A cold front moved slowly southeast into central Iowa. The airmass became unstable around the front with highs in the mid 80s to around 90 ahead of the front with dewpoint temperatures in the 55 to 60 degree range.
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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 cold front moved slowly southeast into central Iowa. The airmass became unstable around the front with highs in the mid 80s to around 90 ahead of the front with dewpoint temperatures in the 55 to 60 degree range. There was 40 to 50 kts of effective shear available, however CAPE was generally only around 500 J/kg in the thunderstorm generation area behind the front. Downdraft CAPE was in the 600 to 800 J/kg range with available in the -10 to -30 C layer of the atmosphere between 100 and 200 J/kg. Precipitable water values were around an inch with a 35 kt low level jet feeding moisture into the area. The freezing level was relatively low, around 11,500 feet. As a result thunderstorms that formed produced hail easily. By the late afternoon into the evening hours an area of thunderstorms formed on the cool side of the front. Several of the storms produced hail up to quarter size. One storm produced a swath of one inch diameter hail in Adams County from Lake Icaria northeast to the county border. By the end of the month a Presidential Disaster Declaration was issued due to the winds and flooding for the following counties: Appanoose, Cedar, Clinton, Davis, Decatur, Des Moines, Iowa, Johnson, Keokuk, Lee, Lucas, Marion, Monroe, Muscatine, Ringgold, Van Buren, Wapello, Warren, and Wayne Counties.
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 Apr 30, 3:18 PM CST, 2 hours 17 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DES MOINES IA 418 PM CDT TUE APR 30 2013 .SHORT TERM.../TONIGHT /... ISSUED AT 407 PM CDT TUE APR 30 2013 FRONTAL BOUNDARY HAS SAGGED INTO CENTRAL IOWA THIS AFTERNOON AND WAS LOCATED AND WAS LOCATED NEAR A CHARLES CITY TO JOHNSTON TO HARLAN LINE. CUMULUS FIELD HAS DEVELOP ALONG AND AHEAD OF THE BOUNDARY THROUGH CENTRAL AND SOUTHWEST IOWA. ANOTHER BAND OF CLOUDS HAS DEVELOPED AROUND 50 MILES TO THE NW OF THE OTHER BAND AND ON THE UP SHEAR SIDE OF THE BOUNDARY WHERE THETA-E ADVECTION IS OVERRUNNING THE SFC BOUNDARY. SFC DEWPOINTS IN THE LOW TO MID 50S IS FOCUSED ALONG THE BOUNDARY WITH TEMPERATURES IN THE LOW 80S. MID LEVEL COOLING SHOULD HELP BREAK THE CAP DURING THE LATTER HALF OF THE AFTERNOON FOR SOME SFC BASED CONVECTION TO DEVELOP NEAR THE BOUNDARY WITH A FEW SEVERE STORMS POSSIBLE WITH THE PRIMARY THREATS BEING LARGE HAIL AND 60 MPH WINDS. THE ACTIVITY SHOULD BECOME MORE POST FRONTAL LATER IN THE EVENING DUE TO OVERRUNNING OF THE BOUNDARY WITH THE PRECIPITATION GRADUALLY ENDING OVER THE CENTRAL PORTION OF THE STATE. THE STORM STEERING FLOW THROUGH THE PERIOD IS FAVORABLE FOR TRAINING STORMS FROM SOUTHWEST TO NORTHEAST THROUGH THE PERIOD AND COULD LEAD TO LOCALLY HEAVY RAINFALL. THE COLD FRONT WILL GET ANOTHER SURGE AFTER MIDNIGHT AND WILL BE THROUGH ALL BUT THE SOUTHEAST QUARTER OF THE FORECAST AREA BY 12Z. A WIDE RANGE IN FORECAST LOWS WITH UPPER 30S NORTHWEST TO AROUND 60 SOUTHEAST. .LONG TERM.../WEDNESDAY THROUGH TUESDAY/... ISSUED AT 407 PM CDT TUE APR 30 2013 FORECAST CHALLENGE OVER THE NEXT SEVERAL DAYS IS WITH LONG DURATION PRECIPITATION EVENT BEGINNING WEDNESDAY AND POTENTIALLY LASTING THROUGH INTO FRIDAY. MODELS ARE IN GOOD AGREEMENT THROUGH THURSDAY