FNUS75 KRIW 221220 FWSRIW Spot Forecast for Bare...US Wildland Fire National Weather Service Riverton WY 620 AM MDT Sat Aug 22 2026 Forecast is based on forecast start time of 0700 MDT on August 22. If conditions become unrepresentative, contact the National Weather Service .DISCUSSION... Deeper moisture will spread over the area starting today, with cooler temperatures and higher humidity than the past couple of days. The increased moisture will increase the chance of showers and thunderstorms, with the greatest chance of a shower or thunderstorm (40 to 60 percent) between 1200 and 1800 this afternoon, although a shower could occur at any time. Any storm could have heavy rain and wind gusts over 35 mph. Otherwise, wind should be largely light before becoming southwest after 1100. Mixing and smoke dispersal will becomes good after 1100. Exact timing of any shower or thunderstorm is still somewhat uncertain. The chance of showers and thunderstorms continues into Sunday and early next week, along with somewhat cooler temperatures. This afternoon and evening still looks like the most likely time of the next several days for wetting rain though. ...Thunderstorms imply strong gusty and erratic winds... .REST OF TODAY... Sky/weather.........Mostly cloudy (70-80 percent) then becoming partly sunny (50-60 percent). Chance of rain showers. Chance of thunderstorms after 1200. CWR.................15 percent. Chance of pcpn......50 percent. Chance of thunder...40 percent. Max temperature.....Around 76. Min humidity........42 percent. Wind (20 ft)........Light winds until 1200, then southwest around 7 mph with gusts to around 11 to 14 mph. Gusty and erratic winds expected near thunderstorms. Ridgetop wind.......Southwest around 10 mph until 0800. Around 15 mph after 1300. Mixing height.......1000 ft AGL until 1000, rising to 7500 ft AGL after 1300. Transport winds.....Southwest 8 to 15 mph. Smoke dispersal.....Poor until 1000, becoming good after 1100. TIME (MDT) 7AM 8AM 9AM 10A 11A 12P 1PM 2PM 3PM 4PM 5PM Sky (%).........85 85 75 80 65 70 75 70 65 50 60 Weather cov.....SCH CHC CHC CHC CHC CHC CHC CHC CHC CHC CHC Weather type....RW RW RW RW RW RW RW RW RW RW RW Tstm cov........ CHC CHC CHC CHC CHC CHC CWR.............0 0 0 0 0 0 0 0 0 0 0 Chc of pcpn (%).20 30 30 30 30 40 40 50 50 50 40 Chc of thdr (%).0 0 10 10 10 30 30 30 40 40 40 Temp............57 57 60 65 68 70 71 72 72 73 71 RH..............67 71 66 55 48 45 44 42 43 44 44 20 FT wind dir..SW SE SE SE S S SW W SW SW SW 20 FT wind spd..5 3 3 4 6 7 7 7 8 7 7 20 FT wind gust.6 4 4 6 7 11 11 11 13 11 11 Ridge wind dir..SW SE SE SE S S SW W SW SW SW Ridge wind spd..10 10 10 10 10 15 15 15 15 15 15 Mix hgt (kft)...0.5 0.5 1.0 2.5 5.5 6.5 7.5 7.5 6.5 6.0 5.5 Transp wind dir.SW SW S SW SW SW SW W W W SW Transp wind spd.10 9 8 10 13 14 14 15 15 14 14 SDspl kt-ft/10005 4 7 25 60 79 89 96 85 74 66 .TONIGHT... Sky/weather.........Partly cloudy (45-55 percent). Chance of showers and thunderstorms in the evening. mainly before 2000. CWR.................5 percent. Chance of pcpn......30 percent. Chance of thunder...25 percent. Min temperature.....Around 52. Max humidity........71 percent. Wind (20 ft)........West around 7 mph. Gusty and erratic winds expected near