719  
FNUS75 KBOU 010157  
FWSBOU  
 
SPOT FORECAST FOR WILLIAMS FORK FIRE...GRAND COUNTY SHERIFFS OFFICE  
NATIONAL WEATHER SERVICE DENVER/BOULDER CO  
757 PM MDT TUE JUN 30 2026  
 
IF CONDITIONS BECOME UNREPRESENTATIVE...CONTACT THE NATIONAL WEATHER  
SERVICE.  
   
..RED FLAG WARNING IN EFFECT UNTIL 9 PM MDT THIS EVENING  
 
   
DISCUSSION  
 
WINDS ARE CURRENTLY WSW AROUND 12 MPH WITH GUSTS REACHING AS HIGH  
AS 20 MPH. WINDS WILL SLOWLY BECOME LIGHT AND SOUTHERLY WITH WIND  
GUSTS NEAR 10 MPH AT MOST AFTER MIDNIGHT. THERE WILL BE MODEST  
HUMIDITY RECOVERY OVERNIGHT AS RH WILL BE IN THE 40S AND 50S FOR  
MOST OF THE OVERNIGHT.  
 
TOMORROW, PATCHY SMOKE IS POSSIBLE MAINLY ALOFT IN THE MORNING.  
RH WILL DROP INTO THE LOW TEENS BY THE AFTERNOON BEFORE HUMIDITY  
RECOVERS TOMORROW NIGHT. WINDS SHOULD BE WESTERLY FOR MUCH OF THE  
DAY WITH GUSTS AROUND 15 TO 20 MPH FOR THE AFTERNOON. HIGH  
TEMPERATURES WILL BE IN THE MID TO UPPER 70S. THERE IS A VERY LOW  
(<10%) CHANCE OF A SHOWER OR THUNDERSTORM LATE TOMORROW AFTERNOON  
BRINGING GUSTIER WINDS TO THE AREA.  
   
REST OF TONIGHT  
 
SKY/WEATHER.........MOSTLY CLEAR (10-20 PERCENT). PATCHY SMOKE  
UNTIL 2200.  
CWR.................3 PERCENT.  
CHANCE OF THUNDER...3 PERCENT.  
MIN TEMPERATURE.....AROUND 37.  
MAX HUMIDITY........59 PERCENT.  
WIND (20 FT)........WEST WINDS 7 TO 15 MPH WITH GUSTS TO AROUND 20  
MPH UNTIL 2400, THEN VARIABLE UP TO 5 MPH.  
MIXING HEIGHT.......BELOW 1000 FT AGL.  
TRANSPORT WINDS.....WEST 9 TO 15 MPH UNTIL 0100, THEN LIGHT UNTIL  
0200, THEN SOUTH AROUND 8 MPH.  
SMOKE DISPERSAL.....POOR.  
 
TIME (MDT) 8PM 9PM 10P 11P MID 1AM 2AM 3AM 4AM 5AM  
SKY (%).........26 26 19 10 5 5 4 6 7 8  
WEATHER COV.....PTY PTY  
WEATHER TYPE....SMK SMK  
TSTM COV........  
CWR.............0 0 0 0 0 0 0 0 0 0  
CHC OF THDR (%).0 0 0 0 0 0 0 0 0 0  
TEMP............65 60 56 52 49 47 45 42 41 39  
RH..............20 23 26 33 37 42 45 53 53 57  
20 FT WIND DIR..W W W W SW SW S S S S  
20 FT WIND SPD..12 9 8 7 5 3 2 2 2 2  
20 FT WIND GUST.20 15 13 12 7 6 3 3 3 3  
MIX HGT (KFT)...0.7 0.6 0.6 0.6 0.6 0.6 0.6 0.5 0.5 0.5  
TRANSP WIND DIR.SW W W W W W S S S S  
TRANSP WIND SPD.15 14 12 10 9 7 5 5 5 6  
VRATE KT-FT/1K..9 7 6 5 5 3 2 2 2 3  
SMOKEDISPERSION.P P P P P P P P P P  
   
