Thunderstorm Wind, Audubon
- When
- August 12, 5:10 PM CST
- Where
- Audubon County, Exira
- Measured
- 52 kt (60 mph) estimated gust
- Property damage
- $3,000
- Reported by
- Public
- Coordinates
- 41.580, -94.880
Damaging Winds in Iowa, August 12, 2007
A cold front sagged south across the state during the previous night and became stationary east-west over far southern Iowa. The airmass became very unstable during the afternoon as temperatures soared into the low to mid 90s.
Where it happened
Every event with a place to put it. Tap one for its entry below.
- Tornadoes
- Tropical storms and surge
- Floods
- Wind
- Hail
- Winter weather
- Heat and drought
- Cold
- Fire, smoke and dust
- Marine and coastal
- Other
The toll
- Deaths
- 0
- Injuries
- 0
- Property damage
- $87,000
- Crop damage
- $6,000
- Events
- 15
Deaths and injuries are direct and indirect together, as the offices filed them. Damage is property and crops in the dollars of the year, not adjusted for inflation, and only where an office estimated it.
What happened
The episode as NWS DMX wrote it up.
A cold front sagged south across the state during the previous night and became stationary east-west over far southern Iowa. The airmass became very unstable during the afternoon as temperatures soared into the low to mid 90s. Dew points pooled over southwest into west central Iowa and were in the upper 70s to low 80s across the area. This lead to CAPE values in excess of 7000 J/kg and a lifted index of -12 C. Needless to say, considerable moisture was available with precipitable water values in the 2 to 2.25 inch range. Thunderstorms developed over Nebraska and moved into Iowa during the afternoon. A strong bow echo developed and advanced east-southeast across the west central, then across the south west into the south central counties of the state. Some of the storms produced hail, but the hail was below severe levels. In spite of the available cape in the -10 to -30 C. layer of the atmosphere being in the 600 to 900 J/kg range, hail was suppressed once again by the high freezing levels. Freezing levels were between 14,500 and 15,000 feet. The LCL was a relatively low 750 to 1000 meters, however downdraft CAPE was very high, between 1200 and 1600 J/kg. Winds dominated the event as the storms advanced rapidly eastward in a shear environment of 40 to 50 kts. There were numerous reports of trees toppled and power line damage. Wind gusts of 60 to 70 MPH were common. Some of the higher gusts came from the Adair area. Mesonet sites reported wind gusts of 66 to 71 MPH in the area.
What forecasters said that day
The local office's own words before the first event, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.
NWS Des Moines, IA wrote its last area forecast discussion before the first event at Aug 12, 1:57 PM CST, 3 hours 13 minutes earlier.
Area forecast discussion, Aug 12, 1:57 PM CST, 3 hours 13 minutes before
