Spot Forecast
Issued by NWS Riverton, WY
Issued by NWS Riverton, WY
838
FNUS75 KRIW 162359
FWSRIW
Spot Forecast for Telephone...USFS
National Weather Service Riverton WY
559 PM MDT Wed Sep 16 2026
Forecast is based on forecast start time of 0600 MDT on September 17.
If conditions become unrepresentative, contact the National Weather
Service
.DISCUSSION...
Rather unsettled for Thursday with chances for showers and
thunderstorms throughout the day. Temperatures will be on the cooler
side with values in the 40s for the morning with highs reaching the
60s by the afternoon. Relative humidity is forecast to remain well
above critical values with min values around 50 percent. Good
recovery is expected through the overnight Thursday into Friday with
max values getting around 90 percent. Winds are likely to be out of
the north at around 5 to 10 mph in the morning. A shift to the
south/southeast is forecast to occur around noon with speeds near 10
mph and gusts of 15 mph possible at times. Some precipitation may be
possible during the morning hours (0700-1000 MDT) Thursday. An
isolated thunderstorm cannot be ruled out during this time. The
better chances for showers and thunderstorms looks to arrive by the
afternoon (1400-1900 MDT) with wetting rain chances around
10-25%. The bulk of precipitation should dissipate by midnight but a
few isolated showers cannot be ruled out during the morning hours
Friday.
...Thunderstorms imply strong gusty and erratic winds...
.THURSDAY...
Sky/weather.........Mostly cloudy (80-90 percent). Chance of rain
showers in the morning, then rain showers
likely and chance of thunderstorms in the
afternoon.
CWR.................0 percent increasing to 35 percent in the
afternoon.
Chance of pcpn......70 percent.
Chance of thunder...29 percent.
Max temperature.....Around 66.
Min humidity........46 percent.
Wind (20 ft)........Light winds. Gusty and erratic winds expected
near thunderstorms in the afternoon.
Ridgetop wind.......North around 10 mph until 1100, then south
until 1400, then southwest.
Mixing height.......2000 ft AGL until 1200, then 3500 ft AGL.
Transport winds.....Northeast 8 to 9 mph until 1000, then south 8
to 10 mph until 1400, then southwest 9 to 12
mph.
Smoke dispersal.....Poor.
TIME (MDT) 6AM 7AM 8AM 9AM 10A 11A 12P 1PM 2PM 3PM 4PM 5PM
Sky (%).........80 90 90 85 90 90 90 85 85 85 85 85
Weather cov..... SCH SCH SCH CHC CHC CHC LKY LKY LKY CHC
Weather type.... 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 40 40 40 40 40 40
Chc of pcpn (%).10 10 20 20 20 30 40 50 70 70 70 50
Chc of thdr (%).0 0 0 10 10 10 30 30 30 30 30 30
Temp............43 46 49 52 55 58 61 61 62 62 62 61
RH..............75 74 72 69 64 58 54 53 54 55 57 59
20 FT wind dir..N N N N NE SE S S SW SW W W
20 FT wind spd..4 4 3 3 3 4 5 5 5 5 4 4
20 FT wind gust.5 5 5 5 6 6 7 10 10 11 11 10
Ridge wind dir..N N N N NE SE S S SW SW W W
Ridge wind spd..10 10 10 10 10 10 10 10 10 10 10 10
Mix hgt (kft)...0.5 0.5 0.5 0.5 1.0 2.0 2.5 3.5 3.5 3.5 3.0 2.5
Transp wind dir.NE NE NE E S S SW SW SW SW W W
Transp wind spd.9 9 8 8 8 9 10 10 10 10 12 9
SDspl kt-ft/10005 4 4 4 8 14 22 31 32 33 32 19
.THURSDAY NIGHT...
Sky/weather.........Mostly cloudy (65-75 percent) then becoming
partly cloudy (40-50 percent) Chance of rain
showers and slight chance of thunderstorms in
the evening, then slight chance of rain showers
overnight.
CWR.................11 percent decreasing to 0 percent overnight.
Chance of pcpn......50 percent.
Chance of thunder...13 percent.
Min temperature.....Around 41.
Max humidity........96 percent.
Wind (20 ft)........Light winds. Gusty and erratic winds expected
near thunderstorms early in the evening.
Ridgetop wind.......West around 10 mph until 1900, then south until
2000, then northwest.
Mixing height.......500 ft AGL.
Transport winds.....Northwest around 9 mph until 2000, then north
around 8 mph until 2100, then east around 9 mph
until 2200, then west 9 to 10 mph.
Smoke dispersal.....Poor.
