A weak cold front moved southeast across Iowa early on the 4th and had become stationary east-west to the south of the state. The thermal gradient increased during the day and moisture pooled along the front by evening.
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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 weak cold front moved southeast across Iowa early on the 4th and had become stationary east-west to the south of the state. The thermal gradient increased during the day and moisture pooled along the front by evening. The atmosphere became quite unstable by late afternoon with temperatures reaching well into the 90s south of the front, and dew point readings rising into the low 70s along the front. CAPE was in the 3000 to 4000 J/kg range by mid to late evening with lifted indices in the -5 to -10 C range. Precipitable water values increased to near 2 inches along the front as the 850 mb jet increased to 30 to 40 kts. Downdraft CAPE was in the 700 to 1000 J/kg range and available CAPE in the -10 to -30 C layer of the atmosphere was 400 to 600 J/kg. The freezing level was relatively high, in the 13,000 to 13,500 foot range, however with effective shear in the 50 to 70 kt range, plenty of dynamic energy was available. Thunderstorms developed initially over southeast Iowa into Missouri and produced large hail. Quarter to golf ball size hail fell in Davis and Appanoose Counties. As the night progressed, the first round of thunderstorms moved southeast of Iowa. By midnight, the second round of storms developed over southern Iowa. Though there was no severe weather with this round, heavy rainfall occurred. A third round moved through during the predawn hours, producing very heavy rainfall of 2 to 3 inches per hour. Total rainfall of 3 to 6 inches was common over south central into part of southwest Iowa. This resulted in flash flooding with numerous highways closed by high water. Evacuations took place in the south of Lamoni as waters rose. Water rose quickly in the middle fork of the Grand River, scouring out the highway on the U.S. 169 bridge south of the 10 mile post marker. Following the flash flooding, areal flooding took places over parts of south central into southwest Iowa for about 24 hours.
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 Jun 4, 5:20 PM CST, 3 hours 2 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DES MOINES IA 620 PM CDT FRI JUN 4 2010 ...HEAVY RAIN AND FLASH FLOODING A CONCERN TONIGHT... .SHORT TERM /TONIGHT/... ACTIVE NIGHT HEADED OUR WAY WITH HYDRO CONCERNS FOR SHORT TERM INTO TOMORROW. FRONT BECOMING EAST...WEST ORIENTED ACROSS SOUTHERN IOWA WITH ZONAL FLOW ALOFT...MID LEVEL WAVE APPROACHING...AND H850 LOW LEVEL JET EXPECTED TO STRENGTHEN OVERNIGHT INTO THE BOUNDARY. SOUTH OF THE BOUNDARY THIS AFTERNOON...DEW POINTS HAVE POOLED INTO THE 65 TO 70 DEGREE RANGE. AT H850 THIS MORNING...SUBJECTIVE ANALYSIS SHOWS LARGE +15C POOL OF DEW POINTS COVERING MOST OF GULF COAST AND LOWER MISSISSIPPI RIVER VALLEY. SOUNDINGS INDICATE EFFICIENT RAINFALL OVERNIGHT WITH FREEZING LEVEL BETWEEN 15-15.5KFT. THOUGH CAPE QUITE IMPRESSIVE THROUGH THE EVENING...SOUNDINGS QUICKLY BECOME SATURATED BY 06Z WHEN MCS EXPECTED TO DEVELOP. WITH THAT IN MIND...MAY BE SOME SVR STORMS THROUGH EVENING HOURS OVER THE FAR SOUTH...BUT LATER IN THE NIGHT IT WILL BECOME MORE DIFFICULT TO BRING WIND AND HAIL TO SFC DUE TO SATURATED COLUMN AND WARM FREEZING LEVEL. WILL BE ISSUING A FF.A FOR THE SOUTHERN AREAS TNT FROM 02Z THROUGH 18Z SATURDAY. THOUGH RAINFALL MAY EXTEND INTO THE AFTERNOON HOURS... BEST DYNAMICS OVERNIGHT TNT AND LESSER HEADING INTO THE