A trough of low pressure lifted north into Iowa during the day on the 24th. A weak short wave lifted northeast across the boundary.
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 trough of low pressure lifted north into Iowa during the day on the 24th. A weak short wave lifted northeast across the boundary. Strong thunderstorms fired to the south of Iowa and became enhanced as they interacted with the boundary. The atmosphere became moderately unstable with CAPE around 1000 to 1500 J/kg and lifted indices fell to around -6 C. The CAPE in the hail producing level was not all that high, but the freezing level was only 11,000 feet. Numerous reports of pea to slightly larger size hail were received. Downdraft CAPE was in the 700 to 1000 J/kg range. Shear was relatively weak with 20 to 30 kts of shear available. As the line lifted through central Iowa, which was during peak heating, it intensified. There were numerous reports of 50 MPH winds all along the line as it extended from west central, through central, into southeast Iowa. One segment of the line became severe and produced 60 to 70 MPH winds at several locations in central Iowa. A few funnel clouds were observed as well. A grain bin and shed were damaged south of Jamaica in Guthrie County. Scattered tree and outbuilding damage occurred across Dallas, Polk, and into Marshall Counties. A exit sign was blown down by the high winds south of Woodward in Dallas County. Lightning struck an accounting building near Charition, blowing out bricks from the building and damaging some electrical components.
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 May 24, 12:08 PM CST, 1 hour 37 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DES MOINES IA 108 PM CDT TUE MAY 24 2011 ...UPDATED FOR THE 18Z AVIATION DISCUSSION... .SHORT TERM /TODAY/... STRONG SHORT WAVE OVER ARIZONA THIS MORNING WILL LIFT INTO WRN KANSAS BY THIS AFTERNOON AND WILL DEEPEN INTO A CLOSED SYSTEM. SFC LOW PRESSURE OVER THE TX AND OK PANHANDLES WILL DEEPEN AS WELL AS THE UPPER LEVEL SYSTEM APPROACHES. THE LOW PRESSURE WILL LIFT NORTHEAST INTO KANSAS TODAY. THE COMBINATION OF THE TWO ALONG WITH DEEP MOISTURE LIFTING FROM THE GULF HAS LED TO A HIGH RISK FOR SEVERE WEATHER OVER PORTIONS OF OK AND KS. REFER TO SWODY1 FOR FURTHER DETAILS REGARDING THIS. THE QG FORCING ASSOCIATED WITH THE UPPER LEVEL SYSTEM WILL REACH FAR SW IA BY LATE THIS AFTERNOON ALONG WITH ASSOCIATED UPPER LEVEL DIVERGENCE. THIS FORCING MAY BE ENOUGH TO FIRE A FEW SFC BASED STORMS BEFORE 00Z OVER THE SW. A FEW ELEVATED STORMS MAY OCCUR FARTHER TO THE NORTH EARLIER IN THE DAY ALONG THE MID LEVEL BOUNDARY. THE SEVERE WEATHER POTENTIAL THROUGH 00Z WILL BE RELEGATED TO THE SOUTHWEST AS THE BETTER FORCING LIFTS TO THE NORTH. HIGH TEMPERATURES TODAY WILL BE IN THE MID TO UPPER 70S MOST LOCATIONS WITH THE EXCEPTION OF THE NORTH WHERE IT WILL BE SLIGHTLY COOLER. .LONG TERM /TONIGHT THROUGH MONDAY/... FOCUS IN THE EXTENDED MAINLY ON FIRST COUPLE OF DAYS...WITH THUNDERSTORM ACTIVITY EXPECTED