A frontal boundary extended southwest to northeast across Iowa during the early morning hours of the 15th. At the same time, a large MCS developed over northern Nebraska and tracked east into southern Minnesota into northern Iowa.
Every event with a place to put it. Tap one for its entry below.
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.
The episode as NWS DMX wrote it up.
A frontal boundary extended southwest to northeast across Iowa during the early morning hours of the 15th. At the same time, a large MCS developed over northern Nebraska and tracked east into southern Minnesota into northern Iowa. The airmass was quite unstable over Iowa and favorable for elevated convection as the system moved in. CAPE values remained in the 2000 to 3500 J/kg range along and south of the boundary with lifted indices in the -8 range. The environment was quite strongly sheared with 50 to 60 kts of shear. The downdraft CAPE was in the 500 to 700 J/kg range. Thunderstorms intensified as they moved across Iowa with a small bow echo element developing as the MCS began to interact with the frontal boundary. The event took shape as it moved into north central Iowa and produced 60 to 70 MPH winds as it moved from Kossuth County, east-southeast toward Tama County. Hail was limited with the event as the freezing level had not changed much from the previous day and was still in the 15,500 foot range. One report of three-quarter inch diameter hail was received from Franklin County. There were numerous reports of tree and power line damage. Two semitrailer trucks were blown off of Interstate 35 in southwest Cerro Gordo County between mile post 185 and 186. The two drivers received minor injuries. Reported wind damage included several out buildings and at least two barns flattened by high winds. Some of the harder hit areas were in Bremer County in the Plainfield area. Barns were blown down, along with numerous trees and power poles. The roof of a convenience store was peeled back in Plainfield. Damage extended along U.S. Highway 218 from Plainfield north to at least the Chickasaw County line.
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 15, 2:02 AM CST, 2 hours 8 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DES MOINES IA 302 AM CDT WED AUG 15 2007 .DISCUSSION... ANOTHER TRICKY DAY IN TEMP FORECASTING WITH THE CONVECTION AROUND THIS MRNG. LARGE MCS NOW CENTERED OVER SERN SD WL PUTH EAST THIS MRNG. INTENSITIES ARE DECREASING FM THE W AS AN IMPL MOVES ENEWD, 257091KTS, THRU THE SYS. THIS IS EVIDENT IN RADAR MOSAIC IMAGERY. EXPECT THE BULK OF THE PCPN TO MOVE OUT OF THE CWA BY MID MRNG OR SO WITH SOME CLEARING AS DRYING SHWN ON H2O VAP ROTATES INTO THE ARE. WET GROUNDS AND OUTFLOW BNDRY WL LKLY KEEP THE N HLF OF THE CWA IN THE 80S. SRN IA SHUD STILL WRM UP. NEXT ROUND OF TSRA ON TAP FOR TNGT AS FNT SINKS INTO THE AREA. THAT SHOULD PUSH TO THE S OF US ON THU AND FEEL GFS SOLNS ON FNTL PSN ARE BETTER THAN THE NAM. NAM LOOKS TOO FAR S WITH IT. RETURN OF WAA LKS GUD FOR FRI NGT AND WUD NOT BE SURPRISED TO SEE A WDSPRD TSRA EVENT FRI NGT INTO SAT. CHCS FOR RAIN DIMINISH A LITTLE OVR THE WKD WITH THE FLY IN THE OINTMENT BEING TD 5. GFS WAS EARLY TO CATCH THIS YDA AND ALL MDLS HAVE CAUGHT ON TO THE SYS. THE GENLY WET PTRN WL CONT INT NXT WK. && .DMX WATCHES/WARNINGS/ADVISORIES...NONE. &&
