204
FNUS75 KRIW 201005
FWSRIW

Spot Forecast for Cone Cabin...Yellowstone National Park
National Weather Service Riverton WY
405 AM MDT Wed Aug 20 2025

Forecast is based on forecast start time of 0500 MDT on August 20.
If conditions become unrepresentative, contact the National Weather
Service

.DISCUSSION...


Increasing clouds this morning becoming mostly cloudy in the
afternoon and evening hours. Light southerly winds 5 to 10 mph
this morning will increasing to 15 to 20 mph after noon lasting
through 7PM before weakening once again towards sunset and
overnight. Some isolated thunderstorm chances after noon with the
best chance through 4PM. Lightning and gusty outflow winds up to
30 to 40 mph possible but confidence low at this point in time (10
to 15 percent). Not as dry this afternoon with minimum relative
humidity values hovering around the 20 percent mark. Smoke
dispersal will go from poor to good morning to afternoon as winds
increase throughout the day.

Otherwise, expect more seasonable temperatures Thursday and
beyond with increasing storm chances and coverage each afternoon
through the weekend and possible even into next week as well.

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

.TODAY...

Sky/weather.........Mostly sunny (40-50 percent). Isolated showers
                    and thunderstorms in the afternoon.
CWR.................0 percent.
Chance of pcpn......20 percent.
Chance of thunder...15 percent.
Max temperature.....Around 77.
Min humidity........21 percent.
Wind (20 ft)........Light winds until 1100, then southwest 9 to 13
                    mph with gusts to around 18 mph. Gusty and
                    erratic winds expected near thunderstorms in
                    the afternoon.
Ridgetop wind.......Southwest 10 to 15 mph until 1200, then around
                    20 mph.
Mixing height.......1500 ft AGL until 1000, then 3500 ft AGL until
                    1100, then 9000 ft AGL until 1600, then 7000 ft
                    AGL.
Transport winds.....Southwest 9 to 18 mph until 1100, then 25 to 29
                    mph.
Smoke dispersal.....Poor until 1000, then fair until 1100, then
                    excellent.

TIME (MDT)      6AM 7AM 8AM 9AM 10A 11A 12P 1PM 2PM 3PM 4PM 5PM
Sky (%).........30  30  35  35  35  40  45  50  55  60  55  55
Weather cov.....                        ISO ISO ISO ISO ISO ISO
Weather type....                        RW  RW  RW  RW  RW  RW
Tstm cov........                        ISO ISO ISO ISO ISO ISO
CWR.............0   0   0   0   0   0   0   0   0   0   0   0
Chc of pcpn (%).10  10  10  10  10  10  20  20  20  20  10  10
Chc of thdr (%).0   0   0   0   0   0   10  10  10  20  10  10
Temp............46  46  52  62  70  74  76  77  75  75  74  74
RH..............60  58  50  41  31  26  23  24  23  22  23  24
20 FT wind dir..S   S   SW  SW  SW  SW  SW  SW  SW  W   W   SW
20 FT wind spd..4   4   4   5   6   9   11  12  13  13  12  12
20 FT wind gust.6   6   6   6   10  13  16  17  18  18  17  17
Ridge wind dir..S   S   SW  SW  SW  SW  SW  SW  SW  W   W   SW
Ridge wind spd..10  10  10  10  15  15  20  20  20  20  20  20
Mix hgt (kft)...1.0 1.0 1.0 1.5 3.5 8.0 9.0 8.5 9.0 8.5 7.0 6.5
Transp wind dir.S   S   S   SW  SW  SW  SW  SW  SW  SW  SW  SW
Transp wind spd.10  10  9   10  18  25  26  25  25  28  29  28
SDspl kt-ft/10008   8   7   12  53  175 208 191 198 203 179 150

.TONIGHT...

Sky/weather.........Partly cloudy (35-45 percent).
CWR.................0 percent.
Chance of pcpn......10 percent.
Chance of thunder...13 percent.
Min temperature.....Around 44.
Max humidity........70 percent.
Wind (20 ft)........Southwest winds 9 to 11 mph with gusts to
                    around 16 mph until 2000, then light. Gusty and
                    erratic winds expected near thunderstorms early
                    in the evening.
Ridgetop wind.......Southwest 15 to 20 mph until 2100, then south
                    around 10 mph until 0100, then light.
Mixing height.......3500 ft AGL until 2000, then 1000 ft AGL.
Transport winds.....Southwest 23 to 28 mph until 2000, then 7 to 15
                    mph until 0500, then north around 7 mph.
Smoke dispersal.....Very good until 1900. Poor after 2000.

