330
FXUS66 KPDT 111731
AFDPDT

Area Forecast Discussion
National Weather Service Pendleton OR
1031 AM PDT Mon May 11 2026

.KEY MESSAGES...

- Limited to Moderate HeatRisk on Tuesday Afternoon

- Mountain rain shower and isolated thunderstorm chances return
  midweek

&&

.DISCUSSION...
Last overnights windy conditions will ramp down quickly this
morning as an upper shortwave exits the region and high pressure
develops as the primary sensible weather driver, resulting in
light winds less than 10-12 knots across the entire forecast for
Today. As compared to Sunday, the NBM is forecasting warmer
temps across the Washington Cascades and central Oregon for This
afternoon, and similar temperatures as compared to Sunday
afternoon elsewhere.

The ridging pattern will become messy by day 2 and 3 (Tuesday
and Wednesday) as the models have to come to a solution on an
eastern Pacific low resolving along the PAC NW. Varying
solutions in the ensemble clustering groups vary between a more
hot and isolated dry thunderstorms pattern with elevated heat
risk, and other members that develop closer to normal
temperatures with more of a pattern recognition favoring
a few more scattered thunderstorms across central Oregon and
the eastern mountains on Wednesday. That said with uncertainty
with how the upper low will play out, at least Tuesday looks
like the warmest day of the week, if the slightly wetter/more
convective pattern develops Wednesday. NBM means on Tuesday
bring highs to the upper 80s across the lower elevations and
even low 90s across central Oregon and the Ochoco John Day
basin. Uncertainty shows up strongly in the NBM`s high temps ,
for instance at Stampede Pass where the forecast highs range
from 45 to 62 degrees on the 25th to 75th percentile, and
likewise 73 to 89 degrees at Pasco. Tuesday the heat risk will
be elevated to level 2 or 3 in central Oregon in the afternoon,
affecting those who are sensitive to heat, especially those
without cooling and hydration as well as some health systems
industries. Lightning will be a possibility on Wednesday into
Thursday, for which at this time, the NBM probability for
thunder on a 6 hour basis Wednesday afternoon is about 18-25%
across the central Oregon to and eastern mountains of Oregon.

&&

.AVIATION /18Z TAFS THROUGH 18Z TUESDAY/...
VFR conditions are forecast for all sites over the next 24
hours, with cloud cover ranging from SKC to SCT250. Winds will
be diurnally and terrain-driven, predominantly 10 kts or less
with periodic afternoon gusts.


&&

.Preliminary Point Temps/PoPs...
PDT  75  48  85  52 /   0   0   0   0
ALW  76  51  87  56 /   0   0   0   0
PSC  80  50  90  56 /   0   0   0  10
YKM  79  50  86  55 /   0   0   0  20
HRI  78  48  87  54 /   0   0   0  10
ELN  74  45  82  49 /   0   0   0  30
RDM  81  45  90  43 /   0   0   0  40
LGD  77  45  91  51 /   0   0   0   0
GCD  83  47  94  49 /   0   0   0  10
DLS  81  53  88  54 /   0   0   0  40

&&

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

&&

$$

DISCUSSION...71
AVIATION...86