FNUS55 KMSO 182003 FWFMSO Fire Weather Planning Forecast for Wrn Montana and N Cntrl Idaho National Weather Service Missoula MT 202 PM MDT Mon May 18 2026 .DISCUSSION... Idaho (Zones 102 and 103): /NOTICE/ The afternoon fire weather zones synopsis and forecast are automatically generated through late spring. Taking a quick look at the next 48 hours... Tonight's weather, partly cloudy. A 20 percent chance of rain until midnight. Widespread frost after midnight. Tuesday, partly cloudy. Widespread frost in the morning. Humidities will be a little lower. Tuesday Night, partly cloudy. Wednesday, mostly cloudy. A 20 percent chance of rain in the afternoon. Humidities will be higher. Northwest MT (Zones 104 and 105): /NOTICE/ The afternoon fire weather zones synopsis and forecast are automatically generated through late spring. Taking a quick look at the next 48 hours... Tonight's weather, mostly cloudy. A 20 percent chance of rain until midnight. Widespread frost after midnight. Tuesday, mostly cloudy. Widespread frost in the morning. Chance of rain showers and a slight chance of thunderstorms in the afternoon. Tuesday Night, mostly cloudy with a 20 percent chance of rain until midnight, then partly cloudy after midnight. Wednesday, a chance of rain and snow in the morning, then rain showers likely and a slight chance of thunderstorms in the afternoon. West Central MT (Zones 106, 107 and 108): /NOTICE/ The afternoon fire weather zones synopsis and forecast are automatically generated through late spring. Taking a quick look at the next 48 hours... Tonight's weather, partly cloudy. A 20 percent chance of rain until midnight. Widespread frost after midnight. Tuesday, partly cloudy. Widespread frost in the morning. A 20 percent chance of showers and thunderstorms in the afternoon. Tuesday Night, partly cloudy. Wednesday, mostly cloudy. Chance of rain showers and a slight chance of thunderstorms in the afternoon. Humidities will be higher. Southwest MT (Zones 109, 110 and 111): /NOTICE/ The afternoon fire weather zones synopsis and forecast are automatically generated through late spring. Taking a quick look at the next 48 hours... Tonight's weather, partly cloudy. Widespread frost after midnight. Tuesday, partly cloudy. It'll be not as cool. Tuesday Night, mostly cloudy with a 20 percent chance of rain and snow showers until midnight, then partly cloudy after midnight. Wednesday, mostly cloudy. A 20 percent chance of showers and thunderstorms in the afternoon. Humidities will be a little higher. IDZ102-103-191000- Palouse/Hells Canyon-Clearwater/Nez Perce- 102 PM PDT Mon May 18 2026 .TONIGHT... * Sky/Weather.........Partly cloudy. Slight chance of rain. Widespread frost after midnight. Snow level 6500 feet. * Min Temperature.....35-40 valleys and 28-38 ridges. * Max Humidity........66-76 percent. * 20-Foot Winds....... * Lower Elevation......Northwest 5-10 mph in the evening becoming downslope/downvalley 2-5 mph. * Ridge Top............Northwest 5-15 mph becoming west up to 5 mph after midnight. * Mixing Height.......6 kft agl until 2000. Below 500 ft to 1 kft agl after 2100. * Transport Winds.....Northwest 10 mph until 2400, then variable less than 10 mph. * Chance Lightning....Near 0 percent. * CWR (> 0.10 Inch)...0 percent. .TUESDAY... * Sky/Weather.........Partly cloudy. Widespread frost in the morning. * Max Temperature.....65-75 valleys and 50-60 ridges. * Min Humidity........29-39 percent. * 20-Foot Winds....... * Lower Elevation......Calm to becoming upslope/upvalley 4-8 mph in the afternoon. * Ridge Top............West 5-15 mph. * Mixing Height.......Below 500 ft to 1 kft agl until 0900. 