141
FXUS66 KPDT 121837
AFDPDT

Area Forecast Discussion
National Weather Service Pendleton OR
1137 AM PDT Tue May 12 2026

.KEY MESSAGES...
- Moderate Heat Risk This Afternoon

- Isolated Thunderstorms possible Tonight and Wednesday

- High Winds on Wednesday

&&

.DISCUSSION...
The warming ridge we are experiencing Today that will bring hot
temperatures in the 80s and 90s will be replaced by a cooling
eastern Pacific trough on Wednesday. A belt of moisture
transport will bring widespread rain showers to the region, with
NBM means showing one o to two tenths of an inch across the
eastern mountains, and slightly less than that across the lower
elevations like the Columbia Basin.

HREF 4 hour probability of thunder suggest the potential for
tapping into instability across the northern Blues and Oregon
cascades by late this evening, but isolated at best with 10 to
20% chances for lightning. That activity remains an overnight
phenomenon ending before sunrise, but regenerating in the
afternoon Wednesday especially across the mountains areas as
overall instability will be weaker but showers more scattered
to numerous (again lightning still isolated at 10%).

Onshore pressure gradients will be the primary driver for winds
developing late Tonight and impacting through the day on
Wednesday as the Portland to Spokane pressure gradient increases
to about 10 mb or higher. This will produce strong sustained
winds above 25 to 30 mph through the Gorge and foothills of the
Blues as well as the Cascade Gaps where gusts will commonly be
pushing 50 mph on Wednesday; as early as in the morning hours.

Wind advisories have been hoisted across the eastern Columbia
Gorge beginning late This Evening, expanding across central
Oregon, Lower Columbia Basin and the foothills of the northern
Blue Mountains in Washington, Yakima and Kittitas Valleys by
sunrise Wednesday. High Wind Warning for higher gust around 60
mph covers the Simcoe Highlands and foot hills of the Blue
Mountains of Oregon Wednesday.

&&

.AVIATION /18Z TAFS THROUGH 18Z WEDNESDAY/...Mostly VFR
conditions to prevail through the period. An upper low
approaching the region will produce showers and isolated to
scattered thunderstorms starting mid to late afternoon through
tomorrow. There is about a <10% chance of an isolated
shower/thunderstorm impacting RDM/BDN later this afternoon, but
otherwise shower chances will increase after 06Z and continue
through the end of the period at these sites and site DLS. For
sites PDT/YKM/ALW/PSC, shower chances will increase after 12Z. A
prob30 for thunder was included at site YKM for the morning
period. Winds of 15-25kts with gusts 25-45kts will develop at
site DLS this evening, then develop at sites PDT/RDM/BDN/ALW/PSC
after 13Z. Strong winds will persist through the end of the
period. Lawhorn/82

&&


.Preliminary Point Temps/PoPs...
PDT  85  51  65  44 /   0   0  70  10
ALW  88  55  65  48 /   0   0  80  20
PSC  91  55  70  47 /   0   0  70  10
YKM  87  53  68  43 /   0  10  80   0
HRI  88  53  68  46 /   0   0  70   0
ELN  83  47  61  39 /   0  20  90  10
RDM  90  42  62  32 /   0  40  60   0
LGD  91  50  63  40 /   0  10  80  20
GCD  94  48  65  37 /   0  20  70   0
DLS  88  52  67  48 /   0  40  70   0

&&

.PDT WATCHES/WARNINGS/ADVISORIES...
WA...Wind Advisory from 8 PM this evening to 11 PM PDT Wednesday
     for WAZ024.
     Wind Advisory from 5 AM to 11 PM PDT Wednesday for WAZ026>029.
     High Wind Warning from 5 AM to 11 PM PDT Wednesday for WAZ521.
OR...Wind Advisory from 8 PM this evening to 11 PM PDT Wednesday
     for ORZ041.
     Wind Advisory from 5 AM to 11 PM PDT Wednesday for ORZ044-510.
     High Wind Warning from 5 AM to 11 PM PDT Wednesday for ORZ507-
     508.

&&

$$

DISCUSSION...71
AVIATION...82