Spot Forecast
Issued by NWS Riverton, WY
Issued by NWS Riverton, WY
128
FNUS75 KRIW 281545
FWSRIW
Spot Forecast for Bull Fire...USFS
National Weather Service Riverton WY
945 AM MDT Sun Sep 28 2025
Forecast is based on forecast start time of 1000 MDT on September 28.
If conditions become unrepresentative, contact the National Weather
Service
.DISCUSSION...
Showers and a few thunderstorms are expected to develop later this
afternoon. Best timing for these showers would occur between 1400
and 1800 this evening. Stronger thunderstorms could produce 0.25"
of rainfall. Any winds outside of thunderstorms will be generally
terrain based upslope and upvalley 3-5 mph. Humidity levels will
remain elevated well above 40 percent through the day.
Expect any showers to end by midnight tonight, with light
downslope winds continuing through the night. Humidity recovery
will be excellent above 90 percent.
Skies will start mostly clear, before daytime cumulus develop
around 1200. Some shower activity is again expected, but will
likely be weaker and more isolated during the afternoon. Winds
will again be terrain influenced, upslope and upvalley around 5
mph. Humidity levels will only fall to 50 to 60 percent.
...Thunderstorms imply strong gusty and erratic winds...
.REST OF TODAY...
Sky/weather.........Mostly cloudy (80-90 percent). Rain
showers likely and chance of thunderstorms.
CWR.................0 percent increasing to 55 percent in the
afternoon.
Chance of pcpn......70 percent.
Chance of thunder...28 percent.
Max temperature.....Around 57.
Min humidity........50 percent.
Wind (20 ft)........Light winds. Gusty and erratic winds expected
near thunderstorms in the afternoon.
Ridgetop wind.......West around 10 mph until 1400, then south.
Mixing height.......1500 ft AGL until 1100, then 5000 ft AGL.
Transport winds.....Southwest 9 to 12 mph.
Smoke dispersal.....Poor until 1200, then increasing to fair.
TIME (MDT) 10A 11A 12P 1PM 2PM 3PM 4PM 5PM
Sky (%).........85 80 80 85 80 80 85 85
Weather cov.....SCH SCH CHC CHC CHC LKY LKY LKY
Weather type....RW RW RW RW RW RW RW RW
Tstm cov........ CHC CHC CHC CHC CHC CHC
CWR.............0 0 60 60 60 60 60 60
Chc of pcpn (%).20 20 40 40 50 60 70 60
Chc of thdr (%).10 10 30 30 30 30 30 30
Temp............52 55 56 56 55 55 53 51
RH..............58 57 51 55 58 63 70 77
20 FT wind dir..W W W SW S SE SE SW
20 FT wind spd..4 5 5 6 5 5 4 4
20 FT wind gust.5 6 6 6 6
Ridge wind dir..W W W SW S SE SE SW
Ridge wind spd..10 10 10 10 10 10 10 10
Mix hgt (kft)...1.5 3.5 5.0 3.5 3.5 3.5 2.5 2.0
Transp wind dir.SW S S S S S SW SW
Transp wind spd.9 10 10 12 10 10 9 9
SDspl kt-ft/100012 31 44 37 33 30 20 15
.TONIGHT...
Sky/weather.........Mostly cloudy (65-75 percent) then becoming
partly cloudy (30-40 percent). Chance of rain
showers and slight chance of thunderstorms
early in the evening.
CWR.................14 percent decreasing to 0 percent overnight.
Chance of pcpn......50 percent.
Chance of thunder...18 percent.
Min temperature.....Around 40.
Max humidity........95 percent.
Wind (20 ft)........Light winds. Gusty and erratic winds expected
near thunderstorms early in the evening.
Ridgetop wind.......Southwest around 10 mph until 1900, then
south around 10 mph.
Mixing height.......1500 ft AGL until 1900, then 500 ft AGL after
2100 until 2200.
Transport winds.....West 7 to 8 mph until 2000, then light.
Smoke dispersal.....Poor.
