447
FXUS66 KPDT 131119
AFDPDT

Area Forecast Discussion
National Weather Service Pendleton OR
419 AM PDT Wed May 13 2026

.KEY MESSAGES...
- Mountain showers, isolated mountain thunderstorms, and breezy
  to gusty low elevation winds Today

&&

.DISCUSSION...
A Pacific NW trough is driving a series of sensible weather
impacts for the region including thunderstorm across the
Cascades crest, increasingly windy conditions areawide This
afternoon and a return to more normal temperatures for early May
over the Inland Northwest. Numerous orographically forced
thunderstorm have worked over the low CAPE environment along the
Oregon cascade crest. Still HREF lightning probabilities show
expansion after about 13-15 z across the Washington Cascade
crest onto the eastern slopes and the Yakima/Kittitas valleys
posing a lighting risk though the morning as colder air aloft
spreads eastward. Also momentum transfer and a strong surface
pressure gradient will cause strong westerly winds across the
entire area resulting in the wind advisories and high wind
warnings already posted for most of the non mountain forecast
zones through midnight.

A more zonal flow aloft takes shape on the synoptic scale for
days 2-4 before the LREF (ensembles) show another chunk of
energy buckling the flow creating a mean 500 mb trough across
the Inland NW/northern Great Basin regions where the largest
differences are between clusters 2 and 4 (warmer vs colder/more
amplified for our region). These differences seemingly have
little impact on the sensible weather as forecast highs at PDT
only vary by about 4 degrees between the 25th and 75th
percentiles for Day5 (Sunday) highs. More meaningful differences
(uncertainty) start showing up by Day 6 Monday, especially
between clusters 2 and 3 (NW flow drier vs colder trough aloft
and showery, tsra pattern, and the drier solution only
represents about 18% of the ensemble members. Additionally
clusters 2 and 4 represents about 45% of the ensembles that
offer wetting rain to parts or much of the eastern mountains.

&&

.AVIATION /12Z TAFS THROUGH 12Z THURSDAY/...

VFR cloud bases (3-7 kft AGL) in showers will be found across
the area Today with windy conditions. Winds will be strong
enough to potentially create blowing dust in the basin, and
valleys, which could impact MVFR vsbys in YKM/DLS/PDT/ALW. Look
for winds gust commonly above 40 knots Today and lingering
through the late evening, with only BDN and RDM having lower
winds gusting less than 30 knots.

&&

.Preliminary Point Temps/PoPs...
PDT  64  44  68  43 /  80  10   0   0
ALW  65  48  68  47 /  90  20   0   0
PSC  70  48  73  45 /  90  10   0   0
YKM  68  42  72  40 /  90   0   0   0
HRI  67  47  71  45 /  80  10   0   0
ELN  61  39  64  37 / 100  10   0   0
RDM  61  31  71  34 /  50   0   0   0
LGD  63  39  68  39 /  80  10   0   0
GCD  64  35  72  37 /  60   0   0   0
DLS  66  48  70  46 /  50   0   0   0

&&

.PDT WATCHES/WARNINGS/ADVISORIES...
WA...Wind Advisory until 11 PM PDT this evening for WAZ024.
     Wind Advisory until 11 PM PDT this evening for WAZ026>029.
     High Wind Warning until 11 PM PDT this evening for WAZ521.
OR...Wind Advisory until 11 PM PDT this evening for ORZ041.
     Wind Advisory until 11 PM PDT this evening for ORZ044-510.
     High Wind Warning until 11 PM PDT this evening for ORZ507-508.

&&

$$

DISCUSSION...71
AVIATION...71