506  
FNUS75 KRIW 271209  
FWSRIW  
 
SPOT FORECAST FOR SVF-2B-7/8...USFS  
NATIONAL WEATHER SERVICE RIVERTON WY  
609 AM MDT THU MAR 27 2025  
 
FORECAST IS BASED ON IGNITION TIME OF 0700 MDT ON MARCH 27.  
IF CONDITIONS BECOME UNREPRESENTATIVE, CONTACT THE NATIONAL WEATHER  
SERVICE  
   
DISCUSSION
 
 
MOSTLY CLEAR SKIES WITH LIGHT WINDS WILL PREVAIL THROUGH THE  
MORNING TODAY. SOUTHWESTERLY WINDS ARE EXPECTED TO START  
INCREASING AROUND 1300 THIS AFTERNOON WITH PERIODIC GUSTS OF 20  
TO 30 MPH. WINDS WILL BRIEFLY SHIFT TO THE NORTH/NORTHWEST  
STARTING AROUND 1700-1900 BEFORE DECREASING, RETURNING TO THE  
SOUTH/SOUTHWEST BY FRIDAY MORNING. A NEARING FRONTAL PASSAGE WILL  
BRING INCREASING CLOUDS THROUGHOUT THE AFTERNOON AND EVENING  
TODAY. THE FRONTAL PASSAGE WILL BRING THE CHANCE (20-40%) FOR  
SOME SHOWERS LATE THIS AFTERNOON/EVENING STARTING AROUND  
1600-2000. COOLER TEMPERATURES AND LIGHTER WINDS ARE EXPECTED FOR  
FRIDAY ALONG WITH INCREASED CHANCES FOR SHOWERS.  
   
..THUNDERSTORMS IMPLY STRONG GUSTY AND ERRATIC WINDS
 
 
   
REST OF TODAY
 
 
SKY/WEATHER.........SUNNY (20-30 PERCENT) THEN BECOMING PARTLY  
SUNNY (65-75 PERCENT).  
CWR.................0 PERCENT.  
CHANCE OF PCPN......10 PERCENT.  
CHANCE OF THUNDER...10 PERCENT.  
MAX TEMPERATURE.....AROUND 55.  
MIN HUMIDITY........39 PERCENT.  
WIND (20 FT)........LIGHT WINDS UNTIL 1300, THEN SOUTHWEST 7 TO 11  
MPH WITH GUSTS TO AROUND 20 MPH.  
RIDGETOP WIND.......EAST AROUND 10 MPH UNTIL 0800, THEN LIGHT UNTIL  
1000, THEN EAST AROUND 10 MPH UNTIL 1100, THEN  
SOUTH UNTIL 1500, THEN SOUTHWEST 15 TO 20 MPH.  
MIXING HEIGHT.......2000 FT AGL UNTIL 1200, THEN 4000 FT AGL UNTIL  
1400, THEN 5500 FT AGL UNTIL 1700, THEN 3500 FT  
AGL.  
TRANSPORT WINDS.....SOUTH 12 TO 20 MPH UNTIL 1500, THEN SOUTHWEST  
17 TO 22 MPH.  
SMOKE DISPERSAL.....POOR UNTIL 1300, THEN FAIR UNTIL 1400, THEN  
GOOD EARLY IN THE MORNING INCREASING TO VERY  
GOOD IN THE AFTERNOON UNTIL 1700, THEN FAIR.  
 
