967
FXUS66 KPDT 151036
AFDPDT

Area Forecast Discussion
National Weather Service Pendleton OR
336 AM PDT Wed Jul 15 2026

.KEY MESSAGES...

- Isolated to scattered thunderstorms will develop mainly across
  the Cascades this afternoon and evening, then across the
  Cascades and eastern mountains on Thursday.

- Low pressure off the coast will move southward through this
  evening, then begin to move northward overnight and on
  Thursday. Models have come into better agreement that the low
  will move around the periphery of high pressure into British
  Columbia.

- A large area high pressure will build into the region with
  warming temperatures into the weekend and early next week,
  possibly reaching or exceeding 100 degrees in the Columbia
  Basin and nearby locations.

&&

.DISCUSSION...
Southwesterly flow across the area and several short waves
moving through it will keep the chance for showers and isolated
to scattered thunderstorms, mainly over the mountains through
Thursday. Additionally, an area of low pressure off the coast
was heading south and east and will provide enhancement to the
southwesterly flow. This low will begin to move northward
tonight and be in British Columbia Friday morning.

Once the low moves north, the ridge to the east will build in
and any precipitation chances will come to an end through the
weekend.

Temperatures will begin to warm, with highs in the upper 90s to
around 100 degrees (if not higher) as we go into the weekend and
early next week across the Columbia Basin, Yakima Valley and
portions of the Blue Mountain Foothills. These temperatures
would be 15 to 10 degrees above normal. HeatRisk will be
solidly Moderate across much of our area, with a 30 to 50
percent chance of Major HeatRisk early next week across the
Columbia Basin and Yakima Valleys.

By early next week, additional southwest flow will bring
additional shower and thunderstorm chance, mainly to the
mountains.

&&

.AVIATION /12Z TAFS THROUGH 12Z THURSDAY/...
VFR conditions are expected through the TAF period, with most
sites having winds 10 kts or less. BDN and RDM will have wind
gusts to around 20 kts this afternoon into the early evening and
YKM could have some gusty winds overnight.

Otherwise, there will be some isolated to scattered TSRA during
the afternoon hours, that should not impact most of the TAF
sites. However, if a TAF site were to be affected, BDN and RDM
look to be the ones. Therefore, have included PROB30 for TSRA
this afternoon at those two locations.

&&

.Preliminary Point Temps/PoPs...
PDT  97  61  92  56 /  10  20  10  10
ALW 100  67  97  63 /   0  10  10  10
PSC 101  66  98  61 /  10  20  20  10
YKM  99  67  96  60 /   0  60  20  10
HRI 100  66  95  60 /  10  20  20   0
ELN  96  64  93  56 /   0  60  30  10
RDM  91  55  86  47 /  40  30  10   0
LGD  96  61  97  58 /   0  10  20  20
GCD  94  58  97  55 /  20  20  10   0
DLS  98  64  84  59 /   0  70  20   0

&&

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

&&

$$

DISCUSSION...77
AVIATION...77