8 kft agl after 1200. * Transport Winds.....Variable less than 10 mph until 1000, then west 10 mph until 1700, then 15 mph. * Chance Lightning....Near 0 percent. * CWR (> 0.10 Inch)...0 percent. .TUESDAY NIGHT... * Sky/Weather.........Partly cloudy. * Min Temperature.....33-43. * Max Humidity........63-73 percent. * 20-Foot Winds....... * Lower Elevation......Downslope/downvalley 1-3 mph. * Ridge Top............West 5-15 mph becoming southwest up to 5 mph after midnight. * Mixing Height.......5 kft agl until 2000. Below 500 ft to 1 kft agl after 0300. * Transport Winds.....West 15 mph until 2100, then variable less than 10 mph. * Chance Lightning....Near 0 percent. * CWR (> 0.10 Inch)...0 percent. .WEDNESDAY... * Sky/Weather.........Mostly cloudy. Snow level 7500 feet. * Max Temperature.....65-75 valleys and 50-60 ridges. * Min Humidity........33-43 percent valleys and 42-52 percent ridges. * 20-Foot Winds....... * Lower Elevation......Calm to becoming upslope/upvalley 4-8 mph in the afternoon. * Ridge Top............West up to 5 mph increasing to 5-15 mph in the afternoon. * Mixing Height.......Below 500 ft to 1 kft agl until 0900. 7 kft agl after 1300. * Transport Winds.....Variable less than 10 mph until 0800, then west 10 mph until 1500, then northwest 15 mph. * Chance Lightning....Near 0 percent over the Palouse/Hells Canyon...and 15 percent toward the Clearwater/Nez Perce. * CWR (> 0.10 Inch)...0 percent. .THURSDAY...Partly cloudy with chance of rain. Chance of rain 30 percent. Lows 40-50. Highs 60-70. Min humidities 20-30 percent. North winds 10-15 mph. .FRIDAY...Partly cloudy. Lows 40-50. Highs 65-75. Min humidities 20-30 percent. Northeast winds 5-10 mph. .SATURDAY...Partly cloudy. Lows 45-55. Highs 70-80. Southwest winds 10-15 mph. .SUNDAY...Partly cloudy. Lows 45-55. Highs 70-80. .MEMORIAL DAY...Partly cloudy with slight chance of rain. Chance of rain 20 percent. Lows 45-55. Highs 65-75. $$ MTZ104-105-191000- Kootenai-Flathead/Glacier Park- 202 PM MDT Mon May 18 2026 .TONIGHT... * Sky/Weather.........Partly cloudy. Slight chance of rain. Widespread frost after midnight. Snow level 6500 feet. * Min Temperature.....28-38. * Max Humidity........92-100 percent valleys and 81-91 percent ridges. * 20-Foot Winds....... * Lower Elevation......Downslope/downvalley 2-5 mph becoming variable less than 5 mph after midnight. * Ridge Top............West 5-15 mph. * Mixing Height.......5 kft agl until 2000. Below 500 ft to 1 kft agl after 2100. * Transport Winds.....Southwest 10 mph. * Chance Lightning....Near 0 percent. * CWR (> 0.10 Inch)...10 percent. .TUESDAY... * Sky/Weather.........Partly cloudy. Widespread frost in the morning. Slight chance of thunderstorms in the afternoon. Snow level 6500 feet. * Max Temperature.....60-70 valleys and 45-55 ridges. * Min Humidity........35-45 percent valleys and 53-63 percent ridges. * 20-Foot Winds....... * Lower Elevation......Southwest 10-15 mph. * Ridge Top............Southwest 10-20 mph. * Mixing Height.......Below 500 ft to 1 kft agl until 0900. 