A moderately unstable airmass was in place across Iowa ahead of an approaching cold front. The airmass was tropical in nature with a clear tropical connection evident on satellite pictures.
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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 moderately unstable airmass was in place across Iowa ahead of an approaching cold front. The airmass was tropical in nature with a clear tropical connection evident on satellite pictures. Precipitable water values were in the 2 to 2.5 inch range by mid afternoon. Considerable debris cloudiness was over much of the state during the day from convection the previous night to the west. The clouds kept temperatures from warming much above the 85 to 90 F. degree range ahead of the cold front, though dew points were in the mid 70s throughout the area. Lifted indices were around -3 C. Moderate CAPE was available and was in the 1500 to 2500 J/kg range. The environment was weakly sheared with 20 to 30 kts of shear. Thunderstorms persisted through the day over northwest Iowa ahead of the front. During the afternoon, additional thunderstorms formed just ahead of the persistent area. There was one report of golf ball size hail in Davis County, but hail was limited given the freezing level of 16,400 feet. A few of the storms produced strong winds with a 60 MPH wind reported in Davis County. The roof was damaged on a house south of Pulaski. Storms downed several outbuildings and flattened a corn field west and north of Lacey in Mahaska County. That same storms also dropped 3 inches of rain in the area. The main feature was the very heavy rainfall. Thunderstorms produced very heavy rainfall in the Osceola area of Clarke County. Reports indicated 4.78 inches fell a half mile north of Osceola in under 2 hours. A young boy and girl were playing in water after the rain near Murray. The little girl went under and several feet underground through a pipe and ended up in a drainage ditch. Her brother followed and suffered a broken leg. Heavy rainfall also occurred in the Ottumwa area with nearly 2 inches falling in about an hour there as well. Lightning struck a house northwest of Drakesville, in Davis County, setting it on fire. The house was a total loss. Another storm caused a fire near New Sharon in Mahaska County. Lightning struck the barn, setting the wiring on fire. Damage was limited to the roof area for the most part. The same storm produced high winds that blew over two sheds and a garage.
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 13, 2:15 PM CST, 45 minutes earlier.
AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE DES MOINES IA 315 PM CDT SUN AUG 13 2006 .SHORT TERM /REST OF TODAY/... UPDATED ZONES AND GRIDS FOR SEVERE THUNDERSTORM WATCH /718/. && .PREV DISCUSSION... (ISSUED 156 PM CDT SUN AUG 13 2006) SHORT TERM /TONIGHT THROUGH TUESDAY/... REGIONAL RADAR CURRENTLY DEPICTING AREA OF SHRA/TSRA ALONG A KRST-KFOD-KLNK LINE...WHICH IS WELL-ALIGNED WITH SW-NE MOISTURE PLUME EVIDENT IN THE WATER VAPOR IMAGERY. WV LOOP ALSO SHOWING ADVANCING S/W TROUGH MOVING EWD ACROSS THE DAKOTAS SPREADING SUFFICIENT LARGE SCALE ASCENT ACROSS MUCH OF THE UPPER MISSISSIPPI VLY. MID AND HIGH LVL CLOUD