039  
FNUS75 KBOI 302051  
FWSBOI  
 
SPOT FORECAST FOR BIG GRASS FIRE...USFS  
NATIONAL WEATHER SERVICE BOISE ID  
251 PM MDT THU JUL 30 2026  
 
FORECAST IS BASED ON FORECAST START TIME OF 0700 MDT ON JULY 31.  
IF CONDITIONS BECOME UNREPRESENTATIVE...CONTACT THE NATIONAL WEATHER  
SERVICE.  
 
PLEASE CONTACT OUR OFFICE AT (208)334-9060, IF YOU HAVE QUESTIONS  
OR CONCERNS WITH THIS FORECAST.  
 
...FIRE WEATHER WATCH IN EFFECT FROM SATURDAY AFTERNOON THROUGH  
SATURDAY EVENING FOR DRY/WINDY CONDITIONS...   
..WINDY CONDITIONS CONTINUE THROUGH MONDAY MORNING
 
 
   
DISCUSSION
 
 
TODAY AND TOMORROW HOT, DRY, AND MILDLY BREEZY CONDITIONS  
CONTINUE. GUSTY WINDS ALONGSIDE A DRY COLD FRONTAL PASSAGE THIS  
WEEKEND HAVE PROMPTED THE ISSUANCE OF A FIRE WEATHER WATCH  
SATURDAY AFTERNOON AND EVENING. WESTERLY WINDS 15 TO 20 MPH WITH  
GUSTS UP TO 30 MPH MOVE THROUGH THE FIRE ALONGSIDE MINIMUM RHS OF  
5 TO 10% DURING THE WATCH. WHILE RHS BEGIN TO RISE AROUND SUNSET,  
WINDS AT THE FIRE WILL BE GUSTING 15 TO 25 MPH THROUGH MONDAY  
MORNING. MINIMUM RHS EACH DAY HOLD RELATIVELY STEADY THROUGH THE  
FORECAST AT 5 TO 15% EACH DAY.  
   
FRIDAY
 
 
SKY/WEATHER.........SUNNY.  
MAX TEMPERATURE.....95 TO 100.  
MIN HUMIDITY........6 TO 11 PERCENT.  
CWR.................0 PERCENT.  
WIND - 20 FOOT......WEST 6 TO 12 MPH. GUSTS UP TO 18 MPH IN THE  
AFTERNOON.  
MIXING HEIGHT.......12000 FT AGL.  
TRANSPORT WINDS.....SOUTHWEST AROUND 10 MPH.  
   
FRIDAY NIGHT
 
 
SKY/WEATHER.........MOSTLY CLEAR.  
MIN TEMPERATURE.....61 TO 66.  
MAX HUMIDITY........20 TO 26 PERCENT.  
CWR.................0 PERCENT.  
WIND - 20 FOOT......SOUTH 4 TO 10 MPH. GUSTS UP TO 18 MPH IN THE  
EVENING.  
MIXING HEIGHT.......200 FT AGL.  
TRANSPORT WINDS.....SOUTH AROUND 5 MPH.  
   
SATURDAY
 
 
SKY/WEATHER.........MOSTLY SUNNY.  
MAX TEMPERATURE.....96 TO 104.  
MIN HUMIDITY........7 TO 12 PERCENT.  
CWR.................0 PERCENT.  
WIND - 20 FOOT......SOUTH 3 TO 6 MPH IN THE MORNING SHIFTING TO THE  
WEST 10 TO 16 MPH WITH GUSTS TO AROUND 22 TO 26 MPH IN  
THE AFTERNOON.  
MIXING HEIGHT.......11000 FT AGL.  
TRANSPORT WINDS.....WEST AROUND 15 MPH.  
 

 
FORECASTER...MACFARLANE  
REQUESTED BY...MATT BROWN FBAN  
TYPE OF REQUEST...WILDFIRE  
.TAG 2618438.6/BOI  
.DELDT 07/31/26  
.FORMATTERVERSION 2.0.0  
.EMAIL MATT.BROWN@SCCFD.ORG  
 
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