316
FNUS76 KPDT 032137
FWSPDT

Spot Forecast for Marks Creek Fire...Central Oregon Type 3 Team
National Weather Service Pendleton OR
237 PM PDT Wed Sep 3 2025

Forecast is based on forecast start time of 1500 PDT on September 03.
***Thunderstorms imply gusty and erratic winds***
***Winds are 20 foot 10-minute averages***
***CWR-Chance of wetting rain 0.10 or greater***
***Ventilation Index is derived from the
   transport wind multiplied by the mixing
   height in 100`s of feet. Index categories
   are a generalized indicator only.***

If you have questions or concerns with this forecast, please
contact our office at (541) 276-8134.

.DISCUSSION...Through Thursday, confidence is high (>80%) in a
weather pattern that favors above-normal temperatures, diurnally
and terrain-driven winds, low minimum RH, moderate overnight RH
recovery, and a slight chance of showers and thunderstorms.
Any thunderstorms that develop will be capable of producing gusty,
erratic outflow winds in excess of 40 mph.

.TONIGHT...

Sky/weather.........Partly to mostly cloudy (30-60 percent).
                    Areas of smoke.
CWR.................0 percent.
Chance of lightning.5 percent.
Min temperature.....62-65.
Max humidity........41-46 percent.
Wind (20 ft)........Downslope and down-valley winds 2-6 mph.
Ridgetop wind.......Northeast winds 3-6 mph with infrequent gusts up to
                    15 mph in the evening.
Mixing height.......Decreasing to 500-800 ft AGL overnight.
Transport winds.....North to northeast winds 5-8 mph.
Ventilation Index...Poor (110) decreasing to poor (30) overnight.

.THURSDAY...

Sky/weather.........Partly to mostly cloudy (35-75 percent). Very low
                    (10-15 percent) chance of showers and thunderstorms
                    in the afternoon.
CWR.................0 percent.
Chance of lightning.10 percent.
Max temperature.....86-89.
Min humidity........17-22 percent.
Wind (20 ft)........Terrain-driven (upslope, up-valley) winds 2-5 mph,
                    shifting to the north-northeast 5-8 mph with gusts
                    up to 15 mph by 1500-1700 PDT.
Ridgetop wind.......Terrain-driven (upslope, up-valley) winds 2-5 mph,
                    shifting to the north-northeast 5-8 mph with gusts
                    up to 15 mph by 1500-1700 PDT.
Mixing height.......Increasing to 7500-8000 ft AGL by afternoon.
Transport winds.....South to southeast winds 4-7 mph in the morning,
                    shifting to the north to northeast 5-8 mph late afternoon.
Ventilation Index...Poor (30) increasing to fair (400) in the
                    afternoon.
$$
Forecaster...Plunkett
Requested by...Chantelle DeLay
Type of request...WILDFIRE
.TAG 2521273.0/PDT
.DELDT 09/03/25
.FormatterVersion 2.0.0
.EMAIL chantelle.delay@usda.gov