WEDNESDAY  
 
SKY/WEATHER.........MOSTLY SUNNY (5-15 PERCENT) UNTIL 1700, THEN  
PARTLY CLOUDY (25-35 PERCENT). PATCHY SMOKE  
AFTER 1200 UNTIL 1500.  
CWR.................0 PERCENT.  
CHANCE OF THUNDER...0 PERCENT.  
MAX TEMPERATURE.....AROUND 74.  
MIN HUMIDITY........11 PERCENT.  
WIND (20 FT)........VARIABLE UP TO 5 MPH UNTIL 1100, THEN WEST 7 TO  
13 MPH WITH GUSTS TO AROUND 20 MPH.  
MIXING HEIGHT.......BELOW 1000 FT AGL UNTIL 0800. 13800 FT AGL  
AFTER 1300.  
TRANSPORT WINDS.....SOUTH AROUND 8 MPH UNTIL 0800, THEN LIGHT UNTIL  
0900, THEN WEST 8 TO 16 MPH UNTIL 1100, THEN  
SOUTHWEST 19 TO 24 MPH.  
SMOKE DISPERSAL.....POOR UNTIL 1000, THEN GOOD UNTIL 1100, THEN  
EXCELLENT.  
 
TIME (MDT) 6AM 7AM 8AM 9AM 10A 11A 12P 1PM 2PM 3PM 4PM 5PM  
SKY (%).........8 6 5 5 6 7 7 7 9 6 15 28  
WEATHER COV..... PTY PTY PTY  
WEATHER TYPE.... SMK SMK SMK  
TSTM COV........  
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............38 43 48 53 61 64 68 70 72 72 73 72  
RH..............59 51 40 33 25 20 16 13 12 11 11 12  
20 FT WIND DIR..S S W NW W W W W W W W W  
20 FT WIND SPD..2 2 2 2 3 7 8 9 9 12 12 10  
20 FT WIND GUST.3 3 3 3 6 12 13 15 17 20 20 16  
MIX HGT (KFT)...0.5 0.5 1.2 2.8 6.9 9.4 11 12 13 14 14 13  
TRANSP WIND DIR.S S SW W W W W W SW SW SW SW  
TRANSP WIND SPD.6 5 5 8 16 20 21 21 22 23 22 21  
VRATE KT-FT/1K..3 2 5 20 97 160 191 220 250 283 264 241  
SMOKEDISPERSION.P P P P G E E E E E E E  
   
WEDNESDAY NIGHT  
 
SKY/WEATHER.........MOSTLY CLEAR (20-30 PERCENT). PATCHY SMOKE  
AFTER 2100 UNTIL 2400.  
CWR.................0 PERCENT.  
CHANCE OF THUNDER...0 PERCENT.  
MIN TEMPERATURE.....AROUND 38.  
MAX HUMIDITY........57 PERCENT.  
WIND (20 FT)........WEST WINDS 6 TO 11 MPH UNTIL 2100. SOUTH AROUND  
5 MPH AFTER 0400.  
MIXING HEIGHT.......12300 FT AGL UNTIL 1900. BELOW 1000 FT AGL  
AFTER 2000.  
TRANSPORT WINDS.....SOUTHWEST 14 TO 19 MPH UNTIL 2000, THEN WEST  
AROUND 9 MPH UNTIL 2100, THEN SOUTHWEST 8 TO 10  
MPH UNTIL 2300, THEN SOUTH 8 TO 11 MPH UNTIL  
0300, THEN 8 TO 9 MPH UNTIL 0500, THEN LIGHT.  
SMOKE DISPERSAL.....EXCELLENT UNTIL 1900, THEN VERY GOOD UNTIL  
2000, THEN POOR.  
 
