134
FNUS75 KMSO 202117
FWSMSO
SPOT FORECAST FOR BUTTERFLY
NATIONAL WEATHER SERVICE MISSOULA MT
317 PM MDT THU AUG 20 2026
FORECAST IS BASED ON FORECAST START TIME OF 0700 MDT ON AUGUST 21.
IF CONDITIONS BECOME UNREPRESENTATIVE...CONTACT THE NATIONAL WEATHER
SERVICE.
DISCUSSION
WARM AND DRY CONDITIONS CONTINUE THROUGH THIS FORECAST
PERIOD. OVERNIGHT RH RECOVERY WILL REMAIN POOR ON THE MID SLOPES
AND UPPER ELEVATIONS FRIDAY NIGHT. TERRAIN DRIVEN DOWN-SLOPE
WINDS MAY DEVELOP OVERNIGHT.
VERY SLIGHT (5%) CHANCE OF DRY THUNDERSTORM OVER THE AREAS ON
FRIDAY AFTERNOON, MORE LIKELY WELL TO THE SOUTH OF THE FIRE. HIGH
BASED SHOWERS START TO DEVELOP SATURDAY MORNING, WITH
THUNDERSTORMS MORE LIKELY IN THE AFTERNOON. WIND GUSTS WILL BE
THE MAIN RISK, WITH ERRATIC GUSTS TO 30-35 MPH POSSIBLE
ASSOCIATED WITH SHOWERS/THUNDERSTORMS OUTFLOW, EVEN FROM STORMS
FURTHER AWAY FROM THE FIRE. CHANCE OF WETTING RAIN IS LOW (<10%),
UNLESS IT IS DIRECT HIT BY A THUNDERSTORM WHICH MAY BE ABLE TO
PRODUCE 0.1-0.2 INCH OF RAINFALL.
FRIDAY
* SKY/WEATHER.........MOSTLY SUNNY.
* CWR (> 0.10 INCH)...0 PERCENT.
* CHANCE LIGHTNING....5 PERCENT.
* MAX TEMPERATURE.....79-84.
* MIN HUMIDITY........16-21 PERCENT.
* WIND (20 FT)........VARIABLE 1-3 MPH IN THE MORNING BECOMING
WEST 5-8 MPH WITH GUSTS TO 15 MPH IN THE AFTERNOON.
* MIXING HEIGHT.......3000 FT AGL INCREASING TO 6500 FT AGL IN THE
AFTERNOON.
* MIXING WINDS........SOUTHWEST 5 MPH.
* PRECIP AMOUNT.......0.00 INCHES.
FRIDAY NIGHT
* SKY/WEATHER.........MOSTLY CLOUDY.
* CWR (> 0.10 INCH)...0 PERCENT.
* CHANCE LIGHTNING....0 PERCENT.
* MIN TEMPERATURE.....60-65.
* MAX HUMIDITY........BOTTOM 53-58 PERCENT. TOP 25- 30 PERCENT.
* WIND (20 FT)........EAST 4-8 MPH GUSTS TO 15 MPH AT TIMES.
* MIXING HEIGHT.......1000 FT AGL DECREASING TO 500 FT AGL IN THE
LATE EVENING AND OVERNIGHT.
* MIXING WINDS........EAST 10 MPH.
* PRECIP AMOUNT.......0.00 INCHES.
SATURDAY
* SKY/WEATHER.........MOSTLY CLOUDY. SLIGHT CHANCE OF SHOWERS IN
THE MORNING. CHANCE OF SHOWERS AND THUNDERSTORMS IN THE AFTERNOON.
* CWR (> 0.10 INCH)...LESS THAN 10 PERCENT.
* CHANCE LIGHTNING....30 PERCENT.
* MAX TEMPERATURE.....75-80.
* MIN HUMIDITY........25-30 PERCENT.
* WIND (20 FT)........VARIABLE 2-4 MPH BECOMING WEST AROUND 5 TO 8
MPH WITH GUSTS TO NEAR 20 MPH IN THE AFTERNOON.
* MIXING HEIGHT.......2500 FT AGL INCREASING TO 5000 FT AGL IN THE
AFTERNOON.
* MIXING WINDS........SOUTHWEST 10 MPH.
* PRECIP AMOUNT.......0.01-0.10 INCHES.
FORECASTER...JENNK
REQUESTED BY...CLINT MENDENHALL
TYPE OF REQUEST...WILDFIRE
.TAG 2618902.19/MSO
.DELDT 08/20/26
.FORMATTERVERSION 2.0.0
.EMAIL CHRIS.MARABETTA@USDA.GOV,CLINT.MENDENHALL@USDA.GOV,JACQUIE_PARKS@FIRENET.GOV,CHRISTOPHER.M.KRAMER@USDA.GOV,2026.NORTHFORKLOSTHORSE.PLANS@FIRENET.GOV
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