Thunderstorm Wind, Wayne
- When
- August 7, 4:44 PM CST
- Where
- Wayne County, 7.83 mi SSW of Humeston
- Measured
- 61 kt (70 mph) estimated gust
- Property damage
- $30,000
- Crop damage
- $5,000
- Reported by
- Emergency Manager
- Coordinates
- 40.770, -93.550
Flash Flood and Hail in Iowa, August 7, 2007
A very moist and unstable airmass remained in place over Iowa with CAPE values in the 3000 to 4500 J/kg range and lifted index values around -8 C. A boundary extended nearly east to west across the southern half of Iowa during the day from the previous night's convection.
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
- $140,000
- Crop damage
- $105,000
- Events
- 11
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 very moist and unstable airmass remained in place over Iowa with CAPE values in the 3000 to 4500 J/kg range and lifted index values around -8 C. A boundary extended nearly east to west across the southern half of Iowa during the day from the previous night's convection. High temperatures reached the low 90s south of the boundary with mid to upper 80s to its north. Dew points were in the low to mid 70s. Deep moisture was in place with precipitable water values in the 2 to 2.25 inch range. An MCV was lifting northeast across northeast Nebraska during the day. Thunderstorms formed over southeast Nebraska into southern Iowa during the late afternoon and evening hours. Downdraft CAPE was in the 1000 to 1500 J/kg range with CAPE in the -10 to -30 C. layer of the atmosphere in the 500 to 700 J/kg range. The freezing level remained quite high, in the 14,500 to 15,900 foot range. This limited the hail production. Effective shear across the area was between 30 and 40 kts with the LCL 1000 to 1250 meters. There was one report of nickel size hail during the event. This occurred in Wayne County, south of Humeston. The rest of the severe weather was in the form of high winds. Several of the storms produced winds of 60 to 70 MPH. A grain bin was destroyed south of Humeston by high winds. Two semitrailer trucks were jackknifed as the result of high winds on Interstate 35 in Warren County near Bevington. In Taylor County, thunderstorms that developed later in the evening flattened a barn west of Bedford. The storms produced copious amounts of rainfall with 2 to as much as 4 inches of rain falling in Warren County, resulting in flash flooding. Water was running 6 inches deep across Interstate 35 between mile post 48 and mile post 50.
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 7, 2:25 PM CST, 2 hours 19 minutes earlier.
Area forecast discussion, Aug 7, 2:25 PM CST, 2 hours 19 minutes before
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DES MOINES IA 325 PM CDT TUE AUG 7 2007 .DISCUSSION... ACTIVE PATTERN WL CONT THRU THE NEXT 48 HRS OR SO AS IA REMAINS IN THE RING OF FIRE. MCV MOVG THRU NERN NEBRASKA EVIDENT ON SAT PIX THIS AFTN WL DRFT EWD SLOWLY OVR NGT INTO WED MRNG. EXPECT DVLPMT OVR NIGHT WITH THAT FEATURE. MOISTURE TRANSPORT INTO THE AREA WED AFTN INTO THE OVR NGT HOURS WL CONTINUE THE CHANCE INTO WED NGT. EXPECT UPR HIGH TO BUILD FARTHER NWD AND PUSH THE ACTIVTY NORTH OF IA BY THU AFTN INTO THE FIRST OF NXT WK. AFTER DEALING WITH THE PCPN CHCS OVR THE NXT 48 HRS, WX WILL BE QUITE WITH THE DOG DAYS OF SUMMER