989
FXUS66 KPDT 291117
AFDPDT

Area Forecast Discussion
National Weather Service Pendleton OR
417 AM PDT Mon Jun 29 2026

.KEY MESSAGES...

- Morning showers in eastern portions of the Columbia Basin

- Below-normal temperatures, breezy to locally windy west
  winds, and occasional light mountain showers through the week

&&

.DISCUSSION...

Deep northerly flow is seen in the satellite data overnight as
the area ins on the backside of the upper low now lifting across
northern Montana and with SPC analysis indicating some weak
moisture transport across eastern Washington with mid level
clouds and light rains overspreading much of this area.
Gradient induced wind gusts continue between about 25 an 35 mph
across the Columbia Basin overnight and are forecast to continue
the pattern through the day. Winds across the Kittitas valley
look to have a weakening trend in the afternoon based on
probabilities of gusts to 40 mph at 7 AM around 80% but falling
to around 30% by 2 PM before up ticking in the evening to around
50%. A similar trend can be expected across the Eastern
Columbia River Gorge, and the Foothills of the Blue
Mountains/Oregon Columbia Basin Today and This Evening. Mid
level clouds and showers will linger across southeast WA and the
Oregon Blue Mountains/Wallowas though about mid afternoon while
breaks of direct insolation will be found farther west and
afternoon high climb back into the 80s for sections of the Lower
Columbia Basin/Yakima Valley. Although weak synoptic troughing
lingers across the region into Tuesday, the wind will be much
lighter on Tuesday, and the character of the day drier and
warmer. Winds may still be noticeably breezy to windy across the
Eastern Columbia River Gorge and Kittitas Valley but more tied
to locally terrain than a widespread wind episode.

Toward the end of the week, enough similarity exists between
the ensembles clusters to bring fairly high confidence in any
precipitation over the July 4th Holiday weekend would be
relegated to the higher terrain/mountain zones an light (only a
few hundredths of an inch over a 24 hour period). Additionally
these clusters show little in the way of MUCAPEs, which would
point to showers rather than risk of anything more than isolated
thunderstorms.

&&

.AVIATION /12Z TAFS THROUGH 12Z TUESDAY/...

Light rains or drizzle is being reported by some METARs form ALW
to PSC and Sunnyside, and may show up at PDT over the 11 to 13z
window, having little if any impact on the VFR category cigs or
visibility (about 6000 ft or higher and still 10 SM). Duration
is uncertain as the HRRR keeps light showers across SE WA and NE
OR through early afternoon but terminals at ALW/PDT/PSC should
expect VCSH though 18z. Other than these morning light showers,
the breezy to gusty westerly winds will weaken in the afternoon,
and undergo more significant weakening after about 6z.

&&

.FIRE WEATHER...

Breezy conditions Today could impact any fire ongoing. The
breezy conditions will begin to wane this afternoon leaving
Tuesday with much lighter winds across the greater area. Tuesday
can still see some locally breezy to gusty conditions across
the Eastern Columbia River Gorge and Kittitas Valley. The cooler
conditions Today will continue to mitigate the overall impact
of relative humidity (keeping it elevated). An isolated
thunderstorm cannot be ruled out over eastern Wallowa county
Tuesday afternoon (less than 20% chance). No thunderstorm/lightning
risk is anticipated for the rest of This Week.

&&

.Preliminary Point Temps/PoPs...
PDT  75  52  76  45 /  40  10   0   0
ALW  76  57  77  51 /  80  10  10   0
PSC  81  58  82  51 /  50  10   0   0
YKM  83  56  83  50 /  20  10   0   0
HRI  79  56  79  49 /  30  10   0   0
ELN  75  53  74  46 /  10   0   0   0
RDM  72  41  74  34 /   0  10   0   0
LGD  70  50  75  43 /  80  10  10   0
GCD  72  48  77  39 /  20  10   0   0
DLS  73  56  72  51 /   0   0   0   0

&&

.PDT WATCHES/WARNINGS/ADVISORIES...
WA...Wind Advisory until 7 AM PDT this morning for WAZ026.
OR...None.

&&

$$

DISCUSSION...82
AVIATION...71
FIRE WEATHER...73