TONIGHT INTO WEDNESDAY. UPPER LOW TO BECOME STACKED OVER NC KANSAS BY LATE TONIGHT...WITH ENERGY ROTATING NORTHEASTWARD THROUGH IOWA TONIGHT. DECENT INSTABILITY AND DEEP LAYER SHEAR TO SUPPORT ORGANIZED STORMS...WITH ONGOING ACTIVITY EXPECTED TO LIFT NORTHEASTWARD/NORTHWARD THROUGH THE CWA TONIGHT. BEST CHANCES ACROSS SOUTHWEST THIS EVENING WITH ACTIVITY SPREADING ACROSS ENTIRE CWA LATE TONIGHT. ACTIVITY EXPECTED TO BE ELEVATED...BUT MAY HAVE SOME SURFACE-BASED STORMS AS SFC BOUNDARY CREEPS INTO SOUTHERN IOWA LATE TONIGHT. STRONG LOW LEVEL SHEAR PARAMETERS AS WELL ACROSS THE SOUTHERN THIRD OF THE STATE RESULTING IN AN ISOLATED TORNADO THREAT...ALBEIT STRONGEST TORNADO THREATS TO REMAIN WELL SOUTHWEST OF THE AREA CLOSER TO THE CENTER OF THE SFC LOW. STILL A THREAT FOR DAMAGING WINDS/LARGE HAIL WITH THE DECENT SHEAR/INSTABILITY ACROSS THE AREA TONIGHT. AS FOR WEDNESDAY...UPPER LOW/SFC LOW SLOWLY MEANDER EAST SOUTHEASTWARD WITH ADDITIONAL WAVES OF ENERGY LIFTING THROUGH THE CWA. THIS WILL BRING ALLOW PRECIPITATION CHANCES TO CONTINUE INTO WEDNESDAY/WEDNESDAY NIGHT WITH DECREASING INSTABILITY ACROSS THE NORTHERN CWA THROUGH THE DAY. SFC FRONT LIFTS INTO EXTREME SOUTHERN IOWA BY WEDNESDAY AFTERNOON WITH ADDITIONAL SEVERE THUNDERSTORM POTENTIAL MAINLY TO THE SOUTHEAST OF THE AREA. SOME LIGHT LINGERING SHOWERS POSSIBLY EXTREME SOUTHEAST THURSDAY...OTHERWISE DRY CONDITIONS EXPECTED THURSDAY INTO THURSDAY NIGHT. MODELS THIS MORE UNCERTAIN TOWARD THE END OF THE WEEK INTO THE WEEKEND. A WARM FRONT TO LIFT NORTHWARD FRIDAY INTO SATURDAY...WITH THE BOTH MODELS SETTING UP A FRONTAL BOUNDARY ACROSS THE STATE SUNDAY INTO MONDAY WITH SOUTHWEST FLOW ALOFT. THIS SCENARIO WOULD LEAD TO ANOTHER ACTIVE PATTERN EXPECTED FOR LATE IN THE WEEKEND AND THE START OF NEXT WEEK. AS FOR TEMPERATURES...EXPECT A COOLING TREND BEHIND THE SYSTEM MOVING THROUGH TONIGHT INTO WEDNESDAY...WITH A WARMING TREND FOR THE WEEKEND INTO EARLY NEXT WEEK. && .AVIATION...24/18Z SFC LOW OVER KS HAS AN ASSOCIATED WARM FRONT LIFTING INTO SOUTHERN IOWA...MAINLY ALONG THE I-80 CORRIDOR. A FAIRLY COMPLEX SITUATION LOOKS TO BE UNDERWAY AS A WAKE LOW BEHIND THESE LINE OF STORMS FORMS. THIS MAY PUSH THE FRONT FURTHER NORTH AND WEST. STORMS WILL LIFT ACROSS THE TAF LOCATIONS THROUGH 02Z. STRONG WIND GUSTS TO 45KTS ARE POSSIBLE WITH SOME STORMS ESPECIALLY ACROSS THE SOUTHERN TAF LOCATIONS. THIS AREA SHOULD LIFT ACROSS THE TAF LOCATIONS THROUGH 02Z FOLLOWED BY A BRIEF RESPITE. A SECOND ROUND OF STORMS WILL ENTER FROM THE SOUTHWEST AFT 03Z AND PERSIST THROUGH THE REMAINDER OF THE FORECAST AREA. HEAVY RAIN WILL BE POSSIBLE ACROSS SOUTHERN TAF LOCATIONS. MVFR CONDITIONS ARE FORECAST WITH LOCAL IFR CONDITIONS IN THUNDERSTORMS. SFC WIND WILL BE SE 15-25KTS BUT WITH MUCH STRONGER WIND GUSTS NI STORMS...ON THE ORDER OF 35-45KTS. && .DMX WATCHES/WARNINGS/ADVISORIES...NONE. && SHORT TERM...DONAVON LONG TERM...BEERENDS AVIATION...FAB
