699
FXUS66 KPDT 152237
AFDPDT

Area Forecast Discussion
National Weather Service Pendleton OR
237 PM PST Mon Dec 15 2025

.DISCUSSION...

Key Messages...

1. Rain, mainly in the Cascades through Tuesday.

2. Breezy to Windy through tonight.

3. Very Windy Wednesday with significant snow over Cascades
   and lower snow levels through the end of the week.

4. River flooding returns to some areas of the Yakima and Naches
   Rivers from Wednesday through the end of the week.


Rain will continue mainly across the mountains through Tuesday.
The lower elevations should be generally dry.

The rain will cause runoff, which will begin around Wednesday at
some points on the Yakima and Naches. River Flood Watches have
been issued. Rivers are expected to remain high into next week,
though they will slowly recede. With less rain and lower snow
levels expected, while rivers will rise, they are not expected to
reach the levels they reached last week.

As this first system moves through, breezy to windy conditions are
expected through tonight and wind advisories remain in effect.

Then the next system, a trough, potent short wave and strong cold
front will move across the region later Tuesday into Wednesday.
These features will bring very strong winds, snow to the mountains
and lowering snow levels. Behind the cold front, there will be
about a 10 degree drop in temperatures, though temperatures will
still be above normal.

Winds will increase and become quite gusty on Wednesday with gusts
in the 40 to 50 mph range area wide and some locations getting as
high as 60 mph plus. NBM probabilities of wind gusts >=47 mph are
>=90 percent over a large part of our area on Wednesday. Wind
gusts >=55 mph are 70 to 90 percent over the Yakima Valley, Simcoe
Highlands, Columbia Basin, amd Foothills of the Blue Mountains.
High wind Watches remain in effect.

Snow levels, which currently range from 8000 to over 9000 feet,
will drop sharply on Wednesday and by Wednesday afternoon, will be
between 2000 to 2500 feet. Snow amounts look to be in the 6 to 10
inch range at Snoqualmie and White Passes.

Precipitation will linger over the weekend in the mountains, but
amounts will be lighter, while over the lower elevations it will
be mainly dry.



&&

.AVIATION...
Aside from temporary sub-VFR conditions within rain showers this
afternoon and evening, predominantly VFR conditions are anticipated
for the next 24 hours. Breezy winds of 10-20 kts with gusts of
25-35 kts are forecast through much of the period. Did include
mention of low-level wind shear at YKM/PSC where winds aloft are
strongest (45-55 kts at 2kft AGL).

&&

.PRELIMINARY POINT TEMPS/POPS...
PDT  43  61  40  50 /  40  10  90  50
ALW  46  60  42  51 /  60  30 100  70
PSC  43  60  42  54 /  20  20  90  30
YKM  37  58  38  50 /  10  50 100  30
HRI  43  61  42  53 /  30  10  90  40
ELN  34  50  33  44 /  30  70 100  50
RDM  37  58  33  45 /  30  10 100  50
LGD  40  55  36  48 /  60  20  90  80
GCD  43  56  36  49 /  40  10  90  80
DLS  45  59  43  51 /  50  60 100  70

&&

.PDT WATCHES/WARNINGS/ADVISORIES...
OR...High Wind Watch from Tuesday evening through Wednesday afternoon
     for ORZ041-044-507-508-510-511.

     Wind Advisory until 10 PM PST this evening for ORZ507-508.

WA...High Wind Watch from Tuesday evening through Wednesday afternoon
     for WAZ024-026>029-521.

     Wind Advisory until 10 PM PST this evening for WAZ026>028.

     Flood Watch through Wednesday morning for WAZ522-523.

     Winter Weather Advisory from 4 PM Tuesday to 10 PM PST Wednesday
     for WAZ522.

&&

$$

SHORT TERM...77
LONG TERM....77
AVIATION...86