347 FNUS76 KPDT 090848 FWSPDT Spot Forecast for STONE...high dessert team 3 National Weather Service Pendleton OR 148 AM PDT Tue Sep 9 2025 Forecast is based on forecast start time of 2000 PDT on September 08. ***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...A slowly approaching weather system will bring another round of afternoon and early evening showers and thunderstorms today and Wednesday. Storms could produce gusty winds, small hail, and brief downpours. Although locally wetting rains are possible, overall CWRs remain generally low today with the best chances for rainfall Wednesday. Moisture from this system will foster both excellent RH recoveries overnight and minimum RHs around 50 percent. Light winds will continue each morning and each overnight, northerly during the afternoon and evening. .TODAY... Sky/weather.........Mostly cloudy (75-85 percent) then becoming mostly sunny (45-55 percent). Slight chance of rain showers in the morning. Rain showers likely and slight chance of thunderstorms in the afternoon. CWR.................8 percent increasing to 15 percent late in the afternoon. Chance of lightning.24 percent. Max temperature.....73-76. Min humidity........42-47 percent. Wind (20 ft)........Light winds becoming north 5 to 7 mph late in the afternoon. Gusty and erratic winds expected near thunderstorms late in the afternoon. Ridgetop wind.......Northwest 3 to 5 mph increasing to 6 to 8 mph late in the afternoon. Mixing height.......5700 ft AGL. Transport winds.....West around 6 mph shifting to the north 6 to 9 mph late in the morning. Ventilation Index...Poor (50) increasing to fair (290) in the afternoon. .TONIGHT... Sky/weather.........Mostly cloudy (60-70 percent). Chance of rain showers and slight chance of thunderstorms in the evening, then slight chance of rain showers late in the evening. Chance of rain showers early in the morning. CWR.................15 percent decreasing to 0 percent late in the evening. Chance of lightning.24 percent. Min temperature.....51-54. Max humidity........89-94 percent. Wind (20 ft)........North winds 5 to 7 mph early in the evening becoming light. Gusty and erratic winds expected near thunderstorms in the evening. Ridgetop wind.......Northwest 6 to 8 mph easing to 3 to 5 mph overnight. Mixing height.......500 ft AGL in the evening and overnight. Transport winds.....Northwest 7 to 9 mph shifting to the west around 5 mph overnight. Ventilation Index...Poor (100) decreasing to poor (30) overnight. .WEDNESDAY... Sky/weather.........Mostly cloudy (65-75 percent). Rain showers likely and slight chance of thunderstorms in the morning, then rain showers and chance of thunderstorms in the afternoon. CWR.................0 percent increasing to 75 percent. Chance of lightning.39 percent. Max temperature.....70-73. Min humidity........56-61 percent. Wind (20 ft)........Light winds becoming north 5 to 7 mph late in the afternoon. Gusty and erratic winds expected near thunderstorms late in the morning. Gusty and erratic winds expected near thunderstorms late in the afternoon. Ridgetop wind.......Northwest 3 to 5 mph increasing to 8 to 10 mph late in the afternoon. Mixing height.......5200 ft AGL early in the morning. Transport winds.....Northwest around 5 mph shifting to the west around 12 mph. Ventilation Index...Poor (30) increasing to fair (310) in the afternoon. $$ Forecaster...NWS Seattle Requested by...chistoph Type of request...WILDFIRE .TAG 2521348.4/PDT .DELDT 09/08/25 .FormatterVersion 2.0.0 .EMAIL Stacy.lauritsen@oregon.gov,orjdcc@firenet.gov,michale.j.cearns@odf.oregon.gov