6 kft agl after 1200. * Transport Winds.....West 15 mph until 1500, then 20 mph. * Chance Lightning....25 percent. * CWR (> 0.10 Inch)...10 percent. .TUESDAY NIGHT... * Sky/Weather.........Partly cloudy. Slight chance of rain. Snow level 7000 feet. * Min Temperature.....30-40. * Max Humidity........90-98 percent valleys and 77-87 percent ridges. * 20-Foot Winds....... * Lower Elevation......Variable less than 5 mph in the evening becoming downslope/downvalley 1-3 mph. * Ridge Top............West 10-20 mph decreasing to 5-10 mph after midnight. * Mixing Height.......5 kft agl until 2000. Below 500 ft to 1 kft agl after 2100. * Transport Winds.....West 15 mph. * Chance Lightning....Near 0 percent. * CWR (> 0.10 Inch)...10 percent. .WEDNESDAY... * Sky/Weather.........Mostly cloudy. Chance of rain and snow in the morning. Slight chance of thunderstorms in the afternoon. Snow level 7000 feet. * Max Temperature.....60-70 valleys and 45-55 ridges. * Min Humidity........44-54 percent valleys and 63-73 percent ridges. * 20-Foot Winds....... * Lower Elevation......Calm to variable less than 7 mph. * Ridge Top............West 5-15 mph. * Mixing Height.......1-2 kft agl until 0900. 7 kft agl after 1300. * Transport Winds.....Variable less than 10 mph until 0800, then northwest 15 mph until 1700, then 10 mph. * Chance Lightning....30 percent. * CWR (> 0.10 Inch)...30 percent over the Kootenai...and 60 percent toward the Flathead/Glacier Park. .THURSDAY...Partly cloudy with chance of rain. Chance of rain 30 percent. Lows 35-45. Highs 60-70. Min humidities 20-30 percent. North winds 5-10 mph. .FRIDAY...Partly cloudy. Lows 40-50. Highs 60-70. Min humidities 20-30 percent. Southwest winds 5-10 mph. .SATURDAY...Partly cloudy. Lows 40-50. Highs 65-75. Southwest winds 10-20 mph. .SUNDAY...Partly cloudy. Lows 45-55. Highs 65-75. .MEMORIAL DAY...Partly cloudy with slight chance of rain. Chance of rain 20 percent. Lows 45-55. Highs 60-70. $$ MTZ106-108-191000- West Lolo-East Lolo- 202 PM MDT Mon May 18 2026 .TONIGHT... * Sky/Weather.........Partly cloudy. Slight chance of rain. Widespread frost after midnight. Snow level 6000 feet. * Min Temperature.....25-35. * Max Humidity........84-94 percent valleys and 75-85 percent ridges. * 20-Foot Winds....... * Lower Elevation......West 5-10 mph in the evening becoming downslope/downvalley 2-5 mph. * Ridge Top............West 5-15 mph. * Mixing Height.......7 kft agl until 1900. Below 500 ft to 1 kft agl after 2100. * Transport Winds.....West 10 mph. * Chance Lightning....Near 0 percent. * CWR (> 0.10 Inch)...10 percent. .TUESDAY... * Sky/Weather.........Partly cloudy. Widespread frost in the morning. * Max Temperature.....53-63. * Min Humidity........28-38 percent valleys and 41-51 percent ridges. * 20-Foot Winds....... * Lower Elevation......West 5-15 mph. * Ridge Top............West 10-20 mph. * Mixing Height.......Below 500 ft to 1 kft agl until 0900. 