001  
FNUS76 KSTO 090140  
FWSSTO  
 
SPOT FORECAST FOR CHALLENGE RX...USFS  
NATIONAL WEATHER SERVICE SACRAMENTO CA  
640 PM PDT FRI MAY 8 2026  
 
FORECAST IS BASED ON IGNITION TIME OF 0600 PDT ON MAY 09.  
IF CONDITIONS BECOME UNREPRESENTATIVE...CONTACT THE NATIONAL WEATHER  
SERVICE.  
   
DISCUSSION  
 
DRY CONDITIONS WITH A WARMING TREND INTO EARLY NEXT WEEK IS  
EXPECTED. DIURNAL, TERRAIN-DRIVEN WINDS INTO EARLY NEXT WEEK WITH  
OCCASIONAL BREEZY AFTERNOON WINDS UP TO 10-15 MPH.  
 
NO PRECIPITATION IS FORECASTED AT THIS WITH DAYTIME HUMIDITY VALUES  
IN THE 40S, LOWERING TO THE LOW 30S BY MONDAY-TUESDAY SO MIN RH  
HAS SEEN A MINOR TREND WETTER FROM YESTERDAY'S FORECAST. THAT  
PERIOD WILL ALSO BE THE HOTTEST STRETCH OVER THE NEXT SEVERAL  
DAYS.  
   
SATURDAY  
 
SKY/WEATHER.........SUNNY.  
MAX TEMPERATURE.....77-81.  
MIN HUMIDITY........38-42 PERCENT.  
WIND (20 FT)........  
SLOPE/VALLEY.......LIGHT NORTHEAST-EAST WINDS SHIFTING TO THE WEST  
IN THE AFTERNOON.  
RIDGETOP...........EAST 5 TO 10 MPH SHIFTING TO THE WEST 5 TO 10 MPH  
LATE IN THE MORNING.  
MIXING HEIGHT.......2600 FT AGL.  
TRANSPORT WINDS.....EAST 5 TO 10 MPH SHIFTING TO THE WEST 5 TO 10 MPH  
LATE IN THE MORNING.  
CWR.................0 PERCENT.  
CHANCE OF THUNDER...0 PERCENT.  
 
TIME (PDT) 6AM 7AM 8AM 9AM 10A 11A 12P 1PM 2PM 3PM 4PM 5PM  
SKY COVER.......CLR CLR CLR CLR CLR CLR MCR CLR CLR CLR MCR MCR  
TEMP............61 63 66 67 69 71 74 77 77 78 79 78  
RH..............48 45 44 48 46 46 47 44 43 41 40 40  
SL/VL WIND DIR..NE NE E E SE SW W W W W W W  
SL/VL WIND SPD..5 3 3 3 3 3 5 5 5 5 5 2  
SL/VL WIND GUST.9 9 8 7 7 8 10 10 12 10 10 8  
RIDGE WIND DIR..NE NE E E SE SW W W W W W W  
RIDGE WIND SPD..9 9 7 7 7 5 5 5 6 6 6 5  
MIX HGT (KFT)...0.4 0.4 1.1 1.1 1.1 2.6 2.6 2.6 2.6 2.6 2.6 1.7  
TRANSP WIND DIR.NE NE E E SE SW W W W W W W  
TRANSP WIND SPD.9 9 7 7 7 5 5 5 6 6 6 5  
   
SATURDAY NIGHT  
 
SKY/WEATHER.........MOSTLY CLEAR.  
MIN TEMPERATURE.....60-64.  
MAX HUMIDITY........55-59 PERCENT.  
WIND (20 FT)........  
SLOPE/VALLEY.......LIGHT WINDS.  
RIDGETOP...........WEST AROUND 5 MPH BECOMING LIGHT OVERNIGHT.  
MIXING HEIGHT.......400 FT AGL.  
TRANSPORT WINDS.....WEST AROUND 5 MPH BECOMING LIGHT OVERNIGHT.  
CWR.................0 PERCENT.  
CHANCE OF THUNDER...0 PERCENT.  
 
