002  
FNUS75 KRIW 101245  
FWSRIW  
 
SPOT FORECAST FOR BLM SOUTH PASS PILES...BLM  
NATIONAL WEATHER SERVICE RIVERTON WY  
545 AM MST TUE DEC 10 2019  
 
FORECAST IS BASED ON IGNITION TIME OF 0900 MST ON DECEMBER 10.  
IF CONDITIONS BECOME UNREPRESENTATIVE...CONTACT THE NATIONAL WEATHER  
SERVICE.  
   
DISCUSSION
 
 
COOL NORTHWEST FLOW WILL CONTINUE THIS MORNING, BRINGING COOL  
TEMPS AND WEST NORTHWEST GUSTY WIND TO THE FIRE SITE. CLOUDS  
SHOULD DECREASE IN THE AFTERNOON, THOUGH WEST WIND WILL INCREASE.  
BOUNDARY LAYER DEPTH IS FAIRLY SHALLOW WITH THIS PATTERN, THOUGH  
WINDS HELP SMOKE DISPERSAL. BREEZY WEST WIND WILL CONTINUE  
OVERNIGHT WITH CLOUDS INCREASING AGAIN EARLY WEDNESDAY MORNING.  
WEAK WEATHER SYSTEM MOVES THROUGH WEDNESDAY WITH ONLY A SLIGHT  
CHANCE OF SNOW LATE WEDNESDAY AND MINIMAL ACCUMULATION.  
   
..HAINES INDEX IS HIGH LEVEL HAINES BOTH DAY AND NIGHT
 
 
FORECASTER...MCDONALD  
   
REST OF TODAY
 
 
SKY/WEATHER.........PARTLY CLOUDY (40-60 PERCENT).  
MAX TEMPERATURE.....25-28.  
MIN HUMIDITY........50-55 PERCENT.  
20-FOOT WINDS.......WEST WINDS 10 TO 15 MPH WITH GUSTS TO AROUND 20  
MPH IN THE MORNING, BECOMING 15 TO 20 MPH WITH  
GUSTS 25 TO 30 MPH AFTER 1200.  
RIDGE TOP WINDS.....WEST 15 TO 20 MPH THROUGH 1200, THEN WEST 20  
TO 25 MPH.  
LAL.................1.  
CHC OF WETTING RAIN.ZERO PERCENT.  
HAINES INDEX........2 OR VERY LOW POTENTIAL FOR LARGE PLUME  
DOMINATED FIRE GROWTH.  
MIXING HEIGHT.......1000 TO 1500 FT AGL IN THE AFTERNOON.  
TRANSPORT WINDS.....WEST 20 TO 25 MPH.  
SMOKE DISPERSAL.....POOR TO FAIR.  
 
TIME (MST) 9AM 10A 11A 12P 1PM 2PM 3PM 4PM 5PM  
SKY (%).........31 34 38 45 52 60 65 71 76  
WEATHER COV.....  
WEATHER TYPE....  
TSTM COV........  
CWR.............0 0 0 0 0 0 0 0 0  
LAL.............1 1 1 1 1 1 1 1 1  
TEMP............18 20 22 23 25 25 24 23 22  
RH..............71 71 70 68 68 68 69 71 72  
20 FT WIND DIR..W W W W W W W W W  
20 FT WIND SPD..11 11 12 13 14 14 14 12 12  
20 FT WIND GUST.21 21 22 23 25 26 25 23 22  
MIX HGT (KFT)...0.5 0.5 0.9 0.9 0.9 1.0 1.0 1.0 0.5  
TRANSP WIND DIR.W W W W W W W W W  
TRANSP WIND SPD.18 18 21 21 21 21 21 21 18  
HAINES INDEX....2 2 2 2 2 2 2 2 2  
SDSPL KT-FT/10008 8 16 16 16 18 18 18 8  
   
TONIGHT
 
 
SKY/WEATHER.........PARTLY CLOUDY (40-50 PERCENT).  
MIN TEMPERATURE.....18 TO 20.  
MAX HUMIDITY........75-80 PERCENT.  
20-FOOT WINDS.......WEST WINDS 13 TO 18 MPH WITH GUSTS TO AROUND 25  
MPH THROUGH 0300, BECOMING WEST-SOUTHWEST 10  
TO 15 MPH WITH GUSTS AROUND 20 MPH.  
RIDGE TOP WINDS.....WEST 20 TO 25 MPH.  
LAL.................1.  
CHC OF WETTING RAIN.ZERO PERCENT.  
HAINES INDEX........2 TO 3 OR VERY LOW POTENTIAL FOR LARGE PLUME  
DOMINATED FIRE GROWTH.  
MIXING HEIGHT.......500 FT AGL.  
TRANSPORT WINDS.....WEST 18 TO 23 MPH.  
SMOKE DISPERSAL.....POOR.  
 
