Spot Forecast
Issued by NWS Riverton, WY

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FNUS75 KRIW 041226
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Spot Forecast for Upper Clarks Fork RX...USFS
National Weather Service Riverton WY
626 AM MDT Thu Apr 4 2024

Forecast is based on ignition time of 0800 MDT on April 05.
If conditions become unrepresentative, contact the National Weather
Service

.DISCUSSION...

Similar forecast for both today and Friday. Clouds will be limited
to high cirrus through Friday afternoon. Temperatures will be
around 60 degrees both days. Humidity recovers to 65 to 70 percent
overnight tonight. Southerly winds Friday will be higher than
today, reaching around 20 mph, with gusts 25 to 30 mph during the
afternoon. Precipitation will begin to increase late afternoon
Friday, generally after 1500, and will begin as mostly rain
before switching over to snow after 1800. Current total snowfall
forecast for the fire location is 7 to 10 inches Friday night
through Sunday night.



.FRIDAY...

Sky/weather.........Sunny (20-30 percent) then becoming partly
                    sunny (50-60 percent). Chance of rain in the
                    afternoon.
CWR.................0 percent.
Chance of pcpn......30 percent.
LAL.................1.
Max temperature.....Around 59.
Min humidity........25 percent.
Wind (20 ft)........Southeast winds 5 to 14 mph with gusts to
                    around 21 mph shifting to the south around 15
                    mph with gusts to around 22 mph late in the
                    afternoon.
Ridgetop wind.......South 10 to 15 mph increasing to southeast 20
                    to 25 mph in the afternoon.
Mixing height.......600 ft AGL increasing to 8500 ft AGL.
Transport winds.....South 10 to 13 mph increasing to 20 to 25 mph
                    in the afternoon.
Smoke dispersal.....Poor (5100 knot-ft) increasing to very good
                    (112000 knot-ft) early in the morning
                    increasing to excellent (186300 knot-ft) in the
                    afternoon in the afternoon.
Haines Index........4 or low potential for large plume dominated
                    fire growth.

TIME (MDT)      8AM 9AM 10A 11A 12P 1PM 2PM 3PM 4PM 5PM
Sky (%).........10  3   10  16  23  28  33  38  47  57
Weather cov.....                CHC CHC CHC CHC CHC CHC
Weather type....                RN  RN  RN  RN  RN  RN
Tstm cov........
CWR.............0   0   0   0   0   0   0   0   0   0
Chc of pcpn (%).0   0   0   0   30  30  30  30  30  30
LAL.............1   1   1   1   1   1   1   1   1   1
Temp............37  44  50  54  56  58  58  59  59  57
RH..............64  54  39  35  31  26  26  25  27  29
20 FT wind dir..S   S   S   SE  SE  SE  SE  S   S   S
20 FT wind spd..5   5   6   8   10  12  13  14  15  15
20 FT wind gust.7   7   10  13  16  18  19  21  22  22
Ridge wind dir..S   S   S   S   SE  SE  SE  S   S   S
Ridge wind spd..10  15  15  15  20  20  20  25  25  25
Mix hgt (kft)...0.6 1.9 1.9 1.9 6.6 6.6 6.6 8.5 8.5 8.5
Transp wind dir.S   S   S   S   S   S   S   S   S   S
Transp wind spd.10  13  13  13  20  20  20  25  25  25
Haines index....4   4   4   4   4   4   4   4   4   4
SDspl kt-ft/10005   21  21  21  112 112 112 186 186 186

.FRIDAY NIGHT...

Sky/weather.........Mostly cloudy (65-75 percent). Rain likely
                    early in the evening. Snow likely early in the
                    evening.
CWR.................6 percent increasing to 42 percent overnight.
Chance of pcpn......60 percent.
LAL.................1.
Min temperature.....Around 26.
Max humidity........79 percent.
Wind (20 ft)........South winds 12 to 15 mph with gusts to around
                    22 mph shifting to the west 6 to 10 mph early
                    in the evening.
Ridgetop wind.......South around 20 mph shifting to the west 10 to
                    15 mph in the late evening and overnight.
Mixing height.......5000 ft AGL decreasing to 600 ft AGL in the
                    late evening and overnight.
Transport winds.....South around 26 mph becoming west 12 to 14 mph
                    in the late evening and overnight.
Smoke dispersal.....Very good (115500 knot-ft) decreasing to poor
                    (7500 knot-ft) in the late evening and
                    overnight.
Haines Index........2 to 4 or very low to low potential for large
                    plume dominated fire growth.

