050
FXUS66 KPDT 132302
AFDPDT

Area Forecast Discussion
National Weather Service Pendleton OR
302 PM PST Thu Nov 13 2025

.AVIATION UPDATE.

.AVIATION...00Z TAFs...A very complicated forecast ahead with the
Basin essentially in a cold pool trapping moisture in the lower
level. Many sites have hovered around 2-5 miles of visibility all
day and will continue to be off and on as we go through the
forecast. Many factors, such as forcing strength, depends if the
moisture can lift or clear the terminal in VFR. Most of the
susceptible areas for MVFR and IFR conditions will be the Basin
sites (ALW/YKM/PDT) with at least a 5-15% chance for sub-VFR
conditions.

The main highlight for the Central OR sites (BDN/RDM) will be the
winds with gusts up to 20-30 mph mainly going through 04Z, before
calming down to 5-10 mph sustained. RDM/BDN will be mostly free of
sub-VFR conditions (80-90% chance) due to more efficient mixing
than in the inner Basin sites.

&&

.KEY POINTS...

1. Persistently wet weather pattern Thursday & Friday afternoon

2. Breezy winds Thursday & Friday

3. Mountain showers and low level dry conditions through  Saturday
   Friday afternoon before widespread rain returns Sunday

.DISCUSSION...Today through Friday afternoon...Current satellite
shows a decent cloud deck overhead across the region. Radar shows
some cells that have the capability of putting down some rain with
ground observations showing 0.03-0.06 inches of rain in and around
Yakima over the last three hours.

Light rain will continue through the day today with 0.01-0.05 inches
of accumulation through tonight. Raw ensembles show a 20-30% chance
for 0.05 inches in the Basin while the remaining areas will see 40-
80% probabilities. Rain will continue through the evening hours
before keeping to mainly the ridgetops after 1 PM Friday. Models
show the wedge between the two upper level systems we are currently
sitting under will continue to cause southwest flow aloft. Warmer
air will continue to advect over the region through the weekend. NBM
shows snow levels to remain above 6-7kft through midweek.

The southwest flow aloft will also lead to the enhancement of the
winds through central OR, through the Ochoco-John Day Highlands and
the foothills of the Blues. Deterministic models show the surface
pressure gradients to continue to tighten through the day bringing
probabilities of 30-40 mph gusts along the aforementioned areas. 70-
90% of the raw ensembles are in agreement with the wind gust speeds.
By Friday, models show the southwest flow aloft begins to shift to a
more west to northwest component bringing the breezy conditions to
the Cascade Gaps, mainly through Yakima Valley and portions of the
WA Cascade east slopes. The Basin will see heightened winds as well
but will remain below 25 mph with 30-50% probabilities.

Friday night through Sunday morning...Models show a bit of a
complex pattern beginning Friday afternoon as the upper level low to
the south of the region begins traversing north in turn flattening
and then lifting the low to the north. Clusters are also showing a
deviation between ensembles as to how this complex pattern will play
out. However, most models seem to agree that flow over the region
begins to take on a northwest flow aloft bringing in cooler air
beginning Sunday. Models show much of the precipitation to be locked
along the Cascade crests with 30-70% probabilities of 0.06 inches
along the OR Cascades and 60-90% along the WA Cascades and bleeding
down into Kittitas Valley with Ellensburg seeing 40-60% probabilities
of up to 0-06 inches as well Saturday. Elsewhere will see little to
no rainfall.

Sunday onwards...Models continue to deviate a bit with regards to
timing and location of the next incoming wave. Clusters are showing
location and timing differences but deterministic models are showing
a elongated trough forming off the coast of B.C.. Southwest flow
aloft will again dominate the region but the air advecting into the
region is more tied up with colder air. NBM ensembles and guidance
shows that snow levels will steadily begin to decrease and by Sunday
night beginning to dip into the 4500-5000 ft range. Light snow
showers along the Cascades will occur while the remainder of the
region will see light rain accumulations through Tuesday. Wednesday
will be the next probable day with any significant rain or snow
accumulations. However, models are slightly all over the place with
regards to the incoming system Wednesday. 90

&&

.PRELIMINARY POINT TEMPS/POPS...
PDT  44  60  42  60 /  80  40  10  10
ALW  48  59  46  58 /  90  50  20  20
PSC  44  61  45  60 /  70  20  10  10
YKM  40  58  40  59 /  40  30  20  10
HRI  44  61  43  61 /  70  20  10  10
ELN  36  52  37  55 /  60  40  40  30
RDM  36  58  32  59 /  60  10   0   0
LGD  44  58  38  58 /  90  50  20  10
GCD  42  59  36  60 /  80  20   0   0
DLS  47  59  46  58 /  80  40  30  30

&&

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

$$

SHORT TERM...90
LONG TERM....90
AVIATION...95