FNUS76 KPDT 041201 FWSPDT Spot Forecast for Grande Ronde Rappellers Mountain Week...USFS National Weather Service Pendleton OR 501 AM PDT Mon May 4 2026 Forecast is based on ignition time of 0700 MDT on May 04. ***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...Good (60%-70%) overnight humidity recoveries this morning will lead to drier (-3%) conditions across the fire area this afternoon. Highs will be similar to Sunday, with clear skies attributing to breezy afternoon winds of up to 18 mph. Winds will subside overnight, but increase quickly mid-morning Tuesday associated with a dropping system to the east. Mixing heights will drop slightly Tuesday, but elevated transport winds should lend similar ventilation as on Monday. Cooler temperatures Tuesday. .REST OF TODAY... Sky/weather.........Sunny (5-15 percent). CWR.................0 percent. Chance of lightning.2 percent. Max temperature.....75-78. Min humidity........15-20 percent. Wind (20 ft)........Light winds becoming north 6 to 12 mph with gusts up to 18 mph after 1000, peaking between 1500 and 1700. Ridgetop wind.......Light winds becoming north 7 to 14 mph with gusts up to 22 mph after 1000, peaking between 1500 and 1700. Mixing height.......8800 ft AGL. Transport winds.....North 8 to 17 mph increasing to around 18 mph late in the afternoon. Ventilation Index...Moderate (250) 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............41 47 56 63 68 70 72 73 74 75 73 71 RH..............67 53 42 33 26 24 22 21 20 21 23 25 20 FT wind dir..NW N N N N N N N N N N N 20 FT wind spd..2 2 7 8 9 9 10 11 11 11 10 10 20 FT wind gust.6 6 10 12 14 15 16 17 17 17 16 15 .TONIGHT... Sky/weather.........Mostly clear (10-20 percent). CWR.................0 percent. Chance of lightning.1 percent. Min temperature.....43-46. Max humidity........67-72 percent. Wind (20 ft)........North winds 6 to 12 mph with gusts up to 18 mph shifting to the northwest 3 to 7 mph after 2200. Ridgetop wind.......North winds 7 to 14 mph with gusts up to 22 mph shifting to the northwest 4 to 8 mph after 2200. Mixing height.......1200 ft AGL. Transport winds.....North 10 to 18 mph. Ventilation Index...Moderate (450) decreasing to low (110) overnight. .TUESDAY... Sky/weather.........Sunny (0-10 percent). CWR.................0 percent. Chance of lightning.2 percent. Max temperature.....72-75. Min humidity........20-25 percent. Wind (20 ft)........Northwest winds 3 to 7 mph shifting to the north 10 to 15 mph with gusts up to 23 mph after 1000. Ridgetop wind.......Northwest winds 4 to 8 mph shifting to the north 13 to 18 mph with gusts up to 27 mph after 1000. Mixing height.......7800 ft AGL. Transport winds.....North 12 to 21 mph. Ventilation Index...Moderate (300) increasing to very high (1050) in the afternoon. $$ Forecaster...Callihan Requested by...Cutler Christensen Type of request...PRESCRIBED .TAG 2612123.0/PDT .DELDT 05/04/26 .FormatterVersion 2.0.0 .EMAIL christensen.cutler@gmail.com