Bend, Oregon 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

897
FXUS66 KPDT 212138
AFDPDT

Area Forecast Discussion
National Weather Service Pendleton OR
238 PM PDT Wed May 21 2025

.SHORT TERM...Tonight through Friday Night...The Pacific Northwest
is under a zonal westerly today with benign weather and mostly clear
skies at this time. Winds have been lighter than the last few days
with a few places like Ellensburg and the Blue Mountain Foothills
reaching 10 to 15 mph, but winds have also been gusty with
occasional gusts to 25 mph. Winds are decreasing as a shortwave
approaches the area and will arrive this evening. Central Oregon is
already seeing some high clouds arriving. Models have this shortwave
moving in further north than previously forecast and while central
Oregon and the Ochoco Mountains had looked to receive the bulk of
the rain, it now looks like it will impact the northern Oregon and
southern Washington Cascades and eastern mountains the most. CAMs
are showing the precipitation arriving in the late evening, around
10 PM, and crossing the area into tomorrow before exiting to the
east in the afternoon. The late night and morning passage limits the
instability, but models show some weak instability in the afternoon,
so have a slight chance of thunderstorms (15-20 percent) in the
eastern mountains and Wallowa County. Precipitation amounts will be
less than a tenth of an inch in the lower elevations and up to a
quarter inch in the mountains. The Cascade gaps will see west to
northwest winds of 15 to 20 mph in the afternoon but will be lighter
elsewhere. Temperatures tomorrow will be generally 3 to 5 degrees
cooler than today with the exception of the Columbia Basin will be
little changed. Highs will be in the mid 60s to lower 70s with mid
50s to lower 60s in the mountains.

After the system leaves to the east, we will have a brief break
before the next wave arrives Friday afternoon. Models have been
increasing the amplitude of the trough to the south which will send
most of the energy into central California and give us a split
westerly flow which will limit precipitation greatly from previous
forecasts. It looks like we just receive very light rain amounts
over the Ochoco, northern Blue and Wallowa mountains, while the rest
of the area is dry. I would not be shocked to see a stray
thunderstorm or two in the eastern mountains in the afternoon, but
chances were too low to include in the forecast. Winds don`t look to
be too significant with this trough as we get 15 to 20 mph winds
again through the Cascade gaps and 10 to 15 mph in the rest of the
Columbia Basin and central Oregon. A southwest flow ahead of the
wave will warm temperatures 4 to 8 degrees to the upper 60s to mid
70s with 60s in the mountains.

Friday night, the wave will depart and the circulation around a
large upper level low in the Gulf of Alaska will help generate some
ridging and keep the area dry into Saturday morning. Perry/83


.LONG TERM...Saturday through Wednesday Night...The first couple
of days of the long term will be dry as ridging is placed over the
region, paving the way for dry and very warm conditions for the
weekend. Ridging will influence the temperature profile through
Sunday, leading to a warming trend from Saturday to Sunday. We
could very well see our first 90 degree day for parts of the
Basin. NBM probabilities highlights a 50-70% chance that the much
of the WA Columbia Basin, including the Tri-Cities area, and
parts of the OR Columbia Basin (although vastly less widespread
than the WA Basin) will receive highs in the 90s on Sunday. Trends
will need to be monitored if probabilities increase as clusters
become a bit disagreement how amplified the ridge will extend on
Sunday. Regardless, much of the area will experience the hottest
temperatures of the year so far this weekend as they rise 10-20
degrees above average.

Agreements and confidence goes down after the holiday weekend, as
members struggle to model the trough right after ridging. There`s
a split in the clusters to bring precip beyond Central OR and the
Blue Mountains but QPF amounts do not appear to be significant
since this appears at this time to be a weak/drier system.
Regardless, thunderstorm chances for Central OR and the Blues
appear to be tapered down to 10-20 percent thanks to the SW/SSW
flow from the trough and excessive heating from the ridge over the
weekend, putting more fuel into the atmosphere for isolated
storms to develop.


&&

.AVIATION...18Z TAFs...VFR conditions mostly expected for the
period. Brief periods of MVFR expected as a band of precip is
expected later tonight and through tomorrow morning to effect all
sites as a weather system pushes through the region. Visibilities
will be obscured during the periods of the heaviest rain, but only
have confidence to put RDM/BDN down to 5SM in a TEMPO group at
04Z. Winds remain light and variable going through the period,
with brief periods of higher gusts being reported in PDT and ALW
that should decrease as we head into the afternoon and evening
hours.


&&

.PRELIMINARY POINT TEMPS/POPS...
PDT  49  68  44  73 /  30  50   0   0
ALW  50  65  47  72 /  30  60  10  10
PSC  50  72  45  77 /  30  30   0   0
YKM  50  70  44  75 /  40  40   0   0
HRI  50  73  46  76 /  30  30   0   0
ELN  48  69  44  73 /  30  40   0   0
RDM  41  65  36  70 /  20  30   0   0
LGD  45  62  40  69 /  30  70  10  10
GCD  44  65  39  71 /  40  40  10  10
DLS  52  70  47  74 /  40  40   0   0

&&

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

$$

SHORT TERM...83
LONG TERM....95
AVIATION...95