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE DES MOINES IA 1109 AM CDT TUE MAY 24 2011 IAZ057-058-070>072-081>084-092>095-251615- AUDUBON-GUTHRIE-CASS-ADAIR-MADISON-ADAMS-UNION-CLARKE-LUCAS-TAYLOR- RINGGOLD-DECATUR-WAYNE- 1109 AM CDT TUE MAY 24 2011 THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF CENTRAL IOWA. .DAY ONE...TODAY AND TONIGHT THUNDERSTORMS ARE EXPECTED TO MOVE ACROSS THE REGION IOWA THIS AFTERNOON. ANOTHER ROUND OF THUNDERSTORMS WILL SPREAD NORTHEAST INTO THE AREA THIS EVENING AND TONIGHT. THERE IS A SLIGHT RISK OF SEVERE WEATHER WITH THE THUNDERSTORM ACTIVITY...MAINLY DURING THE EVENING AND LATE NIGHT HOURS. LARGE HAIL AND DAMAGING WINDS ARE THE PRIMARY SEVERE THREATS...HOWEVER AN ISOLATED TORNADO IS ALSO POSSIBLE. RAINFALL MAY BE HEAVY AT TIMES WITH THE STRONGER STORMS LATE TONIGHT AND EARLY WEDNESDAY. .DAYS TWO THROUGH SEVEN...WEDNESDAY THROUGH MONDAY THUNDERSTORM CHANCES CONTINUE INTO WEDNESDAY AND WEDNESDAY NIGHT. AT THIS TIME THE SEVERE THREAT APPEARS MARGINAL...AS THE MAIN THREAT FOR SEVERE WEATHER HAS SHIFTED INTO SOUTHEAST IOWA. HEAVY RAINFALL AND ISOLATED FLASH FLOODING...MAY BE POSSIBLE WITH THE THUNDERSTORM ACTIVITY WEDNESDAY INTO WEDNESDAY NIGHT. THE CHANCE FOR THUNDERSTORMS RETURNS TO THE AREA FOR FRIDAY INTO FRIDAY NIGHT...AND ACROSS PORTIONS OF THE AREA FOR THE WEEKEND. AT THIS TIME THE THREAT FOR SEVERE WEATHER APPEARS LOW FRIDAY INTO FRIDAY NIGHT. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION MAY BE NEEDED LATE THIS EVENING INTO TONIGHT. IAZ033>038-044>050-059>062-073>075-085-086-096-097-251615- SAC-CALHOUN-WEBSTER-HAMILTON-HARDIN-GRUNDY-CRAWFORD-CARROLL-GREENE- BOONE-STORY-MARSHALL-TAMA-DALLAS-POLK-JASPER-POWESHIEK-WARREN-MARION- MAHASKA-MONROE-WAPELLO-APPANOOSE-DAVIS- 1109 AM CDT TUE MAY 24 2011 THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF CENTRAL IOWA. .DAY ONE...TODAY AND TONIGHT THUNDERSTORMS ARE EXPECTED TO MOVE ACROSS THE OUTLOOK AREA LATE THIS AFTERNOON. A SECOND AREA OF THUNDERSTORMS WILL SPREAD NORTHEAST ACROSS THE AREA THIS EVENING AND TONIGHT. THERE IS A SLIGHT RISK OF SEVERE WEATHER WITH THE THUNDERSTORM ACTIVITY MAINLY THIS EVENING AND TONIGHT. LARGE HAIL AND DAMAGING WINDS ARE THE PRIMARY SEVERE THREATS...HOWEVER AN ISOLATED TORNADO IS ALSO POSSIBLE MAINLY ALONG AND SOUTH OF INTERSTATE 80. RAINFALL MAY BE HEAVY AT TIMES WITH THE STRONGER STORMS TONIGHT AND EARLY WEDNESDAY. .DAYS TWO THROUGH SEVEN...WEDNESDAY THROUGH MONDAY THUNDERSTORM CHANCES CONTINUE INTO WEDNESDAY AND WEDNESDAY NIGHT. AT THIS TIME THE SEVERE THREAT APPEARS MARGINAL...AS THE MAIN THREAT FOR SEVERE WEATHER HAS SHIFTED INTO SOUTHEAST IOWA. HEAVY RAINFALL AND ISOLATED FLASH FLOODING...MAY BE POSSIBLE WITH THE THUNDERSTORM ACTIVITY WEDNESDAY INTO WEDNESDAY NIGHT. THE CHANCE FOR THUNDERSTORMS RETURNS TO THE AREA FOR FRIDAY INTO FRIDAY NIGHT...AND ACROSS PORTIONS OF THE AREA FOR THE WEEKEND. AT THIS TIME THE THREAT FOR SEVERE WEATHER APPEARS LOW FRIDAY INTO FRIDAY NIGHT. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION MAY BE NEEDED LATE THIS AFTERNOON INTO TONIGHT. IAZ006-007-015>017-023-025>028-039-251615- WINNEBAGO-WORTH-PALO ALTO-HANCOCK-CERRO GORDO-POCAHONTAS-WRIGHT- FRANKLIN-BUTLER-BREMER-BLACK HAWK- 1109 AM CDT TUE MAY 24 2011 THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF CENTRAL IOWA. .DAY ONE...TODAY AND TONIGHT THERE IS A THREAT FOR AN ISOLATED THUNDERSTORM LATE THIS AFTERNOON...WITH BETTER CHANCES INTO TONIGHT. AT THIS TIME THE MAIN THREAT FOR SEVERE WEATHER IS SOUTH OF THE AREA...HOWEVER AN ISOLATED SEVERE STORM MAY STILL BE POSSIBLE. LARGE HAIL AND DAMAGING WINDS WOULD BE THE MAIN SEVERE THREATS WITH ANY OF THE STRONGER STORMS. .DAYS TWO THROUGH SEVEN...WEDNESDAY THROUGH MONDAY THUNDERSTORM CHANCES CONTINUE WEDNESDAY AND AGAIN FRIDAY INTO THE WEEKEND. AT THIS TIME THE SEVERE THREAT APPEARS MARGINAL. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION IS NOT ANTICIPATED AT THIS TIME. IAZ004-005-024-251615- EMMET-KOSSUTH-HUMBOLDT- 1109 AM CDT TUE MAY 24 2011 THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF CENTRAL IOWA. .DAY ONE...TODAY AND TONIGHT RIVER FLOOD WARNINGS REMAIN IN EFFECT FOR THE WEST AND EAST FORKS OF THE DES MOINES RIVER. PLEASE REFER TO THE NATIONAL WEATHER SERVICE WEBSITE AT WEATHER.GOV/DESMOINES FOR FURTHER DETAILS. THERE IS A THREAT FOR AN ISOLATED THUNDERSTORM LATE THIS AFTERNOON...WITH BETTER CHANCES INTO TONIGHT. AT THIS TIME THE MAIN THREAT FOR SEVERE WEATHER IS SOUTH OF THE AREA...HOWEVER AN ISOLATED SEVERE STORM MAY STILL BE POSSIBLE. LARGE HAIL AND DAMAGING WINDS WOULD BE THE MAIN SEVERE THREATS WITH ANY OF THE STRONGER STORMS. .DAYS TWO THROUGH SEVEN...WEDNESDAY THROUGH MONDAY THUNDERSTORM CHANCES CONTINUE WEDNESDAY AND AGAIN FRIDAY INTO THE WEEKEND. AT THIS TIME THE SEVERE THREAT APPEARS MARGINAL. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION IS NOT ANTICIPATED AT THIS TIME. REV
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE DES MOINES IA
1022 AM CDT TUE MAY 24 2011
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0325 PM HAIL SUMNER 42.85N 92.10W
05/22/2011 E2.00 INCH BREMER IA UTILITY COMPANY
UTILITY WORKERS REPORT. EAST SIDE OF SUMNER.
&&
DEROYSPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE DES MOINES IA 1253 PM CDT TUE MAY 24 2011 IAZ070-071-081-082-092-093-241900- CASS-ADAIR-ADAMS-UNION-TAYLOR-RINGGOLD- INCLUDING THE CITIES OF...ATLANTIC...GREENFIELD...CORNING... CRESTON...BEDFORD...MOUNT AYR 1253 PM CDT TUE MAY 24 2011 ...STRONG THUNDERSTORMS WILL MOVE ACROSS SOUTHWEST IOWA THROUGH 2 PM... A COMPLEX OF STORMS IS LIFTING NORTHEAST AT 30 MPH OUT OF SOUTHEAST NEBRASKA AND NORTHWEST MISSOURI INTO SOUTHWEST IOWA. THESE STORMS HAVE THE POTENTIAL TO PRODUCE UP TO NICKEL HAIL...LOCALLY HEAVY RAINFALL AND WIND GUSTS BETWEEN 50 AND 55 MPH. BE PREPARED TO MOVE INDOORS AS THE STORMS APPROACH AND EXPECT STRONG WIND GUSTS. FAB
SPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE DES MOINES IA 203 PM CDT TUE MAY 24 2011 IAZ044>047-057>060-072-073-083-084-094-095-242030- CRAWFORD-CARROLL-GREENE-BOONE-AUDUBON-GUTHRIE-DALLAS-POLK-MADISON- WARREN-CLARKE-LUCAS-DECATUR-WAYNE- INCLUDING THE CITIES OF...DENISON...CARROLL...JEFFERSON...BOONE... AUDUBON...GUTHRIE CENTER...ADEL...DES MOINES...WINTERSET... INDIANOLA...OSCEOLA...CHARITON...LEON...CORYDON 203 PM CDT TUE MAY 24 2011 ...STRONG THUNDERSTORMS WILL MOVE ACROSS SOUTHWEST INTO CENTRAL IOWA THROUGH 330 PM... A COMPLEX OF STORMS IS LIFTING OUT OF SOUTHWEST IOWA TO THE NORTHEAST AT 30 MPH. THESE STORMS HAVE TO POTENTIAL TO PRODUCE LOCALLY HEAVY RAINFALL. WIND GUSTS TO 50 MPH ARE POSSIBLE WITH THE STORMS. THE POTENTIAL FOR NON THUNDERSTORM WIND GUST BETWEEN 50 AND 55 MPH ARE ALSO POSSIBLE JUST AFTER THE STORMS PASS. BE PREPARED FOR STRONG WIND GUSTS FOR THE NEXT COUPLE OF HOURS. FAB
SPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE DES MOINES IA 242 PM CDT TUE MAY 24 2011 IAZ033>037-044>048-057>061-072>075-083>086-094>097-242145- SAC-CALHOUN-WEBSTER-HAMILTON-HARDIN-CRAWFORD-CARROLL-GREENE-BOONE- STORY-AUDUBON-GUTHRIE-DALLAS-POLK-JASPER-MADISON-WARREN-MARION- MAHASKA-CLARKE-LUCAS-MONROE-WAPELLO-DECATUR-WAYNE-APPANOOSE-DAVIS- INCLUDING THE CITIES OF...SAC CITY...ROCKWELL CITY...FORT DODGE... WEBSTER CITY...ELDORA...DENISON...CARROLL...JEFFERSON...BOONE... AMES...AUDUBON...GUTHRIE CENTER...ADEL...DES MOINES...NEWTON... WINTERSET...INDIANOLA...KNOXVILLE...OSKALOOSA...OSCEOLA... CHARITON...ALBIA...OTTUMWA...LEON...CORYDON...CENTERVILLE... BLOOMFIELD 242 PM CDT TUE MAY 24 2011 ...STRONG THUNDERSTORMS WILL MOVE ACROSS SOUTHWEST IOWA THROUGH 4 PM... A COMPLEX OF STORMS IS LIFTING NORTHEAST AT 30 MPH ACROSS CENTRAL IOWA. AT 240 PM THE STORMS WERE LIFTING IN AN ARC FROM THE HIGHWAY 30 CORRIDOR ACROSS THE WEST TO ALONG THE INTERSTATE 35 CORRIDOR DOWN BY DECATUR COUNTY. THESE STORMS WILL LIFT INTO EASTERN AND NORTHERN IOWA BY 6 PM BUT AS THEY PASS THEY HAVE THE POTENTIAL TO PRODUCE UP TO NICKEL HAIL... LOCALLY HEAVY RAINFALL AND WIND GUSTS BETWEEN 50 AND 55 MPH. THE POTENTIAL FOR NON THUNDERSTORM WIND GUST BETWEEN 50 AND 55 MPH ARE ALSO POSSIBLE JUST AFTER THE STORMS PASS. BE PREPARED FOR STRONG WIND GUSTS FOR THE NEXT COUPLE OF HOURS. FAB
The Des Moines radar (KDMX), 49 km away, was scanning. The volume nearest the first event began at 19:46 UTC.
10 thunderstorm wind, 1 lightning. Local standard time, as filed.
Grain bin and shed damaged by straight line winds with estimated gusts near 70 MPH along Wood Road.
Trained spotter reports 55 to 60 MPH winds at the WalMart in Grimes. Four inch diameter trees snapped.
Damage to a large wooden railing on the front porch of a house. Winds estimated up to 60 MPH.
AWOS measurement at the Perry Airport.
Highway exit sign was blown down at highway 210 and highway 141.
Power lines down due to high winds.
Six inch tree branch and 14 inch tree branch blown down.
Several three inch diameter tree limbs down at the DMACC campus in Ankeny.
Emergency Manager reported wind gust of 60 MPH.
Law enforcement reports 60 MPH winds.
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, May 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: 293465, 293464, 293462, 293461, 293469, 293466, 293475, 303550, 293467, 293463, 293468.