069
FXUS66 KPDT 310516
AFDPDT

Area Forecast Discussion
National Weather Service Pendleton OR
1016 PM PDT Thu Jul 30 2026

.KEY MESSAGES...
- Weak instability and dry condition present today.

- Critically Windy and dry on Saturday.
  *Fire Weather Watch Issued*

- Dry conditions return through the first half of week.

&&

.DISCUSSION...
Current radar and visible satellite imagery shows dry conditions
as mid-to high level clouds begin to encroach into Central and
North-Central Oregon. This is associated with a passing weak
shortwave that is slightly increasing winds and instability
across the region. Thunderstorms are not anticipated with this
feature, but fire activity may become more active through the
afternoon as a result. High pressure slides in behind the
passing shortwave by Friday morning, leading to light winds and
drier conditions with afternoon humidities between 15-22%.

An approaching upper level trough on Saturday, and an associated
dry cold front, will pass through the Pacific Northwest. This
feature will increase winds out of the west as sustained winds
of 15-30 mph and gusts of 30-40 mph will be possible, with
highest winds expected across the Kittitas Valley and the Simcoe
Highlands. Chances of wind advisory level gusts being reached is
currently 60-80% via the NBM across these areas. Fire weather
concerns also arise as a result of the increased winds and
antecedent dry conditions. As a result, a Fire Weather Watch has
been issued for much of the area on Saturday, including the
Lower Columbia Basin, Eastern Mountains, and portions of Central
Oregon. Afternoon humidities as low as 17% will be possible,
which are more focused to areas of Central Oregon zones.

In the wake of the passing system, the ECMWF and GFS AI
ensembles suggest a building upper level ridge along the coast
will allow for a thermal trough to develop Monday and Tuesday.
Winds will be coming in from the north and east, with afternoon
humidities dropping into the low to mid-teens by Tuesday. A
warming trend will also commence through the early workweek as
highs peak in the low to mid-90s across the Columbia Basin and
Central Oregon on Wednesday. 75

&&

.AVIATION /06Z TAFS THROUGH 06Z SATURDAY/...Mostly VFR
conditions through the period. MVFR CIGs from smoke have
developed at site BDN tonight, and is expected to persist
into the morning hours. Due to northerly winds, smoke will
impact sites RDM/BDN tomorrow, with vsby going down to MVFR.
Otherwise, confidence is too low(15-20%) on timing/impacts of
smoke at other sites. Winds will be light through the period,
except at site DLS where winds 12-17kts with gusts to around
25kts will develop in the afternoon. Lawhorn/82

&&

.FIRE WEATHER...
Elevated fire weather concerns persist through the week under a
dry and diurnally breezy regime. Winds will become more terrain
driven on Friday as a result of increased high pressure in the
wake of a passing system today, but humidities will continue to
trend downward. Concerns peak on Saturday associated with a
passing dry cold front that brings windy conditions through the
Columbia Basin, Eastern Mountains, and Central Oregon. As a
result, Fire Weather Watches have been extended to these areas
to highlight the potential for rapid fire spread and/or spotting
related to new and existing fires. Conditions relax Sunday ahead
of a thermal trough developing along the coast that will
promote significant drying and north/east winds Monday and
Tuesday. Poor to moderate overnight humidities are anticipated
Monday through Wednesday mornings. 75

&&

.Preliminary Point Temps/PoPs...
PDT  55  93  62  84 /   0   0   0   0
ALW  60  96  67  87 /   0   0   0   0
PSC  56  96  64  91 /   0   0   0   0
YKM  57  96  63  87 /   0   0   0   0
HRI  57  95  65  86 /   0   0   0   0
ELN  56  93  61  79 /   0   0   0   0
RDM  47  95  53  84 /   0   0   0   0
LGD  55  99  61  88 /   0   0   0   0
GCD  54 101  58  92 /   0   0   0   0
DLS  58  97  65  81 /   0   0   0   0

&&

.PDT WATCHES/WARNINGS/ADVISORIES...
WA...Fire Weather Watch from Saturday morning through Saturday
     evening for WAZ691>693.
OR...Air Quality Alert until noon PDT Friday for ORZ041-049-050-502-
     503-505-506-509>511.
     Fire Weather Watch from Saturday morning through Saturday
     evening for ORZ691>700.

&&

$$

DISCUSSION...75
AVIATION...82
FIRE WEATHER...75