717
FNUS75 KRIW 031705
FWSRIW

Spot Forecast for Black Fire...BLM
National Weather Service Riverton WY
1105 AM MDT Wed Sep 3 2025

Forecast is based on forecast start time of 1300 MDT on September 03.
If conditions become unrepresentative, contact the National Weather
Service

.DISCUSSION...
A dry northwest flow prevails through midday Thursday ahead of an
approaching weather disturbance. This weather system will create
isolated late day showers and thunderstorms Thursday, but for the
most part dry conditions prevail. The primary weather hazard will
initially be gusty northwest wind Thursday afternoon, which
switches to the east-northeast early Thursday evening behind
passage of a cold front. The first several hours after the cold
front passes will be windy with frequent gusts 25 to 35 mph.

...Thunderstorms imply strong gusty and erratic winds...

.REST OF TODAY...

Sky/weather.........Sunny (0-10 percent).
Chance of pcpn......0 percent.
Chance of thunder...0 percent.
Max temperature.....81 to 84.
Min humidity........11 to 14 percent.
Wind (20 ft)........Light east-northeast wind until 1200L, then
                    becoming west-northwest 9 to 12 mph by 1500L.
Mixing height.......Rising to around 10000 ft AGL by 1500L.
Transport winds.....Northwest 10 to 15 mph.
Smoke dispersal.....Becoming Very Good by 1400L.

TIME (MDT)      1PM 2PM 3PM 4PM 5PM
Sky (%).........5   5   5   5   5
Weather cov.....
Weather type....
Tstm cov........
Chc of pcpn (%).0   0   0   0   0
Chc of thdr (%).0   0   0   0   0
Temp............79  80  81  82  82
RH..............16  14  13  12  12
20 FT wind dir..NE  NW  NW  NW  NW
20 FT wind spd..6   6   7   7   7
20 FT wind gust.10  10  11  12  12
Mix hgt (kft)...11  11  12  12  12
Transp wind dir.NW  NW  NW  NW  NW
Transp wind spd.14  14  14  14  14
SDspl kt-ft/1000124 133 138 137 136

.TONIGHT...

Sky/weather.........Mostly clear (10-20 percent).
Chance of pcpn......0 percent.
Chance of thunder...0 percent.
Min temperature.....51 to 54.
Max humidity........34 to 37 percent.
Wind (20 ft)........West-northwest wind around 10 mph until 1900L,
                    then becoming southwest 3 to 6 mph by 2100L.
Mixing height.......9000 ft AGL until 1900L, then decreasing to
                    less than 1000 ft AGL by 2100L.
Transport winds.....Northwest 10 to 15 mph until 1900L, then
                    becoming west 5 to 8 mph.
Smoke dispersal.....Very Good until 1900L, then becoming Poor
                    by 2100L.

TIME (MDT)      6PM 7PM 8PM 9PM 10P 11P MID 1AM 2AM 3AM 4AM 5AM
Sky (%).........5   10  15  20  15  15  15  15  15  15  15  20
Weather cov.....
Weather type....
Tstm cov........
Chc of pcpn (%).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............82  78  75  71  69  66  64  60  58  57  56  54
RH..............12  13  15  17  18  20  21  24  25  28  28  31
20 FT wind dir..NW  NW  W   W   W   SW  SW  SW  W   W   W   W
20 FT wind spd..6   6   4   4   4   5   5   5   5   5   5   5
20 FT wind gust.11  8   6   5   5   6   6   6   6   6   6   7
Mix hgt (kft)...11  6.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5
Transp wind dir.NW  NW  NW  W   W   SW  SW  W   W   W   W   W
Transp wind spd.13  12  10  9   9   10  12  10  10  10  10  10
SDspl kt-ft/1000114 63  6   5   5   5   6   5   6   5   5   5

.THURSDAY...

Sky/weather.........Mostly sunny (25-35 percent).
Chance of pcpn......10 percent after 1400L.
Chance of thunder...10 percent.
Max temperature.....Around 81.
Min humidity........11 to 14 percent.
Wind (20 ft)........Southwest wind 4 to 7 mph until 1000L, then
                    becoming west-northwest 8 to 12 mph with
                    gusts to around 18 mph by 1300L.
Mixing height.......Less than 1000 ft AGL until 0900L, then
                    gradually increasing to 10000 ft AGL by 1400L.
Transport winds.....West 5 to 10 mph until 1000L, then becoming
                    west-northwest 15 to 20 mph by 1400L.
Smoke dispersal.....Poor until 1000L, then gradually becoming
                    Excellent by 1500L.

TIME (MDT)      6AM 7AM 8AM 9AM 10A 11A 12P 1PM 2PM 3PM 4PM 5PM
Sky (%).........20  20  15  10  15  15  15  20  25  30  35  45
Weather cov.....
Weather type....
Tstm cov........
Chc of pcpn (%).0   0   0   0   0   0   0   0   0   0   10  10
Chc of thdr (%).0   0   0   0   0   0   0   0   0   0   10  10
Temp............52  51  57  63  68  74  77  79  80  81  80  78
RH..............36  37  33  27  24  21  19  17  16  14  15  15
20 FT wind dir..W   W   W   W   W   W   W   W   NW  NW  NW  NW
20 FT wind spd..5   6   7   8   9   9   9   10  11  11  11  10
20 FT wind gust.6   7   10  11  12  14  16  17  18  18  18  16
Mix hgt (kft)...0.5 0.5 0.5 1.0 2.0 5.5 9.0 10  11  12  11  11
Transp wind dir.W   W   W   W   W   NW  NW  NW  W   W   NW  NW
Transp wind spd.10  10  10  12  14  15  17  18  18  20  18  16
SDspl kt-ft/10005   4   4   8   25  71  133 158 174 202 180 148

.FORECAST DAYS 3 THROUGH 5...
.THURSDAY NIGHT...
A cold front will switch the 20-foot wind to the east-northeast
between 1900L and 2100L. The east-northeast wind increases to
15 to 20 mph with gusts 30 to 35 mph until slowly decreasing
early Friday morning. Otherwise, a few evening rain showers,
then decreasing clouds late. Lows 46 to 49.
.FRIDAY...
Partly cloudy. Highs in the lower 70s. Lows in the upper 40s.
Northeast winds 10 to 15 mph.
.SATURDAY...
Partly cloudy with a slight chance of afternoon showers and
thunderstorms. Highs in the mid 70s. Lows in the mid 40s.
Southwest wind 5 to 10 mph.
.SUNDAY...
Mostly cloudy with a chance of showers and thunderstorms. Highs
in the lower 70s. Lows in the upper 40s. West-southwest wind
around 10 mph.

$$
Forecaster...CNJ
Requested by...Cassidy Sturdevant
Type of request...WILDFIRE
.TAG 2521251.0/RIW
.DELDT 09/03/25
.FormatterVersion 2.0.0
.EMAIL cbsturdevant@blm.gov