DEBRIS HAS LIMITED OVERALL INSTABILITY TO SOME DEGREE EARLY THIS AFT...HOWEVER APPEARS BEST SVR THREAT WILL BE ALONG THE LEADING EDGE OF THE CONVECTION ACROSS THE CENTRAL/SCENT CWA WHERE TEMPERATURES HAVE REACHED THE LOW-MID 80S WITH DEWPOINTS REACHING THE LOW 70S DESPITE BKN-OVC SKIES. LATEST RUC SEEMS TO HAVE A FAIRLY DECENT HANDLE ON THE EVOLUTION OF THE CONVECTION AS IT DEVELOPS 1500-2000 J/KG MLCAPES ACROSS THE AFOREMENTIONED AREA FM THIS AFT INTO TNT. LACK OF DRY AIR INTRUSION/ENTRAINMENT INTO THE MID LVLS WILL LIMIT THE OVERALL THREAT OF DAMAGING WINDS ALTHOUGH STILL POSSIBLE WITH 1000+ J/KG DCAPE. HAIL NOT LIKELY GIVEN RATHER HIGH FZ LVLS. LOCALLY HEAVY RAINFALL SEEMS LIKELY GIVEN SREF PWATS /2-3STD/ ABOVE NORMAL AND STRONG LLVL MOISTURE CONVERGENCE/TRANSPORT ALONG THE COLD FRONT. IN ADDITION...FAVORABLE RT ENTRANCE DYNAMICS OF AN /120+KT/ ULJ WILL ALSO BE IN PLACE FM THIS EVE INTO TONIGHT WITH MAIN FOCUS ACROSS THE FAR SOUTH. THUS...SLGHT RISK FOR EXCESSIVE RAINFALL POTENTIAL WITH ISOLD 1.50-2.00 RAINFALL TOTALS NOT OUT OF THE QUESTION ALTHOUGH OVERALL STORM MOVEMENT SHOULD BE PROGRESSIVE. LLVL CAA IN THE WAKE OF THE FROPA WILL ESSENTIALLY KEEP TRAINING OF CELLS TO A SHORT DURATION. HAVE USED A MET/MAV BLEND FOR LOWS TNT AND GRADUALLY TAPER PCPN OUT OF THE CWA BY 12Z MON. THE COLD FRONT WILL REACH THE GREAT LAKES/MID MISSISSIPPI VLY BY MID-DAY MONDAY WITH SFC HI PRES DROPPING ESEWD FM THE NORTHERN PLAINS. THE COOL HIGH PRES SYS WILL PROVIDE DRY CONDITIONS THRU TUESDAY WITH SEASONABLY WARM DAYS AND RELATIVELY COOL NIGHTS. HAVE MIXED DOWN NAM 850 T FOR HIGHS TOMORROW WHICH WILL YIELD UPR 70S-LOW 80S FOR HIGHS. SREF PWATS /1-2STD/ BELOW NORMAL COMBINED WITH CLEAR SKIES AND LIGHT WINDS WILL ALLOW FOR IDEAL RADIATIONAL COOLING ON MONDAY NIGHT WITH NISH VLY LOCATIONS AS WELL AS THE /KALO/KMIW/KAMW/ CORRIDOR TO SEE LOW/MID 50S WITH /KMCW/KEST/ DIPPING TO AROUND 50. HAVE GONE AOB MET/MAV IN THIS TIME FRAME. OVERALL...PLEASANT AND COMFORTABLE CONDITIONS WITH LOW HUMIDITY WILL BE COMMON INTO MID WEEK. LONG TERM /WEDNESDAY THROUGH SUNDAY/... NO SIG CHANGES IN THE XTNDD GIVEN PENDING SVR WX THREAT THIS AFT. AFOREMENTIONED SFC HIGH WILL SLIDE EWD INTO THE LWR GREAT LAKES BY WEDNESDAY WITH WAA/RETURN FLOW REGIME COMMENCING ACROSS THE CENTRAL PLAINS/MID MO VLY. FIRST SHOT AT PCPN APPEARS TO BE WED EVE/NGHT ACROSS THE FAR W AS SURGE OF 850-700MB THETA-E ADV MOVES NNEWD ACROSS THE MID MO VLY. LEE SFC TROUGH DEVELOPS ACROSS THE HIGH PLAINS BY THURS AS NRN STREAM UPR RIDGING TRANSLATES EWD INTO THE UPR GRT LAKES. MED RANGE MODEL SOLNS BEGIN TO DIVERGE BY THIS TIME AS THE ECMWF MORE AGGRESSIVE WITH ADVANCING FRONTAL SYSTEM THAN THE GFS. 13/00Z MREF AND NCEP ENSEMBLE MEAN SEEM TO BE A GOOD COMPROMISE IN THE OUTER PDS GIVEN OVERALL UNCERTAINTY WITH RESPECT TO THE UPPER LEVEL PATTERN WHICH FEATURES SEVERAL NRN STREAM DISTURBANCES TRANSLATING EWD ON THE SRN EDGE OF THE WESTERLIES. AVIATION... OCNL MVFR VIS/CIGS IS TSRA THIS AFT/EVE AS COLD FRONT TRANSLATES ESEWD ACROSS THE STATE. IMPROVEMENT IS EXPECTED BY LATE IN THE PD AS HI PRES MOVES SEWD FROM THE NORTHERN PLAINS AND INTO THE UPPER MISSISSIPPI VALLEY. SSE SFC WNDS BCMG NWERLY IN THE WAKE OF FROPA. HYDROLOGY... LOCALLY HEAVY RAINFALL /RATES/ MAY