348
FXUS66 KPDT 161759
AFDPDT

Area Forecast Discussion
National Weather Service Pendleton OR
1059 AM PDT Thu Jul 16 2026

.KEY MESSAGES...

- Thunderstorms, mainly across eastern areas today.

- Heat Advisories today, then widespread moderate HeatRisk
  returns early next week, with high temperatures near or above
  100 degrees in the Columbia Basin, Yakima Valleys and
  surrounding areas.

&&

.DISCUSSION...
An area of low pressure off the coast will move northward into
British Columbia through Saturday morning.

High pressure will then build back into the region through early
next week.

Current radar shows lingering showers and thunderstorms moving
northward across the region. As the low moves north, it will
continue to supply short wave energy, mainly over eastern areas
later today, which will be supportive of more thunderstorms.
Today should be the last day for shower and thunderstorm
activity as high pressure then builds back in.

High temperatures will be hot again today, especially across
the Columbia Basin and nearby areas, and HeatRisk is moderate.
Probabilities of Major HeatRisk range up to about 40 percent in
some locations. HeatRisk does decrease after today for Friday
and Saturday, but starts to return on Sunday with widespread
moderate returning Sunday (>50 percent) and increasing Monday
and Tuesday (>70 percent). By Monday and Tuesday probabilities
of Major HeatRisk increase to about 30 to 50 percent across the
Columbia Basin, Yakima and Kittitas Valleys.

Also today, there will continue to be critical fire weather
concerns from lingering lightning this morning and possibly from
thunderstorm in the east this afternoon, but areal coverage will
be less.

There will be some gusty winds today in portions of the Gorge,
Basin, and Simcoe Highlands with wind gusts as high as 30 to 35
mph. Diurnal wind gusts will continue through Saturday, with
gusts in the 25 to 35 mph range.

Thunderstorm chances will also return early next week, mainly
over the mountains.

&&

.AVIATION /18Z TAFS THROUGH 18Z FRIDAY/...
VFR conditions are forecast at all sites through the TAF
period. Additional isolated thunderstorms are expected (80%
confidence) to develop this afternoon over the Blue Mountains,
but there is low confidence (30% or less) in SHRA/TSRA this
afternoon affecting PDT/ALW/PSC. Overnight, there is a very low
chance (10% or less) of additional high-based showers
developing over PDT/ALW/PSC.

Winds will become breezy to windy this afternoon and evening,
strongest at DLS. Periods of breezy winds are anticipated to
continue overnight into Friday morning.

Some thin smoke from area wildfires is present across central
Oregon and may reduce VSBYs overnight into Friday, but
confidence was too low (<30%) to introduce in the 18Z TAFs.

&&

.FIRE WEATHER...
Fire weather concerns continue this morning mainly from
lightning as lingering thunderstorms move south to north
across the area. Thunderstorms will develop this afternoon,
mainly over the eastern mountains, but areal coverage should be
less. Gusty winds are expected over portions of the Gorge, Basin
and Simcoe Highlands this afternoon, but RH values are expected
to be higher due to a marine push, but both the thunderstorm
development and RH values will have to be monitored.

&&

.Preliminary Point Temps/PoPs...
PDT  93  56  90  57 /  20   0   0   0
ALW  98  63  92  63 /  20  10   0   0
PSC  99  61  94  60 /  30   0   0   0
YKM  97  59  93  59 /  40   0   0   0
HRI  95  59  92  61 /  20   0   0   0
ELN  94  56  88  56 /  50   0   0   0
RDM  87  46  89  50 /   0   0   0   0
LGD  98  58  93  57 /  20  20   0   0
GCD  98  54  96  54 /  20   0   0   0
DLS  83  58  87  60 /  20   0   0   0

&&

.PDT WATCHES/WARNINGS/ADVISORIES...
WA...Heat Advisory until 9 PM PDT this evening for WAZ026>029.
OR...Heat Advisory until 9 PM PDT this evening for ORZ044-049-050-
     507.

&&

$$

DISCUSSION...77
AVIATION...86
FIRE WEATHER...77