Kennewick, Virginia 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

865
FXUS66 KPDT 170535
AFDPDT

Area Forecast Discussion
National Weather Service Pendleton OR
935 PM PST Tue Dec 16 2025


.AVIATION...

Wind is the primary risk for aviation over the next 12-18 hours,
as a cold front sweeps across the area overnight, bringing strong
momentum transfer/high wind gusts to 40 and 50 knots or higher.
The front and resultant isallobaric pressure rises/strongest
gusts, should be tied to the timing of around 9z on the western
terminals and closer to around 12z for the Lower Columbia Basin
and northern Blue Mountain foothills areas. There is a hint of
weak CAPE of a few hundred J/kg so some convection to aggravate
the winds cant be ruled out, and has the potential to drive gusts
evening higher should any shallow thunderstorms roll near a
terminal (10-15% chances for YKM/BDN/RDM (8-11z) and ALW/PDT
(around 12z). Expect windy conditions to begin to weaken
significantly before 18-21z (speeds and gusts roughly cut by
30-40%). VFR category is anticipated at all terminals. Russell/71


&&

.PREV DISCUSSION... /issued 323 PM PST Tue Dec 16 2025/

DISCUSSION...A shortwave trough and attendant surface cold
front, currently offshore in the Pacific, will swing across the
forecast area overnight into early Wednesday morning. During this
period, 12Z HREF guidance suggests a low-level jet of 50-70 kts
coupled with a surface pressure difference of 10-18 mb between PDX
(Portland) and GEG (Spokane). This will drive a high wind event
across the majority of our forecast area, and High Wind Warnings
and Wind Advisories remain in effect from late this evening
through Wednesday. Strongest wind gusts of 70-80 mph are expected
along wind-prone portions of the Blue Mountain foothills and
slopes of the northern Blue Mountains. Of note, the Storm
Prediction Center (SPC) has placed the majority of our forecast
area under a Marginal risk of severe thunderstorms due to the
potential for severe outflow from low-topped convection with
frontal passage.

After frontal passage Wednesday morning, windy conditions are
forecast to continue through the afternoon hours, gradually
tapering off by late afternoon and evening as winds aloft weaken
and surface pressure gradients relax.

Along with the high winds, the cold front will facilitate a
transition from rain to snow for the mountains. Have opted to
issue additional Winter Weather Advisories for the Oregon
Cascades, northern and southern Blue Mountains, and lower east
slopes of the Washington Cascades due to the potential for near-
blizzard conditions characterized by moderate to heavy snowfall
rates coupled with blowing snow and low visibility with frontal
passage.

Looking ahead, another high wind event is possible Thursday as
winds aloft increase, but confidence is currently low-medium
(20-50 percent) in reaching High Wind criteria. That said, NBM
probabilities indicate better chances (40-70 percent) in reaching
Wind Advisory thresholds across most of our low-elevation zones.

Another concern Wednesday night through Friday is the potential
for winter weather and widespread precipitation as an atmospheric
river is directed into the Pacific Northwest. Will note there is
still ensemble variance in the axis and magnitude of that
precipitation, but the ECMWF EFI is highlighting most of central
to eastern Oregon with values of 0.8-1.0 for QPF, which indicates
good ensemble agreement in a climatologically significant event
for December. Low-elevation snowfall is possible with this system
(30-50 percent chance of measurable snow in central Oregon and the
Kittitas Valley, with higher chances of 70-90 percent in the
Grande Ronde Valley and John Day Basin), but current forecast
snow levels from the NBM quickly rise to 6-8 kft in Oregon and 3-5
kft in Washington Thursday in the wake of a warm frontal passage
which would limit duration of snowfall.

River Flood Watches and Flood Watches remain in effect due to
anticipated rising river levels through the week.

AVIATION...00Z TAFs...VFR conditions prevail with a cold front
approaching the area overnight tonight. This next set of unsettled
weather will bring high winds across the area, bringing some sites
up to 50 knot gusts in the early morning hours, then decreasing by
the late morning hours to early afternoon, albeit winds will
still be 25 to 35 mph in most sites. Embedded with this system
will be precipitation mainly in the form of rain, although VIS and
CIG conditions will remain in VFR. Turbulence is possible in the
overnight hours with wind shear guidance showing 40 to 60 knot
shear across most sites. A small chance (5 to 15 percent chance)
remains for some LLWS across all sites. An Airport Weather Warning
remains in effect for PSC from 1 AM to 5 AM Wednesday due to
elevated winds.

&&

.PRELIMINARY POINT TEMPS/POPS...
PDT  63  40  50  35 /  10  90  50  20
ALW  61  41  52  38 /  20 100  60  20
PSC  61  42  53  37 /  20  90  20  20
YKM  58  38  50  33 /  50  90  30  30
HRI  63  42  52  36 /  10  90  30  30
ELN  50  33  43  30 /  70 100  50  40
RDM  58  32  44  28 /  10 100  50  50
LGD  54  36  48  31 /  20 100  90  30
GCD  55  36  49  30 /  10 100  80  50
DLS  58  43  49  38 /  50 100  60  70

&&

.PDT WATCHES/WARNINGS/ADVISORIES...
OR...High Wind Warning until 4 PM PST Wednesday for ORZ041-044-507-
     508-510-511.

     Wind Advisory until 4 PM PST Wednesday for ORZ049-050-505.

     Winter Weather Advisory from 4 AM to 10 AM PST Wednesday for
     ORZ502-503.

     Winter Weather Advisory from 1 AM to 4 PM PST Wednesday for
     ORZ509.

WA...High Wind Warning until 4 PM PST Wednesday for WAZ024-026>029-
     521.

     Flood Watch through Friday afternoon for WAZ522-523.

     Winter Weather Advisory until 10 PM PST Wednesday for WAZ522.

     Winter Weather Advisory from 1 AM to 10 PM PST Wednesday for
     WAZ523.

&&

$$

SHORT TERM...99
LONG TERM....99
AVIATION...71