A cold front moved slowly into Iowa from the northwest as an upper level shortwave lifted northeast across the area. The atmosphere was marginally unstable with afternoon highs reaching the mid to upper 80s and dewpoint readings in the upper 50s to low 60s.
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 cold front moved slowly into Iowa from the northwest as an upper level shortwave lifted northeast across the area. The atmosphere was marginally unstable with afternoon highs reaching the mid to upper 80s and dewpoint readings in the upper 50s to low 60s. The lifted index was just 0 to -3 C by early evening. CAPE was limited to around 1000 J/kg. With relatively dry air in place, downdraft CAPE was around 1200 J/kg. CAPE in the -10 to -30 C layer of the atmosphere was between 200 and 400 J/kg, but the freezing level was around 15,000 feet. There was sufficient shear available with 50 to 55 kts present. A narrow area of higher precipitable water values moved into the state by evening, with 1.25 to 1.5 inches available. A line of thunderstorms moved into west central and northwest Iowa during the early evening. One of the storms produced severe weather with quarter size hail in Sac County. High winds also occurred with damage from east of Odebolt to Early to Lake View. Numerous power poles were blown down, roofs were taken from outbuildings including turkey and hog confinements. Boats were thrown at a dealership. In the Lake View area, a tree fell and killed a dog. There were no other injuries. Prior to the storms moving into Sac County, wind damage was reported in Crawford County in the Ricketts area. Several trees were blown down.
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 23, 5:52 PM CST, 18 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DES MOINES IA 652 PM CDT WED MAY 23 2012 .SHORT TERM /TONIGHT/... SFC TROUGH AXIS SITUATED TO THE WEST ACROSS ERN NE INTO SW MN...WITH SFC COLD FRONT IN THE SAME VICINITY. MOISTURE CONTINUES TO PUSH NORTHWARD IN STRONG SOUTHERLY FLOW AHEAD OF THE FRONT...WITH DEWPOINTS INTO THE UPPER 50S TO NEAR 60 ACROSS WESTERN IOWA INTO EASTERN NE. INSTABILITY INCREASING ACROSS THE CWA WITH NORTHERN CWA ALREADY SHOWING UNCAPPED ON THE SPC MESO PAGE...HOWEVER FORCING STILL LINGERING BACK TO THE WEST WITH SHORTWAVE JUST ROUNDING THE BASE OF THE TROUGH ACROSS THE WESTERN HIGH PLAINS. THEREFORE AS THIS WAVE APPROACHES AND MOVES EAST NORTHEAST...STORMS EXPECTED TO FIRE ALONG THE SFC COLD FRONT OFF TO THE WEST OF THE CWA AND SPREAD INTO CWA THIS EVENING. THEREFORE KEPT A SLIGHT CHANCE OF STORMS THROUGH 00Z...WITH MUCH GREATER CHANCES ACROSS FAR WESTERN THIRD THIS EVENING AND SPREADING ACROSS NORTHWESTERN HALF TONIGHT. UNIDIRECTIONAL SHEAR PROFILE SUGGESTS MAINLY DAMAGING WIND AND HAIL THREAT WITH ANY OF THE STRONGER STORMS WITH SEVERE POTENTIAL. ALSO STORM MOTION COULD ALLOW FOR TRAINING STORMS ALONG AND JUST AHEAD OF