TIME (MDT) 7AM 8AM 9AM 10A 11A 12P 1PM 2PM 3PM 4PM 5PM  
SKY (%).........10 10 10 20 15 15 35 40 60 70 75  
WEATHER COV.....  
WEATHER TYPE....  
TSTM COV........  
CWR.............0 0 0 0 0 0 0 0 0 0 0  
CHC OF PCPN (%).0 0 0 0 0 0 0 10 10 10 10  
CHC OF THDR (%).0 0 0 0 0 0 0 0 10 10 10  
TEMP............36 36 39 42 44 48 50 52 54 54 53  
RH..............73 72 67 59 52 47 43 41 39 40 42  
20 FT WIND DIR..E NE NE E SE S S SW SW SW SW  
20 FT WIND SPD..3 2 2 3 4 6 7 10 11 10 8  
20 FT WIND GUST.5 4 5 6 8 11 14 18 19 20 19  
RIDGE WIND DIR..E NE NE E SE S S SW SW SW SW  
RIDGE WIND SPD..10 5 5 10 10 10 15 15 20 15 15  
MIX HGT (KFT)...1.0 1.0 1.0 1.5 2.0 3.0 4.0 5.5 5.5 4.0 3.5  
TRANSP WIND DIR.S S S S S S S SW SW SW S  
TRANSP WIND SPD.14 14 12 13 13 13 17 20 22 18 17  
SDSPL KT-FT/100015 15 12 15 23 31 60 97 107 64 55  
   
TONIGHT
 
 
SKY/WEATHER.........MOSTLY CLOUDY (70-80 PERCENT). CHANCE OF RAIN  
SHOWERS IN THE EVENING. RAIN SHOWERS LIKELY  
OVERNIGHT.  
CWR.................9 PERCENT.  
CHANCE OF PCPN......60 PERCENT.  
CHANCE OF THUNDER...11 PERCENT.  
MIN TEMPERATURE.....AROUND 31.  
MAX HUMIDITY........90 PERCENT.  
WIND (20 FT)........LIGHT WINDS UNTIL 2400, THEN NORTHWEST AROUND 7  
MPH WITH GUSTS TO AROUND 13 MPH UNTIL 0100,  
THEN LIGHT.  
RIDGETOP WIND.......SOUTHWEST 10 TO 15 MPH UNTIL 2000, THEN  
NORTHWEST UNTIL 0200, THEN SOUTH UNTIL 0300,  
THEN LIGHT.  
MIXING HEIGHT.......1000 FT AGL.  
TRANSPORT WINDS.....SOUTH 9 TO 15 MPH UNTIL 2300, THEN NORTHWEST 7  
TO 14 MPH.  
SMOKE DISPERSAL.....POOR.  
 
TIME (MDT) 6PM 7PM 8PM 9PM 10P 11P MID 1AM 2AM 3AM 4AM 5AM  
SKY (%).........65 75 80 85 85 90 90 80 70 60 60 65  
WEATHER COV..... SCH SCH CHC CHC LKY CHC SCH  
WEATHER TYPE.... RW RW RW RW RW RW RW  
TSTM COV........  
CWR.............0 0 0 0 0 0 10 10 10 10 10 10  
CHC OF PCPN (%).10 10 20 20 30 50 60 40 20 10 10 0  
CHC OF THDR (%).10 10 10 0 0 0 0 0 0 0 0 0  
TEMP............52 48 45 41 39 38 36 35 34 33 32 32  
RH..............46 51 57 63 70 77 82 82 81 79 82 84  
20 FT WIND DIR..SW W NW N N N NW W S S S SE  
20 FT WIND SPD..6 5 4 4 5 6 7 6 4 2 2 2  
20 FT WIND GUST.18 14 11 8 10 12 13 10 6  
RIDGE WIND DIR..SW W NW N N N NW W S S S SE  
RIDGE WIND SPD..15 10 10 10 10 15 15 10 10 5 5 5  
MIX HGT (KFT)...2.0 1.5 1.0 1.0 1.0 1.5 1.5 1.0 1.0 1.0 1.0 1.0  
TRANSP WIND DIR.SW S S S W W N NW NW SW W W  
TRANSP WIND SPD.15 12 12 9 13 13 14 12 9 8 7 7  
SDSPL KT-FT/100029 15 12 10 14 14 18 12 10 9 8 8  
   