TIME (MDT)      6PM 7PM 8PM 9PM 10P 11P MID 1AM 2AM 3AM 4AM 5AM
Sky (%).........50  45  40  35  30  25  25  25  30  30  30  25
Weather cov.....ISO ISO
Weather type....RW  RW
Tstm cov........ISO ISO
CWR.............0   0   0   0   0   0   0   0   0   0   0   0
Chc of pcpn (%).10  10  10  0   0   0   0   0   0   10  0   0
Chc of thdr (%).10  10  10  0   0   0   0   0   0   0   0   0
Temp............72  69  66  60  58  56  54  51  50  48  47  46
RH..............25  31  36  41  46  49  52  54  58  60  65  68
20 FT wind dir..SW  SW  SW  SW  S   S   S   S   S   S   SE  E
20 FT wind spd..11  9   6   5   4   4   3   2   2   2   2   2
20 FT wind gust.16  13  10  6   6   6   4
Ridge wind dir..SW  SW  SW  SW  S   S   S   S   S   S   SE  E
Ridge wind spd..20  15  15  10  10  10  10  5   5   5   5   5
Mix hgt (kft)...5.0 3.5 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0
Transp wind dir.SW  SW  SW  SW  SW  SW  SW  SW  SW  SW  W   N
Transp wind spd.28  23  15  13  12  12  9   9   8   7   7   7
SDspl kt-ft/1000122 68  13  9   9   9   7   6   6   5   5   5

.THURSDAY...

Sky/weather.........Sunny (15-25 percent).
CWR.................0 percent.
Chance of pcpn......10 percent.
Chance of thunder...11 percent.
Max temperature.....Around 75.
Min humidity........16 percent.
Wind (20 ft)........Light winds until 1200, then southwest 8 to 11
                    mph with gusts to around 19 mph. Gusty and
                    erratic winds expected near thunderstorms in
                    the afternoon.
Ridgetop wind.......Light winds until 0900, then south 10 to 15 mph
                    until 1200, then southwest 15 to 20 mph.
Mixing height.......1500 ft AGL until 1000. 11500 ft AGL after
                    1400.
Transport winds.....East around 7 mph until 0900, then southeast
                    around 8 mph until 1000, then southwest 13 to
                    20 mph until 1200, then west 23 to 26 mph.
Smoke dispersal.....Poor until 1000. Excellent after 1400.

TIME (MDT)      6AM 7AM 8AM 9AM 10A 11A 12P 1PM 2PM 3PM 4PM 5PM
Sky (%).........30  30  20  10  5   10  10  15  20  20  20  25
Weather cov.....                        SCH SCH SCH SCH SCH SCH
Weather type....                        RW  RW  RW  RW  RW  RW
Tstm cov........                        SCH SCH SCH SCH SCH SCH
CWR.............0   0   0   0   0   0   0   0   0   0   0   0
Chc of pcpn (%).0   0   0   0   0   0   10  10  10  10  10  10
Chc of thdr (%).0   0   0   0   0   0   10  10  10  10  10  10
Temp............44  44  49  56  64  68  72  73  74  75  74  73
RH..............68  70  64  52  43  34  27  22  19  18  16  16
20 FT wind dir..NE  E   SE  S   S   SW  SW  SW  W   W   W   W
20 FT wind spd..2   2   2   3   5   6   8   10  11  11  11  10
20 FT wind gust.4   5   6   6   10  13  16  18  19  19  19  18
Ridge wind dir..NE  E   SE  S   S   SW  SW  SW  W   W   W   W
Ridge wind spd..5   5   5   10  10  15  15  15  20  20  20  15
Mix hgt (kft)...1.0 0.5 1.0 1.5 3.0 5.5 8.0 9.5 11  12  12  11
Transp wind dir.E   E   SE  SE  SW  W   W   W   W   W   W   W
Transp wind spd.7   7   7   8   13  20  25  25  26  26  24  23
SDspl kt-ft/10005   4   5   9   33  94  179 205 241 268 240 224

.FORECAST DAYS 3 THROUGH 5...
.FRIDAY...
Mostly clear. Lows in the lower 40s. Highs in the mid 70s. Light
winds.
.SATURDAY...
Mostly clear. Lows in the upper 30s. Highs in the mid 70s. Light
winds.
.SUNDAY...
Partly cloudy. Slight chance of showers and thunderstorms. Lows
around 40. Highs in the lower 70s. Light winds.

$$
Forecaster...Lowe
Requested by...E Folts
Type of request...WILDFIRE
.TAG 2520175.1/RIW
.DELDT 08/20/25
.FormatterVersion 2.0.0
.EMAIL laura_dooley@nps.gov,ed_folts@partner.nps.gov