955  
FNUS75 KCYS 201855  
FWSCYS  
 
SPOT FORECAST FOR BRITTANIA MOUNTAIN...CASPER INTERAGENCY DISPATCH  
NATIONAL WEATHER SERVICE CHEYENNE WY  
1255 PM MDT THU AUG 20 2026  
 
IF CONDITIONS BECOME UNREPRESENTATIVE, CONTACT THE NATIONAL WEATHER  
SERVICE AT (307) 772-2227  
   
DISCUSSION  
 
WARM AND DRY CONDITIONS WILL CONTINUE THROUGH THIS AFTERNOON WITH A  
TEMPERATURE IN THE MID 80S AND A MINIMUM RELATIVE HUMIDITY AROUND  
15 PERCENT. WINDS WILL REMAIN RELATIVELY LIGHT INTO THE EVENING HOURS.  
THERE IS A SLIGHT CHANCE OF SHOWERS THIS EVENING, MAINLY BETWEEN 9 PM  
AND 12 AM. SHOWERS COULD CONTAINS GUSTY AND ERRATIC WINDS. OVERNIGHT  
HUMIDITY RECOVERIES WILL BE RATHER POOR, WITH A MAXIMUM HUMIDITY  
AROUND 45 PERCENT. ANOTHER WARM DAY IS EXPECTED FRIDAY WITH HIGHS IN  
THE UPPER 80S. MINIMUM RELATIVE HUMIDITY WILL ONCE AGAIN BE NEAR 15  
PERCENT. WINDS WILL BE OUT OF THE NORTH TO NORTHWEST AT AROUND 10 MPH.  
THERE IS A SLIGHT CHANCE OF A STRAY SHOWER DURING THE AFTERNOON  
WHICH COULD CONTAIN OCCASIONAL LIGHTNING AND GUSTY WINDS.  
   
REST OF TODAY  
 
SKY/WEATHER.........SUNNY (5-15 PERCENT).  
CWR.................0 PERCENT.  
MAX TEMPERATURE.....AROUND 83.  
MIN HUMIDITY........16 PERCENT.  
WIND (20 FT)........NORTHWEST WINDS 5 TO 7 MPH.  
MIXING HEIGHT.......11600 FT AGL.  
TRANSPORT WINDS.....NORTHWEST 15 TO 17 MPH.  
SMOKE DISPERSAL..... VERY GOOD (126400 KNOT-FT) EARLY IN THE  
MORNING INCREASING TO EXCELLENT (174100  
KNOT-FT) IN THE AFTERNOON.  
 
TIME (MDT) 1PM 2PM 3PM 4PM 5PM  
SKY (%).........6 8 13 13 9  
WEATHER COV.....  
WEATHER TYPE....  
TSTM COV........  
CWR.............0 0 0 0 0  
TEMP............80 82 83 82 82  
RH..............20 18 17 17 17  
20 FT WIND DIR..W NW NW NW NW  
20 FT WIND SPD..5 5 6 6 7  
20 FT WIND GUST.8 9 10 10 12  
MIX HGT (KFT)...9.7 11 11 12 12  
TRANSP WIND DIR.W W NW NW NW  
TRANSP WIND SPD.15 15 17 17 16  
SDSPL KT-FT/1000126 139 167 174 162  
   
TONIGHT  
 
SKY/WEATHER.........MOSTLY CLEAR (20-30 PERCENT).  
CWR.................2 PERCENT.  
MIN TEMPERATURE.....AROUND 62.  
MAX HUMIDITY........43 PERCENT.  
WIND (20 FT)........NORTHWEST WINDS AROUND 7 MPH SHIFTING TO THE  
SOUTHWEST 7 TO 9 MPH LATE IN THE EVENING.  
MIXING HEIGHT.......500 FT AGL.  
TRANSPORT WINDS.....NORTHWEST AROUND 12 MPH SHIFTING TO THE EAST  
AROUND 8 MPH EARLY IN THE EVENING, THEN  
SHIFTING TO THE SOUTH 9 TO 12 MPH LATE IN THE  
EVENING SHIFTING TO THE SOUTHWEST 10 TO 15 MPH  
OVERNIGHT.  
SMOKE DISPERSAL.....GOOD (93600 KNOT-FT) EARLY IN THE EVENING  
DECREASING TO POOR (3500 KNOT-FT) LATE IN THE  
NIGHT.  
 