THE FRONTAL BOUNDARY. THEREFORE POTENTIAL EXISTS FOR HEAVY RAIN AS WELL. FLASH FLOOD GUIDANCE IN THE 3 TO 4 INCH RANGE FOR MUCH OF THE AREA WITH DRIER SOIL CONDITIONS. THEREFORE WILL NOT ISSUE A FLASH FLOOD HEADLINE AT THIS TIME. WILL CONTINUE WIND ADVISORY THROUGH THE EARLY EVENING HOURS AS STRONGEST GUST POTENTIAL EXPECTED NOW THROUGH 00Z...WITH MANY SITES CONTINUING TO MEET ADVISORY CRITERIA THIS AFTERNOON. .LONG TERM /THURSDAY THROUGH WEDNESDAY/... SHORTWAVE WILL ARRIVE FROM THE PLAINS AND LIFT INTO MINNESOTA DURING THE DAY. ATTENDANT COLD FRONT WILL BEGIN ADVANCE ACROSS THE STATE DURING THE DAY AS THE SHORTWAVE PROGRESSES NORTHEAST WITH WITH SURFACE LOW MOVING NORTHWARD ALONG THE BOUNDARY. ONGOING CONVECTION IS EXPECTED ON THURSDAY MORNING NEAR THE FRONT IN THE NORTHWEST THIRD OF THE CWA WITH MAIN CONCERN FROM HEAVY RAINFALL WITH LLJ OF 60KTS+ FEEDING THE STORMS WITH ISOLD SEVERE THREAT. FORCING ASSOCIATED WITH THE SYSTEM WILL PASS RAPIDLY NORTHEAST THROUGH CENTRAL IOWA DURING THE DAY WITH BULK OF CONVECTION/PCPN LIFTING INTO MINNESOTA. HOWEVER...ADDITIONAL DEVELOPMENT IS EXPECTED BY MIDDAY INTO THE AFTERNOON ALONG THE FRONT AS DESTABILIZATION INCREASES WITH DAYTIME HEATING. DEEP SHEAR CERTAINLY WILL REMAIN SUFFICIENT FOR DEVELOPMENT AND SUSTAINING OF UPDRAFTS AND SEVERE WEATHER WILL BE POSSIBLE...MAINLY EAST OF I35 BEFORE CONVECTION MOVES EAST OF THE AREA. DRIER AND COOLER AIR WILL QUICKLY OVERSPREAD CENTRAL IOWA ON THURSDAY NIGHT INTO EARLY FRIDAY AS FRONT STALLS IN MISSOURI. THIS FRONT WILL BEGIN MOVING NORTHWARD ON FRIDAY AS UPPER RIDGING BUILDS JUST EAST OF THE STATE AND WARM ADVECTION INCREASES. MUCH OF FRIDAY APPEARS DRY...ESPECIALLY IN THE NORTH BUT SOME THREAT OF ISOLD CONVECTION WILL REMAIN IN THE SOUTH AS WAA AND THETA-E ADVECTION BEGIN TO INCREASE. SCATTERED CONVECTION IS THEN EXPECTED TO OVERSPREAD THE STATE ON FRIDAY NIGHT INTO SATURDAY MORNING AS THE BOUNDARY LIFTS NORTHWARD THROUGH THE STATE. ISOLATED SEVERE CONVECTION WILL ONCE AGAIN BE POSSIBLE GIVEN THE INSTABILITY AND DECENT SHEAR WITH STRONG VEERING WINDS IN THE PROFILE. VERY WARM AIR WILL OVERSPREAD MUCH OF THE STATE SOUTH OF THE FRONT ON SATURDAY WITH SOME THREAT OF CONVECTION REMAINING NORTH OF THE FRONT IN THE FAR NORTH BY LATE AFTERNOON. MUCH OF THE STATE WILL BE CAPPED OFF ON SATURDAY NIGHT INTO SUNDAY AS IOWA HOLDS IN THE WARM SECTOR. UPPER LOW IN THE WESTERN US WILL LIFT NORTHEAST THROUGH THE PLAINS LATE SUNDAY INTO MONDAY PUSHING A FRONT ACROSS THE STATE. LATEST MODEL RUNS INDICATE MUCH OF THE DEEPER FORCING WILL PASS TO OUR NORTH AND WEST WITH THE BULK OF THE PRECIPITATION. HOWEVER...COOLING ALOFT AND FORCING ALONG THE BOUNDARY SHOULD BE SUFFICIENT FOR CONVECTIVE DEVELOPMENT SUNDAY NIGHT INTO MONDAY AS THE BOUNDARY PASSES THROUGH THE STATE. THEREAFTER...MODELS ARE A BIT MORE FUZZY ON THE EVENTUAL EVOLUTION OF THE PATTERN INTO NEXT WEEK ALTHOUGH THE VERY WARM TEMPERATURES