AFTERNOON. WITH PWATS OF 1.7 TO 1.8 INCHES ACROSS THE BORDER LATE THIS AFTERNOON...AND THAT TO SPREAD NORTH TNT...RAINFALL AMOUNTS MAY REACH 2 TO 4 INCHES IN HEAVIER STORMS IN ANY AREAS THAT TRAIN DURING THE NIGHT HOURS. GFS PEGGED I80 AS THE QPF MAX WHILE OTHER MODELS AND ENSEMBLE HAD MAIN AXIS FARTHER SOUTH ALONG US 34. FFG GUIDANCE AND EXAMINATION OF PREVIOUS 3 DAY RAINFALL TOTALS SHOW THE SOUTH IS OF MOST CONCERN REGARDING FLASH FLOODING SO HAVE KEPT THE AREAL COVERAGE FROM GENERALLY HIGHWAY 20 SOUTH TO THE BORDER COUNTIES. .LONG TERM /SATURDAY THROUGH FRIDAY/... OVERNIGHT MCS WILL BE ONGOING WITH CONTINUED FLASH FLOODING CONCERNS SATURDAY MORNING...MOSTLY LIKELY OVER THE SOUTHEASTERN THIRD OF THE AREA...AND WILL CONTINUE TO SHIFT EAST AND OUT OF THE AREA BY MIDDAY. SFC BOUNDARY WILL BE DRAPED NEAR THE I-80 CORRIDOR IN THE MORNING...BUT AS SFC LOW PRESSURE MOVES EAST ALONG THE MO/IA BORDER...THE BOUNDARY WILL BE PULLED SOUTHWARD DURING THE DAY. ANOTHER SHORTWAVE IS EXPECTED TO CROSS THE REGION SATURDAY AFTN...BUT WITH THE JUICIEST AIR AND BEST SFC CONVERGENCE SHUNTED SOUTH...THIS WAVE WILL HAVE TO WORK WITH AN ELEVATED FRONTAL ZONE THAT SHOWS UP AROUND 850 MB MOVING SOUTH INTO IOWA. SO THE UPSHOT IS THAT BEYOND THE MORNING RAIN...SHOWERS AND STORMS LATER IN THE DAY ARE SOMEWHAT LESS CERTAIN AND SHOULD BE MORE SCATTERED IN NATURE. WILL HAVE A BRIEF RESPITE FROM THE STORMY WEATHER SATURDAY NIGHT THROUGH SUNDAY NIGHT AS SFC HIGH PRESSURE MOVING SOUTH THROUGH THE CENTRAL PLAINS SUPPRESSES BOUNDARY WELL SOUTH OF OUR AREA. HOWEVER...NEXT SHORTWAVE TROUGH ALOFT IN THE QUASI-ZONAL FLOW COMES SHOOTING ACROSS THE NRN ROCKIES MONDAY...AND BY MONDAY NIGHT AND EARLY TUESDAY WE WILL BE SEEING A PATTERN VERY SIMILAR TO TONIGHT. A SFC TROUGH MOVING INTO CENTRAL IA...WITH SFC LOW PRESSURE DEVELOPING IN AREA OF FRONTOGENESIS OVER THE CENTRAL PLAINS. STRONG WARM ADVECTION AND MOISTURE TRANSPORT OVER A DEVELOPING WARM FRONT...AND UNDER STRONG MID-LEVEL FLOW WILL SET UP ANOTHER NIGHT OF MCS ACTIVITY LIKELY THROUGH CENTRAL/SOUTHERN IA. IF WE GET A LOT OF RAIN TONIGHT...ADDITIONAL RAIN WITH THIS MONDAY NIGHT SYSTEM WILL HEIGHTEN OUR CONCERN FOR FLOODING AGAIN. TIMING OF ALL OF THESE WAVES AND EVENTUALLY PLACEMENT OF BOUNDARIES ALL WILL HAVE A SAY IN THE DAY TO DAY FLUCTUATION IN RAIN CHANCES. IF WE HAD TO PICK ANOTHER TIME OF RELATIVELY LOWER CHANCES OF RAIN...WEDNESDAY INTO THURSDAY LOOKS LIKE A GOOD TIME. WE MAY REALLY WARM UP TOWARD THE END OF THE WEEK AS THE UPPER FLOW AMPLIFIES AND A STRONG RIDGE BUILDS OVER THE MIDWEST. NOT AS EXCITED ABOUT THE LOW POPS LATE THURSDAY INTO FRIDAY AS WARMER AIR ALOFT WILL CONTRIBUTE TO GREATER CONVECTIVE INHIBITION. BUT STRENGTH OF WARM ADVECTION AHEAD OF THE CAP MAY SET OFF STORMS...MAINLY ACROSS NRN AREAS. && .AVIATION... 05/00Z...MAIN THUNDERSTORM ACTIVITY THAT WAS SUPPOSED TO BE ACROSS THE SOUTHEASTERN AREA BY KOTM HAS PUSHED SOUTH OF THE AREA. NEXT FOCUS SHIFTS TO PRECIP/THUNDER CHANCES WITH UPPER LEVEL DISTURBANCE MOVING THROUGH OVERNIGHT. MAIN TRACK OF THIS SYSTEM EXPECTED TO BE ACROSS THE CENTRAL CWA IMPACTING KDSM...KALO...KFOD...AND KOTM MORE THAN KMCW WHICH SHOULD BE JUST TO THE NORTH OF THE WIDESPREAD ACTIVITY WHICH IS EXPECTED TO MOVE THROUGH AFTER 06Z FOR THE MOST PART. OTHERWISE SHOWERS AND MAYBE A FEW ISOLATED THUNDERSTORMS POSSIBLE THROUGH THE DAY SATURDAY...WITH THE MAIN AREA OF INSTABILITY ACROSS THE SOUTH AT KDSM AND KOTM. && .DMX WATCHES/WARNINGS/ADVISORIES... FLASH FLOOD WATCH FROM 9 PM CDT THIS EVENING THROUGH 1 PM CDT SATURDAY AFTERNOON FOR ADAIR-ADAMS-APPANOOSE-AUDUBON-BOONE- CASS-CLARKE-DALLAS-DAVIS-DECATUR-GUTHRIE-JASPER-LUCAS-MADISON- MAHASKA-MARION-MARSHALL-MONROE-POLK-POWESHIEK-RINGGOLD-STORY- TAMA-TAYLOR-UNION-WAPELLO-WARREN-WAYNE. && SHORT TERM...REV LONG TERM...MOYER AVIATION...BEERENDS
