542
FNUS75 KMSO 300738
FWSMSO
SPOT FORECAST FOR LOWER BLACKFOOT CORRIDOR F4
NATIONAL WEATHER SERVICE MISSOULA MT
138 AM MDT WED SEP 30 2026
FORECAST IS BASED ON IGNITION TIME OF 0600 MDT ON SEPTEMBER 30.
IF CONDITIONS BECOME UNREPRESENTATIVE...CONTACT THE NATIONAL WEATHER
SERVICE.
DISCUSSION
TODAY IS EXPECTED TO BE SLIGHTLY COOLER WITH HIGHER
MIN RH COMPARED TO YESTERDAY (TUESDAY). LIGHT MORNING WINDS ARE
ANTICIPATED TO SHIFT TO WESTERLY BY MID TO LATE MORNING. A
WARMING AND DRYING TREND IS FORECAST TO BEGIN ON THURSDAY, AFTER
AREAS OF EARLY MORNING FOG.
MIXING HEIGHTS ARE EXPECTED NEAR 4000 FEET BOTH DAYS WITH
TRANSPORT WINDS DECENT TODAY AND FAIRLY LIGHT ON THURSDAY. NO
SIGNIFICANT PRECIPITATION IS EXPECTED FOR AT LEAST THE NEXT 7
DAYS BUT THERE IS A SLIGHT CHANCE OF LIGHT SHOWERS THIS MORNING.
TODAY
* SKY/WEATHER.........PARTLY TO MOSTLY CLOUDY. SLIGHT CHANCE OF
MORNING SHOWERS.
* CWR (> 0.10 INCH)...LESS THAN 10 PERCENT.
* CHANCE LIGHTNING....0 PERCENT.
* MAX TEMPERATURE.....63-68.
* MIN HUMIDITY........43-48 PERCENT.
* WIND (20 FT)........VARIABLE 2-5 MPH BECOMING WEST 5-6 MPH IN
THE LATE MORNING AND EARLY AFTERNOON. GUSTS TO 20 MPH.
* MIXING HEIGHT.......500 FT AGL INCREASING TO 4000 FT AGL IN THE
AFTERNOON.
* MIXING WINDS........WEST 15 MPH.
* PRECIP AMOUNT.......0.00 INCHES.
TIME (MDT) 6AM 7AM 8AM 9AM 10A 11A 12P 1PM 2PM 3PM 4PM 5PM
SKY (%).........52 70 78 60 71 67 67 68 52 45 42 51
WEATHER COV.....SCH SCH
WEATHER TYPE....RW RW
TSTM COV........
CWR.............0 0 0 0 0 0 0 0 0 0 0 0
CHC OF LTNG (%).0 0 0 0 0 0 10 10 10 0 0 0
TEMP............55 53 49 51 53 56 60 62 64 65 66 64
RH..............70 75 80 77 70 63 57 52 50 49 46 46
20 FT WIND DIR..S S SW SW W W W W W W W W
20 FT WIND SPD..3 3 3 5 5 5 6 6 6 6 6 5
20 FT WIND GUST.15 15 15 15 15 15 20 20 20 15 15 15
MIX HGT (KFT)...0.5 0.5 0.5 1.5 2.0 2.5 3.0 3.5 4.0 4.0 4.0 4.0
TRANSP WIND DIR.W W W W W W W W W W W W
TRANSP WIND SPD.10 10 10 15 15 15 15 15 15 15 15 15
TONIGHT
* SKY/WEATHER.........PARTLY CLOUDY. PATCHY FOG LATE IN THE
EVENING. AREAS OF FOG OVERNIGHT.
* CWR (> 0.10 INCH)...0 PERCENT.
* CHANCE LIGHTNING....0 PERCENT.
* MIN TEMPERATURE.....35-40.
* MAX HUMIDITY........95-100 PERCENT.