thunderstorms. Ridgetop wind.......Southwest 10 to 15 mph. Mixing height.......4500 ft AGL until 1900, then 500 ft AGL. Transport winds.....West 10 to 14 mph. Smoke dispersal.....Fair until 1900. Poor after 2000. TIME (MDT) 6PM 7PM 8PM 9PM 10P 11P MID 1AM 2AM 3AM 4AM 5AM Sky (%).........45 40 35 40 40 40 50 60 55 50 55 45 Weather cov.....CHC SCH SCH SCH SCH SCH Weather type....RW RW RW RW RW RW Tstm cov........CHC SCH SCH SCH SCH SCH CWR.............0 0 0 0 0 0 0 0 0 0 0 0 Chc of pcpn (%).30 20 20 20 10 10 10 10 10 10 10 10 Chc of thdr (%).30 20 20 10 10 10 10 10 10 10 10 10 Temp............70 68 65 62 60 59 57 57 57 56 54 54 RH..............50 52 58 62 65 66 66 66 67 69 68 69 20 FT wind dir..SW W W W W SW SW W W W SW SW 20 FT wind spd..6 7 6 6 6 5 6 6 5 6 6 6 20 FT wind gust.10 11 10 10 7 6 10 7 6 7 7 7 Ridge wind dir..SW W W W W SW SW W W W SW SW Ridge wind spd..15 15 15 15 10 10 15 10 10 10 10 10 Mix hgt (kft)...4.5 1.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 Transp wind dir.W W W W W W W W W W W SW Transp wind spd.14 14 13 13 12 10 13 12 12 12 12 12 SDspl kt-ft/100057 20 6 6 6 5 6 6 6 6 6 6 .SUNDAY... Sky/weather.........Partly sunny (30-40 percent). Chance of showers and thunderstorms after 1200. CWR.................0 percent. Chance of pcpn......40 percent. Chance of thunder...39 percent. Max temperature.....Around 73. Min humidity........41 percent. Wind (20 ft)........Light winds until 1200, then west 9 to 11 mph with gusts to around 20 mph. Gusty and erratic winds expected near thunderstorms. Ridgetop wind.......West 10 to 15 mph until 1600, then 15 to 20 mph. Mixing height.......1500 ft AGL until 1000, rising to 8000 feet after 1200. Transport winds.....West 9 to 17 mph until 1300, then 18 to 20 mph. Smoke dispersal.....Poor until 1000, becoming very good after 1200. TIME (MDT) 6AM 7AM 8AM 9AM 10A 11A 12P 1PM 2PM 3PM 4PM 5PM Sky (%).........40 50 35 35 35 20 30 30 35 40 45 35 Weather cov..... CHC CHC SCH SCH SCH CHC Weather type.... RW RW RW RW RW RW Tstm cov........ CHC CHC SCH SCH SCH CHC CWR.............0 0 0 0 0 0 0 0 0 0 0 0 Chc of pcpn (%).10 0 0 0 0 10 30 40 20 20 10 30 Chc of thdr (%).0 0 0 0 0 10 30 40 20 20 10 30 Temp............54 52 54 59 63 68 69 70 71 70 70 70 RH..............71 74 74 67 58 49 44 42 40 42 40 40 20 FT wind dir..SW SW W W W W W W W W W W 20 FT wind spd..4 3 4 3 4 6 9 9 10 10 11 10 20 FT wind gust.6 6 7 6 10 13 17 18 19 20 20 20 Ridge wind dir..SW SW W W W W W W W W W W Ridge wind spd..10 10 10 10 10 15 15 15 15 15 20 15 Mix hgt (kft)...0.5 0.5 0.5 1.5 4.0 6.5 8.0 8.5 6.0 7.0 5.0 6.0 Transp wind dir.W W W W W W W W W W W W Transp wind spd.9 9 10 12 13 16 17 20 18 18 18 18 SDspl kt-ft/10005 4 4 17 42 89 118 143 98 110 81 92 .FORECAST DAYS 3 THROUGH 5... .MONDAY... Partly cloudy. Chance of showers and thunderstorms. Lows around 50. Highs around 70. Light winds. .TUESDAY... Partly cloudy. Chance of showers and thunderstorms. Lows around 50. Highs around 70. Light winds. .WEDNESDAY... Partly cloudy. Chance of showers and thunderstorms. Lows around 50. Highs in the lower 70s. Light winds. $$ Forecaster...Hattings Requested by...Michael Van Patter Type of request...WILDFIRE .TAG 2620207.0/RIW .DELDT 08/22/26 .FormatterVersion 2.0.0 .EMAIL mvanpatter@blm.gov