283
FNUS73 KOAX 191046
FWSOAX

Spot Forecast for Koehrsen South...Iowa DNR
National Weather Service Omaha/Valley NE
546 AM CDT Sat Apr 19 2025

Forecast is based on ignition time of 0900 CDT on April 19.
If conditions become unrepresentative, contact the National Weather
Service.

.DISCUSSION...

The morning will start out with plenty of cloud cover and relative
humidity values in the 75% range in northeast Pottawattamie
County, and mixing heights at the start time of 9 AM being
1600-1700 ft AGL. Winds are expected to stay rather light compared
to the last several days, with the strongest wind gusts possible
not likely to exceed 20 mph, with sustained values ranging in the
5-10 mph range. They start out of the north, and being turning
northeasterly, then easterly quickly after 4 PM. Mixing heights
and are expected to reach 4500 ft AGL by noon, before topping out
at 5600 ft AGL, making for good smoke dispersal. Temperatures
should peak at 6 PM, where relative humidities drop to their
lowest value of 27%, though they could drop lower if we trend
warmer than forecast. Mixing heights and temperatures will drop
quickly at sunset, with RH values quickly rebounding at the same
time from 7-9 PM. Looking ahead to tomorrow, rain should move in
from the south and provide healthy rainfall to much of the area
while winds ramp up to the 25-35 mph range.

Strongest Possible Wind Speeds on Day of Burn: 21 mph

Lowest Possible Relative Humidity on Day of Burn: 20-25%

.REST OF TODAY...

Sky/weather.........Mostly sunny (25-35 percent).
Max temperature.....Around 58.
Min humidity........27 percent.
Eye level winds.....North winds up to 5 mph.
Surface winds (mph).North winds 8 to 9 mph.
Wind (20 ft)........North winds 6 to 8 mph.
Mixing height.......5600 ft AGL.
Transport winds.....North around 12 mph.
Smoke dispersal.....Fair (29500 knot-ft) early in the morning
                    increasing to good (50700 knot-ft) in the
                    afternoon.
GFDI................2.

.TONIGHT...

Sky/weather.........Mostly clear (10-20 percent) then becoming
                    mostly cloudy (60-70 percent).
Min temperature.....Around 39.
Max humidity........71 percent.
Eye level winds.....East winds up to 5 mph.
Surface winds (mph).East winds 6 to 9 mph.
Wind (20 ft)........East winds 5 to 8 mph.
Mixing height.......300 ft AGL.
Transport winds.....East around 12 mph.
Smoke dispersal.....Good (34300 knot-ft) early in the evening
                    decreasing to poor (1200 knot-ft) late in the
                    night.
GFDI................2.

.SUNDAY...

Sky/weather.........Cloudy (85-95 percent). Chance of rain showers
                    in the morning, then rain showers in the
                    afternoon.
Max temperature.....Around 51.
Min humidity........59 percent.
Eye level winds.....East winds 5 to 11 mph with gusts to around 16
                    mph.
Surface winds (mph).East winds 9 to 18 mph with gusts to around 26
                    mph.
Wind (20 ft)........East winds 8 to 15 mph with gusts to around 21
                    mph.
Mixing height.......1600 ft AGL.
Transport winds.....East around 23 mph.
Smoke dispersal.....Poor (6900 knot-ft) early in the morning
                    increasing to good (38000 knot-ft) in the
                    afternoon.
GFDI................3.

$$
Forecaster...Petersen
Requested by...Kody Wohlers
Type of request...PRESCRIBED
.TAG 2511050.0/OAX
.DELDT 04/19/25
.FormatterVersion 2.0.0
.EMAIL kwohlers@inhf.org