FROM THE WEEKEND WILL BE A THING OF THE PAST. && .AVIATION...24/00Z ACTIVE AVIATION WEATHER THE NEXT 24 HOURS. GUSTY SOUTHERLY WINDS WILL DIMINISH A BIT OVERNIGHT AS PROFILES DECOUPLE. THUNDERSTORMS ARE FORECAST OVER NORTHWEST AND NORTH CENTRAL IOWA OVERNIGHT AND WILL BE NEAR THE KFOD AND KMCW VICINITIES. WILL BE MONITORING LOW LEVEL WIND SHEAR OVERNIGHT. DID NOT INCLUDE YET BUT MAY REQUIRE AN AMENDMENT TO ADD IT IF THE LAYER WINDS DO MATERIALIZE. POTENTIAL FOR MVFR CIGS TO DEVELOP OVER THE REGION EARLY THURSDAY ALONG WITH THE RETURN OF GUSTY TO STRONG SOUTHERLY WINDS. A FRONTAL BOUNDARY WILL MOVE THROUGH DURING THE AFTERNOON AND WITH GUSTY WESTERLY WINDS TO FOLLOW. POTENTIAL FOR ADDITIONAL THUNDERSTORMS TO DEVELOP AHEAD OF THIS BOUNDARY. && .DMX WATCHES/WARNINGS/ADVISORIES...WIND ADVISORY FOR NORTHWEST HALF OF CWA THROUGH EARLY EVENING. && SHORT TERM...MJB LONG TERM...COGIL AVIATION...DONAVON
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE DES MOINES IA 1050 AM CDT WED MAY 23 2012 IAZ049-050-061-062-073>075-083>086-094>097-241100- MARSHALL-TAMA-JASPER-POWESHIEK-WARREN-MARION-MAHASKA-CLARKE-LUCAS- MONROE-WAPELLO-DECATUR-WAYNE-APPANOOSE-DAVIS- 1050 AM CDT WED MAY 23 2012 THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF CENTRAL IOWA. .DAY ONE...THIS AFTERNOON AND TONIGHT STRONG SOUTH WINDS ARE EXPECTED INTO THIS AFTERNOON WITH GUSTS APPROACHING 40 MPH. .DAYS TWO THROUGH SEVEN...THURSDAY THROUGH TUESDAY SCATTERED THUNDERSTORMS WILL SPREAD ACROSS MUCH OF CENTRAL IOWA ON THURSDAY INTO THURSDAY EVENING. A FEW SEVERE STORMS WILL BE POSSIBLE DURING THIS TIME WITH LARGE HAIL AND DAMAGING WINDS. ADDITIONAL THREATS FOR THUNDERSTORMS EXIST FRIDAY INTO EARLY SATURDAY AND AGAIN LATE SUNDAY INTO MONDAY. SOME SEVERE WEATHER WILL ALSO BE POSSIBLE AT THESE TIMES. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION MAY BE REQUIRED AT VARIOUS TIMES OVER THE NEXT SEVERAL DAYS. IAZ004>006-015-016-023>025-033>035-044>046-057-058-070-241100- EMMET-KOSSUTH-WINNEBAGO-PALO ALTO-HANCOCK-POCAHONTAS-HUMBOLDT-WRIGHT- SAC-CALHOUN-WEBSTER-CRAWFORD-CARROLL-GREENE-AUDUBON-GUTHRIE-CASS- 1050 AM CDT WED MAY 23 2012 THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF CENTRAL IOWA. .DAY ONE...THIS AFTERNOON AND TONIGHT STRONG SOUTH WINDS ARE EXPECTED TODAY. A WIND ADVISORY IS IN EFFECT FOR THE AREA INTO THE EARLY EVENING. PLEASE REFER TO THE NATIONAL WEATHER SERVICE WEBSITE AT WEATHER.GOV/DESMOINES FOR FURTHER DETAILS. THUNDERSTORMS ARE EXPECTED BY LATE AFTERNOON AND CONTINUING INTO THE OVERNIGHT. SOME SEVERE STORMS WILL BE POSSIBLE DURING THIS TIME WITH LARGE HAIL AND DAMAGING WINDS ALONG WITH AN ISOLATED TORNADO. IN ADDITION...AREAS OF HEAVY RAINFALL ARE EXPECTED OVERNIGHT. .DAYS TWO THROUGH SEVEN...THURSDAY THROUGH TUESDAY SCATTERED THUNDERSTORMS WILL SPREAD ACROSS MUCH OF CENTRAL IOWA ON THURSDAY INTO THURSDAY EVENING. A FEW SEVERE STORMS WILL BE POSSIBLE DURING THIS TIME WITH LARGE HAIL AND DAMAGING WINDS. ADDITIONAL THREATS FOR THUNDERSTORMS EXIST LATE FRIDAY INTO EARLY SATURDAY AND AGAIN LATE SUNDAY INTO MONDAY. SOME SEVERE WEATHER WILL ALSO BE POSSIBLE AT THESE TIMES. