A large thunderstorm complex formed to the south and west of Iowa as an inverted trough moved into western Iowa. The airmass was moderately unstable with around 2000 J/kg of CAPE and lifted indices around -5 C.
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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 large thunderstorm complex formed to the south and west of Iowa as an inverted trough moved into western Iowa. The airmass was moderately unstable with around 2000 J/kg of CAPE and lifted indices around -5 C. There was little shear available however, under 20 kts. Precipitable water values were quite high with 1.5 to 1.75 inches along the inverted trough axis from west central into northwest Iowa. One thunderstorm from the complex to the south pushed into south central Iowa. It produced high winds in the Lamoni area, causing tree limb damage. Along the trough axis, strong thunderstorms formed. Although they were not severe, they did produce very heavy rainfall. A narrow line of 3 to 5 inches of rain extended from Crawford County into Emmet County. In Emmet County at Ringsted, 4.72 inches of rain fell in 2 hours. Three inches fell in Palo Alto County at Emmetsburg in about 90 minutes. Local flooding occurred with standing water blocking one lane of U.S. Highway 18 just east of Emmetsburg.
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 18, 5:30 AM CST, 1 hour 2 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DES MOINES IA 630 AM CDT SAT JUN 18 2011 .UPDATE... UPDATED POPS THROUGH MID MORNING WITH MCS MOVING OUT OF NEBRASKA HOLDING TOGETHER A BIT MORE THAN EXPECTED. STILL EXPECT SYSTEM TO WEAKEN AND DISSIPATE SOMEWHERE ACROSS CENTRAL/SOUTHERN IOWA...SO ONLY HAVE SLIGHT CHANCES POPS ACROSS SOUTHEASTERN CWA WITH HIGHER POPS ACROSS THE SOUTHWEST. .SHORT TERM /TODAY/... FORECAST SHAPING UP SIMILAR TO PAST DAYS WITH SOUTHWEST FLOW ALOFT AND A SFC LOW SITUATED TO THE SOUTHWEST OF THE AREA WITH A SFC TROUGH AXIS EXTENDING NORTHEASTWARD INTO CENTRAL IA/SC MN. MCS OVER SE NE/NE KS EXPECTED TO WEAKEN AS IT PUSHES EASTWARD...BUT EXPECT IT TO MAKE IT TO THE SOUTHWESTERN CWA OVER THE NEXT 3 TO 4 HOURS. NOT A LOT OF SHEAR/INSTABILITY ACROSS THE CWA WITH MOISTURE TRANSPORT ORIENTED FURTHER SOUTH INTO MISSOURI. THEREFORE EXPECT MCS TO WEAKEN EVEN FURTHER AND BE CONFINED TO EXTREME SOUTHERN IOWA IF IT MAINTAINS ITSELF ENOUGH TO MAKE IT ALL THE WAY ACROSS THE CWA. OTHERWISE STRONGER SHORTWAVE ALOFT CURRENTLY OVER THE EASTERN ROCKIES TO MOVE NORTHEASTWARD INTO THE REGION LATE THIS AFTERNOON INTO TONIGHT. TROUGH AXIS TO RETREAT BACK TO THE WEST/NORTHWEST AS WAA STRENGTHENS AND WINDS BECOME MORE SOUTHEAST TO SOUTHERLY WITH MOISTURE ADVECTING NORTHWARD. DEWPOINTS EXPECTED TO CLIMB INTO THE LOWER TO MID 70S ACROSS THE AREA BY THIS AFTERNOON WITH CONVECTION EXPECTED TO DEVELOP JUST TO THE WEST OF THE CWA AS THE SHORTWAVE PUSHES INTO ERN NE/NE KS BY 00Z. THIS ACTIVITY COULD PUSH INTO THE FAR SOUTHWESTERN CWA BY LATE AFTERNOON...BUT EXPECT MAJORITY OF ACTIVITY TO BE INTO TONIGHT. HAVE ANOTHER WEAK BOUNDARY SITUATED ACROSS THE NORTHEASTERN CWA THIS AFTERNOON AND 00Z WRF TRYING TO DEVELOP SOME ISOLATED ACTIVITY IN THE VICINITY OF KMCW BY LATE AFTERNOON AS WELL. THEREFORE DO HAVE SLIGHT CHANCES FOR THE NE TOO. TEMPERATURES ALOFT SLIGHTLY COOLER THAN IN PREVIOUS DAYS...SO KEPT TEMPS A BIT COOLER IN THE 80 TO 85 RANGE AS WELL. .LONG TERM /SATURDAY THROUGH FRIDAY/... NOT MUCH