209
FNUS73 KDMX 201012
FWSDMX

Spot Forecast for CBG - Darnell east...Polk County Conservation
National Weather Service Des Moines IA
512 AM CDT Thu Aug 20 2026

Forecast is based on ignition time of 1200 CDT on August 20.
If conditions become unrepresentative...contact the National Weather
Service.

An initial observation at ignition and a mid burn observation are required.

Please relay them to the National Weather Service for each prescribed burn.

.DISCUSSION...

Light and variable wind this morning will become light from the
southeast to south late this morning and into the afternoon. Mixed
layer winds are light as well, which will limit smoke dispersal.
Mostly sunny skies are expected and minimum relative humidity
values this afternoon will be near 60 percent.

.REST OF TODAY...

Sky/weather.........Sunny (0-10 percent).
Max temperature.....Around 81.
Min humidity........60 percent.
Wind (20 ft)........Light winds becoming south 5 to 6 mph late in
                    the afternoon.
Mixing height.......4000 ft AGL.
Transport winds.....South 6 to 8 mph.
Smoke dispersal.....Poor (15900 knot-ft).
GFDI................0.

TIME (CDT)      12P 1PM 2PM 3PM 4PM 5PM
Sky (%).........2   1   3   5   0   7
Weather cov.....
Weather type....
Tstm cov........
Temp............76  78  79  81  81  81
RH..............71  67  64  60  60  60
20 FT wind dir..S   S   S   S   S   S
20 FT wind spd..3   3   5   6   6   6
20 FT wind gust.6   7   9   10  10  10
Mix hgt (kft)...3.2 3.7 3.8 4.0 3.7 3.4
Transp wind dir.S   S   S   S   S   S
Transp wind spd.6   6   7   7   7   8
GFDI............0   0   0   0   0   0
Smoke Dispersal.16  18  23  24  22  24
Smoke Cat.......PR  PR  PR  PR  PR  PR

.TONIGHT...

Sky/weather.........Mostly clear (10-20 percent).
Min temperature.....Around 66.
Max humidity........97 percent.
Wind (20 ft)........South winds around 5 mph early in the evening
                    becoming light, then becoming south around 5
                    mph in the late evening and overnight.
Mixing height.......400 ft AGL.
Transport winds.....South 7 to 10 mph.
Smoke dispersal.....Poor (2500 knot-ft).
GFDI................0.

TIME (CDT)      6PM 7PM 8PM 9PM 10P 11P MID 1AM 2AM 3AM 4AM 5AM
Sky (%).........15  22  20  16  23  19  9   15  17  4   19  23
Weather cov.....
Weather type....
Tstm cov........
Temp............80  79  76  73  71  70  69  69  68  68  67  67
RH..............65  69  76  84  87  90  93  90  93  93  97  97
20 FT wind dir..S   S   S   S   S   S   S   S   S   S   S   S
20 FT wind spd..5   5   3   3   5   5   5   5   5   5   5   5
20 FT wind gust.8   7   6   6   6   7   8   8   8   8   9   8
Mix hgt (kft)...2.5 0.8 0.4 0.4 0.4 0.4 0.4 0.4 0.4 0.4 0.5 0.4
Transp wind dir.S   S   S   S   S   S   S   S   S   SW  SW  SW
Transp wind spd.8   7   7   7   8   9   9   10  10  10  10  10
GFDI............0   0   0   0   0   0   0   0   0   0   0   0
Smoke Dispersal.17  5   3   3   3   4   3   4   4   4   4   4
Smoke Cat.......PR  PR  PR  PR  PR  PR  PR  PR  PR  PR  PR  PR

.FRIDAY...

Sky/weather.........Sunny (10-20 percent).
Max temperature.....Around 84.
Min humidity........61 percent.
Wind (20 ft)........Southwest winds 5 to 7 mph shifting to the
                    northwest around 7 mph late in the afternoon.
Mixing height.......3900 ft AGL.
Transport winds.....West 10 to 14 mph shifting to the northwest 10
                    to 12 mph late in the afternoon.
Smoke dispersal.....Poor (3900 knot-ft).
GFDI................0.

TIME (CDT)      6AM 7AM 8AM 9AM 10A 11A 12P 1PM 2PM 3PM 4PM 5PM
Sky (%).........20  20  12  3   9   8   6   5   24  14  11  9
Weather cov.....
Weather type....
Tstm cov........
Temp............66  67  68  71  75  77  80  82  83  84  84  83
RH..............100 97  97  93  84  79  74  67  65  63  61  63
20 FT wind dir..SW  SW  SW  SW  W   W   W   W   W   NW  NW  NW
20 FT wind spd..5   5   6   6   7   7   7   7   8   8   8   7
20 FT wind gust.9   8   10  10  12  13  13  13  14  14  14  13
Mix hgt (kft)...0.4 0.4 0.7 1.2 1.4 2.1 2.5 3.1 3.8 3.9 3.7 3.0
Transp wind dir.SW  SW  W   W   W   W   W   W   NW  NW  NW  NW
Transp wind spd.10  12  12  14  13  14  13  12  12  12  12  10
GFDI............0   0   0   0   0   0   0   0   0   0   0   0
Smoke Dispersal.4   4   7   14  16  25  28  31  38  39  37  27
Smoke Cat.......PR  PR  PR  PR  PR  PR  PR  PR  PR  PR  PR  PR

$$
Forecaster...Donavon
Requested by...Lael Neal
Type of request...PRESCRIBED
.TAG 2620027.0/DMX
.DELDT 08/20/26
.FormatterVersion 2.0.0
.EMAIL lael.neal@polkcountyiowa.gov