7 kft agl after 1500. * Transport Winds.....West 10 mph until 1000, then 15 mph. * Chance Lightning....Near 0 percent over the West Lolo...and 20 percent toward the East Lolo. * CWR (> 0.10 Inch)...0 percent. .TUESDAY NIGHT... * Sky/Weather.........Partly cloudy. * Min Temperature.....30-40. * Max Humidity........77-87 percent valleys and 69-79 percent ridges. * 20-Foot Winds....... * Lower Elevation......Southwest 10-15 mph. * Ridge Top............Southwest 10-15 mph. * Mixing Height.......6 kft agl until 2000. Below 500 ft to 1 kft agl after 2100. * Transport Winds.....West 15 mph. * Chance Lightning....Near 0 percent. * CWR (> 0.10 Inch)...0 percent. .WEDNESDAY... * Sky/Weather.........Mostly cloudy. Slight chance of thunderstorms in the afternoon. Snow level 7000 feet. * Max Temperature.....60-70 valleys and 50-60 ridges. * Min Humidity........33-43 percent valleys and 48-58 percent ridges. * 20-Foot Winds....... * Lower Elevation......West 5-15 mph. * Ridge Top............West 5-15 mph. * Mixing Height.......1-2 kft agl until 0900. 7 kft agl after 1100. * Transport Winds.....West 15 mph. * Chance Lightning....20 percent over the West Lolo...and 25 percent toward the East Lolo. * CWR (> 0.10 Inch)...20 percent. .THURSDAY...Partly cloudy with chance of rain. Chance of rain 30 percent. Lows 35-45. Highs 60-70. Min humidities 20-30 percent. North winds 10-15 mph. .FRIDAY...Partly cloudy. Lows 40-50. Highs 65-75. Min humidities 15-25 percent. West winds 5-10 mph. .SATURDAY...Partly cloudy. Lows 40-50. Highs 65-75. Southwest winds 10-15 mph. .SUNDAY...Partly cloudy. Lows 45-55. Highs 70-80. .MEMORIAL DAY...Partly cloudy with slight chance of rain. Chance of rain 20 percent. Lows 45-55. Highs 65-75. $$ MTZ107-191000- Flathead Reservation- 202 PM MDT Mon May 18 2026 .TONIGHT... * Sky/Weather.........Partly cloudy. Slight chance of rain. Areas of frost after midnight. Snow level 6500 feet. * Min Temperature.....30-40. * Max Humidity........68-78 percent. * 20-Foot Winds....... * Lower Elevation......Southwest 5-10 mph. * Ridge Top............Southwest 5-10 mph. * Mixing Height.......6 kft agl until 1900. Below 500 ft to 1 kft agl after 2000. * Transport Winds.....West 10 mph until 2200, then variable less than 10 mph. * Chance Lightning....Near 0 percent. * CWR (> 0.10 Inch)...10 percent. .TUESDAY... * Sky/Weather.........Partly cloudy. Slight chance of thunderstorms in the afternoon. Snow level 7000 feet. * Max Temperature.....65-70 valleys and 45-50 ridges. * Min Humidity........35-45 percent valleys and 48-58 percent ridges. * 20-Foot Winds....... * Lower Elevation......Southwest 5-15 mph. * Ridge Top............West 5-15 mph increasing to 10-20 mph in the afternoon. * Mixing Height.......Below 500 ft to 1 kft agl until 0900. 7 kft agl after 1200. * Transport Winds.....Southwest 10 mph until 1200, then west 15 mph. * Chance Lightning....20 percent over areas west of Highway 93...and 25 percent toward the Mission Mtns and areas east of Highway 93. * CWR (> 0.10 Inch)...10 percent. .TUESDAY NIGHT... * Sky/Weather.........Partly cloudy. * Min Temperature.....40-45 valleys and 30-35 ridges. * Max Humidity........69-79 percent valleys and 76-86 percent ridges. * 20-Foot Winds....... * Lower Elevation......Southwest 10-15 mph. * Ridge Top............Southwest 10-15 mph. * Mixing Height.......5 kft agl until 2000. Below 500 ft to 1 kft agl after 2100. * Transport Winds.....West 15 mph until 0100, then southwest 10 mph. * Chance Lightning....Near 0 percent. * CWR (> 0.10 Inch)...0 percent. .WEDNESDAY... * Sky/Weather.........Mostly cloudy. Slight chance of rain in the morning. Slight chance of thunderstorms in the afternoon. Snow level 7000 feet. * Max Temperature.....65-70 valleys and 45-50 ridges. * Min Humidity........43-53 percent valleys and 58-68 percent ridges. * 20-Foot Winds....... * Lower Elevation......Calm to variable less than 7 mph. * Ridge Top............West 5-15 mph. * Mixing Height.......Below 500 ft to 1 kft agl until 0900. 