CHANGE IN THE PREVIOUS THINKING WITH QUASI-ACTIVE WEATHER EXPECTED THROUGH MID WEEK. MODELS HAVE BUILT FAIRLY DECENT CONSENSUS ON SHORTWAVE PASSING THROUGH THE STATE TONIGHT. THIS WAVE ALONG WITH SFC LOW MOVING ACRS THE STATE SHOULD BE SUFFICIENT FOR CONVECTION TONIGHT OVER MUCH OF CENTRAL IOWA. SOME SEVERE STORMS REMAIN POSSIBLE ALONG WITH SPOTTY HEAVY RAINFALL BUT WAVE REMAIN FAIRLY PROGRESSIVE KEEPING PCPN DURATION LIMITED. SOME BREAK IN THE STORMS ON SUNDAY WITH SUBSIDENCE BEHIND THE DEPARTING WAVE. HOWEVER...NEXT VIGOROUS SHORTWAVE WILL ROUND BASE OF WESTERN TROF WITH WAA AND INCREASING THETA-E ADVECTION INTO SUNDAY NIGHT. THIS WILL INCREASE CHANCES OF THUNDERSTORMS BY LATE SUNDAY NIGHT AS WARM FRONT PUSHES NORTHWARD INTO THE STATE. BOTH GFS AND EURO STALL THIS FRONT IN IOWA INTO EARLY NEXT WEEK. THEREFORE...SEEMS REASONABLE TO EXPECT SOME CONVECTION IN CENTRAL IA DURING THIS TIME...WITH BEST CHANCES IN THE NORTH WHERE CAP WILL LIKELY BE WEAKEST AND NOCTURNAL LLJ WILL BREAK IN THIS AREA. SEVERE WEATHER THREAT WILL ALSO BE A CONCERN DURING THIS TIME WITH INCREASED SHEAR AND RELATIVELY STRONG INSTABILITY LEADING TO MULTIPLE MODES OF SEVERE WEATHER MONDAY AFTERNOON INTO TUESDAY NIGHT. HEAVY RAIN POSSIBILITIES WILL ALSO BE PREVALENT AS PWATS IN AND AROUND 1.5 TO 1.75 INCHES. TEMPERATURES TO BE VERY WARM SOUTH OF THE FRONT WITH HIGHS NEAR 90 WITH COOLER READING NORTH DUE TO COOLER EASTERLY FLOW AND MORE CLOUDS. THIS TEMPERATURE CUTOFF WILL ALL BE IN PLACEMENT OF THE FRONT WHICH IS DIFFICULT TO PINPOINT AT THIS TIME. SOME DECREASE IN PCPN THREAT INTO WEDNESDAY AS UPPER LOW GRADUALLY PULLS AWAY WITH DRY WEATHER INTO THURSDAY. && .AVIATION...18/12Z TRICKY FORECAST THIS MORNING WITH AREA OF STORMS MOVING INTO WESTERN IOWA. DID NOT INCLUDE PRECIPITATION WITH THIS AREA OF STORMS AT KDSM OR KFOD AS SYSTEM IS EXPECTED TO WEAKEN/DISSIPATE AS IT PUSHES EASTWARD. WILL HAVE TO MONITOR AS THERE IS A POSSIBILITY IT COULD HOLD TOGETHER LONG ENOUGH TO REACH KDSM OR KFOD. OTHERWISE BETTER CHANCES FOR WIDESPREAD PRECIPITATION WITH A STRONG UPPER LEVEL SYSTEM EXPECTED TO MOVE THROUGH THE AREA TONIGHT. CIGS EXPECTED TO LOWER TO VERY LOW VFR CATEGORY AND POSSIBLY INTO THE MVFR CATEGORY WITH THUNDERSTORMS TONIGHT. && .DMX WATCHES/WARNINGS/ADVISORIES...NONE. && SHORT TERM...BEERENDS LONG TERM...COGIL AVIATION...BEERENDS
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE DES MOINES IA 534 AM CDT SAT JUN 18 2011 IAZ004-005-024-191100- EMMET-KOSSUTH-HUMBOLDT- 534 AM CDT SAT JUN 18 2011 THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF CENTRAL IOWA. .DAY ONE...TODAY AND TONIGHT A FEW ISOLATED NON SEVERE THUNDERSTORMS WILL BE POSSIBLE THIS MORNING. MORE NUMEROUS THUNDERSTORMS ARE EXPECTED TONIGHT WITH STRONG WIND GUSTS...SOME MARGINALLY LARGE HAIL APPROACHING ONE INCH ALONG WITH HEAVY RAINFALL. RIVER FLOOD WARNINGS ARE IN EFFECT FOR PORTIONS OF THE UPPER DES MOINES RIVER BASIN. PLEASE REFER TO THE NATIONAL WEATHER SERVICE WEBSITE AT WEATHER.GOV/DESMOINES FOR FURTHER DETAILS. .DAYS TWO THROUGH SEVEN...SUNDAY THROUGH FRIDAY NUMEROUS CHANCES FOR THUNDERSTORMS ARE POSSIBLE FROM SUNDAY NIGHT INTO TUESDAY NIGHT. CONFIDENCE IS INCREASING FOR SIGNIFICANT SEVERE WEATHER ON MONDAY AFTERNOON AND EVENING WITH LARGE HAIL...DAMAGING WINDS AND A FEW TORNADOES. SEVERE WEATHER WILL ALSO BE POSSIBLE INTO TUESDAY. HEAVY RAIN IS ALSO EXPECTED DURING THIS TIME WHICH MAY PROLONG AND ENHANCE ONGOING RIVER FLOODING. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION IS APPEARING LIKELY INTO EARLY NEXT WEEK. IAZ006-007-015>017-023-025>028-035>039-049-050-191100- WINNEBAGO-WORTH-PALO ALTO-HANCOCK-CERRO GORDO-POCAHONTAS-WRIGHT- FRANKLIN-BUTLER-BREMER-WEBSTER-HAMILTON-HARDIN-GRUNDY-BLACK HAWK- MARSHALL-TAMA- 534 AM CDT SAT JUN 18 2011 THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF CENTRAL IOWA. .DAY ONE...TODAY AND TONIGHT A FEW ISOLATED NON SEVERE THUNDERSTORMS WILL BE POSSIBLE THIS MORNING. MORE NUMEROUS THUNDERSTORMS ARE EXPECTED TONIGHT WITH STRONG WIND GUSTS...SOME MARGINALLY LARGE HAIL APPROACHING ONE INCH ALONG WITH HEAVY RAINFALL. .DAYS TWO THROUGH SEVEN...SUNDAY THROUGH FRIDAY NUMEROUS CHANCES FOR THUNDERSTORMS ARE POSSIBLE FROM SUNDAY NIGHT INTO TUESDAY NIGHT. CONFIDENCE IS INCREASING FOR SIGNIFICANT SEVERE WEATHER ON MONDAY AFTERNOON AND EVENING WITH LARGE HAIL...DAMAGING WINDS AND A FEW TORNADOES. SEVERE WEATHER WILL ALSO BE POSSIBLE INTO TUESDAY. HEAVY RAIN IS ALSO EXPECTED DURING THIS TIME. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION MAY BE NEEDED TONIGHT AND IS APPEARING LIKELY INTO EARLY NEXT WEEK...ESPECIALLY MONDAY AFTERNOON AND EVENING. IAZ033-034-044>048-057>062-070>075-081>086-092>097-191100- SAC-CALHOUN-CRAWFORD-CARROLL-GREENE-BOONE-STORY-AUDUBON-GUTHRIE- DALLAS-POLK-JASPER-POWESHIEK-CASS-ADAIR-MADISON-WARREN-MARION- MAHASKA-ADAMS-UNION-CLARKE-LUCAS-MONROE-WAPELLO-TAYLOR-RINGGOLD- DECATUR-WAYNE-APPANOOSE-DAVIS- 534 AM CDT SAT JUN 18 2011 THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF CENTRAL IOWA. .DAY ONE...TODAY AND TONIGHT SCATTERED THUNDERSTORMS WILL MOVE ACROSS PORTION OF CENTRAL IOWA THIS MORNING. A FEW WIND GUSTS MAY APPROACH 60 MPH WITH THESE STORMS ALONG WITH SOME SMALL HAIL. ADDITIONAL THUNDERSTORMS ARE EXPECTED LATE THIS AFTERNOON INTO THIS EVENING. THESE STORMS MAY ALSO PRODUCE LARGE HAIL AND DAMAGING WINDS. .DAYS TWO THROUGH SEVEN...SUNDAY THROUGH FRIDAY NUMEROUS CHANCES FOR THUNDERSTORMS ARE POSSIBLE FROM SUNDAY NIGHT INTO TUESDAY NIGHT. CONFIDENCE IS INCREASING FOR SIGNIFICANT SEVERE WEATHER ON MONDAY AFTERNOON AND EVENING WITH LARGE HAIL...DAMAGING WINDS AND A FEW TORNADOES...ESPECIALLY NORTH OF HIGHWAY 30. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION MAY BE NEEDED LATER TODAY AND AGAIN INTO EARLY NEXT WEEK. CC
SPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE DES MOINES IA 646 AM CDT SAT JUN 18 2011 IAZ092>094-181300- TAYLOR-RINGGOLD-DECATUR- INCLUDING THE CITIES OF...BEDFORD...MOUNT AYR...LEON 646 AM CDT SAT JUN 18 2011 ...THUNDERSTORMS WITH GUSTY WINDS AND HEAVY RAIN... A LINE OF THUNDERSTORMS WILL BE MOVING INTO FAR SOUTHERN IOWA. THESE STORMS ARE CAPABLE OF PRODUCING WINDS OF 40 TO 50 MPH...AND HEAVY DOWNPOURS. JB
The Des Moines radar (KDMX), 125 km away, was scanning. The volume nearest the first event began at 12:32 UTC.
2 heavy rain, 1 thunderstorm wind. Local standard time, as filed.
Two large tree branches down on the north side of town. One was down across the road.
Observer reported 4.72 inches of rain in the past 2 hours, in which 4.25 inches of the rain fell in less than 90 minutes from 0830 to 0954 CST.
Observer reported 2.96 inches of rain in 90 minutes.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Iowa in 2011Every state in 2011This day in weather historyWarnings in Iowa, June 2011
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: 300778, 300782, 300784.