* WIND (20 FT)........WEST AROUND 5 MPH EARLY IN THE EVENING
BECOMING VARIABLE 1-3 MPH.
* MIXING HEIGHT.......1500 FT AGL DECREASING TO 500 FT AGL EARLY IN
THE EVENING.
* MIXING WINDS........WEST 15 MPH DECREASING TO 10 MPH EARLY IN THE
EVENING, THEN SHIFTING TO THE NORTHWEST 5 MPH OVERNIGHT.
* PRECIP AMOUNT.......0.00 INCHES.
TIME (MDT) 6PM 7PM 8PM 9PM 10P 11P MID 1AM 2AM 3AM 4AM 5AM
SKY (%).........47 46 40 56 56 39 49 53 56 72 61 60
WEATHER COV..... PTY ARS ARS ARS ARS ARS ARS
WEATHER TYPE.... FOG FOG FOG FOG FOG FOG FOG
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............62 59 54 50 48 45 43 41 41 40 39 39
RH..............54 60 72 80 85 95 100 100 100 100 100 100
20 FT WIND DIR..W W W N N N N N N N N N
20 FT WIND SPD..5 2 1 0 0 0 0 0 0 0 0 0
20 FT WIND GUST.15 10 5 5 5
MIX HGT (KFT)...3.5 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 NW N NW NW NW
TRANSP WIND SPD.15 10 5 10 5 5 5 5 5 5 5 5
THURSDAY
* SKY/WEATHER.........MOSTLY CLOUDY IN THE MORNING THEN PARTLY
CLOUDY. AREAS OF FOG EARLY IN THE MORNING, THEN PATCHY FOG LATE
IN THE MORNING.
* CWR (> 0.10 INCH)...0 PERCENT.
* CHANCE LIGHTNING....0 PERCENT.
* MAX TEMPERATURE.....66-71.
* MIN HUMIDITY........33-38 PERCENT.
* WIND (20 FT)........VARIABLE 1-3 MPH, THEN WEST IN THE
AFTERNOON WITH GUSTS TO 12 MPH.
* MIXING HEIGHT.......500 FT AGL INCREASING TO 4000 FT AGL IN THE
AFTERNOON.
* MIXING WINDS........NORTHWEST 5 MPH SHIFTING TO THE NORTH 5 MPH
EARLY IN THE MORNING, THEN SHIFTING TO THE WEST 10 MPH IN THE
LATE MORNING AND AFTERNOON.
* PRECIP AMOUNT.......0.00 INCHES.
TIME (MDT) 6AM 7AM 8AM 9AM 10A 11A 12P 1PM 2PM 3PM 4PM 5PM
SKY (%).........84 84 84 65 65 65 42 42 42 41 41 41
WEATHER COV.....ARS ARS ARS ARS PTY
WEATHER TYPE....FOG FOG FOG FOG FOG
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............38 38 37 39 45 51 57 62 65 67 68 66
RH..............100 100 100 100 97 69 59 50 43 37 37 40
20 FT WIND DIR..N N N N N N W W W W W W
20 FT WIND SPD..0 0 0 0 0 0 1 1 1 2 2 2
20 FT WIND GUST. 5 5 5 5 5 5 10 12 10
MIX HGT (KFT)...0.5 0.5 0.5 1.0 1.5 2.5 3.5 4.0 4.0 4.0 4.0 4.0
TRANSP WIND DIR.W NW N SW SW W W W W W W W
TRANSP WIND SPD.5 5 5 5 5 5 5 10 10 5 10 10
FORECASTER...BOOTH
REQUESTED BY...MAX HARRISON
TYPE OF REQUEST...PRESCRIBED
.TAG 2622582.3/MSO
.DELDT 09/30/26
.FORMATTERVERSION 2.0.0
.EMAIL DANIEL.SULLIVAN@USDA.GOV,MAX.HARRISON@USDA.GOV,STRYKER.CLARK@USDA.GOV
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