TIME (MDT)      6PM 7PM 8PM 9PM 10P 11P MID 1AM 2AM 3AM 4AM 5AM
Sky (%).........55  56  56  57  57  57  57  66  75  84  84  84
Weather cov.....LKY LKY LKY LKY LKY LKY LKY LKY LKY LKY LKY LKY
Weather type....RN  RN  RS  SN  SN  SN  SN  SN  SN  SN  SN  SN
Tstm cov........
CWR.............10  10  10  10  10  10  40  40  40  40  40  40
Chc of pcpn (%).60  60  60  60  60  60  60  60  60  60  60  60
LAL.............1   1   1   1   1   1   1   1   1   1   1   1
Temp............55  50  43  39  37  36  35  32  32  29  28  27
RH..............30  37  53  62  69  69  72  75  73  78  79  79
20 FT wind dir..S   S   SW  W   W   W   W   W   W   W   W   W
20 FT wind spd..15  12  10  8   7   6   6   6   6   6   6   7
20 FT wind gust.22  18  16  13  11  10  10  10  10  10  10  11
Ridge wind dir..S   S   S   W   W   W   W   W   W   W   W   W
Ridge wind spd..20  20  20  15  15  15  10  10  10  10  10  10
Mix hgt (kft)...5.0 5.0 5.0 0.6 0.6 0.6 0.8 0.8 0.8 1.2 1.2 1.2
Transp wind dir.S   S   S   SW  SW  SW  W   W   W   W   W   W
Transp wind spd.26  26  26  14  14  14  12  12  12  12  12  12
Haines index....4   4   4   4   4   4   2   2   2   2   2   2
SDspl kt-ft/1000116 116 116 8   8   8   8   8   8   12  12  12

.SATURDAY...

Sky/weather.........Mostly cloudy (80-90 percent). Snow likely in
                    the morning, then snow in the afternoon.
CWR.................82 percent increasing to 92 percent in the
                    afternoon.
Chance of pcpn......80 percent.
LAL.................1.
Max temperature.....Around 37.
Min humidity........59 percent.
Wind (20 ft)........West winds 7 to 15 mph. Gusts up to 28 mph late
                    in the morning.
Ridgetop wind.......West 15 to 20 mph increasing to around 25 mph
                    in the afternoon.
Mixing height.......2300 ft AGL increasing to 3900 ft AGL in the
                    afternoon.
Transport winds.....West 15 to 24 mph.
Smoke dispersal.....Poor (22200 knot-ft) early in the morning
                    increasing to good (81000 knot-ft) in the
                    afternoon.
Haines Index........2 or very low potential for large plume
                    dominated fire growth.

TIME (MDT)      6AM 7AM 8AM 9AM 10A 11A 12P 1PM 2PM 3PM 4PM 5PM
Sky (%).........84  82  81  79  81  83  85  86  86  87  87  88
Weather cov.....LKY LKY LKY LKY LKY LKY DEF DEF DEF DEF DEF DEF
Weather type....SN  SN  SN  SN  SN  SN  SN  SN  SN  SN  SN  SN
Tstm cov........
CWR.............80  80  80  80  80  80  90  90  90  90  90  90
Chc of pcpn (%).70  70  70  70  70  70  80  80  80  80  80  80
LAL.............1   1   1   1   1   1   1   1   1   1   1   1
Temp............27  26  27  30  33  35  36  37  37  37  37  36
RH..............79  79  78  73  66  64  62  60  60  59  60  60
20 FT wind dir..W   W   W   W   W   W   W   W   W   W   W   W
20 FT wind spd..7   7   7   8   9   11  12  13  14  14  14  15
20 FT wind gust.11  11  11  13  14  17  18  19  21  21  21  22
Ridge wind dir..W   W   W   W   W   W   W   W   W   W   W   W
Ridge wind spd..15  15  15  20  20  20  25  25  25  25  25  25
Mix hgt (kft)...1.7 1.7 1.7 2.3 2.3 2.3 3.1 3.1 3.1 3.9 3.9 3.9
Transp wind dir.W   W   W   W   W   W   W   W   W   W   W   W
Transp wind spd.15  15  15  18  18  18  23  23  23  24  24  24
Haines index....2   2   2   2   2   2   2   2   2   2   2   2
SDspl kt-ft/100022  22  22  38  38  38  62  62  62  81  81  81

.FORECAST DAYS 3 THROUGH 5...
.SUNDAY...
Snow likely. Lows in the mid 20s. Highs in the upper 30s. West
winds around 13 mph.
.MONDAY...
Mostly cloudy with snow likely. Lows in the lower 20s. Highs
around 40. West winds around 9 mph.
.TUESDAY...
Partly cloudy. Slight chance of snow. Lows in the lower 20s.
Highs in the mid 40s. West winds around 9 mph.

$$
Forecaster...Straub
Requested by...Peter Freire
Type of request...PRESCRIBED
.TAG 2409376.0/RIW
.DELDT 04/04/24
.FormatterVersion 2.0.0
.EMAIL peter.freire@usda.gov


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