376
FXUS66 KPDT 011708
AFDPDT

Area Forecast Discussion
National Weather Service Pendleton OR
1008 AM PDT Mon Jun 1 2026

.KEY MESSAGES...
- Dry conditions and warming temperatures into the middle of the
  week

- Mountain showers and thunderstorms return Wednesday, and again
  Friday into the weekend

- Breezy winds will redevelop in the lower elevations late
  Wednesday and persist into the weekend

&&

.DISCUSSION...
Today through Early Wednesday: Water Vapor
satellite imagery tonight shows a broad upper low centered over
northern MT, with visible satellite showing thin cirrus
extending across portions of eastern WA.

Today, the intermountain PacNW will sit between the upper low
over MT and a developing upper level ridge offshore. Tomorrow
through early Wednesday, the ridge will slide over the PacNW,
bringing temperatures into the upper 70s to mid 80s in the lower
elevations. Otherwise, conditions will remain dry with locally
breezy afternoon winds.

Wednesday through Sunday: Ensemble guidance is in good
agreement of an upper shortwave trough sliding across the PacNW
Wednesday, though there remains some uncertainty in the exit timing
and strength of this feature. While the main consensus is for a
return of mountain showers and breezy lowland winds into
Thursday morning, under half the members (~45%) favor a
stronger shortwave that will bring area wide showers late
Wednesday that will linger across the Blues/Wallowas into
Thursday afternoon. Otherwise, this pattern would also favor a
return of afternoon/evening isolated thunderstorms over the
mountain areas Wednesday.

Dry conditions will return to the area after the shortwave exit
sometime Thursday, but breezy to locally gusty Cascade gap
winds will persist(confidence 60-70%). Ensemble guidance is in
good agreement that an upper low will arrive offshore the PacNW
Friday then push inland Saturday morning. Showers will develop
along the Cascade crest Friday, then spread along the east
slopes and over the northern Blues late Saturday morning
(confidence 50-60%). Disagreement grows amongst ensemble
guidance Saturday afternoon through Sunday in regards to how
quick the trough passes overhead, with the leading solutions
(~60% of members) favoring the trough exiting to the eat by
Sunday afternoon, while the remaining members favor the trough
still over the region. The former solution would favor drier
conditions developing by Sunday afternoon, while latter favor s
continued mountain showers through Sunday. Overall forecast
confidence is low-moderate(35-45%) at this time. Besides
precipitation, the upper low arrival and subsequent passage will
produce breezy winds across the lower elevations and below
normal temperatures through the weekend (confidence 50-60%).
Lawhorn/82

&&

.AVIATION /18Z TAFS THROUGH 18Z TUESDAY/...
VFR conditions prevail with light winds of 12 knots of less.
Wind will be driven by terrain at times, especially in the
early morning hours. No CIG or VIS issues expected.

&&

.Preliminary Point Temps/PoPs...
PDT  77  48  81  50 /   0   0   0   0
ALW  77  52  81  54 /   0   0   0   0
PSC  82  51  85  52 /   0   0   0   0
YKM  82  53  84  54 /   0   0   0   0
HRI  81  50  84  51 /   0   0   0   0
ELN  77  48  79  52 /   0   0   0   0
RDM  74  41  82  49 /   0   0   0   0
LGD  73  44  79  46 /   0   0   0   0
GCD  76  42  83  46 /   0   0   0   0
DLS  83  57  87  60 /   0   0   0   0

&&

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

&&

$$

DISCUSSION...82
AVIATION...95