Thunderstorms moved across Iowa during the evening. As they departed, a wake low developed.
Every event with a place to put it; 2 filed by county or forecast zone are drawn at its center, in a lighter ring. 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.
Thunderstorms moved across Iowa during the evening. As they departed, a wake low developed. Strong southeast winds of 25 to 45 MPH occurred for a few hours in the storms wake. Winds gusted to 58 MPH in the Marshalltown area for a brief period. HIgh winds southwest of Traer in Tama County blew large sections of agricultural tiling several feet. Most of the other wind gusts were in the 50 to 55 MPH range over the central into the southeast and east central 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 Mar 29, 10:13 PM CST, 47 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DES MOINES IA 1113 PM CDT THU MAR 29 2012 .UPDATE 30/06Z AVIATION DISCUSSION... .SHORT TERM /TONIGHT/... MAIN FOCUS IS SHOWER AND THUNDERSTORM DEVELOPMENT AS SURFACE LOW...CURRENTLY OVER NORTHERN KANSAS MOVES ACROSS SOUTHERN IOWA TONIGHT. WHILE THIS IS HAPPENING...A COLD FRONT ACROSS THE EASTERN DAKOTAS INTO NEBRASKA WILL ALSO MOVE ACROSS IOWA TONIGHT...SO THERE COULD BE TWO ROUNDS OF PRECIPITATION FOCUS. WHAT WAS TO BE A WARM FRONT HAS REMAINED STALLED ALONG THE MISSOURI RIVER IN MISSOURI...WITH ONLY LIMITED PUSH NORTH INTO SE NEBRASKA...DUE TO PERSISTENT CONVECTION IN NORTHERN MISSOURI. FRONT APPEARS UNLIKELY TO MAKE INTO IOWA UNTIL MID OR LATE EVENING...SO THE OPPORTUNITY FOR SURFACE BASED CONVECTION AND SIGNIFICANT SEVERE WEATHER POTENTIAL APPEARS LIMITED. LOW-LEVEL SHEAR AND HELICITY WILL BE MODERATELY STRONG OVER THE SOUTHWESTERN FORECAST AREA...BUT STORMS MOVING INTO THAT AREA ARE LIKELY TO BE SOMEWHAT ELEVATED...SO MAIN THREAT WOULD BE LARGE HAIL AND POTENTIALLY DAMAGING WINDS. SHOWERS AND THUNDERSTORMS ARE EXPECTED TO DEVELOP NEAR AND NORTHEAST OF THE SURFACE LOW AS IT TRACKS INTO IOWA THIS EVENING. MORE SCATTERED DEVELOPMENT IS EXPECTED ALONG AND AHEAD OF THE COLD FRONT AS IT MOVES EAST. RUC MODEL SEEMS TO HAVE A GOOD HANDLE ON THIS EVOLUTION. SEVERE THREAT IS LIKELY TO DIMINISH AFTER 9-10 PM. THERE IS SOME POTENTIAL FOR THE SOUTHERN CONVECTION TO BLOSSOM NORTHWARD AS THE COLD FRONT APPROACHES...SO THE HEAVIER PRECIPITATION AXIS IS LIKELY TO BE FROM LAMONI TO EAST OF DES MOINES WITH 0.5-0.75 INCHES POSSIBLE. TEMPERATURES WILL NOT FALL RAPIDLY OVERNIGHT DUE TO CLOUD COVER AND WARM AND MOIST ADVECTION FOR A GOOD PORTION OF THE NIGHT. .LONG TERM /FRIDAY THROUGH THURSDAY/... FORECAST HAS CHANGED SOMEWHAT FROM PREVIOUS ISSUANCES WITH A BIT MORE EMPHASIS ON PRECIP FRIDAY NIGHT AND SATURDAY NIGHT. CURRENT SYSTEM WILL HAVE DEPARTED BY ONSET OF THE PERIOD WITH FAIR WEATHER AND MORE MILD TEMPERATURES FRIDAY. HOWEVER SOME SEMBLANCE OF CURRENT INSTABILITY GRADIENT AND BAROCLINIC ZONE JUST TO OUR SOUTH IS EXPECTED TO RETURN NORTHWARD FRIDAY NIGHT AND COULD VERY WELL ACTIVE MUCH LIKE IT HAS SINCE YESTERDAY. NAM/GFS/SREF ARE NOT REALLY SUGGESTING MUCH IN THE WAY OF PRECIP TOMORROW NIGHT...HOWEVER RECENT GEM REGIONAL AND GLOBAL MODELS AS WELL AS ECMWF RUNS HAVE SUGGESTED ELEVATED CONVECTION WILL DEVELOP OVER EASTERN SECTIONS OVERNIGHT. ECMWF HAS SHOWN NICE BAROCLINIC ZONE AND LIFT ALONG 300K ISENT SURFACE. DO NOT EXPECT ANYTHING SIGNIFICANT BUT AM NO LONGER COMFORTABLE GOING DRY SO SLIGHTS HAVE BEEN INTRODUCED. SIMILAR