TIME (PDT) 6PM 7PM 8PM 9PM 10P 11P MID 1AM 2AM 3AM 4AM 5AM  
SKY COVER.......MCR MCR MCR MCR MCR CLR CLR CLR CLR CLR CLR CLR  
TEMP............77 75 72 71 70 67 67 66 64 64 63 62  
RH..............40 51 51 53 54 57 57 57 56 55 54 55  
SL/VL WIND DIR..W W E E E NE NE NE NE NE NE NE  
SL/VL WIND SPD..2 2 2 2 2 2 2 2 3 3 3 2  
SL/VL WIND GUST.8 8 6 6 6 6 6 6 6 6 6 6  
RIDGE WIND DIR..E E E E E SE SE S S S S S  
RIDGE WIND SPD..5 5 2 2 2 6 6 6 7 7 7 6  
MIX HGT (KFT)...1.7 1.7 0.4 0.4 0.4 0.4 0.4 0.4 0.4 0.4 0.4 0.4  
TRANSP WIND DIR.W W E E E E E E NE NE NE NE  
TRANSP WIND SPD.5 5 2 2 2 6 6 6 7 7 7 6  
   
SUNDAY  
 
SKY/WEATHER.........SUNNY.  
MAX TEMPERATURE.....77-81.  
MIN HUMIDITY........40-44 PERCENT.  
WIND (20 FT)........  
SLOPE/VALLEY.......LIGHT WINDS BECOMING SOUTHWEST 4 TO 7 MPH LATE  
IN THE MORNING  
RIDGETOP...........NORTHEAST 4 TO 6 MPH SHIFTING TO THE SOUTHWEST  
6 TO 10 MPH LATE IN THE MORNING.  
MIXING HEIGHT.......3000 FT AGL.  
TRANSPORT WINDS.....NORTHEAST 4 TO 6 MPH SHIFTING TO THE SOUTHWEST  
6 TO 10 MPH LATE IN THE MORNING.  
CWR.................0 PERCENT.  
CHANCE OF THUNDER...0 PERCENT.  
 
TIME (PDT) 6AM 7AM 8AM 9AM 10A 11A 12P 1PM 2PM 3PM 4PM 5PM  
SKY COVER.......CLR CLR CLR CLR CLR CLR CLR CLR MCR MCR MCR MCR  
TEMP............64 66 69 70 70 70 73 76 78 79 79 79  
RH..............52 50 50 52 54 55 53 49 46 43 42 42  
SL/VL WIND DIR..NE NE NE NE NE SW SW SW SW SW SW SW  
SL/VL WIND SPD..2 2 1 1 1 5 5 5 3 3 3 3  
SL/VL WIND GUST.6 6 3 3 3 9 9 9 10 10 10 9  
RIDGE WIND DIR..NE NE NE NE NE SW SW SW SW SW SW SW  
RIDGE WIND SPD..6 6 5 5 5 6 6 6 7 7 7 7  
MIX HGT (KFT)...0.4 0.4 0.7 0.7 0.7 2.4 2.4 2.4 3.0 3.0 3.0 2.7  
TRANSP WIND DIR.NE NE NE NE NE SW SW SW SW SW SW SW  
TRANSP WIND SPD.6 6 5 5 5 6 6 6 7 7 7 7  
   
FORECAST DAYS 3 THROUGH 5  
   
MONDAY  
 
MOSTLY CLEAR. LOWS IN THE LOWER 60S. HIGHS IN THE MID 80S. LIGHT  
WINDS.    
TUESDAY  
 
MOSTLY CLEAR. LOWS IN THE MID 60S. HIGHS IN THE LOWER 80S. LIGHT  
WINDS.    
WEDNESDAY  
 
NOT AS WARM. MOSTLY CLEAR. LOWS IN THE LOWER 60S. HIGHS IN THE  
LOWER 70S. LIGHT WINDS.  
   
OUTLOOK FOR SATURDAY MAY 16 THROUGH FRIDAY MAY 22  
 
 
FORECASTER...DA  
REQUESTED BY...JASON MILLER  
TYPE OF REQUEST...PRESCRIBED  
.TAG 2613009.2/STO  
.DELDT 05/09/26  
.FORMATTERVERSION 2.0.0  
.EMAIL JASON.T.MILLER@USDA.GOV,JAMES.LICO@USDA.GOV,JESSE.STEVENS@USDA.GOV  
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