262
FXUS66 KPDT 302322
AFDPDT

Area Forecast Discussion
National Weather Service Pendleton OR
422 PM PDT Tue Jun 30 2026

.KEY MESSAGES...
- Cool and breezy conditions through the midweek.

- Warming trend returns above normal high temperatures Friday.

- Heat and low humidities peak Saturday through Monday.

&&

.DISCUSSION...
Current radar and infrared satellite imagery shows a broken
line of showers extending across Union and Wallowa counties
under mostly clear to partly cloudy skies. This is in response
to a weak upper level shortwave slowly passing through the
region, which will lead to the potential for isolated
thunderstorms over these areas through the afternoon and early
evening. The Storm Prediction Center has placed Wallowa county
in their general thunderstorms (0 out of 5) category for the
day, highlighting the likelihood of sub-severe storms.
Precipitable water values are between 0.75-0.9" or 140-160%
above normal, so any storm cells that do develop should include
a wetting rain (>0.10"). This shortwave feature has also
attributed to a pressure gradient developing along the Cascades
to bring breezy winds across the Lower Columbia Basin/Gorge,
east slopes of the Cascades, and the Kittitas Valley. Sustained
west winds of 20-27 mph with gusts of 30-35 mph are expected in
these areas, but the NBM does suggest there to be a 25-45%
chance of advisory level wind gusts (+45 mph) for the Dalles and
Ellensburg areas - peaking around 5 PM. This will continue to
be monitored through the afternoon in case an advisory is
needed.

A second upper level shortwave passes through the area
Wednesday, broadening out the upper level trough and leading to
another breezy day across the Lower Columbia Basin, Simcoe
Highlands, Eastern Gorge, and Kittitas Valley with similar
sustained winds and gusts as today. This broadening of the
overall trough feature that is draped across the Pacific
Northwest will again be stretched late Thursday as yet another
shortwave moves into the region. This third shortwave will lead
to flow aloft turning from the northwest to the west to
intensify the gradual warming trend experienced earlier in the
week. As a result, high temperatures will be near to above
normal Friday before becoming above normal through the weekend
with highs in the low to mid-90s across the Lower Columbia
Basin.

A building upper level ridge across the Desert Southwest, and
surface high pressure to our east will stall a cold front across
Central WA/OR over the weekend which will further enhance
warming and drying. Afternoon humidities will drop into the
single digits over portions of Central Oregon, and in the low to
mid-teens across the Lower Columbia Basin on Saturday. Very
slight improvement is expected through Monday, but overnight
humidity recoveries will continue to decrease and eventually
reach values between 35-55% by Tuesday morning. 75

&&

.AVIATION /00Z TAFS THROUGH 00Z THURSDAY/...VFR conditions to
prevail through the period. Breezy winds (15-25kts with gusts
up to 35kts) will continue at site DLS through the period.
Breezy winds (12-17kts with gusts up to 25kts) at sites
PDT/RDM/BDN/YKM/ALW will become 12kts or less overnight, with
light winds prevailing at most sites tomorrow. Site PDT will see
breezy winds redevelop after 17Z. Lawhorn/82

&&

.Preliminary Point Temps/PoPs...
PDT  44  76  46  79 /   0   0   0   0
ALW  51  77  52  81 /   0   0   0   0
PSC  49  81  50  83 /   0   0   0   0
YKM  49  82  50  83 /   0   0   0   0
HRI  47  79  49  82 /   0   0   0   0
ELN  45  74  46  77 /   0   0   0   0
RDM  34  75  38  79 /   0   0   0   0
LGD  43  76  45  81 /   0   0   0   0
GCD  40  78  43  83 /   0   0   0   0
DLS  50  73  51  79 /   0   0   0   0

&&

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

&&

$$

DISCUSSION...75
AVIATION...82