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION MAY BE REQUIRED LATE THIS AFTERNOON AND TONIGHT. ADDITIONAL SPOTTER ACTIVATION MAY BE NEEDED AT VARIOUS TIMES OVER THE NEXT SEVERAL DAYS. IAZ007-017-026>028-036>039-047-048-059-060-071-072-081-082-092-093- 241100- WORTH-CERRO GORDO-FRANKLIN-BUTLER-BREMER-HAMILTON-HARDIN-GRUNDY- BLACK HAWK-BOONE-STORY-DALLAS-POLK-ADAIR-MADISON-ADAMS-UNION-TAYLOR- RINGGOLD- 1050 AM CDT WED MAY 23 2012 THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF CENTRAL IOWA. .DAY ONE...THIS AFTERNOON AND TONIGHT STRONG SOUTH WINDS ARE EXPECTED TODAY. A WIND ADVISORY IS IN EFFECT FOR THE AREA INTO THE EARLY EVENING. PLEASE REFER TO THE NATIONAL WEATHER SERVICE WEBSITE AT WEATHER.GOV/DESMOINES FOR FURTHER DETAILS. A FEW SCATTERED THUNDERSTORMS ARE EXPECTED OVERNIGHT WITH AN ISOLATED SEVERE STORM POSSIBLE. THE MAIN THREAT WILL BE FROM LARGE HAIL OR DAMAGING WINDS. .DAYS TWO THROUGH SEVEN...THURSDAY THROUGH TUESDAY SCATTERED THUNDERSTORMS WILL SPREAD ACROSS MUCH OF CENTRAL IOWA ON THURSDAY INTO THURSDAY EVENING. A FEW SEVERE STORMS WILL BE POSSIBLE DURING THIS TIME WITH LARGE HAIL AND DAMAGING WINDS. ADDITIONAL THREATS FOR THUNDERSTORMS EXIST FRIDAY INTO EARLY SATURDAY AND AGAIN LATE SUNDAY INTO MONDAY. SOME SEVERE WEATHER WILL ALSO BE POSSIBLE AT THESE TIMES. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION MAY BE NEEDED TONIGHT AND AT VARIOUS TIMES OVER THE NEXT SEVERAL DAYS. CC
The Omaha radar (KOAX), 115 km away, was scanning. The volume nearest the first event began at 00:09 UTC.
4 thunderstorm wind, 3 hail. Local standard time, as filed.
A number of trees in a nearby grove were either downed or lost large limbs. A gustnado was also observed. Winds were estimated between 60 and 65 MPH.
Strong winds also reported.
Damage swath observed from east of Odebolt through the Early area, to the east side of Lake View. Numerous power poles down, roof blown off outbuildings, turkey, and hog confinements buildings, and boats were thrown at a dealership.
Thirteen large power poles were snapped along a mile long stretch of Perkins Ave. One third of the roof of a hog confinement building was ripped off one half mile up the road. Another half mile up the road, one third of a machine shed was destroyed. Little damage was noted east or west of this area. Wind speeds were estimated around 90 MPH.
Measured by weather station. One half mile to my north, a boat dealership reported damage.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Iowa in 2012Every state in 2012This day in weather historyWarnings in Iowa, May 2012
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: 372557, 372558, 372490, 372492, 372491, 372582, 372637.