586
FXUS66 KPDT 110517
AFDPDT

Area Forecast Discussion
National Weather Service Pendleton OR
1017 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

&&

.UPDATE...
Lowered min temps for tonight through the Columbia Basin,
Foothills of the Blues, and Yakima/Kittitas Valley. Can expect
temps to be near freezing through the overnight hours (40-50%
chance) but difficult to produce a Freeze Warning with low
confidence it would last sufficiently enough to meet criteria
(10-30% chance). For now, I`ve left minimum temps in the mid to
upper 30s in most places but isolated freezing temps is possible
with dew points hovering in the mid to upper 20s.

&&

.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 short term ensemble models and the NBM`s
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 doesn`t 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 season-ending
freeze. Showers across the Wallowas are also possible Sunday
night as the NBM is putting in fairly 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 the 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
NBM`s favored temps for non mountain zones.

&&

.AVIATION /06Z TAFS THROUGH 06Z MONDAY/...
VFR conditions forecasted for all sites through the forecast
period, with light and general winds initiating. Will see
breezy/elevated winds develop in late morning to early afternoon
with most places topping 10-20 knots sustained. Areas around
RDM, PSC, and YKM could see wind gusts up to 20 to 30 knots with
lighter winds in the late afternoon to early evening hours.

Low chances (10-30% chance) of seeing some MVFR CIGs/VISs
through the overnight hours at BDN/RDM develop. Chances decrease
as we head into the later morning to early afternoon hours with
increase mixing decreasing low deck formation.

&&

.Preliminary Point Temps/PoPs...
PDT  33  54  31  57 /   0  10  10  10
ALW  38  55  35  57 /   0  10  10  20
PSC  39  60  35  62 /   0   0   0   0
YKM  39  59  34  62 /  10   0   0   0
HRI  36  58  34  61 /   0   0   0   0
ELN  35  55  29  59 /  40   0   0   0
RDM  32  48  22  55 /   0   0   0   0
LGD  35  50  31  54 /   0  10  30  40
GCD  29  50  29  54 /   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.

&&

$$

UPDATE...95
DISCUSSION...71
AVIATION...95