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DES MOINES IA 257 PM CDT SUN AUG 12 2007 .DISCUSSION... BOUNDARY HAS SLID THROUGH THE STATE AND INTO NORTHERN MISSOURI EARLY THIS AFTERNOON. SOME WEAK CAA BEHIND THE BOUNDARY HAS KEPT TEMPERATURES IN CHECK ACRS THE NORTH BUT LOW TO MID 90S STILL EXIST IN THE FAR SOUTH. MOISTURE POOLING NEAR THE BOUNDARY HAS KEPT DEWPOINTS IN THE MID 70S WITH HEAT INDICES HOLDING RIGHT AT 105 THIS AFTERNOON NEAR THE MISSOURI BORDER. OTHERWISE...CONVECTIVE SYSTEM IS PUSHING THROUGH NEBRASKA AND WL LIKELY FOLLOW INSTABILITY AXIS INTO SOUTHWEST IOWA LATER TODAY. OVERNIGHT CONCERN WL FOCUS ON PLACEMENT AND STRENGTH OF CONVECTION CURRENTLY IN NEBRASKA. GIVEN MLCAPES OF OVER 3000 J/KG...SOME SEVERE STORMS WILL CERTAINLY BE POSSIBLE...HOWEVER INSTABILITY IS LOCATED ONLY IN FAR SOUTHWESTERN PORTIONS OF THE CWA AND EXPECT THIS INITIAL CONVECTION TO MAINLY STAY SOUTH OF A KCIN-KLWD LINE. HOWEVER...WL CONTINUE TO SEE STRONG MOISTURE AND THERMAL ADVECTION INTO WESTERN IOWA OVERNIGHT WITH THE THREAT OF SOME CONVECTION REMAINING...PRIMARILY WEST OF I35. SOME RESIDUAL STORMS MAY CONTINUE INTO TUESDAY MORNING ACRS NORTH CENTRAL IOWA...HOWEVER CAP WL BE INCREASING DURING THE DAY WHICH SHOULD GRADUALLY END THE THREAT OF CONVECTION BY MIDDAY. TEMPS TO REBOUND NICELY AS THERMAL RIDGE BUILDS TOWARD THE STATE ALTHOUGH SOME CLDS MAY KEEP READINGS IN CHECK ACRS THE NORTH. NEXT SHORTWAVE IN FLOW WL PASS ACRS THE NORTHERN MIDWEST LATE MONDAY INTO EARLY TUESDAY. EXPECT CONVECTION TO IGNITE ACRS MN/WI MONDAY AFTERNOON AND DROP SOUTHEAST TOWARD NORTHEAST IOWA MONDAY NIGHT. THIS CONVECTION MAY GRAZE THE NORTHEAST PORTIONS OF THE CWA AND HAVE LEFT POPS IN ACRS THOSE LOCATIONS. REMAINDER OF THE FORECAST WL HAVE A BOUNDARY IN VICINITY OF THE STATE THROUGH NEXT WEEKEND. SOME COOLER AIR SHOULD INFILTRATE THE STATE BY MID TO LATE WEEK WITH THE THREAT OF THUNDERSTORMS DURING LATE AND OVERNIGHT PERIODS. HAVE DROPPED TEMPS SOME BY LATE IN THE WEEK BUT CONTINUED THE THREAT OF THUNDERSTORMS. && .AVIATION...12/18Z SKC THIS AFTERNOON WITH STRONG CAP AND DRY ALOFT LITTLE IF ANY CLOUDS THOUGH BY EVENING EXPECT CIRRUS TO SPILL OVER INTO THE STATE. AFTER MIDNIGHT CHANCE FOR THUNDERSTORMS THOUGH STORMS WILL BE HIGH BASED 6000 FEET AND VISIBILITY NOT REDUCED GREATLY. NRLY WINDS BECOMING MORE EASTERLY THEN SRLY ON MONDAY. && .DMX WATCHES/WARNINGS/ADVISORIES...NONE. && SHORT TERM/AVIATION...FORSTER/20/14/4 MID/LONG TERM...COGIL
Hazardous weather outlook, Aug 12, 3:05 PM CST, 2 hours 5 minutes before
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE DES MOINES IA 405 PM CDT SUN AUG 12 2007 IAZ057-058-070>075-081>086-092>097-131100- AUDUBON-GUTHRIE-CASS-ADAIR-MADISON-WARREN-MARION-MAHASKA-ADAMS- UNION-CLARKE-LUCAS-MONROE-WAPELLO-TAYLOR-RINGGOLD-DECATUR-WAYNE- APPANOOSE-DAVIS- 405 PM CDT SUN AUG 12 2007 THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF SOUTHERN IOWA...GENERALLY SOUTH OF INTERSTATE 80. .DAY ONE...THIS AFTERNOON AND TONIGHT SCATTERED THUNDERSTORMS ARE EXPECTED TO MOVE INTO SOUTHERN IOWA LATE THIS AFTERNOON AND EVENING. SOME STORMS MAY PRODUCE VERY STRONG STRAIGHT LINE WIND GUSTS AROUND 80 MPH AND HAIL AROUND ONE INCH IN DIAMETER. AN ISOLATED TORNADO IS ALSO POSSIBLE THROUGH EARLY EVENING...ESPECIALLY OVER EXTREME SOUTHWEST IOWA...ALONG AND SOUTHWEST OF A CORNING TO MOUNT AYR LINE. ADDITIONAL THUNDERSTORMS ARE POSSIBLE AFTER MIDNIGHT WITH ISOLATED SEVERE WEATHER POSSIBLE. .DAYS TWO THROUGH SEVEN...MONDAY THROUGH SATURDAY HOT WEATHER IS EXPECTED TO RETURN FOR TUESDAY. AFTERNOON HEAT INDICES WILL REACH 100 TO 108 DEGREES. THUNDERSTORMS ARE EXPECTED TUESDAY NIGHT THROUGH THURSDAY. SOME OF THE STORMS MAY BE SEVERE AND ALSO PRODUCE LOCALLY HEAVY RAINFALL. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION MAY BE NEEDED THROUGH THIS EVENING AND AGAIN OVERNIGHT. ACTIVATION MAY ALSO BE NEEDED FOR DURING THE PERIOD TUESDAY NIGHT THROUGH THURSDAY. IAZ004>007-015>017-023>028-033>039-044>050-059>062-131100- EMMET-KOSSUTH-WINNEBAGO-WORTH-PALO ALTO-HANCOCK-CERRO GORDO- POCAHONTAS-HUMBOLDT-WRIGHT-FRANKLIN-BUTLER-BREMER-SAC-CALHOUN- WEBSTER-HAMILTON-HARDIN-GRUNDY-BLACK HAWK-CRAWFORD-CARROLL-GREENE- BOONE-STORY-MARSHALL-TAMA-DALLAS-POLK-JASPER-POWESHIEK- 405 PM CDT SUN AUG 12 2007 THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF CENTRAL AND NORTHERN IOWA...GENERALLY NORTH OF INTERSTATE 80. .DAY ONE...THIS AFTERNOON AND TONIGHT THERE WILL BE A CHANCE OF THUNDERSTORMS TONIGHT. THE THREAT FOR SEVERE WEATHER IS LOW...ALTHOUGH AN ISOLATED SEVERE STORM WITH 60 MPH WINDS AND PENNY SIZE HAIL CANNOT BE RULED OUT. .DAYS TWO THROUGH SEVEN...MONDAY THROUGH SATURDAY HOT WEATHER IS EXPECTED TO RETURN FOR TUESDAY. AFTERNOON HEAT INDICES WILL REACH 95 TO 105 DEGREES. THUNDERSTORMS ARE EXPECTED TUESDAY NIGHT AND WEDNESDAY. SOME OF THE STORMS MAY BE SEVERE AND ALSO PRODUCE LOCALLY HEAVY RAINFALL. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION IS NOT ANTICIPATED FOR TONIGHT...BUT MAY BE NEEDED FOR PORTIONS OF THE PERIOD TUESDAY NIGHT THROUGH WEDNESDAY. REV/KINNEY
The radar
The Des Moines radar (KDMX), 98 km away, was scanning. The volume nearest the first event began at 23:11 UTC.
Event by event
15 thunderstorm wind. Local standard time, as filed.
Thunderstorm Wind, Audubon
- When
- August 12, 5:17 PM CST
- Where
- Audubon County, 2.18 mi ESE of Imballton
- Measured
- 52 kt (60 mph) estimated gust
- Property damage
- $3,000
- Reported by
- Trained Spotter
- Coordinates
- 41.620, -95.030
Thunderstorm Wind, Cass
- When
- August 12, 5:30 PM CST
- Where
- Cass County, 3.33 mi SE of Fletcher Chapel to 1.53 mi SE of Cumberland
- Measured
- 54 kt (62 mph) measured gust
- Property damage
- $5,000
- Reported by
- Trained Spotter
- Coordinates
- 41.270, -94.950
A trained spotter measured a 62 MPH wind gust.
Thunderstorm Wind, Adair
- When
- August 12, 5:38 PM CST
- Where
- Adair County, 0.52 mi E of Adair
- Measured
- 50 kt (58 mph) measured gust
- Property damage
- $2,000
- Reported by
- Mesonet
- Coordinates
- 41.500, -94.640
Thunderstorm Wind, Adair
- When
- August 12, 5:41 PM CST
- Where
- Adair County, 0.52 mi E of Adair
- Measured
- 62 kt (71 mph) measured gust
- Property damage
- $35,000
- Crop damage
- $2,000
- Reported by
- Mesonet
- Coordinates
- 41.500, -94.640
Thunderstorm Wind, Guthrie
- When
- August 12, 5:43 PM CST
- Where
- Guthrie County, 4.18 mi N of Adair to 1.85 mi ENE of Casey
- Measured
- 56 kt (64 mph) estimated gust
- Property damage
- $5,000
- Crop damage
- $2,000
- Reported by
- Trained Spotter
- Coordinates
- 41.560, -94.640
A trained spotter estimated wind gusts of 60 to 70 MPH.
