Spot Forecast
Issued by NWS Riverton, WY
Issued by NWS Riverton, WY
281
FNUS75 KRIW 202040
FWSRIW
Spot Forecast for Bare...USFS
National Weather Service Riverton WY
240 PM MDT Thu Aug 20 2026
Forecast is based on forecast start time of 0700 MDT on August 21.
If conditions become unrepresentative, contact the National Weather
Service
.DISCUSSION...
Cloud cover will gradually increase through the morning, with
scattered rain showers and thunderstorms developing by 1300.
Monsoonal moisture will push into the area from the south Friday
evening and result in increasing chances for rain Friday evening
into Friday night. Humidity will remain low Friday afternoon down
to about 20%, but recovery will be very good Friday night. Minimum
Humidity values will average 35-40% this weekend as moisture
remains in the area. Better chances for rain and thunderstorms
arrive this weekend as well. CWR will remain very low through this
weekend unless a storm develops directly over the fire.
...Thunderstorms imply strong gusty and erratic winds...
.FRIDAY...
Sky/weather.........Mostly sunny to partly cloudy (35-45 percent).
CWR.................0 percent.
Chance of pcpn......20 percent.
Chance of thunder...15 percent.
Max temperature.....Around 79.
Min humidity........25 percent.
Wind (20 ft)........Light winds.
Ridgetop wind.......Light winds until 1100, then southeast around
10 mph until 1300, then west.
Mixing height.......500 ft AGL until 1000, then increasing to 10000
ft AGL after 1200 until 1600, then 7000 ft AGL.
Transport winds.....West around 7 mph until 0900, then light until
1000, then west 7 to 12 mph.
Smoke dispersal.....Poor until 1000 increasing through the morning
to very good in the afternoon after 1200.
TIME (MDT) 7AM 8AM 9AM 10A 11A 12P 1PM 2PM 3PM 4PM 5PM
Sky (%).........30 25 20 15 20 15 35 45 55 55 65
Weather cov.....
Weather type....
Tstm cov........
CWR.............0 0 0 0 0 0 0 0 0 0 0
Chc of pcpn (%).0 0 0 0 0 0 0 10 10 0 0
Chc of thdr (%).0 0 0 0 0 10 0 10 10 0 0
Temp............57 59 65 71 75 77 78 78 79 78 77
RH..............46 46 40 33 29 26 25 26 26 27 28
20 FT wind dir..W W S E SE S W W NW SW W
20 FT wind spd..2 2 1 2 4 6 6 6 6 6 5
20 FT wind gust. 6 7 7 7 7 7 6
Ridge wind dir..W W S E SE S W W NW SW W
Ridge wind spd..5 5 5 5 10 10 10 10 10 10 10
Mix hgt (kft)...0.5 0.5 0.5 3.5 6.5 10 10 9.5 9.5 7.0 6.0
Transp wind dir.W W SW W W W W W W W W
Transp wind spd.7 7 6 7 10 12 12 12 12 12 10
SDspl kt-ft/10003 3 4 21 59 100 102 96 93 68 54
.FRIDAY NIGHT...
Sky/weather.........Mostly cloudy (50-80 percent). Chance of
showers after 3 am.
CWR.................1 percent.
Chance of pcpn......40 percent.
Chance of thunder...15 percent.
Min temperature.....Around 57.
Max humidity........64 percent.
Wind (20 ft)........Light winds. Gusty and erratic winds expected
near thunderstorms early in the evening.
Ridgetop wind.......Northwest around 10 mph until 2200, then
southwest.
Mixing height.......4500 ft AGL until 1900, then 500 ft AGL.
Transport winds.....Variable around 10 knots.
Smoke dispersal.....Fair until 1900, then poor.