TIME (MST) 6PM 7PM 8PM 9PM 10P 11P MID 1AM 2AM 3AM 4AM 5AM  
SKY (%).........72 67 63 56 50 44 50 54 57 61 64 68  
WEATHER COV.....  
WEATHER TYPE....  
TSTM COV........  
CWR.............0 0 0 0 0 0 0 0 0 0 0 0  
LAL.............1 1 1 1 1 1 1 1 1 1 1 1  
TEMP............22 21 21 21 21 20 22 23 23 22 21 21  
RH..............74 75 76 74 76 75 67 61 67 64 71 73  
20 FT WIND DIR..W W W W W W W W W W W W  
20 FT WIND SPD..11 11 12 12 12 13 14 15 16 15 13 12  
20 FT WIND GUST.21 21 22 22 23 24 26 28 29 26 24 23  
MIX HGT (KFT)...0.5 0.5 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 W W W W W  
TRANSP WIND SPD.18 18 20 20 20 22 22 22 23 23 23 21  
HAINES INDEX....2 2 2 2 2 3 3 3 3 3 3 2  
SDSPL KT-FT/10008 8 9 9 9 10 10 10 10 10 10 10  
   
WEDNESDAY
 
 
SKY/WEATHER.........PARTLY CLOUDY (40-50 PERCENT), BECOMING  
MOSTLY CLOUDY (70-80PERCENT) BY 1200. A SLIGHT  
CHANCE OF SNOW SHOWERS AFTER 1500.  
MAX TEMPERATURE.....25-28.  
MIN HUMIDITY........50-55 PERCENT.  
20-FOOT WINDS.......WEST SOUTHWEST WINDS 12 TO 15 MPH WITH GUSTS  
TO AROUND 20 MPH.  
RIDGE TOP WINDS.....WEST AROUND 20 MPH.  
LAL.................1.  
CHC OF WETTING RAIN.ZERO PERCENT.  
HAINES INDEX........2 OR VERY LOW POTENTIAL FOR LARGE PLUME  
DOMINATED FIRE GROWTH.  
MIXING HEIGHT.......1000 TO 1500 FT AGL IN THE AFTERNOON.  
TRANSPORT WINDS.....WEST 20 TO 25 MPH.  
SMOKE DISPERSAL.....POOR TO FAIR.  
 
TIME (MST) 6AM 7AM 8AM 9AM 10A 11A 12P 1PM 2PM 3PM 4PM 5PM  
SKY (%).........69 70 71 72 73 74 71 67 63 59 56 52  
WEATHER COV.....  
WEATHER TYPE....  
TSTM COV........  
CWR.............0 0 0 0 0 0 0 0 0 0 0 0  
LAL.............1 1 1 1 1 1 1 1 1 1 1 1  
TEMP............20 20 22 23 24 25 26 26 26 24 23 21  
RH..............71 70 60 57 55 53 53 59 60 63 74 67  
20 FT WIND DIR..W W W W W W W W W W W W  
20 FT WIND SPD..12 12 13 13 12 13 13 13 13 13 14 14  
20 FT WIND GUST.22 23 23 23 23 23 23 24 24 24 25 26  
MIX HGT (KFT)...0.5 0.5 0.5 0.5 0.5 0.8 0.8 0.8 1.0 1.0 1.0 0.6  
TRANSP WIND DIR.W W W W W W W W W W W W  
TRANSP WIND SPD.21 21 21 21 21 21 21 21 21 21 21 21  
HAINES INDEX....2 2 2 2 2 2 2 2 2 2 2 2  
SDSPL KT-FT/100010 10 10 10 10 15 15 15 18 18 18 11  
   
FORECAST DAYS 3 THROUGH 5
 
   
WEDNESDAY NIGHT
 
 
PARTLY TO MOSTLY CLOUDY. A SLIGHT CHANCE OF SNOW SHOWERS EARLY  
IN THE EVENING. LOWS AROUND 17. WEST WINDS AROUND 12 MPH.    
THURSDAY
 
 
MOSTLY CLOUDY WITH CHANCE OF SNOW. LOWS IN THE LOWER 20S. HIGHS  
IN THE UPPER 20S. SOUTHWEST WINDS 15 TO 20 MPH.    
FRIDAY
 
 
PARTLY CLOUDY WITH CHANCE OF SNOW. LOWS AROUND 13. HIGHS IN THE  
UPPER 20S. WEST WINDS AROUND 15 MPH.    
SATURDAY
 
 
MOSTLY CLOUDY. CHANCE OF SNOW. LOWS AROUND 9. HIGHS IN THE LOWER  
20S. WEST WINDS AROUND 10 MPH.  
 

 
FORECASTER...MCDONALD  
REQUESTED BY...JAMIE GEERDES  
TYPE OF REQUEST...PRESCRIBED  
.TAG 1919924.0/RIW  
.DELDT 12/10/19  
.EMAIL JGEERDES@BLM.GOV  
 
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