032
FXUS66 KPDT 232229
AFDPDT

Area Forecast Discussion
National Weather Service Pendleton OR
329 PM PDT Thu Apr 23 2026

.KEY MESSAGES...
- Breezy winds linger today.
  *Wind Advisory Active*

- Cooling into Friday, freezing morning temperatures Saturday

- Light mountain showers Sunday, including foothills on Monday.

&&

.DISCUSSION...
Current radar and visible satellite imagery very light returns
across northern Columbia and Wallowa counties under mostly clear to
partly cloudy skies. This is in response to an upper level trough to
our northeast that will strengthen and extend south, bringing a cold
front passage overnight tonight before slowly pushing east over the
weekend. The frontal passage will bring breezy winds for the
remainder of the evening, as well as cooler temperatures Friday as
highs are expected to peak in the upper 50s to low 60s across lower
elevations of the Columbia Basin and Central Oregon. Current wind
gusts across much of the area are between 15-25 mph and will
continue to slowly subside through the remainder of the evening.
However, areas along the east slopes of the Washington Cascades,
primarily through the Kittitas Valley, will experience more
prolonged and heightened gusts of between 35-45 mph. Thus, a
Wind Advisory has been issued across the Kittitas Valley until 9
PM this evening as gusts of up to 50 mph will be possible.

The cold front will pass to our south on Friday as the upper
level trough continues to dip south, providing northern flow
aloft. This will bring cooler temperatures on Friday under sunny
skies. These clear skies will persist through the day and into
Saturday, allowing efficient radiational cooling to occur as
surface high pressure slides in behind the cold front. As a
result, frigid morning temperatures are expected as morning lows
will dip into the upper 20s to low 30s across the Lower Columbia
Basin and Central Oregon. Confidence in these freezing Saturday
morning temperatures is high as the NBM advertises a 70-90%
chance through Central Oregon and Union county (Bend, Redmond,
Madras, John Day), with a 40-70% chance over the Blue Mountain
foothills and Kittitas Valley (Ellensburg, Pendleton, Walla
Walla, Heppner, Condon) of experiencing morning temperatures of
32 degrees or lower. There is even a 45-65% chance of Central
Oregon and Union county dipping into the upper 20s Saturday
morning via the NBM.

The upper level trough will continue to dip south as an
embedded shortwave approaches from the northwest on Sunday,
bringing a return to mountain rain and high elevation snow
chances to the area Sunday and Monday. The trough will dip south
and tap into slight moisture Sunday to bring a 25-35% chance of
showers to the Cascades, Blue Mountains, and John Day Highlands
Sunday, with minimal amounts expected (<0.05"). The shortwave
arrives on Monday to enhance rain chances (30-50%) and extend
along the Blue Mountain foothills and the John Day Basin
(20-40%). Monday`s rain amounts are still expected to be minimal
as the ECWMF AI Ensemble and GFS ensembles showcase
Precipitable Water amounts of between 0.25-0.45" (80-90% of
normal). Rain amounts over higher terrain across the Blue
Mountains and Elkhorns may reach a wetting rain (0.10" or more),
but lower elevations are likely to stay well below that amount
with very little (less than 0.02") along the foothills. Snow
levels will hover between 5000-6000 feet Sunday and Monday.

The trough begins to move east into Monday, opening the door to
a slow moving upper level ridge and surface high pressure
Tuesday onward. This will bring dry and warming conditions
across the area as high temperatures reach into the upper 70s to
low 80s through the Lower Columbia Basin on Friday. The NBM
suggests a 45-60% chance of high temperatures reaching 80
degrees or above for the Tri-Cities area, Yakima, and The
Dalles, and a 20-30% chance for Walla Walla and Hermiston
Friday. Confidence in these chances are rather low as ensemble
members struggle with the strength of the incoming shortwave
that enhances southwest upper level flow to advect a warmer
airmass into the region late in the week. Currently, 51% of
ensemble members showcase the present ridge effectively shearing
the incoming shortwave north versus the ridge shifting east and
breaking down as the shortwave pushes inland earlier. Either
way, the overall pattern aligns with warming and drying
conditions through the workweek after light mountains showers
Monday. 75

&&

.AVIATION /00Z TAFS THROUGH 00Z SATURDAY/...VFR conditions to
prevail through the period. An isolated shower or two may impact
site ALW late this afternoon into the early evening, with a
PRO30 of light rain included in the TAF. Winds will be 12-17kts
with gusts up to 27kts at sites DLS/PDT/YKM into this evening,
with light winds developing overnight and prevailing through
tomorrow. All other sites will see light winds prevail through
the period. Lawhorn/82

&&

.Preliminary Point Temps/PoPs...
PDT  36  56  32  58 /  30   0   0   0
ALW  37  57  35  60 /  40  10   0  10
PSC  38  63  33  65 /  20   0   0   0
YKM  39  60  34  63 /  10   0   0   0
HRI  37  60  32  63 /  20   0   0   0
ELN  34  57  32  59 /  10   0   0   0
RDM  29  57  27  57 /   0   0   0   0
LGD  34  52  30  55 /  50  10   0  10
GCD  33  52  29  55 /  10   0   0  10
DLS  41  64  37  66 /   0   0   0   0

&&

.PDT WATCHES/WARNINGS/ADVISORIES...
WA...Wind Advisory until 9 PM PDT this evening for WAZ026.
OR...None.

&&

$$

DISCUSSION...75
AVIATION...82