CAUSES SOME MINOR FLOODING /URBAN-POOR DRAINAGE AREAS/ PROBLEMS FM THIS AFT INTO TONIGHT AS CONVECTION CONTINUES TO MOVE EWD ALONG ADVANCING COLD FRONT. HOWEVER...STORM MOTION WILL BE RATHER PROGRESSIVE WHICH SHOULD LIMIT ANY WIDESPREAD +RA. IN ADDITION...SLIGHT RISK OF EXCEEDING FFG ACROSS PTNS OF FAR SOUTHERN IA CWA PER HPC. && .DMX WATCHES/WARNINGS/ADVISORIES...SEVERE THUNDERSTORM WATCH 718 ALONG AND EAST OF A GREENFIELD...STORY CITY TO PARKERSBURG LINE. && .SHORT TERM...STEINBUGL
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE DES MOINES IA 115 PM CDT SUN AUG 13 2006 IAZ004>007-015>017-023>025-033>035-044-045-141100- EMMET-KOSSUTH-WINNEBAGO-WORTH-PALO ALTO-HANCOCK-CERRO GORDO- POCAHONTAS-HUMBOLDT-WRIGHT-SAC-CALHOUN-WEBSTER-CRAWFORD-CARROLL- 115 PM CDT SUN AUG 13 2006 THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF CENTRAL IOWA GENERALLY NORTHWEST OF A LINE FROM CARROLL TO FORT DODGE TO MASON CITY. .DAY ONE...THIS AFTERNOON AND TONIGHT SCATTERED SHOWERS AND THUNDERSTORMS ARE EXPECTED TO CONTINUE REDEVELOPING INTO EARLY EVENING...BEFORE MOVING OFF TO THE EAST. EXPECT BRIEF DOWNPOURS AND OCCASIONAL LIGHTNING...BUT MOST OF THE THREAT FOR SEVERE WEATHER OR HEAVY RAIN SHOULD BE OFF TO THE SOUTHEAST OF CARROLL...FORT DODGE AND MASON CITY. .DAYS TWO THROUGH SEVEN...MONDAY THROUGH SATURDAY THERE IS A CHANCE OF THUNDERSTORMS FROM WEDNESDAY NIGHT INTO NEXT WEEKEND. IT IS TOO EARLY TO DETERMINE SEVERE POTENTIAL. .SPOTTER INFORMATION STATEMENT... SPOTTERS ARE NOT LIKELY TO BE NEEDED. IAZ026>028-036>039-046>050-057>062-070>075-081>086-092>097-141100- FRANKLIN-BUTLER-BREMER-HAMILTON-HARDIN-GRUNDY-BLACK HAWK-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- 115 PM CDT SUN AUG 13 2006 THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF CENTRAL IOWA GENERALLY SOUTHEAST OF A LINE FROM CARROLL TO FORT DODGE TO MASON CITY. .DAY ONE...THIS AFTERNOON AND TONIGHT ONGOING THUNDERSTORMS SHOULD BEGIN TO RE-INTENSIFY LATER THIS AFTERNOON FROM SOUTHWEST IOWA INTO CENTRAL IOWA AND THE IOWA FALLS AND WATERLOO AREAS. THE MAIN THREAT FROM THESE STORMS SHOULD BE HEAVY RAINFALL...BUT THERE IS ALSO A SLIGHT RISK FOR DAMAGING THUNDERSTORM WINDS WITH A FEW OF THE STRONGER STORMS. ISOLATED RAINFALL AMOUNTS IN EXCESS OF 2 INCHES ARE POSSIBLE...WHICH COULD CAUSE URBAN FLOODING. THE THUNDERSTORMS SHOULD GRADUALLY MOVE OFF TO THE SOUTHEAST...EXITING SOUTHERN AND SOUTHEAST IOWA BETWEEN 9 PM AND MIDNIGHT. .DAYS TWO THROUGH SEVEN...MONDAY THROUGH SATURDAY THERE IS A CHANCE OF THUNDERSTORMS FROM WEDNESDAY NIGHT INTO NEXT WEEKEND. IT IS TOO EARLY TO DETERMINE SEVERE POTENTIAL. .SPOTTER INFORMATION STATEMENT... SPOTTERS ACTIVATION IS LIKELY OVER PORTIONS OF CENTRAL AND SOUTHERN IOWA BETWEEN 4 PM AND 9 PM. JUNGBLUTH
The Des Moines radar (KDMX), 78 km away, was scanning. The volume nearest the first event began at 22:09 UTC.
5 thunderstorm wind, 2 flash flood, 2 hail, 2 lightning. Local standard time, as filed.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Iowa in 2006Every state in 2006This day in weather historyWarnings in Iowa, August 2006
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: 5528445, 5528517, 5528518, 5528519, 5528520, 5528521, 5528516, 5528446, 5528448, 5528515, 5528447.