537
FXUS66 KPDT 082200
AFDPDT

Area Forecast Discussion
National Weather Service Pendleton OR
300 PM PDT Mon Jun 8 2026

.KEY MESSAGES...
- Widespread rain shower chances and isolated thunderstorms
  across the forecast area Today into Tuesday

- Breezy lower elevations winds develop tonight through
  Wednesday

- Drying and warming trend late week through the weekend

&&

.DISCUSSION...
Today through Wednesday: Satellite imagery this
afternoon shows a shortwave trough with an attendant surface low
just offshore the PacNW, with cloudy conditions across much of
the region. Area radar shows the western half of WA/OR covered
in showers, with shower activity extending to the east slopes of
the Cascades, eastern Columbia River Gorge, and central OR.

A shortwave trough and surface low will continue to swing
across the PacNW today through tonight. A rain shield will
spread north and east from the Cascade crest through the
remainder of this afternoon and evening, with isolated to
scattered showers developing overnight. CAMs continue to
indicate weak surface based instability developing across the
eastern OR mountains this afternoon will also result in low
chances (5-15%) of isolated thunderstorms. In the Columbia
Basin, breezy winds will develop ahead of the precipitation late
this afternoon, with wind gusts generally remaining less than
35 mph.

Tuesday, shower activity will retreat mostly to the mountain
areas and Blue mountain foothills as northwest flow aloft
develops behind the trough axis exit. Weak instability will
develop across the WA Cascade crest, far northeast OR, and
southeast WA late in the morning and afternoon Tuesday,
resulting in a slight chance (15-20%) of isolated thunderstorms.
However, thunderstorm activity is expected to diminish late in
the afternoon as the trough lifts into MT. Otherwise, widespread
breezy southwest to west winds (15-25 mph with gusts up to 40
mph) will develop tonight through tomorrow as a cold front
boundary passage tightens pressure gradients across the forecast
area. In the lower elevations, the strongest winds (sustained
winds 25-35 mph with gusts up to 50 mph) are expected to develop
across portions of north central OR, the eastern Columbia River
Gorge, Simcoe Highlands, OR Columbia Basin, OR Blue Mtn
foothills, and the Kittitas valley.

By Wednesday, the trough will slide further east of the region
while upper level ridging will develop over the northeast
Pacific. Any lingering shower activity over the mountains will
diminish by the afternoon as the region comes under the
influence of the upper ridge offshore. breezy to locally breezy
winds will continue into Wednesday evening, but will become
light Wednesday night into Thursday.

Thursday through Sunday: Late in the work week through the
weekend, there is great agreement amongst ensemble guidance in
warmer and drier conditions developing as upper level ridging
continues to build offshore the PacNW. That said, uncertainty
does grow in the amplitude and position of the ridge offshore.
While ensemble cluster solutions all keep the region dry through
this period, about half of the members keep the upper ridge
further offshore with a northerly flow into the intermountain
PacNW. These solutions also favor a shortwave trough to clip the
region, which would increase winds in the lower elevations and
bring elevated fire weather concerns. The other half of
solutions keep the ridge axis much closer with northwest flow
over the region. This solution would keep the trend of light
winds, but would favor increased warming across the forecast
area over the weekend. Speaking of temperatures, the NBM shows a
40-60% chance of areas of the Columbia Basin/Gorge and Yakima
valley reaching 90 degrees Saturday, with a widespread 40-75%
chance of 90 degrees across most lower elevation locations
Sunday. Lawhorn/82

&&

.AVIATION /00Z TAFS THROUGH 00Z WEDNESDAY/...

Current radar shows widespread light showers across the region,
with heavier showers/isolated thunderstorms near the Cascade
Crest. Current guidance doesn`t support thunderstorms at TAF
sites for this period, but a small (0 to 10 percent) chance
proceeds through Tuesday that a storm impacts the TAF sites.
Light to moderate rain showers will continue through the evening
hours, with most areas chances of rain dropping to PROB30`s by
the early morning hours. Winds for the most part will be breezy
to windy with sites gusting up to 35 to 45 mph through the TAF
period. Although VFR conditions are currently forecasted to
prevail, small confidence (5 to 15 percent chance) remains that
the more moderate/heavier showers could produce less than 3000
feet cloud decks and less than six mile visibility.

&&

.Preliminary Point Temps/PoPs...
PDT  49  67  42  69 /  90  20  10   0
ALW  52  67  47  69 /  90  50  20  10
PSC  48  73  44  75 /  90  10   0   0
YKM  48  70  42  74 /  80  10   0   0
HRI  48  71  44  73 /  80  10   0   0
ELN  45  63  39  65 / 100  30  10   0
RDM  43  65  32  69 /  50  10   0   0
LGD  46  63  41  64 /  90  60  30  20
GCD  43  67  37  67 /  90  20  10   0
DLS  53  68  49  70 /  90  30  10   0

&&

.PDT WATCHES/WARNINGS/ADVISORIES...
WA...Wind Advisory from 2 AM to 11 PM PDT Tuesday for WAZ024-521.
     Wind Advisory from 8 AM to 11 PM PDT Tuesday for WAZ026.
OR...Wind Advisory from 2 AM to 11 PM PDT Tuesday for ORZ041-044-
     508.
     Wind Advisory from 8 AM to 11 PM PDT Tuesday for ORZ507.
     Wind Advisory from 11 PM this evening to 5 PM PDT Tuesday for
     ORZ510.

&&

$$

DISCUSSION...82
AVIATION...95