143
FXUS66 KPDT 292053
AFDPDT

Area Forecast Discussion
National Weather Service Pendleton OR
153 PM PDT Fri May 29 2026

.KEY MESSAGES...

1. Wind Advisories through 11 PM Friday night

2. Friday afternoon showers and thunderstorms over the eastern
   mountains

3. Dry and cool over the weekend warming up beginning Monday

&&

.DISCUSSION...
Current satellite is showing some convection beginning in southern
Grant County with a cell that is putting out a few strokes of
lightning. Satellite and radar both show a solid line of showers
that expands much of OR and WA moving into the Cascades with ground
observations showing 0.01-0.03 inches of rain along the crests of
the Cascades and portions of the eastern slopes. Also, ground
observations are also showing winds beginning to pick up in the
Kittitas Valley and across the Simcoe Highlands and the lower
Columbia Basin.

Winds today are expected to reach advisory levels through the
Kittitas Valley, Simcoe Highlands, foothills of the southern Blues
and the Gorge of WA and OR. Highest confidence in seeing 25-35 mph
sustained winds and 50 mph gusts is 80-90% through the Kittitas
Valley. Moderate to high confidence in the remaining areas seeing
winds of 20-30 mph sustained and 45-50 mph gusts. A wind advisory is
in effect through 11 PM Friday night.

Mountain showers are already beginning to occur across the Cascades
and are expected to occur over the eastern mountains this afternoon
with 70-90% probabilities of 0.01-0.05 inches of rain for the next
24 hours. Not only will there be rain showers, models also show
there to be increased chances of thunderstorms along the eastern
mountains this afternoon with radar already picking up a cell in
Grant County. As for the rest of the eastern mountains, there is a
15-30% probability of thunderstorms. CAMs models show there to be a
deep layer of instability between 300-500 J/kg, lapse rates in the 8-
9 C/km and lifted indices of -3 to -5 and effective bulk shear
around 25 kts. This is a prime environment for a few isolated
thunderstorms to pop off over the eastern mountains later this
afternoon.

After today, models show the upper level low to traverse across the
region to the north while westerly flow aloft moves in. The westerly
flow aloft will bring dry and cooler temperatures across the area
through the weekend with many places seeing temperatures in the low
to mid 60s Saturday with isolated 70s in the Basin (70-90%
probabilities). Sunday will see slightly warmer temperatures in the
mid to upper 60s with the foothills of the Blues, the Gorge and the
Basin seeing low to mid 70s (70-90% probabilities). In house
calculations show these temperatures to be between 5 to 10 degrees
below seasonal average for this time of year.

Lastly, models show an upper level ridge pushing into the region
bringing back dry and warming conditions. By Tuesday, in house
comparisons show temperatures to be heading towards 5 to 10 degrees
above normal again. NBM shows temperatures to be in the mid to upper
70s with isolated 80s in the Basin and the Gorge Monday increasing
to low to mid widespread 80s Tuesday. By Tuesday night models show
the upper level low to retrograde back towards the region bringing
with it chances of precipitation and eastern mountain
thunderstorms midweek onwards.

&&

.AVIATION /18Z TAFS THROUGH 18Z SATURDAY/...
VFR conditions will generally prevail through the period. The
only exception is at RDM, where there has been some MVFR CIGS
this morning. These CIGS may linger for another hour or two
before returning to VFR.

Otherwise, expect expect gusty winds to around 30 kts this
afternoon at DLS, YKM and PDT and 20 to 25 kts at most other
sites. Winds should decrease to 10 kts or less overnight. DLS
and PDT will gust to around 25 kts on Saturday afternoon as
well.

&&

.Preliminary Point Temps/PoPs...
PDT  41  67  42  71 /  10   0   0   0
ALW  47  68  47  72 /  10  10   0   0
PSC  45  73  43  77 /  10   0   0   0
YKM  43  72  42  77 /   0   0   0   0
HRI  43  70  43  74 /   0   0   0   0
ELN  39  65  40  72 /   0   0   0   0
RDM  31  62  30  67 /   0   0   0   0
LGD  41  64  37  68 /  10  10   0   0
GCD  36  65  34  70 /  30   0   0   0
DLS  45  69  45  76 /   0   0   0   0

&&

.PDT WATCHES/WARNINGS/ADVISORIES...
WA...Wind Advisory until 11 PM PDT this evening for WAZ024-026-521.
OR...Wind Advisory until 11 PM PDT this evening for ORZ041-044-508.

&&

$$

DISCUSSION...90
AVIATION...77