145  
FNUS76 KSTO 190428  
FWSSTO  
 
SPOT FORECAST FOR BUTTERFLY VALLEY RX...CAL FIRE  
NATIONAL WEATHER SERVICE SACRAMENTO CA  
928 PM PDT FRI APR 18 2025  
 
FORECAST IS BASED ON IGNITION TIME OF 0900 PDT ON APRIL 19.  
IF CONDITIONS BECOME UNREPRESENTATIVE...CONTACT THE NATIONAL WEATHER  
SERVICE.  
   
DISCUSSION
 
 
WARMER AND DRIER WEATHER IS EXPECTED THROUGH THE WEEKEND AND INTO  
EARLY NEXT WEEK. THERE WILL BE GENERALLY DIURNALLY DRIVEN WINDS.  
A COOLING TREND RETURNS MID TO LATE WEEK.  
 

 
   
SATURDAY
 
 
SKY/WEATHER.........SUNNY.  
MAX TEMPERATURE.....72-76.  
MIN HUMIDITY........15-19 PERCENT.  
WIND (20 FT)........  
SLOPE/VALLEY.......LIGHT WINDS BECOMING WEST UP TO 6 MPH LATE IN  
THE AFTERNOON.  
RIDGETOP...........EAST AROUND 6 MPH SHIFTING TO THE WEST 3 TO 9  
MPH LATE IN THE MORNING.  
MIXING HEIGHT.......7100 FT AGL.  
TRANSPORT WINDS.....EAST AROUND 6 MPH SHIFTING TO THE WEST 3 TO 9  
MPH LATE IN THE MORNING.  
CWR.................1 PERCENT.  
CHANCE OF THUNDER...1 PERCENT.  
 
TIME (PDT) 9 AM 1 PM 5 PM  
SKY COVER.......CLEAR MCLEAR MCLEAR  
CWR.............0 0 0  
CHC OF THDR (%).0 0 0  
TEMP............44 70 72  
RH..............39 18 21  
SL/VL WIND......N 0G1 W 2G6 W 6G12  
RIDGETOP WIND...N 15 N 10 N 5  
MIX HGT (FT)....2300 4700 4500  
TRANSPORT WIND..E 6 W 3 W 9  
   
SATURDAY NIGHT
 
 
SKY/WEATHER.........MOSTLY CLEAR.  
MIN TEMPERATURE.....38-42.  
MAX HUMIDITY........85-89 PERCENT.  
WIND (20 FT)........  
SLOPE/VALLEY.......WEST WINDS 5 TO 6 MPH EARLY IN THE EVENING  
BECOMING LIGHT.  
RIDGETOP...........SOUTHWEST 3 TO 9 MPH SHIFTING TO THE EAST  
AROUND 5 MPH OVERNIGHT.  
MIXING HEIGHT.......1400 FT AGL.  
TRANSPORT WINDS.....WEST AROUND 9 MPH SHIFTING TO THE SOUTHWEST 3  
TO 9 MPH IN THE EVENING AND OVERNIGHT, THEN  
SHIFTING TO THE EAST AROUND 5 MPH 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 CLR CLR CLR CLR CLR CLR CLR CLR CLR CLR  
CWR.............0 0 0 0 0 0 0 0 0 0 0 0  
CHC OF THDR (%).0 0 0 0 0 0 0 0 0 0 0 0  
TEMP............71 66 59 55 52 50 48 45 43 42 41 40  
RH..............24 34 46 54 62 68 73 76 79 82 84 85  
SL/VL WIND DIR..W W SW SW SW S S S N N N N  
SL/VL WIND SPD..6 6 2 2 2 1 1 1 0 0 0 0  
SL/VL WIND GUST.12 12 7 7 7 2 2 2 1 1 1 1  
RIDGE WIND DIR..N N N N N N N NW W W W W  
RIDGE WIND SPD..10 10 10 10 5 5 5 0 0 0 5 10  
MIX HGT (KFT)...4.5 4.5 1.7 1.7 1.7 1.4 1.4 1.4 1.4 1.4 1.4 1.4  
TRANSP WIND DIR.W W SW SW SW S S S E E E SE  
TRANSP WIND SPD.9 9 6 6 6 3 3 3 5 5 5 5  
   
SUNDAY
 
 
SKY/WEATHER.........SUNNY.  
MAX TEMPERATURE.....73-77.  
MIN HUMIDITY........23-27 PERCENT.  
WIND (20 FT)........  
SLOPE/VALLEY.......LIGHT WINDS BECOMING SOUTHWEST 5 TO 7 MPH LATE  
IN THE AFTERNOON.  
RIDGETOP...........SOUTHEAST AROUND 5 MPH SHIFTING TO THE WEST 5  
TO 10 MPH LATE IN THE MORNING.  
MIXING HEIGHT.......8000 FT AGL.  
TRANSPORT WINDS.....SOUTHEAST AROUND 5 MPH SHIFTING TO THE WEST 10  
TO 17 MPH LATE IN THE MORNING.  
CWR.................1 PERCENT.  
CHANCE OF THUNDER...2 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  
CWR.............0 0 0 0 0 0 0 0 0 0 0 0  
CHC OF THDR (%).0 0 0 0 0 0 0 0 0 0 0 0  
TEMP............40 41 44 50 57 63 68 72 74 75 75 73  
RH..............85 83 77 66 54 42 34 28 25 22 22 25  
SL/VL WIND DIR..N N N N N SW SW SW SW SW SW SW  
SL/VL WIND SPD..0 0 0 0 0 1 1 1 6 6 6 7  
SL/VL WIND GUST.1 1 5 5 5 13 13 13 16  
RIDGE WIND DIR..W W W W W W W W W W W W  
RIDGE WIND SPD..5 5 5 5 5 10 10 10 16 16 16 17  
MIX HGT (KFT)...1.4 1.4 2.0 2.0 2.0 4.9 4.9 4.9 8.0 8.0 8.0 7.2  
TRANSP WIND DIR.SE SE S S S W W W W W W W  
TRANSP WIND SPD.5 5 5 5 5 10 10 10 16 16 16 17  
   
FORECAST DAYS 3 THROUGH 5
 
   
MONDAY
 
 
CLEAR. LOWS IN THE LOWER 40S. HIGHS IN THE UPPER 70S. LIGHT  
WINDS.    
TUESDAY
 
 
CLEAR. LOWS IN THE LOWER 40S. HIGHS IN THE MID 70S. LIGHT WINDS.    
WEDNESDAY
 
 
MOSTLY CLEAR. LOWS IN THE LOWER 40S. HIGHS IN THE LOWER 70S.  
LIGHT WINDS.  
 

 
FORECASTER...CS  
REQUESTED BY...ERIK HANSEN  
TYPE OF REQUEST...PRESCRIBED  
.TAG 2511019.0/STO  
.DELDT 04/19/25  
.FORMATTERVERSION 2.0.0  
.EMAIL ERIK.HANSEN@FIRE.CA.GOV,ROBBIE.WHITCHURCH@FIRE.CA.GOV  
 
CLICK HERE TO GO TO PREVIOUS BULLETINS.

The Nexlab CA Page Main Text Page