190
FXUS66 KPDT 290535
AFDPDT

Area Forecast Discussion
National Weather Service Pendleton OR
1035 PM PDT Tue Jul 28 2026

.KEY MESSAGES...
- Mostly warm, dry conditions persist through the next few days.

- Elevated fire weather conditions for wind/low RH continue.

- Small chance (0-10%) of dry thunderstorm development across
  the Southern Blues and Eastern Mountains Wednesday and
  Thursday.

&&

.DISCUSSION...
Current satellite shows a few cumulus clouds across the Cascades
with mostly sunny conditions across most of the region. Smoke
and haze originating from wildfires in Central Oregon through
parts of the Southern Blues is clearly visible streaming from
the SW to NE, bringing hazy conditions across the Colombia
Basin. An Air Quality Advisory initiated via the Department of
Environmental Quality is in effect through much of the Colombia
Basin and Blue Mountains through noon tomorrow due to ongoing
smoke transport.

Synoptically, southwest flow continues and will persist through
the next couple of days as a trough just offshore of British
Colombia paves way through the PacNW through Friday evening.
Periods of embedded shortwaves within the trough will bring very
low chances of dry thunderstorm development (0 to 10 percent
chance) across portions of the Southern Blues and Eastern
Mountains, potentially triggering new ignitions.
Deterministics Wednesday and Thursday advertise a pocket of
very slight moist air with 45-65% RH in the low to mid levels
passing through the Southern Blues and Eastern Mountains, along
with 150-300 J/kg of MUCAPE developing during peak heating
according to the REFS. Precipitable water values stay at below
1.00 inch in the development region (80-90% chance), suggesting
any thunderstorm that initiate will be mostly dry in nature
with little to no potential for wetting rains to occur.

As the trough approaches the area early Saturday morning to
afternoon, tight pressure gradients will develop and bring gusty
to locally windy conditions across the region. Areas across the
Kittitas/Yakima Valley`s, Columbia Basin of Oregon, and the
Cascade Gap region have the greatest chance of exceeding wind
advisory criteria (>45 mph gusts) Saturday. Chances of
exceedance reaches 50-80% across the mentioned areas, with wind
highlights possible as we get closer to the event. This will
also consequently enable to the potential of elevated to
critical fire weather conditions developing Saturday. Joint
probabilities of 25% or less humidity AND sustained winds of 20
mph or more are advertised at 15-35% chances by 5 PM Saturday.
Will monitor for the trend going through tomorrow to see if fire
weather highlights are warranted.

&&

.AVIATION /06Z TAFS THROUGH 06Z THURSDAY/...VFR conditions to
prevail through the period. Low confidence (15-25%) in smoke
impacts at sites through the period. Winds will increase to
12-18kts with gusts to around 25kts at site DLS, with periodic
gusts up to 20kts at sites RDM/BDN in the afternoon. Winds will
otherwise be light through the period. Lawhorn/82

&&

.Preliminary Point Temps/PoPs...
PDT  54  86  56  88 /   0   0   0   0
ALW  59  88  62  90 /   0   0   0   0
PSC  56  90  60  92 /   0   0   0   0
YKM  55  89  58  91 /   0   0   0   0
HRI  56  89  60  91 /   0   0   0   0
ELN  51  85  55  86 /   0   0   0   0
RDM  47  88  48  88 /   0   0   0   0
LGD  53  91  57  92 /   0   0   0   0
GCD  52  94  55  94 /   0   0   0   0
DLS  58  87  60  86 /   0   0   0   0

&&

.PDT WATCHES/WARNINGS/ADVISORIES...
WA...None.
OR...Air Quality Alert until noon PDT Wednesday for ORZ041-044-049-
     050-502-503-505>511.

&&

$$

DISCUSSION...95
AVIATION...82