472
FNUS75 KRIW 171159
FWSRIW

Spot Forecast for Merna Butte fire...BTF
National Weather Service Riverton WY
559 AM MDT Sat Aug 17 2024

Forecast is based on forecast start time of 0600 MDT on August 17.
If conditions become unrepresentative, contact the National Weather
Service

.DISCUSSION...

Today will start off warmer and drier than yesterday. However, a
surge of monsoonal moisture will arrive around 1600. This will
bring showers and thunderstorms as well as increased wind to the
area. Expect wind to increase out of the southwest or south
between 1600 and 1700 with gusts to 35 mph. Brief heavy rain is
possible if a storm goes directly over the fire. Any showers or
storms in the area will end between 2100 and midnight, with winds
becoming lighter overnight. Humidity recovery will be excellent
tonight.

Shower and thunderstorms chances return Sunday afternoon. These
will have a slightly better chance of producing a wetting rain.

...Thunderstorms imply strong gusty and erratic winds...
...Haines index is high level haines both day and night...

.TODAY...

Sky/weather.........Sunny (5-15 percent) then becoming partly sunny
                    (65-75 percent). Isolated showers and
                    thunderstorms late in the afternoon.
CWR.................0 percent.
Chance of pcpn......20 percent.
LAL.................1 until 1700, then 2.
Max temperature.....Around 76.
Min humidity........22 percent.
Wind (20 ft)........Light winds until 1300, then southwest 9 to 13
                    mph becoming southwest 13 to 18 mph with gusts
to 30 mph after 1600. Gusty and erratic winds
expected near thunderstorms.
Ridgetop wind.......Generally southeast around 10 mph until 1200,
                    then southwest until 1600, then around 20 mph.
Mixing height.......Increasing to 12000 ft AGL by 1500.
Transport winds.....South 7 to 18 mph until 1600, then southwest 20
                    to 30 mph.
Smoke dispersal.....Poor increasing to excellent by 1300.
Haines Index........5 to 6.

TIME (MDT)      6AM 7AM 8AM 9AM 10A 11A 12P 1PM 2PM 3PM 4PM 5PM
Sky (%).........0   5   5   5   5   5   5   20  55  70  75  80
Weather cov.....                                            ISO
Weather type....                                            RW
Tstm cov........                                            ISO
CWR.............0   0   0   0   0   0   0   0   0   0   0   0
Chc of pcpn (%).0   0   0   0   0   0   0   0   0   0   0   20
LAL.............1   1   1   1   1   1   1   1   1   2   2   2
Temp............42  43  47  55  61  66  71  74  74  76  73  70
RH..............69  68  64  53  42  35  29  25  25  24  29  35
20 FT wind dir..W   W   SW  E   E   SE  S   SW  SW  W   W   SW
20 FT wind spd..4   3   2   3   4   6   6   9   10  9   13  18
20 FT wind gust.5   4       4   6   7   7   13  14  13  20  30
Ridge wind dir..W   W   SW  E   E   SE  S   SW  SW  W   W   SW
Ridge wind spd..10  10  5   10  10  10  10  15  15  15  20  30
Mix hgt (kft)...1.0 1.0 1.0 1.0 2.0 3.5 8.5 10  11  12  11  5.5
Transp wind dir.SW  S   S   S   S   SW  SW  SW  SW  W   SW  SW
Transp wind spd.9   8   7   8   9   12  16  17  18  18  20  30
Haines index....5   5   5   5   5   5   6   6   6   6   6   6
SDspl kt-ft/10006   6   5   6   16  37  118 151 177 189 172 98

.TONIGHT...

Sky/weather.........Mostly cloudy (70-80 percent) then becoming
                    partly cloudy (40-50 percent). Scattered
                    showers and thunderstorms.
CWR.................3 percent.
Chance of pcpn......40 percent.
LAL.................3 until 2100, then 2 until 0400, then 1.
Min temperature.....Around 42.
Max humidity........97 percent.
Wind (20 ft)........South 20 to 25 mph becoming light
downslope/downvalley after 2100.
Ridgetop wind.......South 20 to 25 mph until 2000, then southeast
                    10 to 15 mph until 0300, then northwest.
Mixing height.......1500 ft AGL until 2100, then 1000 ft AGL.
Transport winds.....South 21 to 24 mph until 2000, then 8 to 14
                    mph.
Smoke dispersal.....Decreasing to poor after 2000.
Haines Index........3.

TIME (MDT)      6PM 7PM 8PM 9PM 10P 11P MID 1AM 2AM 3AM 4AM 5AM
Sky (%).........90  90  95  85  70  55  55  65  45  50  45  40
Weather cov.....SCT SCT SCT ISO ISO ISO ISO ISO ISO ISO
Weather type....RW  RW  RW  RW  RW  RW  RW  RW  RW  RW
Tstm cov........SCT SCT SCT ISO ISO ISO ISO ISO ISO ISO
CWR.............0   0   0   0   0   0   0   0   0   0   0   0
Chc of pcpn (%).30  40  30  20  20  20  20  20  20  20  10  10
LAL.............3   3   3   2   2   2   2   2   2   2   2   2
Temp............65  62  58  55  52  49  47  46  46  45  44  43
RH..............48  55  67  74  81  86  92  89  93  91  93  95
20 FT wind dir..S   S   SE  S   S   SE  SE  SE  SE  NW  NW  NW
20 FT wind spd..16  13  7   6   4   4   3   3   3   3   3   3
20 FT wind gust.22  18  10  7   6   6   4   4   4   4   4   4
Ridge wind dir..S   S   SE  S   S   SE  SE  SE  SE  NW  NW  NW
Ridge wind spd..25  20  15  10  10  10  10  10  10  10  10  10
Mix hgt (kft)...3.0 2.5 1.5 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0
Transp wind dir.S   S   S   SE  S   S   S   S   S   S   S   S
Transp wind spd.24  21  14  12  10  9   8   8   8   8   8   8
Haines index....3   3   3   3   3   3   3   3   3   3   3   3
SDspl kt-ft/100066  49  20  8   7   6   6   6   6   6   6   6

.FORECAST DAYS 2 THROUGH 5...
.SUNDAY...
Partly cloudy. Chance of afternoon showers and thunderstorms.
Lows in the lower 40s. High in the lower 70s. Southwest wind
4 to 8 mph.
.MONDAY...
Partly cloudy. Showers likely and chance of thunderstorms. Lows
in the mid 40s. Highs in the lower 70s. Light winds.
.TUESDAY...
Mostly clear. Slight chance of showers and thunderstorms. Lows in
the mid 40s. Highs in the mid 70s. Light winds.
.WEDNESDAY...
Mostly clear. Lows in the mid 40s. Highs in the mid 70s.
Southwest winds around 7 mph.

$$
Forecaster...Myers
Requested by...Hayden Hoelscher
Type of request...WILDFIRE
.TAG 2420042.4/RIW
.DELDT 08/17/24
.FormatterVersion 2.0.0
.EMAIL hayden.hoelscher@usda.gov