393  
FNUS73 KILX 201358  
FWSILX  
 
SPOT FORECAST FOR JEPC UNIT #8...IDNR  
NATIONAL WEATHER SERVICE LINCOLN IL  
758 AM CST WED DEC 20 2017  
 
FORECAST IS BASED ON IGNITION TIME OF 1000 CST ON DECEMBER 20.  
IF CONDITIONS BECOME UNREPRESENTATIVE...CONTACT THE NATIONAL WEATHER  
SERVICE.  
 
PLEASE CONTACT OUR OFFICE AT (217) 732-3089 IF YOU HAVE QUESTIONS  
OR CONCERNS WITH THIS FORECAST.  
   
DISCUSSION
 
 
HIGH PRESSURE WILL BUILD ACROSS THE AREA TODAY. NORTHEAST WINDS TO  
START THE DAY WILL TREND EASTERLY BY MIDDAY, AND SOUTHEAST BY  
THURSDAY. WIND SPEEDS SHOULD GENERALLY BE UNDER 10 MPH, BUT A FEW  
GUSTS TO 15 MPH ARE POSSIBLE INTO THIS AFTERNOON. MIXING HEIGHTS  
ARE ON THE LOW SIDE AND THESE WILL COMBINE WITH THE LIGHT WINDS TO  
PROVIDE ONLY POOR TO FAIR SMOKE DISPERSION. SMOKE DISPERSION WILL  
BE BETTER DURING THE AFTERNOON HOURS.  
 
CLOUDS WILL INCREASE ON THURSDAY AND MIXING HEIGHTS WILL DECREASE  
FURTHER. THIS SCENARIO WILL FURTHER DEGRADE SMOKE DISPERSION.  
RELATIVE HUMIDITY LEVELS WILL ALSO BE HIGHER THURSDAY.  
 
   
REST OF TODAY
 
 
SKY/WEATHER.........SUNNY (20-30 PERCENT).  
CHANCE OF PCPN......0 PERCENT.  
LAL.................  
MAX TEMPERATURE.....AROUND 44.  
MIN HUMIDITY........39 PERCENT.  
WIND (20 FT)........  
SLOPE/VALLEY.......EAST WINDS 6 TO 8 MPH. GUSTS UP TO 15 MPH LATE  
IN THE MORNING.  
MIXING HEIGHT.......900-2300 FT AGL.  
TRANSPORT WINDS.....EAST 9 TO 14 MPH.  
SMOKE DISPERSAL.....POOR TO FAIR (7300-22100 KNOT-FT).  
SMOKE DISPERSAL.....POOR TO FAIR (7300-22100 KNOT-FT).  
HAINES INDEX........4 OR LOW POTENTIAL FOR LARGE PLUME DOMINATED  
FIRE GROWTH.  
 
TIME (CST) 10 AM NOON 2 PM 4 PM  
SKY (%).........26 26 23 22  
WEATHER COV.....  
WEATHER TYPE....NONE NONE NONE NONE  
TSTM COV........  
CHC OF PCPN (%).0 0 0 0  
LAL.............M M M M  
TEMP............36 42 44 43  
RH..............54 43 39 41  
20 FT WIND......NE 8 E 7 E 7 E 7  
20 FT WIND GUST.15 15 15 15  
MIX HGT (FT)....1600 2000 2300 1600  
TRANSPORT WIND..E 14 E 10 E 12 E 10  
HAINES INDEX....4 4 4 4  
VRATE KT-FT/100019 18 22 15  
SDSPL KT-FT/100019 18 22 15  
   
TONIGHT
 
 
SKY/WEATHER.........PARTLY CLOUDY (30-40 PERCENT) THEN BECOMING  
MOSTLY CLOUDY (60-70 PERCENT).  
CHANCE OF PCPN......0 PERCENT.  
LAL.................  
MIN TEMPERATURE.....AROUND 29.  
MAX HUMIDITY........88 PERCENT.  
WIND (20 FT)........  
SLOPE/VALLEY.......SOUTHEAST WINDS 6 TO 7 MPH.  
MIXING HEIGHT.......200-400 FT AGL.  
TRANSPORT WINDS.....SOUTHEAST 7 TO 8 MPH.  
SMOKE DISPERSAL.....POOR (1400 KNOT-FT).  
SMOKE DISPERSAL.....POOR (1400 KNOT-FT).  
HAINES INDEX........2 VERY LOW POTENTIAL FOR LARGE PLUME  
DOMINATED FIRE GROWTH  
 
TIME (CST) 6 PM 8 PM 10 PM MIDNGT 2 AM 4 AM  
SKY (%).........23 37 50 63 66 70  
WEATHER COV.....  
WEATHER TYPE....NONE NONE NONE NONE NONE NONE  
TSTM COV........  
CHC OF PCPN (%).0 0 0 0 0 0  
LAL.............M M M M M M  
TEMP............34 31 29 29 29 29  
RH..............61 72 81 85 88 88  
20 FT WIND......E 6 E 6 E 6 SE 7 SE 6 SE 6  
20 FT WIND GUST.10 10 10 10 10 10  
MIX HGT (FT)....300 300 400 400 300 300  
TRANSPORT WIND..E 8 SE 8 SE 8 SE 8 SE 7 SE 7  
HAINES INDEX....4 4 3 2 2 2  
VRATE KT-FT/10002 2 3 3 2 2  
SDSPL KT-FT/10002 2 3 3 2 2  
   
THURSDAY
 
 
SKY/WEATHER.........MOSTLY CLOUDY (75-85 PERCENT).  
CHANCE OF PCPN......10 PERCENT.  
LAL.................  
MAX TEMPERATURE.....AROUND 47.  
MIN HUMIDITY........58 PERCENT.  
WIND (20 FT)........  
SLOPE/VALLEY.......SOUTHEAST WINDS 5 TO 7 MPH BECOMING LIGHT.  
MIXING HEIGHT.......300-1900 FT AGL INCREASING TO 1200-2400 FT AGL  
EARLY IN THE AFTERNOON.  
TRANSPORT WINDS.....SOUTH 7 TO 13 MPH.  
SMOKE DISPERSAL.....POOR TO FAIR (1700-26100 KNOT-FT).  
SMOKE DISPERSAL.....POOR TO FAIR (1700-26100 KNOT-FT).  
HAINES INDEX........2 OR VERY LOW POTENTIAL FOR LARGE PLUME  
DOMINATED FIRE GROWTH.  
 
TIME (CST) 6 AM 8 AM 10 AM NOON 2 PM 4 PM  
SKY (%).........74 83 86 86 84 85  
WEATHER COV.....  
WEATHER TYPE....NONE NONE NONE NONE NONE NONE  
TSTM COV........  
CHC OF PCPN (%).10 10 10 10 10 10  
LAL.............M M M M M M  
TEMP............29 31 37 43 47 46  
RH..............88 85 72 62 60 68  
20 FT WIND......SE 7 SE 7 SE 7 SE 6 SE 5 SE 5  
20 FT WIND GUST.10 10 10  
MIX HGT (FT)....300 500 900 1400 2300 1900  
TRANSPORT WIND..SE 7 SE 10 S 13 S 13 S 13 S 12  
HAINES INDEX....2 2 2 2 2 2  
VRATE KT-FT/10002 4 9 16 26 19  
SDSPL KT-FT/10002 4 9 16 26 19  
 

 
FORECASTER...BAK  
REQUESTED BY...RAY GEROFF  
TYPE OF REQUEST...PRESCRIBED  
.TAG 1720120.0/ILX  
.EMAIL RAY.GEROFF@ILLINOIS.GOV  
 
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