FRIDAY
 
 
SKY/WEATHER.........MOSTLY CLOUDY (75-85 PERCENT). SLIGHT CHANCE OF  
RAIN SHOWERS AND SNOW SHOWERS LATE IN THE  
MORNING. CHANCE OF RAIN SHOWERS LATE IN THE  
AFTERNOON. CHANCE OF SNOW SHOWERS LATE IN THE  
AFTERNOON.  
CWR.................4 PERCENT.  
CHANCE OF PCPN......50 PERCENT.  
CHANCE OF THUNDER...6 PERCENT.  
MAX TEMPERATURE.....AROUND 46.  
MIN HUMIDITY........46 PERCENT.  
WIND (20 FT)........LIGHT WINDS.  
RIDGETOP WIND.......LIGHT WINDS UNTIL 1200, THEN NORTH AROUND 10  
MPH UNTIL 1700, THEN LIGHT.  
MIXING HEIGHT.......2000 FT AGL UNTIL 1000. 5500 FT AGL AFTER 1400.  
TRANSPORT WINDS.....WEST AROUND 7 MPH UNTIL 0700, THEN SOUTH UNTIL  
0800, THEN LIGHT UNTIL 1000, THEN SOUTHWEST 7  
TO 13 MPH UNTIL 1600, THEN WEST.  
SMOKE DISPERSAL.....POOR UNTIL 1000. POOR EARLY IN THE MORNING  
INCREASING TO GOOD IN THE AFTERNOON AFTER 1400.  
 
TIME (MDT) 6AM 7AM 8AM 9AM 10A 11A 12P 1PM 2PM 3PM 4PM 5PM  
SKY (%).........65 65 70 70 75 85 90 90 90 95 90 90  
WEATHER COV..... SCH SCH SCH SCH CHC CHC CHC  
WEATHER TYPE.... RS RS RS RS RW RS RS  
TSTM COV........  
CWR.............0 0 0 0 0 0 0 0 0 0 0 0  
CHC OF PCPN (%).0 0 0 0 10 20 20 20 20 50 50 50  
CHC OF THDR (%).0 0 0 0 0 0 0 0 0 10 10 10  
TEMP............31 31 32 33 35 38 40 42 43 45 43 41  
RH..............85 82 77 72 66 59 55 52 51 52 55 60  
20 FT WIND DIR..SE S SW W W W NW NW N N N N  
20 FT WIND SPD..2 2 1 1 2 2 3 3 3 3 3 2  
20 FT WIND GUST. 2 2 5 6 6 6 5 4 4  
RIDGE WIND DIR..SE S SW W W W NW NW N N N N  
RIDGE WIND SPD..5 5 5 5 5 5 10 10 10 10 10 5  
MIX HGT (KFT)...1.0 1.0 1.0 2.0 3.0 3.5 4.0 4.5 5.0 5.5 4.5 4.0  
TRANSP WIND DIR.W S S S S SW SW SW SW W W W  
TRANSP WIND SPD.7 7 6 6 7 7 8 9 12 13 12 12  
SDSPL KT-FT/10008 8 6 10 17 20 28 36 50 61 47 39  
   
FORECAST DAYS 3 THROUGH 5
 
   
SATURDAY
 
 
MOSTLY CLOUDY WITH SNOW SHOWERS LIKELY AND CHANCE OF SHOWERS.  
LOWS IN THE MID 20S. HIGHS AROUND 40. LIGHT WINDS.    
SUNDAY
 
 
MOSTLY CLOUDY. CHANCE OF SNOW SHOWERS. LOWS AROUND 20. HIGHS IN  
THE LOWER 40S. LIGHT WINDS.    
MONDAY
 
 
MOSTLY CLOUDY WITH SNOW SHOWERS. LOWS IN THE MID 20S. HIGHS IN  
THE LOWER 40S. LIGHT WINDS.  
 

 
FORECASTER...DZIEWALTOWSKI  
REQUESTED BY...WILL HALL  
TYPE OF REQUEST...PRESCRIBED  
.TAG 2507914.1/RIW  
.DELDT 03/27/25  
.FORMATTERVERSION 2.0.0  
.EMAIL MICHAEL.MCEWEN@USDA.GOV,WILLIAM.HALL@USDA.GOV  
 
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