CONTINUING. HIGHS IN THE UPPER 80S AND 90S WITH LOWS IN THE LOW TO MID 70S. ATTM FEEL THAT THE HEAT INDX WILL REMAIN BLO CRITERIA BY A FEW DEGREES THRU FCST PD. && .AVIATION...07/18Z SFC FRONTAL BOUNDARY STILL LOCATED ACROSS CNTRL IA AND PRIMARY UPPER LEVEL SYSTEM OVER CNTRL NEBRASKA. EXPECT LIGHT AND VARIABLE WINDS ACROSS MUCH OF THE SITES THROUGH PERIOD. THIS AFTERNOON CUMULUS FILLING IN WHERE SUNSHINE HAS OCCURRED AND WILL LEAD TO AREAS OF MVFR CEILINGS THIS AFTERNOON AT ALL SITES. BY LATE THIS AFTERNOON UPPER LEVEL SYSTEM IS EXPECTED TO MAKE A PUSH EAST AND LEAD TO INCREASING THUNDERSTORMS CHANCES THROUGH THIS EVENING AT DSM AND OTM. ADDITIONAL THUNDERSTORMS MAY DEVELOP OVER SW IA LATE WITH VCTS MENTIONED AT DSM AFTER 09Z. && .DMX WATCHES/WARNINGS/ADVISORIES...NONE. &&
Hazardous weather outlook, Aug 7, 2:43 PM CST, 2 hours 1 minute before
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE DES MOINES IA 343 PM CDT TUE AUG 7 2007 IAZ033>039-044>050-057>062-070>075-081>086-092>097-082045- SAC-CALHOUN-WEBSTER-HAMILTON-HARDIN-GRUNDY-BLACK HAWK-CRAWFORD- CARROLL-GREENE-BOONE-STORY-MARSHALL-TAMA-AUDUBON-GUTHRIE-DALLAS- POLK-JASPER-POWESHIEK-CASS-ADAIR-MADISON-WARREN-MARION-MAHASKA- ADAMS-UNION-CLARKE-LUCAS-MONROE-WAPELLO-TAYLOR-RINGGOLD-DECATUR- WAYNE-APPANOOSE-DAVIS- 343 PM CDT TUE AUG 7 2007 THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF CENTRAL AND SOUTHERN IOWA SOUTH OF HIGHWAY 18. .DAY ONE...THIS AFTERNOON AND TONIGHT THUNDERSTORMS ARE EXPECTED TO DEVELOP OVER WESTERN IOWA THIS AFTERNOON AND MOVE EAST ACROSS THE AREA THROUGH THE EVENING HOURS. A FEW SEVERE STORMS WITH DAMAGING WINDS ARE POSSIBLE ESPECIALLY SOUTH OF INTERSTATE 80. ADDITIONAL THUNDERSTORMS ARE EXPECTED TO DEVELOP OVER SOUTHWEST IOWA LATE TONIGHT. LOCALIZED HEAVY RAINFALL UP TO 2 INCHES IS POSSIBLE TONIGHT AS WELL. .DAYS TWO THROUGH SEVEN...WEDNESDAY THROUGH MONDAY THE SCENARIO REMAINS SIMILAR FOR WEDNESDAY INTO THURSDAY WITH CONTINUED CHANCES FOR THUNDERSTORMS...WITH A FEW SEVERE STORMS POSSIBLE WITH DAMAGING WINDS. CHANCES FOR HEAVY RAINFALL WILL CONTINUE DURING THIS TIME. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION MAY BE POSSIBLE TONIGHT BETWEEN 5 PM TO 11 PM SOUTH OF INTERSTATE 80. IN ADDITION...RAINFALL REPORTS ARE ALWAYS APPRECIATED. IAZ004>007-015>017-023>028-082045- EMMET-KOSSUTH-WINNEBAGO-WORTH-PALO ALTO-HANCOCK-CERRO GORDO- POCAHONTAS-HUMBOLDT-WRIGHT-FRANKLIN-BUTLER-BREMER- 343 PM CDT TUE AUG 7 2007 THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF NORTH CENTRAL IOWA MAINLY NORTH OF HIGHWAY 18. .DAY ONE...THIS AFTERNOON AND TONIGHT SCATTERED THUNDERSTORMS ARE POSSIBLE LATE TONIGHT THROUGH THIS EVENING. NO SEVERE WEATHER IS EXPECTED. .DAYS TWO THROUGH SEVEN...WEDNESDAY THROUGH MONDAY THE SCENARIO REMAINS SIMILAR FOR WEDNESDAY INTO THURSDAY WITH CONTINUED CHANCES FOR THUNDERSTORMS...WITH A FEW SEVERE STORMS POSSIBLE WITH DAMAGING WINDS. CHANCES FOR HEAVY RAINFALL WILL CONTINUE DURING THIS TIME. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION IS NOT EXPECTED THOUGH RAINFALL REPORTS ARE ALWAYS APPRECIATED. DONAVON
The radar
The Des Moines radar (KDMX), 108 km away, was scanning. The volume nearest the first event began at 22:43 UTC.
Event by event
9 thunderstorm wind, 1 hail, 1 flash flood. Local standard time, as filed.
