FNUS76 KPDT 070722 FWSPDT Spot Forecast for Grande Ronde Rappellers Mountain Week...USFS National Weather Service Pendleton OR 1222 AM PDT Thu May 7 2026 Forecast is based on ignition time of 0700 MDT on May 07. ***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...Excellent (80-90%) overnight humidity recoveries this morning will lead to slightly cooler (-2) temperatures and drier (-3%) afternoon conditions today. A weak cold front will move in early Friday which will increase cloud cover and cause elevated, breezy west winds Friday afternoon. .THURSDAY... Sky/weather.........Mostly sunny (10-20 percent). CWR.................0 percent. Chance of lightning.0 percent. Max temperature.....75-78. Min humidity........11-16 percent. Wind (20 ft)........Light winds 2 to 6 mph becoming west 4 to 8 mph after 0900 and shifting from the northwest around 1500. Ridgetop wind.......Light winds 3 to 7 mph becoming west 5 to 10 mph after 0900 and shifting from the northwest around 1500. Mixing height.......7100 ft AGL. Transport winds.....West 9 to 14 mph. Ventilation Index...Low (140) increasing to very high (760) 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............42 46 51 60 66 68 72 73 74 75 73 72 RH..............79 67 50 35 25 21 19 17 15 15 16 18 20 FT wind dir..W W W W W W W NW NW NW NW NW 20 FT wind spd..3 4 4 5 5 7 8 8 8 8 6 5 20 FT wind gust. 11 12 13 14 15 14 14 12 11 .THURSDAY NIGHT... Sky/weather.........Partly cloudy (30-40 percent). CWR.................0 percent. Chance of lightning.0 percent. Min temperature.....Around 40. Max humidity........59-64 percent. Wind (20 ft)........Northwest winds 4 to 8 mph, becoming light and downsloping 1 to 4 mph after 2000. Ridgetop wind.......Northwest winds 5 to 10 mph, becoming light and downsloping 1 to 4 mph after 2000. Mixing height.......4500 ft AGL early in the evening then 500 ft AGL overnight. Transport winds.....Northwest 6 to 10 mph. Ventilation Index...Low (180) decreasing (30) overnight. .FRIDAY... Sky/weather.........Partly sunny (55-65 percent) then becoming sunny (5-15 percent) after 1700. CWR.................0 percent. Chance of lightning.0 percent. Max temperature.....74-77. Min humidity........11-16 percent. Wind (20 ft)........Light downsloping winds becoming west after 0500 and increasing to 6 to 12 mph with gusts up to 18 mph after 1300. Ridgetop wind.......Light downsloping winds becoming west after 0500 and increasing to to 7 to 14 mph with 22 mph after 1300. Mixing height.......7800 ft AGL. Transport winds.....West 8 to 17 mph. Ventilation Index...Low (120) increasing to very high (930) in the afternoon. $$ Forecaster...Callihan Requested by...Cutler Christensen Type of request...PRESCRIBED .TAG 2612123.3/PDT .DELDT 05/07/26 .FormatterVersion 2.0.0 .EMAIL christensen.cutler@gmail.com