418
FXUS66 KPDT 062102
AFDPDT

Area Forecast Discussion
National Weather Service Pendleton OR
202 PM PDT Sat Jun 6 2026

.KEY MESSAGES...

- Isolated Thunderstorms and scattered showers across the
  Cascade Crest with breezy conditions in the lower elevations
  today

- Widespread rain shower chances and isolated thunderstorms
  across the forecast area Monday into Tuesday

- Breezy lower elevations winds develop Tuesday through
  Wednesday

&&

.DISCUSSION...Today through Sunday: Satellite and radar imagery
this afternoon shows an upper low swinging into the PacNW with
shower/isolated thunderstorm activity mostly west of the
Cascade crest. A few isolated showers have made there way east
into portions of the WA Columbia Basin. Otherwise, breezy
Cascade gap winds have spread into the lower elevations.

Breezy winds and mostly Cascade crest rain showers will continue
through the evening as the upper low tracks across the PacNW. A
few isolated thunderstorms will be possible along the Cascade
crest and east slopes through this evening thanks to weak CAPE
(100-250 J/kg), moderate mid-level lapse rates, and upslope
flow. Shower activity will diminish across the Cascade crest
tonight as the upper low pushes east of the forecast area with a
transient ridge following close behind. However light showers
will be possible through the early morning across the Eagle Caps
and ridges in eastern Wallowa county. Breezy winds today will
become locally breezy tomorrow as a cross-Cascade pressure
gradient weakens slightly under the transient ridge.

Mid to high elevation valleys will see near to below freezing
temperatures develop Sunday morning. Temperatures below freezing
in central Oregon and Wallowa county will be dependent on how
quickly a drier airmass on the backside of the low settles into
the region tonight, as well as winds becoming light and terrain
induced.

Monday through Wednesday: Ensemble cluster guidance starts in
great agreement Monday of an upper shortwave trough amplifying
over the PacNW as it rounds a closed low in the northeast
Pacific. The trough will continue to swing east over the region
through Tuesday and push into the northern Rockies by Wednesday
morning. Offshore, ensemble guidance is in agreement in an upper
level ridge developing sometime Tuesday through Wednesday, but
disagreement grows in the positioning and amplitude of the
ridge Tuesday night through Wednesday.

Confidence is mod-high (65-80%) in widespread showers developing
Monday as the trough moves inland, then shower activity
retreating to the mountains Tuesday as the trough axis moves
east of the Cascade crest. Isolated to widely scattered weak
thunderstorms will also develop in areas underneath and just
east of the trough axis Tuesday afternoon into the evening
hours. By Wednesday, forecast confidence becomes low-mod(30-50%)
in shower activity continuing across the Cascade crest and
eastern mountains through Wednesday, owing to the ensemble
uncertainty in the evolution of the offshore ridge. Otherwise,
there is mod- high confidence (70-80%) in breezy winds (15-25mph
with gusts up to 45mph) developing through the Cascade gaps and
spreading into the lower elevations Tuesday and Wednesday.

Thursday through Friday: Ensemble guidance remains in
disagreement over the evolution of the synoptic pattern through
the end of the work week. About 40% of ensemble cluster members
favor the upper ridge extending across the PacNW, resulting in
drier and warmer conditions developing during this period.
Meanwhile, the remaining members favor the PacNW just on the
edge of a broad upper level low centered over the Canadian
Plains while an upper ridge amplifies poleward offshore. These
solutions would all result in light rain showers over the
WA Cascade crest and higher terrain over the northern Blues, and
weaker warming trend across the forecast area. Confidence in the
forecast through this period is low (20-35%). Lawhorn/82


&&

.AVIATION /18Z TAFS THROUGH 18Z SUNDAY/...VFR conditions
prevail through the period. Breezy winds at times at the TAF
sites, with PROB30 chances of a slight shower at the DLS site
later today. Not expecting any significant CIG or VIS issues.

&&

.Preliminary Point Temps/PoPs...
PDT  40  70  46  68 /   0   0  20  20
ALW  45  70  50  70 /   0   0   0  10
PSC  42  75  48  73 /   0   0  10  10
YKM  40  74  48  69 /  10   0  10  30
HRI  41  73  47  71 /   0   0  20  20
ELN  36  66  42  64 /  10   0  20  40
RDM  28  69  42  63 /   0   0  20  60
LGD  38  67  42  68 /  10   0   0  30
GCD  36  68  41  67 /  10   0   0  30
DLS  43  72  51  67 /  30   0  20  70

&&

.PDT WATCHES/WARNINGS/ADVISORIES...
WA...None.
OR...Freeze Warning from 11 PM this evening to 8 AM PDT Sunday for
     ORZ050-511.

&&

$$

DISCUSSION...82
AVIATION...95