TIME (MDT) 6PM 7PM 8PM 9PM 10P 11P MID 1AM 2AM 3AM 4AM 5AM  
SKY (%).........9 13 14 22 17 29 28 37 33 27 30 34  
WEATHER COV.....  
WEATHER TYPE....  
TSTM COV........  
CWR.............0 0 0 0 0 0 0 0 0 0 0 0  
TEMP............82 80 76 71 70 69 68 67 65 64 63 63  
RH..............16 19 23 28 30 32 36 37 40 43 43 39  
20 FT WIND DIR..N NW NW W SW SW S SW SW SW W W  
20 FT WIND SPD..7 7 7 7 7 7 7 7 8 8 9 9  
20 FT WIND GUST.12 13 13 13 14 14 14 15 15 16 16 17  
MIX HGT (KFT)...9.4 2.0 0.5 0.5 0.5 0.5 0.6 0.5 0.6 0.5 0.5 0.5  
TRANSP WIND DIR.NW E E SE S S S SW W W SW W  
TRANSP WIND SPD.12 8 8 9 9 12 10 10 12 13 13 15  
SDSPL KT-FT/100094 14 4 4 4 5 5 5 6 6 5 7  
   
FRIDAY  
 
SKY/WEATHER.........MOSTLY SUNNY (30-40 PERCENT).  
CWR.................2 PERCENT.  
MAX TEMPERATURE.....AROUND 87.  
MIN HUMIDITY........16 PERCENT.  
WIND (20 FT)........WEST WINDS 7 TO 9 MPH SHIFTING TO THE NORTH  
AROUND 7 MPH LATE IN THE AFTERNOON.  
MIXING HEIGHT.......7700 FT AGL INCREASING TO 12400 FT AGL IN THE  
AFTERNOON.  
TRANSPORT WINDS.....WEST 14 TO 16 MPH SHIFTING TO THE NORTHWEST 13  
TO 14 MPH LATE IN THE AFTERNOON.  
SMOKE DISPERSAL.....POOR (6500 KNOT-FT) EARLY IN THE MORNING  
INCREASING TO GOOD (99900 KNOT-FT) IN THE  
AFTERNOON INCREASING TO VERY GOOD (111900  
KNOT-FT) IN THE AFTERNOON.  
 
TIME (MDT) 6AM 7AM 8AM 9AM 10A 11A 12P 1PM 2PM 3PM 4PM 5PM  
SKY (%).........31 35 31 28 25 23 21 36 51 44 49 38  
WEATHER COV.....  
WEATHER TYPE....  
TSTM COV........  
CWR.............0 0 0 0 0 0 0 0 0 0 0 0  
TEMP............62 65 69 71 77 83 85 85 87 84 83 86  
RH..............39 34 30 29 24 19 17 17 16 17 18 16  
20 FT WIND DIR..W W W W W W W NW NW N N N  
20 FT WIND SPD..9 9 9 8 8 8 7 7 7 7 7 7  
20 FT WIND GUST.17 17 17 16 16 15 15 14 14 14 14 13  
MIX HGT (KFT)...0.5 0.5 0.5 0.9 3.1 7.7 11 12 12 10 12 11  
TRANSP WIND DIR.W W W W W W NW NW NW NW NW NW  
TRANSP WIND SPD.16 16 15 15 15 15 15 14 14 13 13 14  
SDSPL KT-FT/10007 7 7 12 41 100 137 145 149 112 127 135  
 
 
FORECASTER...FULLER  
REQUESTED BY...S.DAUBIN  
TYPE OF REQUEST...WILDFIRE  
.TAG 2620097.0/CYS  
.DELDT 08/20/26  
.FORMATTERVERSION 2.0.0  
.EMAIL BURKE.LEE.R@GMAIL.COM  
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