Hail, Wayne
- When
- August 7, 4:50 PM CST
- Where
- Wayne County, 6.95 mi WSW of Bentonville
- Measured
- 0.88 in hail
- Property damage
- $3,000
- Crop damage
- $25,000
- Reported by
- Emergency Manager
- Coordinates
- 40.760, -93.500
Thunderstorm Wind, Taylor
- When
- August 7, 5:25 PM CST
- Where
- Taylor County, 0.52 mi W of Lenox
- Measured
- 52 kt (60 mph) estimated gust
- Property damage
- $10,000
- Reported by
- Law Enforcement
- Coordinates
- 40.880, -94.560
Thunderstorm Wind, Union
- When
- August 7, 5:48 PM CST
- Where
- Union County, 0.87 mi SE of Creston
- Measured
- 53 kt (61 mph) measured gust
- Property damage
- $5,000
- Reported by
- Mesonet
- Coordinates
- 41.060, -94.360
Thunderstorm Wind, Union
- When
- August 7, 5:48 PM CST
- Where
- Union County, Creston Arpt
- Measured
- 53 kt (61 mph) measured gust
- Property damage
- $2,000
- Crop damage
- $10,000
- Reported by
- AWOS
- Coordinates
- 41.020, -94.370
Thunderstorm Wind, Warren
- When
- August 7, 6:39 PM CST
- Where
- Warren County, 0.69 mi S of Indianola
- Measured
- 50 kt (58 mph) estimated gust
- Property damage
- $4,000
- Reported by
- Law Enforcement
- Coordinates
- 41.360, -93.570
Flash Flood, Warren
- When
- August 7, 6:45 PM CST to 8:30 PM CST
- Where
- Warren County, 4.27 mi NNW of New Virginia to 4.69 mi SW of St Marys
- Cause
- Heavy Rain
- Property damage
- $5,000
- Crop damage
- $25,000
- Reported by
- Law Enforcement
- Coordinates
- 41.233, -93.773
Thunderstorm Wind, Warren
- When
- August 7, 6:45 PM CST
- Where
- Warren County, 0.86 mi SE of Bevington
- Measured
- 61 kt (70 mph) estimated gust
- Property damage
- $25,000
- Crop damage
- $10,000
- Reported by
- Law Enforcement
- Coordinates
- 41.360, -93.790
Thunderstorm Wind, Warren
- When
- August 7, 6:57 PM CST
- Where
- Warren County, 1.38 mi N of Norwalk
- Measured
- 52 kt (60 mph) estimated gust
- Property damage
- $1,000
- Reported by
- Trained Spotter
- Coordinates
- 41.500, -93.680
Thunderstorm Wind, Marion
- When
- August 7, 7:05 PM CST
- Where
- Marion County, 1.38 mi N of Dunreath
- Measured
- 61 kt (70 mph) estimated gust
- Property damage
- $5,000
- Crop damage
- $5,000
- Reported by
- Trained Spotter
- Coordinates
- 41.490, -93.180
Thunderstorm Wind, Taylor
- When
- August 7, 9:30 PM CST
- Where
- Taylor County, 4.2 mi W of Bedford
- Measured
- 70 kt (81 mph) estimated gust
- Property damage
- $50,000
- Crop damage
- $25,000
- Reported by
- Law Enforcement
- Coordinates
- 40.670, -94.800
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.
- Hail
- Hail three-quarters of an inch or larger, or smaller hail that caused damage, filed with the largest stone measured.
- Flash Flood
- Flooding that begins within six hours of the rain that causes it, or of a dam or levee failure or ice jam release, often with deadly speed.
After NWS Directive 10-1605, the rules offices file Storm Data by.
The same day elsewhere
- Heat in Arkansas, August 7 to 17, 2007
- Damaging Wind in Illinois, August 7, 2007
- Lightning Strike in Alabama, August 7, 2007
- Flash Flooding and Hail in Ohio, August 7, 2007
- Flash Flooding and Flooding in Illinois, August 7, 2007
- Hail and Damaging Winds in North Dakota, August 7, 2007
- Lightning Strike in Florida, August 7, 2007
- Damaging Winds in Pennsylvania, August 7, 2007
- Hail and Lightning Strike in Nebraska, August 7, 2007
- Damaging Winds in Pennsylvania, August 7, 2007
- Tornado and Damaging Winds in Pennsylvania, August 7, 2007
- Flash Flood and Damaging Wind in Nebraska, August 7, 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: 38623, 38622, 38624, 38628, 38630, 38626, 38621, 38627, 38700, 38629, 38676.