MORNING BEFORE LARGE DISCREPANCIES DEVELOP WITH THE TIMING AND PLACEMENT OF UPPER LOW LATE THIS WEEK AND INTO THE WEEKEND. LEANED TOWARD NAM/GFS/SREF BLEND THROUGH 12Z THURSDAY...THEN MORE TOWARDS THE GFS LATE THIS WEEK INTO THE EARLY PART OF THE WEEKEND. WEDNESDAY THROUGH FRIDAY...LARGE SCALE FORCING WILL SLOWLY MIGRATE SOUTHEAST DURING THE DAY WEDNESDAY BEHIND THE BOUNDARY...AND LOOKS TO BE FOCUSED ACROSS WEST TO NORTH-CENTRAL IOWA. HAVE A VERY SHARP GRADIENT FOR POPS AND MAX TEMPS TOMORROW AS THE BULK OF THE FORCING AND MOISTURE IS ALONG AND BEHIND FRONTAL BOUNDARY STALLED ACROSS THE SOUTHEAST SECTION OF THE STATE. CAA ALOFT FINALLY COMPLETELY COOLS THE COLUMN ACROSS NORTHERN IOWA BY 06Z THURSDAY...WITH A RAIN/SNOW MIX LIKELY WEDNESDAY NIGHT. STRONG DEFORMATION ZONE COMBINED WITH IMPRESSIVE FRONTOGENETICAL FORCING BETWEEN 850-700MB AND 600-650MB WILL PERSIST LATE WEDNESDAY NIGHT INTO THURSDAY MORNING. HAVE MENTION OF ALL SNOW BETWEEN 06-12Z THURSDAY OVER NORTHERN IOWA RESULTING IN HIGHEST POTENTIAL FOR ACCUMULATING SNOWFALL. QUESTIONABLE HOW MUCH SNOW WILL ACCUMULATE WITH THE WARM GROUND/ROAD TEMPS BUT WITH SNOWFALL RATES UNDERNEATH THE STRONGEST FRONTOGENETICAL BANDING...CANNOT RULE OUT AREAS RECEIVING 2-5 INCHES BAND OVER NORTH-CENTRAL IOWA BY THURSDAY MORNING. COOLED MAX TEMPS SEVERAL DEGREES ON THURSDAY AS MODELS ARE IN MUCH BETTER AGREEMENT WITH THE CAA CONTINUING THROUGHOUT THE DAY. UPPER LEVELS REMAIN COLD ENOUGH FOR SNOW THURSDAY MORNING AND AGAIN BY THURSDAY EVENING OVER CENTRAL TO NORTHERN IOWA. SURFACE TEMPS SHOULD WARM UP ENOUGH FOR A RAIN/SNOW MIX DURING THE AFTERNOON HOURS WHICH WILL LIMIT SNOW ACCUMULATIONS. NAM KEEPS THE WESTERN HALF OF THE FORECAST AREA DRY...WHILE THE 00Z ECMWF/12Z GFS KEEP MUCH OF THE STATE UNDER DEEPER MOISTURE AND FORCING INTO FRIDAY. RAIN CHANCES CONTINUE INTO FRIDAY WITH WARMER TEMPS FILTERING AS WAA ALOFT DEVELOPS. SATURDAY THROUGH TUESDAY...ACTIVE PATTERN CONTINUES THROUGHOUT THE WEEKEND AND INTO EARLY NEXT WEEK WITH CUTOFF UPPER LOW SLOWLY MOVING EAST AND CLEARING THE FORECAST AREA BY MONDAY. && .AVIATION...30/18Z ISSUED AT 1226 PM CDT TUE APR 30 2013 FRONTAL BOUNDARY OVER CENTRAL IOWA WILL STALL THIS AFTERNOON AND EVENING BEFORE BEGINNING TO SHIFT BACK SOUTHEAST LATE TONIGHT AND INTO WEDNESDAY. SCATTERED THUNDERSTORMS ARE EXPECTED TO DEVELOP ALONG THE BOUNDARY BY MID TO LATE THIS AFTERNOON BEFORE DIMINISHING AFTER MIDNIGHT. ADDITIONAL PRECIPITATION MAY REDEVELOP BY WEDNESDAY MORNING OVER THE NORTHWEST TAF SITES WITH MVFR CIGS DEVELOPING. EXPECT SOUTH TO SOUTHWEST WINDS SOUTH OF THE BOUNDARY BECOMING NORTHERLY WITH THE FRONTAL PASSAGE. && .HYDROLOGY... ISSUED AT 407 PM CDT TUE APR 30 2013 THE LATEST 5-DAY QPF AMOUNTS SUGGEST SIGNIFICANT WITHIN BANK RISES ALONG MANY STREAMS ACROSS THE CWA. MINOR FLOODING IS POSSIBLE AT SOME LOCATIONS...WITH A SMALLER RISK OF MODERATE FLOODING DEPENDING ON HOW MUCH RAIN ACTUALLY FALLS. AT THIS TIME THE STREAMS OF MOST CONCERN INCLUDE PORTIONS OF THE CEDAR...DES MOINES AND RACCOON RIVERS AS WELL AS THEIR TRIBUTARIES. THE ACTUAL RAINFALL AMOUNTS...COMBINED WITH THEIR GEOGRAPHIC AND TEMPORAL DISTRIBUTION WILL BE KEY FACTORS IN THE ACTUAL RESPONSES. CHANGES TO THE QPF AMOUNTS OR LOCATIONS WILL HAVE SIGNIFICANT IMPACTS ON THE EXPECTED RESPONSES OF AREA RIVERS. && .DMX WATCHES/WARNINGS/ADVISORIES...NONE. && SHORT TERM...DONAVON LONG TERM...PODRAZIK AVIATION...DONAVON HYDROLOGY...ZOGG
