FNUS76 KPDT 061142 FWSPDT Spot Forecast for Grande Ronde Rappellers Mountain Week...USFS National Weather Service Pendleton OR 442 AM PDT Wed May 6 2026 Forecast is based on ignition time of 0700 MDT on May 06. ***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 and Thursday. Winds will be mostly diurnally and terrain-driven this morning, turning northwesterly by late afternoon and evening. Low afternoon RH is forecast Thursday. .REST OF TODAY... Sky/weather.........Mostly sunny (5-30 percent). CWR.................0 percent. Chance of lightning.2 percent in the afternoon. Max temperature.....77-80. Min humidity........18-23 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 northwest winds 6-10 mph with gusts up to 15 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 northwest winds 6-10 mph with gusts up to 15 mph by late afternoon. Mixing height.......Increasing to 7500-8000 ft AGL by late morning. Transport winds.....West to northwest 8-12 mph. Ventilation Index...Low (100) increasing to very high (870) 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............38 43 53 61 68 70 73 76 77 79 77 75 RH..............85 73 59 39 30 28 26 24 21 20 21 22 20 FT wind dir..W SW SE SE SE SE SE W NW NW NW NW 20 FT wind spd..2 3 3 3 6 6 6 8 8 8 8 8 20 FT wind gust. 11 11 11 14 14 14 14 14 .TONIGHT... Sky/weather.........Partly to mostly cloudy (40-80 percent). CWR.................0 percent. Chance of lightning.2 percent in the evening. Min temperature.....38-41. Max humidity........75-80 percent. Wind (20 ft)........West to northwest winds 6-10 mph with gusts up to 15 mph in the evening, becoming drainage 1-4 mph overnight. Ridgetop wind.......West to northwest winds 6-10 mph with gusts up to 15 mph in the evening, becoming drainage 1-4 mph overnight. Mixing height.......Decreasing to 300-700 ft AGL overnight. Transport winds.....West to northwest 8-12 mph. Ventilation Index...Moderate (260) decreasing to low (40) overnight. .THURSDAY... Sky/weather.........Partly to mostly cloudy (40-70 percent) then becoming mostly sunny (10-20 percent) by afternoon. CWR.................0 percent. Chance of lightning.0 percent. Max temperature.....75-78. Min humidity........12-17 percent. Wind (20 ft)........Drainage winds 1-4 mph early morning, becoming west to northwest 4-8 mph with gusts up to 15 mph by mid-morning. Ridgetop wind.......Drainage winds 1-4 mph early morning, becoming west to northwest 4-8 mph with gusts up to 15 mph by mid-morning. Mixing height.......Increasing to 6500-7000 ft AGL by late morning. Transport winds.....West to northwest 8-12 mph. Ventilation Index...Low (150) increasing to very high (820) in the afternoon. $$ Forecaster...Plunkett Requested by...Cutler Christensen Type of request...PRESCRIBED .TAG 2612123.2/PDT .DELDT 05/06/26 .FormatterVersion 2.0.0 .EMAIL christensen.cutler@gmail.com