TIME (MDT) 6PM 7PM 8PM 9PM 10P 11P MID 1AM 2AM 3AM 4AM 5AM
Sky (%).........65 75 80 80 80 90 80 65 60 50 55 55
Weather cov.....SCH SCH CHC CHC
Weather type....RW RW RW RW
Tstm cov........SCH SCH
CWR.............0 0 0 0 0 0 0 0 0 0 0 0
Chc of pcpn (%).10 10 10 10 0 0 0 0 0 0 30 30
Chc of thdr (%).10 10 10 10 0 0 0 0 0 0 10 10
Temp............76 73 69 66 65 63 62 62 62 61 61 60
RH..............29 35 40 45 44 48 48 50 50 51 51 55
20 FT wind dir..N N NW W SW SW SW SW SW W SW SW
20 FT wind spd..5 3 4 4 4 4 3 3 4 4 3 3
20 FT wind gust.6 4 6 6 6 6 4 4 6 6 4 4
Ridge wind dir..N N NW W SW SW SW SW SW W SW SW
Ridge wind spd..10 10 10 10 10 10 10 10 10 10 10 10
Mix hgt (kft)...4.5 1.0 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5
Transp wind dir.NW NE N SE NW S SE SW SW SW W W
Transp wind spd.10 8 9 9 9 9 8 8 9 12 10 10
SDspl kt-ft/100043 7 4 5 5 5 4 4 5 6 5 5
.SATURDAY...
Sky/weather.........Mostly cloudy (75-85 percent). Chance of
showers and thunderstorms in the afternoon.
CWR.................5 percent.
Chance of pcpn......50 percent.
Chance of thunder...35 percent.
Max temperature.....Around 72.
Min humidity........41 percent.
Wind (20 ft)........Light winds. Gusty and erratic winds expected
near thunderstorms in the afternoon.
Ridgetop wind.......Southwest around 10 mph. 10 to 15 mph after 1400.
Mixing height.......500 ft AGL until 1000, then increasing through
the morning to 6500 ft after 1200 until 1700,
then 4500 ft AGL.
Transport winds.....Southwest 8 to 13 mph until 1600, then west 10
to 15 mph.
Smoke dispersal.....Poor until 1000 increasing through the morning
to good in the afternoon after 1200.
TIME (MDT) 6AM 7AM 8AM 9AM 10A 11A 12P 1PM 2PM 3PM 4PM 5PM
Sky (%).........70 80 80 85 80 75 75 70 70 70 70 70
Weather cov.....SCH SCH SCH SCH SCH SCH CHC CHC CHC CHC CHC CHC
Weather type....RW RW RW RW RW RW RW RW RW RW RW RW
Tstm cov........ CHC CHC CHC CHC CHC CHC
CWR.............0 0 0 0 0 0 10 10 10 10 10 10
Chc of pcpn (%).10 10 10 10 10 10 50 50 50 50 50 50
Chc of thdr (%).0 0 0 10 10 10 30 30 30 30 30 30
Temp............59 57 58 60 63 66 70 71 72 72 72 71
RH..............57 63 64 64 58 50 43 41 41 42 42 44
20 FT wind dir..SW SW S SE S S S SW SW SW W W
20 FT wind spd..3 3 3 3 4 5 6 6 6 6 6 6
20 FT wind gust.4 4 4 4 6 6 7 10 10 10 10 7
Ridge wind dir..SW SW S SE S S S SW SW SW W W
Ridge wind spd..10 10 10 10 10 10 10 15 15 15 15 10
Mix hgt (kft)...0.5 0.5 0.5 0.5 2.5 4.5 6.5 6.5 6.5 6.5 5.5 4.5
Transp wind dir.S SW S SE S S SW SW SW SW W W
Transp wind spd.12 10 9 8 9 10 12 13 13 13 13 12
SDspl kt-ft/10006 5 5 4 21 41 65 72 72 73 61 45
.FORECAST DAYS 3 THROUGH 5...
.SUNDAY...
Partly cloudy. Chance of showers and thunderstorms. Lows in the
lower 50s. Highs in the lower 70s. West wind between 10 to 15
mph in the afternoon.
.MONDAY...
Partly cloudy. Chance of showers and thunderstorms. Lows in the
lower 50s. Highs in the upper 60s. West wind around 10 mph in
the afternoon.
.TUESDAY...
Partly cloudy. Chance of showers and thunderstorms. Lows in the
upper 40s. Highs around 70. West wind around 10 mph in the
afternoon.
$$
Forecaster...Rowe
Requested by...Stan Mitchem
Type of request...WILDFIRE
.TAG 2619432.9/RIW
.DELDT 08/20/26
.FormatterVersion 2.0.0
.EMAIL Stan@mitchem.com,paul_mitchem@firenet.gov