814
FNUS75 KMSO 211810
FWSMSO
SPOT FORECAST FOR LBC F4
NATIONAL WEATHER SERVICE MISSOULA MT
1210 PM MDT MON SEP 21 2026
FORECAST IS BASED ON IGNITION TIME OF 1200 MDT ON SEPTEMBER 23.
IF CONDITIONS BECOME UNREPRESENTATIVE...CONTACT THE NATIONAL WEATHER
SERVICE.
DISCUSSION
HIGH PRESSURE WILL REMAIN OVER THE REGION WEDNESDAY,
WITH LOWERING HEIGHTS ON THURSDAY IN RESPONSE TO DEEPENING PACIFIC
TROUGH. WINDS BECOME SOUTHWESTERLY ON THURSDAY AND INCREASE LATE
AFTERNOON GUSTS FROM 15 TO 24. THURSDAY WILL HAVE BETTER
VENTILATION THAN WEDNESDAY, WITH THE BEST VENTILATION EACH DAY
AFTER 1-2PM.
WEDNESDAY
* SKY/WEATHER.........MOSTLY SUNNY.
* CWR (> 0.10 INCH)...0 PERCENT.
* CHANCE LIGHTNING....0 PERCENT.
* MAX TEMPERATURE.....76-81.
* MIN HUMIDITY........27-32 PERCENT.
* WIND (20 FT)........VARIABLE 2-4 MPH BECOMING WEST 5-9 MPH WITH
GUSTS TO 14 MPH LATE IN THE AFTERNOON.
* MIXING HEIGHT.......6000 FT AGL.
* MIXING WINDS........SOUTHWEST 15 MPH.
* PRECIP AMOUNT.......0.00 INCHES.
TIME (MDT) 12P 1PM 2PM 3PM 4PM 5PM
SKY (%).........8 8 8 23 23 23
WEATHER COV.....
WEATHER TYPE....
TSTM COV........
CWR.............0 0 0 0 0 0
CHC OF LTNG (%).0 0 0 0 0 0
TEMP............69 73 76 77 78 77
RH..............48 40 36 33 31 31
20 FT WIND DIR..SW SW SW W W W
20 FT WIND SPD..2 2 2 5 5 5
20 FT WIND GUST.5 5 5 15 15 15
MIX HGT (KFT)...4.0 5.0 5.5 6.0 6.0 5.5
TRANSP WIND DIR.SW SW W W W W
TRANSP WIND SPD.10 15 15 15 15 15
WEDNESDAY NIGHT
* SKY/WEATHER.........PARTLY CLOUDY.
* CWR (> 0.10 INCH)...0 PERCENT.
* CHANCE LIGHTNING....0 PERCENT.
* MIN TEMPERATURE.....41-46.
* MAX HUMIDITY........85-90 PERCENT.
* WIND (20 FT)........VARIABLE 1-3 MPH.
* MIXING HEIGHT.......3500 FT AGL DECREASING TO LESS THAN 100 FT
AGL EARLY IN THE EVENING.
* MIXING WINDS........WEST 10 MPH SHIFTING TO THE NORTHWEST 5 MPH
LATE IN THE EVENING, THEN SHIFTING TO THE NORTHEAST 5 MPH LATE IN
THE EVENING.
* PRECIP AMOUNT.......0.00 INCHES.
TIME (MDT) 6PM 7PM 8PM 9PM 10P 11P MID 1AM 2AM 3AM 4AM 5AM
SKY (%).........27 27 27 40 40 40 34 34 34 26 26 26
WEATHER COV.....
WEATHER TYPE....
TSTM COV........
CWR.............0 0 0 0 0 0 0 0 0 0 0 0
CHC OF LTNG (%).0 0 0 0 0 0 0 0 0 0 0 0
TEMP............75 71 66 61 58 56 54 52 50 48 46 45
RH..............33 39 46 55 62 66 71 77 82 87 88 89
20 FT WIND DIR..W W W N N N N N N N N N
20 FT WIND SPD..5 4 2 0 0 0 0 0 0 0 0 0
20 FT WIND GUST.10 10 5 5 5 5
MIX HGT (KFT)...5.0 3.5 2.0 0.5 0.1 0.1 0.5 0.5 0.5 0.5 0.5 0.5
TRANSP WIND DIR.W W NW NW N NE NE NE NE NE E E
TRANSP WIND SPD.10 10 5 5 5 5 5 5 5 5 5 5
THURSDAY
* SKY/WEATHER.........PARTLY CLOUDY.
* CWR (> 0.10 INCH)...0 PERCENT.
* CHANCE LIGHTNING....0 PERCENT.
* MAX TEMPERATURE.....81-86.
* MIN HUMIDITY........24-29 PERCENT.
* WIND (20 FT)........WEST 8-12 MPH WITH GUSTS TO 24 MPH.
* MIXING HEIGHT.......3000 FT AGL INCREASING TO 6500 FT AGL LATE
IN THE AFTERNOON.
* MIXING WINDS........EAST 5 MPH SHIFTING TO THE SOUTHWEST 15 MPH
LATE IN THE AFTERNOON.
* PRECIP AMOUNT.......0.00 INCHES.
TIME (MDT) 6AM 7AM 8AM 9AM 10A 11A 12P 1PM 2PM 3PM 4PM 5PM
SKY (%).........43 43 43 38 38 38 17 17 17 21 21 21
WEATHER COV.....
WEATHER TYPE....
TSTM COV........
CWR.............0 0 0 0 0 0 0 0 0 0 0 0
CHC OF LTNG (%).0 0 0 0 0 0 0 0 0 0 0 0
TEMP............44 44 45 48 55 63 71 77 80 82 83 83
RH..............90 90 89 87 69 51 40 32 29 27 26 26
20 FT WIND DIR..N N N E E E E W W SW SW SW
20 FT WIND SPD..0 0 0 1 1 1 1 6 7 8 10 10
20 FT WIND GUST. 5 5 5 5 10 10 15 20 15
MIX HGT (KFT)...0.5 0.5 0.5 0.5 0.5 1.0 1.5 3.0 5.0 6.5 5.5 2.5
TRANSP WIND DIR.E E E E E SE SE S S SW SW S
TRANSP WIND SPD.5 5 5 5 5 5 5 10 10 15 15 10
FORECASTER...BEC
REQUESTED BY...DANIEL SULLIVAN
TYPE OF REQUEST...PRESCRIBED
.TAG 2622253.0/MSO
.DELDT 09/21/26
.FORMATTERVERSION 2.0.0
.EMAIL MAX.HARRISON@USDA.GOV,JONATHAN.SCHMIDT@USDA.GOV,STRYKER.CLARK@USDA.GOV,DANIEL.SULLIVAN@USDA.GOV
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page