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE DES MOINES IA 654 PM CDT FRI JUN 4 2010 IAZ004>007-015>017-023>028-033>039-044>046-051000- 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- 654 PM CDT FRI JUN 4 2010 THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF CENTRAL IOWA. .DAY ONE...TONIGHT THUNDERSTORMS WILL DEVELOP LATER TONIGHT...MAINLY SOUTH OF HIGHWAY 20. LOCALLY HEAVY RAIN WILL BE THE MAIN THREAT...AND AN ISOLATED SEVERE STORM OR TWO IS POSSIBLE...PRODUCING HAIL UP TO QUARTER SIZE AND DAMAGING WIND GUSTS. .DAYS TWO THROUGH SEVEN...SATURDAY THROUGH THURSDAY SCATTERED MAINLY NON SEVERE THUNDERSTORMS ARE POSSIBLE SATURDAY. ADDITIONAL CHANCES FOR THUNDERSTORMS WILL OCCUR MONDAY...TUESDAY AND THURSDAY. THE SEVERE WEATHER POTENTIAL FOR THIS PERIOD WILL BE BETTER DEFINED IN THE COMING DAYS. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION IS NOT ANTICIPATED AT THIS TIME. IAZ047>050-057>062-070>075-081>086-092>097-051000- 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- 654 PM CDT FRI JUN 4 2010 THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF CENTRAL IOWA. .DAY ONE...TONIGHT THUNDERSTORMS WILL REDEVELOP LATER THIS EVENING...AND ARE EXPECTED TO MOVE WEST TO EAST ACROSS THE SOUTHERN HALF OF IOWA THROUGH THE OVERNIGHT HOURS. HEAVY RAINFALL WILL BE THE MAIN THREAT OVERNIGHT...BUT A FEW THUNDERSTORMS COULD ALSO BE SEVERE WITH HAIL TO THE SIZE OF QUARTERS AND DAMAGING WIND GUSTS. A FLASH FLOOD WATCH IS IN EFFECT FOR THE AREA. PLEASE REFER TO THE NATIONAL WEATHER SERVICE WEBSITE AT WEATHER.GOV/DESMOINES FOR FURTHER DETAILS. .DAYS TWO THROUGH SEVEN...SATURDAY THROUGH THURSDAY SCATTERED THUNDERSTORMS ARE POSSIBLE SATURDAY...WITH SOME STORMS IN THE AFTERNOON POSSIBLY BECOMING SEVERE. LARGE HAIL AND DAMAGING WINDS WILL BE THE MAIN THREAT. ADDITIONAL CHANCES FOR THUNDERSTORMS WILL OCCUR MONDAY...TUESDAY AND THURSDAY. THE SEVERE WEATHER POTENTIAL FOR THIS PERIOD WILL BE BETTER DEFINED IN THE COMING DAYS. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION MAY BE NEEDED LATE TONIGHT AND SATURDAY. MJB
The Des Moines radar (KDMX), 147 km away, was scanning. The volume nearest the first event began at 02:21 UTC.
8 flash flood, 5 flood, 4 hail, 1 heavy rain. Local standard time, as filed.
Heavy rain and strong winds occurred with the hail.
Estimated winds of 50 MPH occurred as well.
Strong winds along with heavy rain also reported.
Rainfall of 3.19 inches.
Eight inches of standing water in town. Highway 69 closed due to water on the road and stranded vehicles.
Water covering Highway P27 with ditches full of water.
Manhole cover was lifted due to rushing water at the intersection of Highway 34 and Elm St. Some underpasses submerged on Osage St.
Water over the roads near 150th and Union.
Water over Willow Road near the intersection of 150th St.
Water over Pole Road just north of the intersection of 250th St.
Highway 169 bridge closed just south of the 10 mile post due to scouring of water from the middle fork of the Grand River.
Water on road approximately 3 miles of west of Highway 25 on Highway 34.
Highway 169 underwater.
Water over numerous roads.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Iowa in 2010Every state in 2010This day in weather historyWarnings in Iowa, June 2010
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: 223479, 223480, 223481, 223482, 223534, 223521, 223522, 223523, 223524, 223526, 223529, 223531, 223533, 223714, 223716, 223717, 223718, 223715.