409
FNUS73 KUNR 092238
FWSUNR

Spot Forecast for Lookout Flats Rx...NPS
National Weather Service Rapid City SD
438 PM MDT Wed Apr 9 2025

Forecast is based on ignition time of 0800 MDT on April 10.
If conditions become unrepresentative, contact the National Weather
Service.

.DISCUSSION...Overnight RH recovery will be poor tonight/Thursday
morning - starting the day out Thursday with RH around 40 to 45
percent. Warm and dry conditions expected through the afternoon
Thursday as temperatures warm into the mid 60s and RH bottoms out
around 15 to 20 percent. Winds will be out of the northwest around
10 mph with an occasional gust to 15 mph through peak heating.
Winds will begin to diminish and turn northeasterly after 1600,
becoming light and variable after 2200 through the overnight
hours.

Expect another night of poor overnight RH recovery Thursday night into
Friday morning (~40-45%). Friday will be much warmer with highs
pushing into the mid to upper 70s with daytime minimum RH falling
to around 15 percent. Southwesterly winds will persist through the
day Friday with gusts 15 to 20 mph.

Regarding smoke dispersal - good to very good smoke dispersal expected
Thursday and Friday under well-mixed conditions, especially after the
inversion lifts after 0900-1000 each morning.


.THURSDAY...

Sky/weather.........Sunny (0-10 percent).
Max temperature.....Around 64.
Min humidity........16 percent.
Wind (20 ft)........Northwest winds around 10 mph shifting to the
                    east late in the afternoon. Gusts up to 20 mph.
CWR.................0 percent.
Mixing height.......8100 to 8600 ft agl.
Transport winds.....Northwest 15 to 25 mph shifting to the north
                    around 15 mph late in the afternoon.
Smoke dispersal.....Very good.

TIME (MDT)      8AM 9AM 10A 11A 12P 1PM 2PM 3PM 4PM 5PM
Sky (%).........4   4   5   5   6   6   5   5   7   10
Weather cov.....
Weather type....
Tstm cov........
CWR.............0   0   0   0   0   0   0   0   0   0
Temp............44  49  54  56  59  61  62  62  64  62
RH..............38  32  25  23  20  19  17  17  16  17
20 FT wind dir..NW  NW  NW  N   N   N   N   N   E   E
20 FT wind spd..9   9   9   9   8   8   8   7   7   7
20 FT wind gust.17  18  18  17  18  18  17  16  15  13
Mix hgt (kft)...1.1 4.5 6.0 7.2 7.9 8.2 8.4 8.6 7.5 6.3
Transp wind dir.NW  NW  NW  NW  NW  NW  NW  NW  N   NE
Transp wind spd.23  23  21  18  16  15  14  14  13  13

.THURSDAY NIGHT...

Sky/weather.........Mostly clear (15-25 percent).
Min temperature.....Around 41.
Max humidity........41 percent.
Wind (20 ft)........East winds 5 to 10 mph with gusts to around 15
                    mph. Becoming light and variable after 2200.
CWR.................0 percent.
Mixing height.......500 to 1000 ft agl.
Transport winds.....Northeast 10 to 15 mph shifting to the south 5
                    to 10 mph late in the evening, then shifting to
                    the southwest 10 to 15 mph after 3 am.
Smoke dispersal.....Poor.

TIME (MDT)      6PM 7PM 8PM 9PM 10P 11P MID 1AM 2AM 3AM 4AM 5AM
Sky (%).........13  15  17  19  22  25  28  24  20  17  15  13
Weather cov.....
Weather type....
Tstm cov........
CWR.............0   0   0   0   0   0   0   0   0   0   0   0
Temp............60  57  51  48  46  45  45  44  43  43  41  41
RH..............19  23  28  33  34  35  36  38  39  38  40  41
20 FT wind dir..E   E   E   NE  E   S   SW  SW  SW  SW  SW  SW
20 FT wind spd..6   5   3   3   2   2   2   2   2   2   2   3
20 FT wind gust.12  10  8   7   6   5   3   3   5   6   6   7
Mix hgt (kft)...5.2 3.6 2.0 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5
Transp wind dir.NE  NE  NE  NE  E   SE  S   S   SW  SW  SW  SW
Transp wind spd.12  10  9   7   6   5   3   6   8   10  10  12

.FRIDAY...

Sky/weather.........Sunny (15-25 percent).
Max temperature.....Around 76.
Min humidity........16 percent.
Wind (20 ft)........South winds around 5 mph increasing to 5 to
                    10 mph with gusts to around 15 to 20 mph.
CWR.................0 percent.
Mixing height.......7200 to 7700 ft agl.
Transport winds.....Southwest 15 to 20 mph.
Smoke dispersal.....Good increasing to very good late in the
                    afternoon.

TIME (MDT)      6AM 7AM 8AM 9AM 10A 11A 12P 1PM 2PM 3PM 4PM 5PM
Sky (%).........11  9   11  14  15  15  16  15  14  13  21  29
Weather cov.....
Weather type....
Tstm cov........
CWR.............0   0   0   0   0   0   0   0   0   0   0   0
Temp............42  45  50  55  59  63  67  70  73  75  76  76
RH..............40  37  32  27  25  24  22  20  18  17  16  17
20 FT wind dir..SW  SW  SW  S   S   S   S   S   S   S   S   S
20 FT wind spd..3   3   5   6   7   8   9   9   9   9   8   7
20 FT wind gust.7   8   10  12  14  16  17  18  18  18  16  14
Mix hgt (kft)...0.5 0.7 0.9 1.2 1.6 2.0 2.4 4.2 5.9 7.7 6.0 4.4
Transp wind dir.SW  SW  SW  SW  SW  SW  SW  SW  SW  SW  SW  SW
Transp wind spd.12  12  12  12  13  15  16  17  17  16  15  13

$$
Forecaster...13
Requested by...Dan Swanson
Type of request...PRESCRIBED
.TAG 2509117.3/UNR
.DELDT 04/09/25
.FormatterVersion 2.0.0
.EMAIL dan_swanson@nps.gov,kenn_perreault@nps.gov