SITUATION SATURDAY NIGHT ALTHOUGH DOMESTIC MODELS ARE NOW ON BOARD TOO IN SIMILAR AREAS SO HAVE ADDED SLIGHT MENTIONS THERE AS WELL. MODELS CONTINUE TO HAVE VARIED SOLUTIONS FOR SYSTEM EARLY NEXT WEEK WITH DIFFERENT IDEAS ON STRENGTH OF SHORT WAVE IN BASE OF THE LONG WAVE TROUGH AND OVERALL TIMING. GFS/GEM SOLUTIONS ARE SLOWER WITH MORE EMPHASIS ON SRN PLAINS CLOSED LOW WHILE ECWMF HAS MORE NRN STREAM ENERGY AND FASTER SOLUTION. THESE VARIED SOLUTIONS DO NOT HAVE MUCH IMPACT ON SENSIBLE WEATHER HOWEVER WITH CHANCES INCREASE EARLY MONDAY MORNING AND CONTINUE INTO MONDAY EVENING CENTRAL AND EAST. REMAINDER OF THE FORECAST IS MILD AND DRY WITH UPPER LEVEL RIDGING BUILDING BACK INTO THE MO VALLEY. NO FROST OR FREEZING CONDITIONS APPEAR TO BE IN THE OFFING...AT LEAST THROUGH THE END OF THE NEXT WORK WEEK. && .AVIATION...30/06Z THUNDER CONTINUES OVER THE EAST AND ANOTHER LINE FORMING IN THE NORTHWEST WILL MOVE EAST SOUTHEAST THROUGH 11Z. STRONGER STORMS ACROSS THE SOUTH AND EAST WILL AFFECT KALO...KOTM...THROUGH 10Z WITH LOWERING CIGS FROM 06Z THROUGH 11Z AS MOIST BOUNDARY LAYER CONTINUES NEAR SATURATION. HAVE MVFR CIGS/VISBYS WITH SOME CHANCE OF IFR FOR BRIEF PERIOD NORTH AND EAST. OTHERWISE SOME REDUCTION IN VSBY BY 11-14Z THEN IMPROVING FROM 14Z ONWARD. LIGHT WINDS AND GENERALLY VFR CIGS EXPECTED FOR THE REMAINDER OF TAF PERIOD. WINDS SWING BACK TO SOUTHEAST AFT 31/00Z. && .DMX WATCHES/WARNINGS/ADVISORIES...NONE. && SHORT TERM...JUNGBLUTH AVIATION...REV LONG TERM...SMALL
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE DES MOINES IA 853 PM CDT THU MAR 29 2012 IAZ070>074-081>085-092>096-310200- CASS-ADAIR-MADISON-WARREN-MARION-ADAMS-UNION-CLARKE-LUCAS-MONROE- TAYLOR-RINGGOLD-DECATUR-WAYNE-APPANOOSE- 853 PM CDT THU MAR 29 2012 THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF SOUTH CENTRAL IOWA. .DAY ONE...TONIGHT THUNDERSTORMS ARE EXPECTED OVER SOUTHWEST AND SOUTH CENTRAL IOWA AS THEY MOVE EAST AND NORTHEAST THIS EVENING. THERE IS A SLIGHT RISK OF SEVERE WEATHER THROUGH LATE THIS EVENING. LARGE HAIL AND STRONG WINDS ARE THE PRIMARY THREATS...ALTHOUGH THERE IS A SMALL THREAT OF AN ISOLATED TORNADO SOUTH OF HIGHWAY 34 AND WEST OF INTERSTATE 35. .DAYS TWO THROUGH SEVEN...FRIDAY THROUGH WEDNESDAY THUNDERSTORM CHANCES WILL RETURN FRIDAY NIGHT AND SATURDAY NIGHT IN EASTERN IOWA...AND THEN AGAIN ON MONDAY FOR ALL OF IOWA. THE POTENTIAL FOR SEVERE WEATHER APPEARS LOW AT THIS TIME. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION IS POSSIBLE IN SOUTHERN IOWA THIS EVENING. IAZ057>062-075-086-097-310200- AUDUBON-GUTHRIE-DALLAS-POLK-JASPER-POWESHIEK-MAHASKA-WAPELLO-DAVIS- 853 PM CDT THU MAR 29 2012 THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF CENTRAL IOWA. .DAY ONE...TONIGHT MAINLY NON SEVERE THUNDERSTORMS ARE EXPECTED OVER THE OUTLOOK AREA THROUGH MIDNIGHT. THERE IS A SLIGHT RISK OF OF AN ISOLATED SEVERE STORM THROUGH ABOUT MIDNIGHT. LARGE HAIL IS THE PRIMARY THREAT. .DAYS TWO THROUGH SEVEN...FRIDAY THROUGH WEDNESDAY THUNDERSTORM CHANCES WILL RETURN FRIDAY NIGHT AND SATURDAY NIGHT IN EASTERN IOWA...AND THEN AGAIN ON MONDAY FOR ALL OF IOWA. THE POTENTIAL FOR SEVERE WEATHER APPEARS LOW AT THIS TIME. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION IS NOT ANTICIPATED AT THIS TIME. IAZ004>007-015>017-023>028-033>039-044>050-310200- 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- BOONE-STORY-MARSHALL-TAMA- 853 PM CDT THU MAR 29 2012 THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF CENTRAL IOWA. .DAY ONE...TONIGHT SCATTERED THUNDERSTORMS ARE EXPECTED TO MOVE NORTHEASTWARD ACROSS NORTHERN AND EASTERN IOWA THIS EVENING AND OVERNIGHT. SEVERE IS NOT LIKELY. .DAYS TWO THROUGH SEVEN...FRIDAY THROUGH WEDNESDAY THUNDERSTORM CHANCES WILL RETURN FRIDAY NIGHT AND SATURDAY NIGHT IN EASTERN IOWA...AND THEN AGAIN ON MONDAY FOR ALL OF IOWA. THE POTENTIAL FOR SEVERE WEATHER APPEARS LOW AT THIS TIME. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION IS NOT ANTICIPATED AT THIS TIME. REV
SPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE DES MOINES IA 901 PM CDT THU MAR 29 2012 IAZ046>048-058>060-072-073-083-094-300415- GREENE-BOONE-STORY-GUTHRIE-DALLAS-POLK-MADISON-WARREN-CLARKE- DECATUR- INCLUDING THE CITIES OF...JEFFERSON...BOONE...AMES... GUTHRIE CENTER...ADEL...DES MOINES...WINTERSET...INDIANOLA... OSCEOLA...LEON 901 PM CDT THU MAR 29 2012 ...THUNDERSTORMS WITH SOME HAIL MOVING INTO THE AREA AN AREA OF THUNDERSTORMS IS MOVING ACROSS CENTRAL IOWA AND WILL BE CAPABLE OF PRODUCING DIME TO PENNY SIZED HAIL IN SOME OF THE STRONGER STORMS. ALONG WITH THAT GUSTY WINDS AND BRIEF HEAVY DOWNPOURS WILL BE POSSIBLE. THE STORMS ARE MOVING EAST NORTHEAST AT 20 MPH. THE THUNDERSTORMS WILL CONTINUE THROUGH LATE THIS EVENING AND INTO EARLY FRIDAY MORNING. A SEVERE THUNDERSTORM WATCH IS IN EFFECT FOR A PORTION OF THE AREA MAINLY SOUTH OF INTERSTATE 80 AND WEST OF HIGHWAY 63. REV
SPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE DES MOINES IA 919 PM CDT THU MAR 29 2012 IAZ046>048-058>060-072-073-083-094-300430- GREENE-BOONE-STORY-GUTHRIE-DALLAS-POLK-MADISON-WARREN-CLARKE- DECATUR- INCLUDING THE CITIES OF...JEFFERSON...BOONE...AMES... GUTHRIE CENTER...ADEL...DES MOINES...WINTERSET...INDIANOLA... OSCEOLA...LEON 919 PM CDT THU MAR 29 2012 ...THUNDERSTORMS WITH SOME HAIL MOVING INTO THE AREA... AN AREA OF THUNDERSTORMS IS MOVING ACROSS CENTRAL IOWA AND WILL BE CAPABLE OF PRODUCING DIME TO PENNY SIZED HAIL IN SOME OF THE STRONGER STORMS. ALONG WITH THAT GUSTY WINDS AND BRIEF HEAVY DOWNPOURS WILL BE POSSIBLE. THE STORMS ARE MOVING EAST NORTHEAST AT 20 MPH. THE THUNDERSTORMS WILL CONTINUE THROUGH LATE THIS EVENING AND INTO EARLY FRIDAY MORNING. A SEVERE THUNDERSTORM WATCH IS IN EFFECT FOR A PORTION OF THE AREA MAINLY SOUTH OF INTERSTATE 80 AND WEST OF HIGHWAY 63. IAZ039-300430- BLACK HAWK- INCLUDING THE CITY OF...WATERLOO 919 PM CDT THU MAR 29 2012 ...SMALL AREA OF THUNDERSTORMS WITH POSSIBLE HAIL... A SMALL AREA OF THUNDERSTORMS IS MOVING ACROSS NORTHEAST IOWA AND WILL BE CAPABLE OF PRODUCING DIME SIZED HAIL. ALONG WITH THAT GUSTY WINDS AND BRIEF HEAVY DOWNPOURS WILL BE POSSIBLE. THE STORMS ARE MOVING EAST NORTHEAST AT 20 MPH. THE THUNDERSTORMS WILL CONTINUE THROUGH LATE THIS EVENING AND INTO EARLY FRIDAY MORNING. REV
PRELIMINARY LOCAL STORM REPORT...SUMMARY
NATIONAL WEATHER SERVICE DES MOINES IA
940 PM CDT THU MAR 29 2012
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0754 PM HAIL 4 NE GRISWOLD 41.27N 95.07W
03/29/2012 E1.75 INCH CASS IA TRAINED SPOTTER
0810 PM HAIL 3 S GRISWOLD 41.19N 95.14W
03/29/2012 E1.00 INCH CASS IA TRAINED SPOTTER
&&
BFPRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE DES MOINES IA
954 PM CDT THU MAR 29 2012
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0953 PM HAIL ALTOONA 41.65N 93.48W
03/29/2012 M1.00 INCH POLK IA TRAINED SPOTTER
ON INTERSTATE 80.