TIME (MDT) 6PM 7PM 8PM 9PM 10P 11P MID 1AM 2AM 3AM 4AM 5AM
Sky (%).........85 80 70 65 55 45 35 30 25 20 20 25
Weather cov.....CHC CHC CHC 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 30 20 20 20 20 20 20 10 10 10
Chc of thdr (%).20 20 20 10 10 10 10 10 10 0 0 0
Temp............50 48 47 46 44 43 42 42 41 41 41 41
RH..............83 85 86 87 88 90 91 92 93 93 93 92
20 FT wind dir..SW W NW NW W SW S S SW SW SW S
20 FT wind spd..3 2 1 1 1 2 2 3 2 2 2 1
20 FT wind gust.7 6 4 2 2 2
Ridge wind dir..SW W NW NW W SW S S SW SW SW S
Ridge wind spd..10 5 5 5 5 5 5 10 5 5 5 5
Mix hgt (kft)...1.5 0.1 0.1 0.5 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1
Transp wind dir.W W W NE E E SE SW SW SW W W
Transp wind spd.8 7 6 6 6 7 7 8 7 7 7 6
SDspl kt-ft/100011 1 1 1 1 1 1 2 1 1 1 1
.MONDAY...
Sky/weather.........Partly sunny (45-55 percent). Chance of rain
showers and slight chance of thunderstorms in
the afternoon.
CWR.................6 percent.
Chance of pcpn......30 percent.
Chance of thunder...17 percent.
Max temperature.....Around 57.
Min humidity........59 percent.
Wind (20 ft)........Light winds. Gusty and erratic winds expected
near thunderstorms in the afternoon.
Ridgetop wind.......Light winds until 0900. Southwest around 10 mph
after 1200.
Mixing height.......4000 ft AGL after 1100.
Transport winds.....Light winds until 0700, then southwest 7 to 10
mph.
Smoke dispersal.....Poor.
TIME (MDT) 6AM 7AM 8AM 9AM 10A 11A 12P 1PM 2PM 3PM 4PM 5PM
Sky (%).........25 35 25 20 10 30 45 50 55 60 60 55
Weather cov..... CHC CHC CHC CHC CHC CHC
Weather type.... RW RW RW RW RW RW
Tstm cov........ SCH SCH SCH SCH SCH SCH
CWR.............0 0 0 0 0 0 10 10 10 10 10 10
Chc of pcpn (%).10 10 10 10 10 10 30 30 30 30 30 30
Chc of thdr (%).0 0 0 0 0 0 20 20 20 20 20 20
Temp............41 40 40 42 46 50 52 54 55 55 55 54
RH..............91 80 86 80 74 68 64 62 62 63 63 63
20 FT wind dir..SE S SE SE S S SW SW SW SW SW SW
20 FT wind spd..1 2 2 3 4 4 5 5 5 5 5 5
20 FT wind gust.2 5 5 6 6 8 10 10 10 10 10 10
Ridge wind dir..SE S SE SE S S SW SW SW SW SW SW
Ridge wind spd..5 5 5 10 10 10 10 10 10 10 10 10
Mix hgt (kft)...0.1 0.1 0.1 0.5 1.5 3.0 4.0 4.0 4.0 3.5 3.5 3.5
Transp wind dir.W SW SW SW SW SW S SW SW SW SW SW
Transp wind spd.6 7 7 8 9 9 10 10 10 10 10 10
SDspl kt-ft/10001 1 0 3 12 23 38 36 35 33 31 29
.FORECAST DAYS 3 THROUGH 5...
.TUESDAY...
Mostly cloudy with showers likely and chance of thunderstorms.
Lows in the mid 40s. Highs in the lower 50s. South winds around
7 mph.
.WEDNESDAY...
Partly cloudy. Chance of showers and slight chance of
thunderstorms. Lows in the upper 30s. Highs in the mid 50s. Light
winds.
.THURSDAY...
Mostly clear. Lows around 40. Highs in the upper 50s. South winds
around 7 mph.
$$
Forecaster...Straub
Requested by...Matt Ziegler
Type of request...WILDFIRE
.TAG 2522667.0/RIW
.DELDT 09/28/25
.FormatterVersion 2.0.0
.EMAIL wytdc@firenet.gov