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE DES MOINES IA 134 PM CDT TUE AUG 14 2007 IAZ004>007-015>017-023>028-033>039-047>050-061-062-074-075-151100- EMMET-KOSSUTH-WINNEBAGO-WORTH-PALO ALTO-HANCOCK-CERRO GORDO- POCAHONTAS-HUMBOLDT-WRIGHT-FRANKLIN-BUTLER-BREMER-SAC-CALHOUN- WEBSTER-HAMILTON-HARDIN-GRUNDY-BLACK HAWK-BOONE-STORY-MARSHALL- TAMA-JASPER-POWESHIEK-MARION-MAHASKA- 134 PM CDT TUE AUG 14 2007 THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF CENTRAL IOWA. .DAY ONE...THIS AFTERNOON AND TONIGHT SCATTERED THUNDERSTORMS ARE POSSIBLE BY EARLY THIS EVENING...WITH MORE WIDESPREAD THUNDERSTORM ACTIVITY OVERNIGHT. SOME OF THE STORMS MAY BE SEVERE WITH EARLY THIS EVENING WITH WINDS THE PRIMARY THREAT. LARGE HAIL WILL POSE A SECONDARY THREAT. .DAYS TWO THROUGH SEVEN...WEDNESDAY THROUGH MONDAY SCATTERED THUNDERSTORMS ARE EXPECTED AGAIN FOR WEDNESDAY INTO WEDNESDAY NIGHT. SOME OF THE STORMS MAY BE SEVERE WITH HIGH WINDS AND THE POSSIBILITY OF LARGE HAIL. PERIODIC THUNDERSTORMS ARE EXPECTED FROM FRIDAY NIGHT INTO MONDAY. AT THIS TIME IT IS TO EARLY TO DETERMINE THE SEVERE POTENTIAL. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION MAY BE NEEDED THIS EVENING INTO TONIGHT...AND AGAIN WEDNESDAY LATE AFTERNOON AND EVENING. IAZ044>046-057>060-070>073-081>086-092>097-151100- CRAWFORD-CARROLL-GREENE-AUDUBON-GUTHRIE-DALLAS-POLK-CASS-ADAIR- MADISON-WARREN-ADAMS-UNION-CLARKE-LUCAS-MONROE-WAPELLO-TAYLOR- RINGGOLD-DECATUR-WAYNE-APPANOOSE-DAVIS- 134 PM CDT TUE AUG 14 2007 THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF CENTRAL IOWA. .DAY ONE...THIS AFTERNOON AND TONIGHT THUNDERSTORMS WILL BECOME MORE WIDESPREAD OVERNIGHT TONIGHT WITH THE POTENTIAL FOR A FEW SEVERE STORMS TONIGHT. HIGH WINDS WILL BE THE PRIMARY THREAT. .DAYS TWO THROUGH SEVEN...WEDNESDAY THROUGH MONDAY SCATTERED THUNDERSTORMS ARE EXPECTED AGAIN FOR WEDNESDAY INTO WEDNESDAY NIGHT. SOME OF THE STORMS MAY BE SEVERE WITH HIGH WINDS AND THE POSSIBILITY OF LARGE HAIL. PERIODIC THUNDERSTORMS ARE EXPECTED FROM FRIDAY NIGHT INTO MONDAY. AT THIS TIME IT IS TO EARLY TO DETERMINE THE SEVERE POTENTIAL. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION MAY BE NEEDED AFTER TONIGHT...AND AGAIN LATE WEDNESDAY AFTERNOON INTO WEDNESDAY NIGHT. FORSTER
The Des Moines radar (KDMX), 169 km away, was scanning. The volume nearest the first event began at 10:11 UTC.
16 thunderstorm wind, 1 hail. Local standard time, as filed.
Two power poles downed one half mile north of Burt and tree limbs were downed in Burt.
High winds partially blew down a barn. The Emergency manager also reported power lines blown down.
A garage was picked up with debris deposited on nearby cars. In addition, a two foot diameter tree was blown down.
The top one quarter of the tree tops were snapped off of 3 large trees. One was a cottonwood and 2 locust trees.
Two semis were blown over between mile markers 185 and 186 on interstate 35.
Several 6 to 8 inch tree limbs were blown down, some possibly larger, were blocking at least 10 roads in the town of Rockwell.
Small tree limbs were also reported blown down.
Several 4 to 6 inch tree limbs were blown down.
Numerous trees were blown down, some up to one to two feet in diameter. One large tree fell on a home causing damage to the home. Power lines were down on roadways along with the trees.
A NWS Employee estimated wind gusts of 65 to 70 mph in the town of Clarksville.
High winds blew the roof off of a convenience store. The roof flew one block, shearing off power poles and knocking out power to entire town. Trees were blown down on houses in Plainfield. Trees and power poles were down just west of Plainfield.
Numerous trees were blown down along highway 218 from the Chickasaw/Bremer County line, south through at least Plainfield. Trees were blown down on roads and some homes. Power poles were also blown down on roads. Large areas were without electricity. a few barns were also blown down.
Several 10 to 12 inch diameter pine tree limbs were blown down.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Iowa in 2007Every state in 2007This day in weather historyWarnings in Iowa, August 2007
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: 40195, 40309, 40308, 40178, 40179, 40180, 40181, 40183, 40177, 40184, 40186, 40191, 40188, 40189, 40190, 40310, 49304.