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE DES MOINES IA 330 PM CDT TUE APR 30 2013 IAZ004>007-015-016-023-024-033-034-044-012030- EMMET-KOSSUTH-WINNEBAGO-WORTH-PALO ALTO-HANCOCK-POCAHONTAS-HUMBOLDT- SAC-CALHOUN-CRAWFORD- 330 PM CDT TUE APR 30 2013 THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF NORTH CENTRAL IOWA. .DAY ONE...THIS AFTERNOON AND TONIGHT ISOLATED TO SCATTERED THUNDERSTORMS ARE POSSIBLE TONIGHT. AN ISOLATED SEVERE STORM WITH QUARTER SIZED HAIL IS POSSIBLE BEFORE 9 PM. .DAYS TWO THROUGH SEVEN...WEDNESDAY THROUGH MONDAY RAIN WILL REMAIN IN THE FORECAST WEDNESDAY FRIDAY NIGHT. RAINFALL AMOUNTS OF 1 TO 3 INCHES MAY CAUSE SIGNIFICANT WITHIN BANK RISES ALONG MANY RIVERS WITH MINOR FLOODING OCCURRING IN SOME LOCATIONS. IN ADDITION...ACCUMULATING SNOWFALL ON GRASSY AREAS IS POSSIBLE WEDNESDAY NIGHT THROUGH THURSDAY. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION IS NOT EXPECTED. IAZ017-025>028-035>039-045>050-057>062-070>074-081>083-092-093- 012030- CERRO GORDO-WRIGHT-FRANKLIN-BUTLER-BREMER-WEBSTER-HAMILTON-HARDIN- GRUNDY-BLACK HAWK-CARROLL-GREENE-BOONE-STORY-MARSHALL-TAMA-AUDUBON- GUTHRIE-DALLAS-POLK-JASPER-POWESHIEK-CASS-ADAIR-MADISON-WARREN- MARION-ADAMS-UNION-CLARKE-TAYLOR-RINGGOLD- 330 PM CDT TUE APR 30 2013 THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF CENTRAL IOWA. .DAY ONE...THIS AFTERNOON AND TONIGHT THUNDERSTORMS ARE EXPECTED TO DEVELOP ALONG A COLD FRONT LATE THIS AFTERNOON AND INTO THE EVENING. A FEW SEVERE STORMS ARE POSSIBLE WITH HALF DOLLAR SIZED HAIL AND 60 MPH WINDS POSSIBLE. IN ADDITION...CONDITIONS ARE FAVORABLE FOR TRAINING STORMS WHICH MAY LEAD TO A NARROW BAND OF HEAVY RAINFALL. .DAYS TWO THROUGH SEVEN...WEDNESDAY THROUGH MONDAY RAIN WILL REMAIN IN THE FORECAST WEDNESDAY FRIDAY NIGHT. RAINFALL AMOUNTS OF 1 TO 3 INCHES MAY CAUSE SIGNIFICANT WITHIN BANK RISES ALONG MANY RIVERS WITH MINOR FLOODING OCCURRING IN SOME LOCATIONS. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION MAY BE NEED BETWEEN 5 PM AND 10 PM. IAZ075-084>086-094>097-012030- MAHASKA-LUCAS-MONROE-WAPELLO-DECATUR-WAYNE-APPANOOSE-DAVIS- 330 PM CDT TUE APR 30 2013 THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF SOUTH CENTRAL IOWA. .DAY ONE...THIS AFTERNOON AND TONIGHT THUNDERSTORMS AREA EXPECTED TO DEVELOP BY MID AFTERNOON AND CONTINUING INTO TONIGHT. SEVERE STORMS ARE POSSIBLE LATE THIS AFTERNOON AND EVENING WITH THE MAIN THREAT BEING LARGE HAIL AND DAMAGING WINDS. THE AREA OF HIGHEST THREAT APPEARS TO BE IN A 75 MILE WIDE BAND EXTENDING FROM WATERLOO...THROUGH DES MOINES...TO ATLANTIC. .DAYS TWO THROUGH SEVEN...WEDNESDAY THROUGH MONDAY RAIN WILL REMAIN IN THE FORECAST WEDNESDAY FRIDAY NIGHT. RAINFALL AMOUNTS OF 1 TO 3 INCHES MAY CAUSE SIGNIFICANT WITHIN BANK RISES ALONG MANY RIVERS WITH MINOR FLOODING OCCURRING IN SOME LOCATIONS. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION IS NOT EXPECTED TONIGHT.
The Des Moines radar (KDMX), 113 km away, was scanning. The volume nearest the first event began at 23:36 UTC.
4 hail. Local standard time, as filed.
The Adams County EM stated that there was a swath of 1 inch diameter hail that fell from the Lake Icaria area, northeast to the county border. Hail fell from 1735 to 1805 CST.
Near the town of Carl.
Report forwarded by WOI television.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Iowa in 2013Every state in 2013This day in weather historyWarnings in Iowa, April 2013
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: 438020, 438018, 438021, 438019.