630
FXUS66 KPDT 091143
AFDPDT

Area Forecast Discussion
National Weather Service Pendleton OR
443 AM PDT Mon Mar 9 2026

.DISCUSSION...

The region is undergoing strong cold advection which will drive
down snow levels with time as a weak westerly moisture belt
gets channeled inland over the next 24 hours. Winter Weather
Advisory is in effect from This morning through Tuesday
Afternoon for the Upper Slopes of the WA Cascade Crest. Road
temperatures at pass levels have fallen to 32 and as road cams
begin to show more snow transitioning from the wet roads to
slick with deteriorating visibility. Likewise, the hourly
version of WSSI (weather storm severity index) was hitting in
the moderate category already on the snow rate element, as of
around midnight, so the winter wx advisory was started right
now. A Winter Storm Watch is in effect for late Tuesday though
Friday morning for which the current expected snow at the pass
level is around 2-feet of snow for the 2 day total (NBM mean).
The Experimental Winter Storm Outlook is pegging the entire
Upper Eastern Slope of WA Cascade in WA are 65 to greater than
80% confidence in criteria, measured in feet of snow. Many river
forecast point hydrographs indicate within bank rises late
week and through the weekend. None of these are being shown to
flood at this time.

&&

.AVIATION /12Z TAFS THROUGH 12Z TUESDAY/...

Precipitation showing on radar this morning is largely
orographic and will remain tied to ridgetops and mountain
slopes, and it will be hard to get any ceilings lower than an
MVFR category at the local terminals. Some brief periods of -RA
or -RASN are favorable for DLS and ALW while other terminals
are rain shadowed. Gusty westerly surface winds into the 25-35
knot range this afternoon can be be found at
DLS/PDT/YKM/PSC/ALW.

&&

.Preliminary Point Temps/PoPs...
PDT  47  28  47  32 /  10  20  10  10
ALW  48  31  47  35 /  30  50  30  20
PSC  54  29  52  35 /  10  10   0  10
YKM  48  25  48  30 /  10  10  10  40
HRI  51  30  51  34 /   0  10   0  10
ELN  43  24  42  28 /  30  30  10  50
RDM  45  22  43  28 /   0   0   0  10
LGD  43  25  42  27 /  30  40  40  20
GCD  43  24  41  27 /  20  10  20  10
DLS  50  32  49  36 /  40  30  30  50

&&

.PDT WATCHES/WARNINGS/ADVISORIES...
WA...Winter Weather Advisory until 5 PM PDT Tuesday for WAZ522.
     Winter Storm Watch from late Tuesday night through Friday
     morning for WAZ522.
OR...None.

&&

$$

DISCUSSION...71
AVIATION...71