346
FXUS66 KPDT 262244
AFDPDT

Area Forecast Discussion
National Weather Service Pendleton OR
344 PM PDT Sun Jul 26 2026

.KEY MESSAGES...

- Quiet, dry weather with diurnal winds/breezes through
this week.

- Elevated fire weather conditions/concerns continue with
breezy winds and low RH persisting.

- Air Qualities Advisories/Alerts persist through Monday.

&&

.DISCUSSION...
A mean upper trough was in place with a center of low pressure
at 500 mb off the nrn BC coast. Southwest flow aloft across
the Pacific and Interior NW Today is resulting in a surface
ridge of high pressure across the coastal Oregon areas and
across the Columbia Basin of WA/OR. This will largely result in
light to slightly breezy winds over the next couple of days with
terrain driven winds overnight as boundary layer mixing ceases.
On Monday most of of the middle range models (EC/HI-Res ARW,
GFS NAM), are showing a stronger compact vorticity core move
into the base of the upper trough and that should promote a
frontal passage for the region Monday night and Tuesday, which
will have little impact on temperatures but keep weather temps
steady though mid week. It may uptick the moisture profiles
Tuesday before a drying out (lower dew points) begins Wednesday,
allowing temperatures to begin to rise each afternoon back
through the low to mid 90s, peaking on Friday. Models are
leaning toward a frontal passage after Friday that would leave
more windy conditions across the greater area with increased
risk for fire weather impact levels based on low RH and winds.
In the meantime, AQI remains in the 150 to 500 range across in
the vicinity of the larger fires across the Blue Mountains and
adjacent foothills zones, and air quality advisories remains in
effect for these areas from central Oregon to the Wallowas as
well as southeast Washington/Walla Walla county to the Tri
Cities east of the Columbia River . The Air quality advisories
are in effect though Monday afternoon and may be extended based
on DEQ evaluation.

&&

.AVIATION /00Z TAFS THROUGH 00Z TUESDAY/...
VFR conditions with small chances (5 to 15%) of a passing haze
or smoke plume that could bring MVFR conditions to all TAF
sites. Current area of smoke/haze in PSC persist, that is
expected to last for the next few hours. Not anticipating sub-
MVFR conditions immediately due to a mixed atmosphere. Winds
will be generally light with breezy winds developing with 20 to
30 knot gusts along in the afternoon hours (except for YKM, PSC,
and ALW) and last through the early evening hours.

&&

.FIRE WEATHER...
No red flag warnings are anticipated for this forecast/model
cycle. The areas south and west of of White swan/Harrah/Toppenish
could see meteorological red flag conditions briefly late this
afternoon into early evening that could last as little as an hour
in any locations along the fire zone 694/691 interface. For
Monday relative humidity will continue to be very dry to critical
across the OR/WA691 zones to the Wallowas and Grand Ronde valley
eastern OR700 and the John Day basin, but lacking winds. The
reverse is true over central Oregon and and northern central
Oregon where breezy conditions meets a little more moisture to
prevent red flag.

&&

.Preliminary Point Temps/PoPs...
PDT  56  88  57  86 /   0   0   0   0
ALW  61  90  62  89 /   0   0   0   0
PSC  59  92  60  91 /   0   0   0   0
YKM  57  90  59  89 /   0   0   0   0
HRI  60  91  61  89 /   0   0   0   0
ELN  54  84  55  81 /   0   0   0   0
RDM  49  88  49  86 /   0   0   0   0
LGD  55  90  56  88 /   0   0   0   0
GCD  54  92  54  91 /   0   0   0   0
DLS  59  87  61  84 /   0   0   0   0

&&

.PDT WATCHES/WARNINGS/ADVISORIES...
WA...Air Quality Alert until 11 AM PDT Monday for WAZ028>030.
OR...Air Quality Alert until noon PDT Monday for ORZ049-050-502-503-
     505-506-508-509-511.

&&

$$

DISCUSSION...77
AVIATION...95
FIRE WEATHER...71