34 /   0   0   0  20
GCD  58  30  58  35 /   0   0   0  30
DLS  57  33  58  41 /  10   0   0  70

&&

.PDT WATCHES/WARNINGS/ADVISORIES...
WA...None.
OR...Dense Fog Advisory until 10 AM PST this morning for ORZ049.

&&

$$

DISCUSSION...86
AVIATION...86