Pendleton, Oregon 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

949
FXUS66 KPDT 141129
AFDPDT

Area Forecast Discussion
National Weather Service Pendleton OR
429 AM PDT Wed May 14 2025

Updated Aviation Discussion

.SHORT TERM...Today through Friday...

1. Mountain rain through this morning and again Thursday afternoon
   through Friday

2. Dry conditions Wednesday through Thursday afternoon

3. Breezy gap winds Today

Current radar very little in the way of precipitation over the CWA.
However, there are some showers moving towards the Cascades. Night
time satellite show the region to be under mostly low and mid level
clouds with low clouds hovering over the eastern mountains and up
through the Wallowas. These should steadily break away to mostly
sunny skies for much of the lower and mid elevations with partly
cloudy skies along the northern Blues, eastern mountains and Wallowa
County.

As the back end of the upper level trough continues to steadily move
across the Cascades and an upper level shortwave ripples down it
later this morning, continued mountain rains will persist through
the late morning early afternoon. 60-80% of the raw ensembles show
that the Cascades as well as the Northern Blues will see between
0.05 to 0.10 inches of rainfall with this shortwave. A short break
in between systems will allow for dry conditions until Thursday late
afternoon when the models show the leading edge of yet another upper
level system making its way towards the PacNW. 50-70% of the raw
ensembles show the Northern Cascades amd southern OR Cascades will
see an additional 0.05 inches and the northern Blues will see 80-90%
probabilities of 0.05 inches as well. 50-70% of the higher terrains
of the eastern mountains will see around 0.01-0.03 inches as well.
Otherwise, the lower and mid elevations will remain dry Through
THursday. The next system will bring another round of precipitation
to the region, however, models show the precipitation to be
relatively light along the lower and mid elevations with 40-60%
probabilities of 0.01-0.03 inches and 30-40% probabilities of 0.03-
0.05 inches along the higher terrains.

Lastly, surface pressure gradients tighten today as a shortwave
ripples down the back edge of the system. 60-80% of the raw
ensembles show the Gorge and Kittitas Valley seeing gusts between 35
to 40 mph. Winds will settle as the upper level ridge continues to
push across the region with raw ensembles showing 60-80%
probabilities of only 15-20 mph gusts. Thursday winds will decrease
as the ridge slowly moves onshore. Raw ensembles show winds to be 20-
25 mph with 60-80% probabilities. As the next upper level trough
moves closer however, 60-80% of the raw ensembles show winds in the
mountain gaps to increase to between 30-35 mph gusts. While this is
nothing new for the area, please be mindful of the winds while
driving through the mountain gaps (I-84 & I-90) today and tomorrow.
Bennese/90

.LONG TERM...Saturday through Wednesday...Sensible weather
concerns through the extended forecast will involve the passage of
an upper trough over the PacNW that will bring widespread
showers, breezy winds, and isolated thunderstorm chances Saturday.
Otherwise, light showers will continue across the mountains with
persistent breezy conditions in the lower elevation locations into
next week.

Ensemble guidance is in great agreement in an upper trough sliding
southeast across the PacNW Saturday, then developing into a closed
low in the eastern Great Basin Sunday afternoon. This will provide
widespread shower activity across the forecast area the first half
of Saturday, but shower activity will retreat to the mountains as
the trough/low digs further southeast of the forecast area
Saturday night through Sunday. Through Sunday morning, the Cascade
crest and the eastern mountains will see a 70-80% chance of 0.25
inches of QPF, with a 40-70% chance of 0.1 inches in the lower
elevations. Surface pressure gradients will also strengthen with
the trough passage Saturday, resulting in breezy winds (gusts
25-40mph) developing through the Cascade gaps and into portions of
the Columbia Basin and Southern Blue mountain foothills(confidence
60-80%).

Light showers will continue across the Cascade crest, northern
Blues, and the Eagle Caps through Sunday afternoon, but a brief
period of dry conditions will develop over the entire forecast
area as the upper low pushes further east. A cross-Cascade surface
pressure gradient will slightly strengthen through Sunday,
resulting in a 60-80% chance of peak wind gusts meeting or
exceeding 45mph in the Eastern Columbia River Gorge and the
Kittitas valley. In the remainder of the lower elevations, wind
gusts will remain near 25-35mph (confidence 50-70%).

Monday, ensemble cluster guidance shows upper level zonal flow
aloft developing over the PacNW while ridging builds offshore the
western CONUS and upper level troughing in the Gulf of Alaska
swings a weak shortwave into the region. Light upslope showers
will develop across the Cascade crest, Blues, and Wallowas for
Monday, with dry conditions in the lower elevations(confidence
50-65%). Breezy winds will continue through Cascade Gaps into
portions of the lower elevations as a strengthened cross-Cascade
pressure gradient remains.

Tuesday into Wednesday, upper level ridging offshore will continue
to build then move across the PacNW, resulting in dry conditions
developing across the mountains and for breezy winds to weaken
over the two days. That said, there are about 20% of individual
ensemble members that favor another shortwave trough moving across
the PacNW with an increase in shower activity across the
mountains early Tuesday through Wednesday. Lawhorn/82

.AVIATION...12Z TAFS...VFR conditions to prevail through the
period. BKN-OVC CIGs will generally remain AOA 5kft-10kt AGL
through this morning, with CIGs lifting to 10kft AGL or higher or
clear skies developing. Breezy winds 15-25kts with gusts 30-35kts
will continue at sites DLS/PDT through the period, with winds
increasing to 12-17kts with gusts to around 25kts at all other
sites this afternoon. Winds will weaken to 12kts or less at sites
RDM/BDN/YKM/ALW/PSC after 3Z-4Z. Lawhorn/82


&&

.PRELIMINARY POINT TEMPS/POPS...
PDT  65  41  67  46 /   0   0   0  30
ALW  65  43  66  47 /  10  10   0  30
PSC  72  40  70  46 /   0   0   0  20
YKM  70  40  69  46 /   0   0   0  10
HRI  70  42  70  46 /   0   0   0  20
ELN  64  41  65  43 /   0   0   0  10
RDM  60  31  64  38 /   0   0   0  20
LGD  58  37  63  43 /  10  10   0  40
GCD  57  34  64  41 /  10   0   0  50
DLS  66  43  65  46 /   0   0   0  10

&&

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

$$

SHORT TERM...90
LONG TERM....82
AVIATION...82