TIME (MDT) 6PM 7PM 8PM 9PM 10P 11P MID 1AM 2AM 3AM 4AM 5AM  
SKY (%).........24 24 24 41 36 24 19 18 9 4 6 7  
WEATHER COV..... PTY PTY PTY  
WEATHER TYPE.... SMK SMK SMK  
TSTM COV........  
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............72 69 65 60 56 53 50 48 45 43 42 40  
RH..............13 15 18 24 30 36 42 46 51 55 55 57  
20 FT WIND DIR..W W W S S S S S S S S S  
20 FT WIND SPD..10 10 7 7 5 5 5 5 5 5 3 3  
20 FT WIND GUST.16 16 12 12 7 7 7 7 7 7 6 6  
MIX HGT (KFT)...12 11 0.6 0.6 0.6 0.6 0.6 0.6 0.6 0.5 0.5 0.5  
TRANSP WIND DIR.W SW W W SW S S S S S S S  
TRANSP WIND SPD.18 14 9 7 7 7 7 9 8 6 7 6  
VRATE KT-FT/1K..196 126 5 3 3 3 4 5 4 3 3 3  
SMOKEDISPERSION.E VG P P P P P P P P P P  
   
THURSDAY  
 
SKY/WEATHER.........MOSTLY SUNNY (5-15 PERCENT).  
CWR.................0 PERCENT.  
CHANCE OF THUNDER...0 PERCENT.  
MAX TEMPERATURE.....AROUND 75.  
MIN HUMIDITY........10 PERCENT.  
WIND (20 FT)........VARIABLE UP TO 5 MPH UNTIL 0900, THEN NORTH  
AROUND 7 MPH UNTIL 1000, THEN VARIABLE UP TO 5  
MPH UNTIL 1100, THEN WEST 6 TO 12 MPH WITH  
GUSTS TO AROUND 21 MPH.  
MIXING HEIGHT.......BELOW 1000 FT AGL UNTIL 0800. 14900 FT AGL  
AFTER 1200.  
TRANSPORT WINDS.....SOUTHEAST 8 TO 9 MPH UNTIL 0800, THEN SOUTHWEST  
8 TO 16 MPH UNTIL 1200, THEN 19 TO 24 MPH.  
SMOKE DISPERSAL.....POOR UNTIL 1000, THEN GOOD UNTIL 1100, THEN  
VERY GOOD UNTIL 1200, THEN EXCELLENT.  
 
TIME (MDT) 6AM 7AM 8AM 9AM 10A 11A 12P 1PM 2PM 3PM 4PM 5PM  
SKY (%).........10 9 5 1 2 3 4 7 10 13 16 19  
WEATHER COV.....  
WEATHER TYPE....  
TSTM COV........  
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............39 44 49 55 60 65 69 71 72 73 74 75  
RH..............57 49 40 31 23 17 13 12 11 10 10 10  
20 FT WIND DIR..S S N N W W W W W W W W  
20 FT WIND SPD..3 2 2 7 2 5 6 7 8 10 12 13  
20 FT WIND GUST.6 3 3 12 3 7 9 12 13 16 18 21  
MIX HGT (KFT)...0.5 0.6 2.3 3.9 7.0 10 13 14 15 15 15 14  
TRANSP WIND DIR.SE SE S SW SW SW SW SW SW SW SW W  
TRANSP WIND SPD.6 7 8 8 12 16 20 21 21 22 22 22  
VRATE KT-FT/1K..2 4 16 28 70 140 221 249 263 293 284 274  
SMOKEDISPERSION.P P P P G VG E E E E E E  
 
 
FORECASTER...VARELA  
REQUESTED BY...DIRECTOR MACCHIONE  
TYPE OF REQUEST...WILDFIRE  
.TAG 2616556.0/BOU  
.DELDT 06/30/26  
.FORMATTERVERSION 2.0.0  
.EMAIL AMACCHIONE@CO.GRAND.CO.US  
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