7 kft agl after 1300. * Transport Winds.....Southwest 10 mph until 1400, then northwest 15 mph. * Chance Lightning....25 percent. * CWR (> 0.10 Inch)...30 percent. .THURSDAY...Partly cloudy with rain likely. Chance of rain 70 percent. Lows 40-50. Highs 60-70. Min humidities 25-35 percent. North winds 10-15 mph. .FRIDAY...Partly cloudy. Lows 40-50. Highs 65-75. Min humidities 20-30 percent. South winds 5-10 mph. .SATURDAY...Partly cloudy. Lows 45-55. Highs 70-80. Southwest winds 10-15 mph. .SUNDAY...Partly cloudy. Lows 45-55. Highs 70-80. .MEMORIAL DAY...Partly cloudy with slight chance of rain. Chance of rain 20 percent. Lows 45-55. Highs 65-75. $$ MTZ109-191000- Bitterroot- 202 PM MDT Mon May 18 2026 .TONIGHT... * Sky/Weather.........Partly cloudy. Slight chance of rain and snow. Widespread frost after midnight. Snow level 6000 feet. * Min Temperature.....25-35. * Max Humidity........67-77 percent. * 20-Foot Winds....... * Lower Elevation......Northwest 5-10 mph in the evening becoming downslope/downvalley 2-5 mph. * Ridge Top............West 5-15 mph. * Mixing Height.......5 kft agl until 2000. Below 500 ft to 1 kft agl after 2200. * Transport Winds.....Northwest 10 mph until 0100, then variable less than 10 mph. * Chance Lightning....Near 0 percent. * CWR (> 0.10 Inch)...10 percent. .TUESDAY... * Sky/Weather.........Partly cloudy. * Max Temperature.....65-70 valleys and 45-50 ridges. * Min Humidity........19-29 percent valleys and 33-43 percent ridges. * 20-Foot Winds....... * Lower Elevation......West 5-15 mph. * Ridge Top............West 5-15 mph. * Mixing Height.......Below 500 ft to 1 kft agl until 0900. 8 kft agl after 1400. * Transport Winds.....West 10 mph until 1500, then 15 mph. * Chance Lightning....Near 0 percent. * CWR (> 0.10 Inch)...0 percent. .TUESDAY NIGHT... * Sky/Weather.........Partly cloudy. * Min Temperature.....30-40. * Max Humidity........61-71 percent. * 20-Foot Winds....... * Lower Elevation......West 5-10 mph in the evening becoming downslope/downvalley 2-5 mph. * Ridge Top............West 10-20 mph becoming southwest 5-10 mph after midnight. * Mixing Height.......7 kft agl until 2000. Below 500 ft to 1 kft agl after 2100. * Transport Winds.....West 15 mph until 2200, then variable less than 10 mph. * Chance Lightning....Near 0 percent. * CWR (> 0.10 Inch)...0 percent. .WEDNESDAY... * Sky/Weather.........Mostly cloudy. Slight chance of thunderstorms in the afternoon. Snow level 7000 feet. * Max Temperature.....65-70 valleys and 50-55 ridges. * Min Humidity........29-39 percent valleys and 43-53 percent ridges. * 20-Foot Winds....... * Lower Elevation......West 5-15 mph. * Ridge Top............West 5-15 mph. * Mixing Height.......1-2 kft agl until 0900. 