Thunderstorm Wind, Adair
- When
- August 12, 5:45 PM CST
- Where
- Adair County, 0.52 mi E of Adair
- Measured
- 57 kt (66 mph) measured gust
- Property damage
- $10,000
- Crop damage
- $2,000
- Reported by
- Mesonet
- Coordinates
- 41.500, -94.640
Thunderstorm Wind, Taylor
- When
- August 12, 6:00 PM CST
- Where
- Taylor County, 2.51 mi WNW of Gravity
- Measured
- 52 kt (60 mph) estimated gust
- Property damage
- $2,000
- Reported by
- Trained Spotter
- Coordinates
- 40.790, -94.770
Thunderstorm Wind, Union
- When
- August 12, 6:08 PM CST
- Where
- Union County, Creston
- Measured
- 50 kt (58 mph) measured gust
- Property damage
- $2,000
- Reported by
- Mesonet
- Coordinates
- 41.070, -94.370
Thunderstorm Wind, Taylor
- When
- August 12, 6:10 PM CST
- Where
- Taylor County, 4.73 mi SW of Bedford Arpt
- Measured
- 50 kt (58 mph) estimated gust
- Property damage
- $5,000
- Reported by
- Other Federal Agency
- Coordinates
- 40.587, -94.790
Thunderstorm Wind, Taylor
- When
- August 12, 6:10 PM CST
- Where
- Taylor County, 4.86 mi SW of Bedford Arpt
- Measured
- 50 kt (58 mph) estimated gust
- Property damage
- $5,000
- Reported by
- Other Federal Agency
- Coordinates
- 40.590, -94.796
Thunderstorm Wind, Union
- When
- August 12, 6:18 PM CST
- Where
- Union County, Afton
- Measured
- 50 kt (58 mph) measured gust
- Property damage
- $2,000
- Reported by
- Mesonet
- Coordinates
- 41.030, -94.200
Thunderstorm Wind, Warren
- When
- August 12, 6:36 PM CST
- Where
- Warren County, 1.38 mi N of New Virginia
- Measured
- 52 kt (60 mph) estimated gust
- Property damage
- $2,000
- Reported by
- Law Enforcement
- Coordinates
- 41.200, -93.730
Thunderstorm Wind, Clarke
- When
- August 12, 6:40 PM CST
- Where
- Clarke County, 3.43 mi WSW of Lacelle to 1.34 mi WSW of Leslie
- Measured
- 52 kt (60 mph) estimated gust
- Property damage
- $3,000
- Reported by
- Trained Spotter
- Coordinates
- 40.930, -93.910
A trained spotter reported large tree limbs blown down by high wind.
Thunderstorm Wind, Warren
- When
- August 12, 6:47 PM CST
- Where
- Warren County, 1.04 mi E of Norwalk
- Measured
- 52 kt (60 mph) estimated gust
- Property damage
- $3,000
- Reported by
- Trained Spotter
- Coordinates
- 41.480, -93.660
What these are
- Thunderstorm Wind
- Winds from a thunderstorm of 50 knots (58 mph) or more, or lower winds that caused damage or casualties. Measured gusts are marked MG, estimated EG.
After NWS Directive 10-1605, the rules offices file Storm Data by.
The same day elsewhere
- Excessive Heat in Texas, August 12 to 13, 2007
- Wildfire in Hawaii, August 12 to 19, 2007
- Damaging Winds in Missouri, August 12 to 13, 2007
- Damaging Winds in Illinois, August 12, 2007
- Damaging Winds and Lightning Strike in Michigan, August 12, 2007
- Flash Flooding and Damaging Winds in Nebraska, August 12, 2007
- Hail and Damaging Winds in Missouri, August 12, 2007
- Damaging Winds and Heavy Rain in Iowa, August 12, 2007
- Excessive Heat in Missouri, August 12 to 16, 2007
- Drought in North Carolina, August 12 to 31, 2007
- Damaging Winds in Illinois, August 12 to 13, 2007
- Marine Thunderstorm Winds in Lake Michigan, August 12, 2007
More
Every storm in Iowa in 2007Every state in 2007This day in weather historyWarnings in Iowa, August 2007
Sources
NOAA National Centers for Environmental Information, Storm Events Database, compiled from the National Weather Service’s monthly Storm Data. Complete through 2026-06; NCEI adds each month about 75 days after it ends and revises past years a few times a year. Rebuilt 2026-09-24. Each event’s entry at NCEI: 39771, 39467, 39468, 39471, 39472, 39473, 39474, 39475, 39479, 39806, 39807, 39476, 39477, 39469, 39478.