&&
KSSPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE DES MOINES IA 1041 PM CDT THU MAR 29 2012 IAZ048-059-060-072-073-081>083-092>094-300645- STORY-DALLAS-POLK-MADISON-WARREN-ADAMS-UNION-CLARKE-TAYLOR- RINGGOLD-DECATUR- INCLUDING THE CITIES OF...AMES...ADEL...DES MOINES...WINTERSET... INDIANOLA...CORNING...CRESTON...OSCEOLA...BEDFORD...MOUNT AYR... LEON 1041 PM CDT THU MAR 29 2012 AN AREA OF THUNDERSTORMS IS MOVING ACROSS CENTRAL IOWA AND WILL BE CAPABLE OF PRODUCING DIME TO PENNY SIZED HAIL IN SOME OF THE STRONGER STORMS. ALONG WITH THAT GUSTY WINDS AND BRIEF HEAVY DOWNPOURS WILL BE POSSIBLE. THE STORMS ARE MOVING EAST NORTHEAST AT 20 MPH. THE THUNDERSTORMS WILL CONTINUE THROUGH LATE THIS EVENING AND INTO EARLY FRIDAY MORNING. A SEVERE THUNDERSTORM WATCH IS IN EFFECT FOR A PORTION OF THE AREA MAINLY SOUTH OF INTERSTATE 80 AND WEST OF HIGHWAY 63. IAZ027-028-038-039-049-050-061-062-074-075-300645- BUTLER-BREMER-GRUNDY-BLACK HAWK-MARSHALL-TAMA-JASPER-POWESHIEK- MARION-MAHASKA- INCLUDING THE CITIES OF...ALLISON...WAVERLY...GRUNDY CENTER... WATERLOO...MARSHALLTOWN...TOLEDO...NEWTON...GRINNELL... KNOXVILLE...OSKALOOSA 1041 PM CDT THU MAR 29 2012 AN AREA OF THUNDERSTORMS IS MOVING INTO EASTERN IOWA AND WILL BE CAPABLE OF PRODUCING DIME TO PENNY SIZED HAIL IN SOME OF THE STRONGER STORMS. ALONG WITH THAT GUSTY WINDS AND BRIEF HEAVY DOWNPOURS WILL BE POSSIBLE. THE STORMS ARE MOVING EAST AT 20 MPH. THE THUNDERSTORMS WILL CONTINUE THROUGH INTO EARLY FRIDAY MORNING. A SEVERE THUNDERSTORM WATCH IS IN EFFECT FOR A PORTION OF THE AREA MAINLY SOUTH OF INTERSTATE 80 AND WEST OF HIGHWAY 63. REV
PRELIMINARY LOCAL STORM REPORT...SUMMARY
NATIONAL WEATHER SERVICE DES MOINES IA
1127 PM CDT THU MAR 29 2012
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0754 PM HAIL 4 NE GRISWOLD 41.27N 95.07W
03/29/2012 E1.75 INCH CASS IA TRAINED SPOTTER
0810 PM HAIL 3 S GRISWOLD 41.19N 95.14W
03/29/2012 E1.00 INCH CASS IA TRAINED SPOTTER
0953 PM HAIL ALTOONA 41.65N 93.48W
03/29/2012 M1.00 INCH POLK IA TRAINED SPOTTER
ON INTERSTATE 80.
&&
BFThe national radar mosaic for the moment the first event began.
2 high wind. Local standard time, as filed.
Large sections of tiling used for agricultural drainage were blown several feet.
A 50 knot wind gust was recorded at the Marshalltown RWIS site.
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, March 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: 363530, 363387.