Area Forecast Discussion
Issued by NWS Pendleton, OR

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792
FXUS66 KPDT 121147
AFDPDT

Area Forecast Discussion
National Weather Service Pendleton OR
446 AM PDT Sun Oct 12 2025

.Updated Aviation Discussion.


.DISCUSSION...The PacNW finds itself in the transition zone between
two upper-level waves early this morning, stemming from a parent low
centered over western Canada. Satellite imagery this morning shows
some clearing in the Basin as the forecast area lies between these
two waves, with the resulting pressure gradient making for some
gusty winds through the Cascade Gaps spilling into the Basin. Once
this wave passes through the region, making for widespread precip
chances, a cold, trough pattern will envelop the area for much of
the upcoming work week, making for mild daytime highs and chilly
overnight lows bordering on freezing for many areas that have still
yet to see a season-ending hard freeze.

The more northerly origin of this next wave will cause snow levels
to drop to around 3500 ft in the Washington Cascades and 4500 ft
elsewhere as cold air rushes in from behind. Expect the Cascades to
see its first round of accumulating snowfall, especially for areas
above 4000 ft. Winter Weather Advisories remain in effect for our
upper Cascade zones in Washington and Oregon through Monday morning.
Current thinking is that Snoqualmie Pass will largely be spared of
any meaningful accumulating snowfall, but White, Blewett, and
Santiam Passes may see a few inches from this system. Elsewhere,
models have become a bit more bullish on lowland precip with the
system, with NBM probabilistic guidance suggesting 60-70% chances
for even the lower Basin to receive wetting rains by Monday morning.
With this combination of widespread rain and mountain snow and
colder air following, the hope is that this weekend`s action will
help further draw this wildfire season to a close.

With ensembles in good agreement on this parent trough being
followed up by cool northwesterly flow, followed by another trough
later in the week, temperatures are expected to drop Monday through
the midweek, with light precip lingering through the week across the
mountains. Did opt to issue a Freeze Watch for the Kittitas Valley
for Tuesday morning, as the Valley is quite sensitive to these
northerly flow events and the NBM already depicts Ellensburg
dropping to 29 Monday morning. The Yakima Valley and Simcoe
Highlands will also flirt with an overnight freeze, especially
Tuesday morning, but with the flow more northwesterly in nature,
will be interesting to see how much cloud cover spills over from the
Cascades into the lowlands and complicates the temperature
forecast. 74

&&

.AVIATION...12Z TAFS...VFR conditions currently across all sites,
but conditions will be degrading to MVFR for most sites due to
reduced visibilities of 5SM for KRDM/KBDN and decreased ceilings of
2-3kft for KDLS/KPDT/KYKM/KPSC toward the end of the period. This is
a result of a dropping system offshore that will bring periods of
light rain to all sites beginning this afternoon, and extending
overnight into Monday morning. 75


&&

.PRELIMINARY POINT TEMPS/POPS...
PDT  55  39  55  34 /  70  70  50  10
ALW  54  42  58  38 /  80  80  50  10
PSC  58  41  59  37 /  50  80  50   0
YKM  57  37  52  36 /  50  80  80   0
HRI  57  42  58  37 /  70  80  50   0
ELN  51  34  51  29 /  60  90  70  10
RDM  51  32  48  27 /  50  80  70  20
LGD  49  37  53  34 /  80  70  70  20
GCD  51  37  53  34 /  60  80  70  10
DLS  57  43  55  40 /  80  80  80  10

&&

.PDT WATCHES/WARNINGS/ADVISORIES...
OR...Winter Weather Advisory from 2 PM this afternoon to 1 PM PDT
     Monday for ORZ509.

WA...Winter Weather Advisory from 2 PM this afternoon to 1 PM PDT
     Monday for WAZ522.

     Freeze Watch from Monday evening through Tuesday morning for
     WAZ026.

&&

$$

SHORT TERM...74
LONG TERM....74
AVIATION...75