317
FXUS66 KPDT 102143
AFDPDT

Area Forecast Discussion
National Weather Service Pendleton OR
243 PM PDT Sat Oct 10 2026

.KEY MESSAGES...

- Cold air mass expected to move through the area this weekend
  and next week

- Breezy conditions this weekend along the Eastern Oregon
  Cascades, Washington Cascades, Lower Columbia Basin and Yakima
  Valley

- Return of mostly dry conditions, light winds, and above normal
  temperatures middle of next week

&&

.DISCUSSION...

Scattered to broken cloud layers around 6000 ft were common
across the forecast area This Afternoon with of more sun through
the Columbia River Gorge and southeast Washington. A zonal flow
pattern was giving way to a mid level troughing of cooler air
aloft over the PAC NW that will continue to amplify through
Monday Night into the Great Basin. Challenging forecast in terms
of where the cold air will have impacts. There is a large
discrepancy in the the short term ensemble models and the the
NBMs more weighted raw inputs and bias corrected member data
having very cold air the the 20s across the Wallowa valley
overnight. HREF shows a more muted temp trend as cloud cover,
which kept temps in the the mid 30 last night again shows its
hand overnight not only in the total cloud cover but in low
level HRRR fields between about midnight and 14z (increasing
trends). The uncertainty lies in the cloud cover; if any
appreciable clearing occurs or the clouds fail to redevelop,
colder sub freezing temperatures could will develop quickly. At
this time, forecaster confidence doesnt reach the thresholds to
continue freeze warnings in the very near term. With Redmond
and Bend reaching 32 and colder last night, the central Oregon
forecast zone is now being considered as having its seasonal
ending freeze. Showers across the Wallowas are also possible
Sunday night as the NBM is putting in fairy high pops in the 50
to 70% range over these high elevations. Monday night and
Tuesday morning may present the same issues with cloud cover
across a larger area with respect to freeze headlines. There is
a ensemble member trend where the cloud cover is clearing out
better across the western zones, if not Monday morning across
the northwest, certainly by Tuesday morning, over the entire
area. North central Oregon , some of the Foothills of the Blues
and northward into he Kittitas and Yakima valley areas should be
prone to freezing by Tuesday morning. Kittitas valley already
has an 80% chance from NBM members of reaching below 32 degrees
for Monday morning, coincident with high confidence in clearing
sky and a freeze watch is being hoisted for that zone.

Once the upper low/trough moves through the region Tuesday,
temperatures begin a sharp rebound as afternoon highs rise out
of the 60s and back into the 70s for the Columbia Basin and
River Gorge, for the latter half of the week. Corresponding not
as cold lows in the upper 30s and lower to mid 40s are the
NBMs favored temps for non mountain zones.


&&

.AVIATION /18Z TAFS THROUGH 18Z SUNDAY/...

Predominantly VFR conditions are forecast at all sites today,
albeit with FEW-BKN clouds ~4-7 kft AGL. Aside from breezy
westerly winds at DLS, and periodic gusts elsewhere, light winds
of 10 kts or less are forecast. North to northeast winds will
increase in magnitude at RDM/BDN/YKM/PSC Sunday morning.

Chances of MVFR CIGs/VSBYs increase overnight, mainly at
BDN/RDM where 12Z HREF probabilities are 50-90% for MVFR CIGs
and 10-40% for MVFR VSBYs, and 12Z REFS probabilities are 40-60%
for MVFR CIGs and <10% for MVFR VSBYs. Elsewhere, chances of
MVFR conditions are low (20% or less).

&&

.Preliminary Point Temps/PoPs...
PDT  38  54  31  57 /   0  10  10  10
ALW  40  55  35  57 /   0  10  10  10
PSC  44  60  35  62 /   0  10   0   0
YKM  42  59  34  63 /  20  10   0   0
HRI  41  58  34  61 /   0  10   0   0
ELN  38  55  29  60 /  40  10   0   0
RDM  32  48  22  55 /   0  10   0   0
LGD  35  50  31  55 /   0  10  20  10
GCD  29  50  29  55 /   0   0  10  10
DLS  45  63  38  67 /   0   0   0   0

&&

.PDT WATCHES/WARNINGS/ADVISORIES...
WA...Freeze Watch from Sunday evening through Monday morning for
     WAZ026.
OR...None.

&&

$$

DISCUSSION...71
AVIATION...86