111  
FNUS73 KGRR 241304  
FWSGRR  
 
SPOT FORECAST FOR POWERLINE...USFS  
NATIONAL WEATHER SERVICE GRAND RAPIDS MI  
904 AM EDT TUE JUL 24 2018  
 
FORECAST IS BASED ON IGNITION TIME OF 1100 EDT ON JULY 24.  
IF CONDITIONS BECOME UNREPRESENTATIVE...CONTACT THE NATIONAL WEATHER  
SERVICE.  
 
PLEASE CONTACT OUR OFFICE AT (616) 949-5150, IF YOU HAVE QUESTIONS  
OR CONCERNS WITH THIS FORECAST.  
   
DISCUSSION
 
 
STUBBORN LOW PRESSURE FINALLY MOVING OUT TODAY, SO EXPECT DECREASING  
CLOUDS THIS AFTERNOON WITH WINDS OUT OF THE NORTHWEST UP TO 10 MPH.  
A DRY AND WARMER DAY WITH LOWER RELATIVE HUMIDITIES IS IN STORE FOR  
WEDNESDAY.  
   
REST OF TODAY
 
 
SKY/WEATHER.........MOSTLY CLOUDY (65-75 PERCENT) THEN BECOMING  
SUNNY (10-20 PERCENT).  
TEMPERATURE.........73 AT IGNITION...MAX 82.  
RH..................83 PERCENT AT IGNITION...MIN 56 PERCENT.  
WIND (20 FT)........WINDS NORTHWEST AT 8 MPH AT  
IGNITION...OTHERWISE NORTHWEST WINDS 5 TO 10  
MPH.  
MIXING HEIGHT.......1500 FT AGL AT IGNITION...OTHERWISE 4700-5200  
FT AGL DECREASING TO 2200 FT AGL IN THE  
EVENING.  
MIXING WINDS........NORTHWEST 7 TO 14 MPH.  
SMOKE DISPERSAL.....100 /POOR/ AT IGNITION. MAX...700 /EXCELLENT/.  
HAINES INDEX........3 OR VERY LOW POTENTIAL FOR LARGE PLUME  
DOMINATED FIRE GROWTH AT IGNITION...MAX 5.  
 
TIME (EDT) 11 AM 1 PM 3 PM 5 PM 7 PM 9 PM  
SKY (%).........81 54 34 19 10 6  
WEATHER COV.....  
WEATHER TYPE....NONE NONE NONE NONE NONE NONE  
TSTM COV........  
TEMP............73 77 80 80 78 74  
RH..............83 71 60 58 61 73  
20 FT WIND......NW 8 NW 7 NW 7 NW 9 NW 9 W 9  
20 FT WIND GUST. 8 8 11 11  
MIX HGT (FT)....1500 4000 5200 4400 2200 600  
HAINES INDEX....3 3 4 5 5 4  
SMOKE DISPERSAL 100 500 700 600 300 0  
   
TONIGHT
 
 
SKY/WEATHER.........MOSTLY CLEAR (15-25 PERCENT). PATCHY FOG  
THROUGH ABOUT 2 AM. AREAS OF FOG OVERNIGHT.  
TEMPERATURE.........MIN 59.  
RH..................MAX 100 PERCENT.  
WIND (20 FT)........NORTHWEST WINDS 5 TO 8 MPH UNTIL MIDNIGHT  
BECOMING LIGHT, THEN BECOMING NORTHWEST 5 TO 9  
MPH OVERNIGHT.  
MIXING HEIGHT.......700-1200 FT AGL.  
MIXING WINDS........WEST 1 TO 9 MPH SHIFTING TO THE NORTH 1 TO 2  
MPH TOWARD DAYBREAK.  
SMOKE DISPERSAL.....0-100 (POOR).  
HAINES INDEX........3 TO 5 OR OR VERY LOW POTENTIAL FOR LARGE PLUME  
DOMINATED FIRE GROWTH TO OR MODERATE POTENTIAL  
FOR LARGE PLUME DOMINATED FIRE GROWTH.  
   
WEDNESDAY
 
 
SKY/WEATHER.........SUNNY (15-25 PERCENT). AREAS OF FOG EARLY IN  
THE MORNING.  
TEMPERATURE.........MAX 82.  
RH..................MIN 41 PERCENT.  
WIND (20 FT)........WEST WINDS 5 TO 10 MPH.  
MIXING HEIGHT.......5400-5900 FT AGL DECREASING TO 2800-3300 FT AGL  
LATE IN THE DAY.  
MIXING WINDS........NORTHWEST 2 TO 10 MPH INCREASING TO 9 TO 14 MPH  
IN THE AFTERNOON.  
SMOKE DISPERSAL.....0-800 (POOR TO EXCELLENT).  
HAINES INDEX........3 TO 5 OR OR VERY LOW POTENTIAL FOR LARGE PLUME  
DOMINATED FIRE GROWTH TO OR MODERATE POTENTIAL  
FOR LARGE PLUME DOMINATED FIRE GROWTH.  
 

 
FORECASTER...MEADE  
REQUESTED BY...KEVIN SHERRETZ  
TYPE OF REQUEST...PRESCRIBED  
.TAG 1813328.0/GRR  
.DELDT 07/24/18  
.EMAIL KSHERRETZ@FS.FED.US  
 
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