8 kft agl after 1300. * Transport Winds.....West 10 mph until 1300, then 15 mph. * Chance Lightning....15 percent over the Darby, Sula, and West Fork Districts...and 20 percent toward areas north of Hamilton. * CWR (> 0.10 Inch)...0 percent. .THURSDAY...Partly cloudy with chance of rain and slight chance of snow. Chance of precipitation 50 percent. Lows 35-45. Highs 55-65. Min humidities 20-30 percent. North winds 10-20 mph. .FRIDAY...Partly cloudy. Lows 35-45. Highs 60-70. Min humidities 15-25 percent. Northwest winds 10-15 mph. .SATURDAY...Partly cloudy. Lows 40-50. Highs 65-75. Southwest winds 10-15 mph. .SUNDAY...Partly cloudy. Lows 45-55. Highs 70-80. .MEMORIAL DAY...Partly cloudy with slight chance of rain showers and thunderstorms. Chance of precipitation 20 percent. Lows 45-55. Highs 65-75. $$ MTZ110-111-191000- Deerlodge/West Beaverhead-East Beaverhead- 202 PM MDT Mon May 18 2026 .TONIGHT... * Sky/Weather.........Partly cloudy. Widespread frost after midnight. * Min Temperature.....20-30. * Max Humidity........75-85 percent valleys and 66-76 percent ridges. * 20-Foot Winds....... * Lower Elevation......North 10-15 mph in the evening becoming downslope/downvalley 5-10 mph. * Ridge Top............North 10-20 mph becoming west 5-10 mph after midnight. * Mixing Height.......7 kft agl until 2000. Below 500 ft to 1 kft agl after 2100. * Transport Winds.....North 15 mph until 2100, then variable less than 10 mph. * Chance Lightning....Near 0 percent. * CWR (> 0.10 Inch)...0 percent. .TUESDAY... * Sky/Weather.........Partly cloudy. * Max Temperature.....55-65 valleys and 45-50 ridges. * Min Humidity........18-28 percent. * 20-Foot Winds....... * Lower Elevation......West 5-15 mph. * Ridge Top............West 5-15 mph. * Mixing Height.......1-2 kft agl until 0900. 10 kft agl after 1200. * Transport Winds.....West 10 mph until 1500, then 15 mph. * Chance Lightning....Near 0 percent. * CWR (> 0.10 Inch)...0 percent. .TUESDAY NIGHT... * Sky/Weather.........Partly cloudy. Slight chance of rain showers and snow showers. Snow level 7000 feet. * Min Temperature.....30-35. * Max Humidity........64-74 percent. * 20-Foot Winds....... * Lower Elevation......Southwest 10-15 mph. * Ridge Top............Southwest 10-15 mph. * Mixing Height.......7 kft agl until 2000. Below 500 ft to 1 kft agl after 2100. * Transport Winds.....West 15 mph until 0100, then southwest 10 mph. * Chance Lightning....Near 0 percent. * CWR (> 0.10 Inch)...10 percent. .WEDNESDAY... * Sky/Weather.........Partly cloudy. Slight chance of thunderstorms in the afternoon. Snow level 7000 feet. * Max Temperature.....55-60 valleys and 45-50 ridges. * Min Humidity........27-37 percent. * 20-Foot Winds....... * Lower Elevation......Calm to becoming west 5-15 mph in the afternoon. * Ridge Top............West 5-15 mph. * Mixing Height.......Below 500 ft to 1 kft agl until 0800. 9 kft agl after 1300. * Transport Winds.....West 10 mph until 1100, then 15 mph. * Chance Lightning....20 percent. * CWR (> 0.10 Inch)...10 percent. .THURSDAY...Mostly cloudy with rain likely and chance of snow. Chance of precipitation 70 percent. Lows 35-45. Highs 55-65. Min humidities 20-30 percent. North winds 10-20 mph. .FRIDAY...Partly cloudy. Lows 30-40. Highs 60-70. Min humidities 15-25 percent. Northwest winds 10-15 mph. .SATURDAY...Partly cloudy. Lows 35-45. Highs 65-75. Southwest winds 10-15 mph. .SUNDAY...Partly cloudy. Lows 40-50. Highs 70-80. .MEMORIAL DAY...Partly cloudy. Lows 45-55. Highs 70-80. $$