FNUS76 KPDT 051246 FWSPDT Spot Forecast for Grande Ronde Rappellers Mountain Week...USFS National Weather Service Pendleton OR 546 AM PDT Tue May 5 2026 Forecast is based on ignition time of 0700 MDT on May 05. ***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 transport wind multiplied by the mixing height in 100's of ft. Categories are a generalized indicator only: low (< 200), moderate (200-500), high (500-700), and very high (> 700). *** If you have questions or concerns with this forecast, please contact our office at (541) 276-8134. .DISCUSSION...Warm, dry conditions are forecast today. Winds are expected (80 percent confidence) to become north to northeast later this morning through afternoon, and gusty. There is a very low (10 percent) chance of showers and even lower (2 percent) chance of thunderstorms. Overnight and Wednesday, lighter diurnally and terrain-driven winds are forecast. .REST OF TODAY... Sky/weather.........Mostly sunny (5-15 percent) becoming partly cloudy (20-40 percent) by afternoon. Very low (10 percent) chance of rain showers in the afternoon. CWR.................1 percent. Chance of lightning.2 percent. Max temperature.....70-73. Min humidity........23-28 percent. Wind (20 ft)........Northwest winds 3-6 mph early morning, becoming north winds 10-15 mph with gusts of 20-30 mph by middle to late morning. Ridgetop wind.......Northwest winds 3-6 mph early morning, becoming north winds 10-15 mph with gusts of 20-30 mph by middle to late morning. Mixing height.......Increasing to 7000-7500 ft AGL by late morning. Transport winds.....North 5-10 mph increasing to 20-25 mph late in the morning. Ventilation Index...Moderate (340) increasing to very high (1050) in the afternoon. TIME (MDT) 8AM 9AM 10A 11A 12P 1PM 2PM 3PM 4PM 5PM 6PM 7PM Chc of ltng (%).0 0 0 0 0 0 0 0 0 0 0 0 Temp............45 50 54 62 65 67 68 68 69 70 67 65 RH..............74 62 50 39 31 28 28 28 27 27 30 30 20 FT wind dir..NW N N N N N N N N N N N 20 FT wind spd..6 9 10 10 13 13 13 14 14 14 12 12 20 FT wind gust. 18 18 18 22 22 22 23 23 23 23 23 .TONIGHT... Sky/weather.........Mostly clear (10-20 percent). CWR.................0 percent. Chance of lightning.1 percent. Min temperature.....38-41. Max humidity........75-80 percent. Wind (20 ft)........North winds 8-12 mph with gusts of 15-25 mph in the evening, becoming drainage 1-5 mph overnight. Ridgetop wind.......North winds 8-12 mph with gusts of 15-25 mph in the evening, becoming drainage 1-5 mph overnight. Mixing height.......Decreasing to 200-600 ft AGL overnight. Transport winds.....North 15-20 mph in the evening, decreasing to 5-10 mph overnight. Ventilation Index...Moderate (480) decreasing to low (80) overnight. .WEDNESDAY... Sky/weather.........Mostly sunny (5-15 percent), becoming partly cloudy (20-40 percent) by afternoon. CWR.................0 percent. Chance of lightning.2 percent. Max temperature.....73-76. Min humidity........20-25 percent. Wind (20 ft)........Drainage winds 1-5 mph very early morning, becoming upslope then upvalley winds 2-6 mph by early to mid-morning then north to northwest winds 4-8 mph by late afternoon. Ridgetop wind.......Drainage winds 1-5 mph very early morning, becoming upslope then upvalley winds 2-6 mph by early to mid-morning then north to northwest winds 4-8 mph by late afternoon. Mixing height.......Increasing to 7500-8000 ft AGL by late morning. Transport winds.....Northwest 8-12 mph. Ventilation Index...Low (50) increasing to high (610) in the afternoon. $$ Forecaster...Plunkett Requested by...Cutler Christensen Type of request...PRESCRIBED .TAG 2612123.1/PDT .DELDT 05/05/26 .FormatterVersion 2.0.0 .EMAIL christensen.cutler@gmail.com