TIME (MDT) 6PM 7PM 8PM 9PM 10P 11P MID 1AM 2AM 3AM 4AM 5AM
Sky (%).........85 55 50 40 45 45 40 55 50 55 65 35
Weather cov.....CHC CHC SCH SCH SCH SCH SCH SCH SCH
Weather type....RW RW RW RW RW RW RW RW RW
Tstm cov........SCH SCH SCH
CWR.............10 10 10 10 10 10 0 0 0 0 0 0
Chc of pcpn (%).50 50 20 20 20 20 10 20 20 20 10 10
Chc of thdr (%).10 10 10 10 10 10 10 10 10 0 0 0
Temp............61 63 57 53 50 48 47 46 45 46 44 44
RH..............61 59 66 73 79 85 87 91 93 94 93 93
20 FT wind dir..W S W NW N NW N N N NW NW NW
20 FT wind spd..3 4 3 4 5 5 4 4 4 4 4 4
20 FT wind gust.8 6 4 6 6 6 8 8 8 7 7 7
Ridge wind dir..W S W NW N NW N N N NW NW NW
Ridge wind spd..10 10 10 10 10 10 10 10 10 10 10 10
Mix hgt (kft)...2.0 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.W NW N E W W NW W NW NW W W
Transp wind spd.9 9 8 9 10 10 9 9 9 9 9 10
SDspl kt-ft/100014 10 5 5 5 5 4 4 4 4 5 5
.FRIDAY...
Sky/weather.........Mostly sunny (35-45 percent) then becoming
mostly cloudy (70-80 percent). Slight chance of
rain showers in the morning, then rain showers
likely and chance of thunderstorms in the
afternoon.
CWR.................0 percent increasing to 39 percent in the
afternoon.
Chance of pcpn......70 percent.
Chance of thunder...28 percent.
Max temperature.....Around 68.
Min humidity........49 percent.
Wind (20 ft)........Light winds until 1500, then southwest around 7
mph with gusts to around 14 mph until 1700,
then light. Gusty and erratic winds expected
near thunderstorms in the afternoon.
Ridgetop wind.......Northwest around 10 mph until 1100, then
southwest.
Mixing height.......1500 ft AGL until 1000, then 4000 ft AGL until
1200, then 5500 ft AGL until 1300, then 8000 ft
AGL until 1500, then 6000 ft AGL until 1700,
then 4000 ft AGL.
Transport winds.....West 9 to 14 mph until 1200, then southwest 13
to 15 mph.
Smoke dispersal.....Poor until 1100, then fair early in the morning
increasing to good in the afternoon until 1300,
then fair early in the morning increasing to
very good in the afternoon until 1700, then
fair.
TIME (MDT) 6AM 7AM 8AM 9AM 10A 11A 12P 1PM 2PM 3PM 4PM 5PM
Sky (%).........15 25 25 30 35 45 50 55 65 70 75 80
Weather cov.....SCH SCH SCH SCH SCH SCH LKY LKY LKY LKY LKY LKY
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 40 40 40 40 40 40
Chc of pcpn (%).20 20 20 20 20 20 70 70 70 70 70 70
Chc of thdr (%).0 0 0 10 10 10 30 30 30 30 30 30
Temp............43 42 45 51 56 60 64 66 66 66 66 65
RH..............97 100 96 87 75 62 51 47 48 49 48 48
20 FT wind dir..N N NW W W W SW SW SW SW SW SW
20 FT wind spd..3 3 3 3 3 4 5 6 6 7 7 6
20 FT wind gust.6 6 6 7 8 10 11 13 14 14 14 14
Ridge wind dir..N N NW W W W SW SW SW SW SW SW
Ridge wind spd..10 10 10 10 10 10 10 10 15 15 15 15
Mix hgt (kft)...0.5 0.5 0.5 1.5 2.5 4.0 5.5 8.0 7.0 6.0 5.0 4.0
Transp wind dir.NW NW W NW W W SW SW SW SW SW SW
Transp wind spd.10 9 10 10 10 14 13 15 15 15 14 13
SDspl kt-ft/10005 4 6 12 22 50 61 104 91 78 59 42
.FORECAST DAYS 3 THROUGH 5...
.SATURDAY...
Showers and chance of thunderstorms. Lows in the upper 30s. Highs
in the lower 60s. Light winds.
.SUNDAY...
Mostly cloudy. Chance of showers and slight chance of
thunderstorms. Lows in the mid 30s. Highs in the lower 60s.
Northwest winds around 7 mph.
.MONDAY...
Mostly clear. Lows in the lower 30s. Highs in the upper 60s.
Light winds.
$$
Forecaster...Dziewaltowski
Requested by...Brandon Bones
Type of request...WILDFIRE
.TAG 2621796.3/RIW
.DELDT 09/16/26
.FormatterVersion 2.0.0
.EMAIL timothy.sherwin@blm.gov,timothy.sherwin@usda.gov,brandon.bonenberger@usda.gov