An area of thunderstorms moved across the state. The storms were elevated in nature and well north of the frontal boundary.
Every event with a place to put it; 10 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.
An area of thunderstorms moved across the state. The storms were elevated in nature and well north of the frontal boundary. A strong high pressure area was poised to the north in Canada, creating a moderate easterly flow across the state. As the precipitation ended a wake low formed behind the convection. High winds resulted over several counties. The strongest winds was recorded from an RWIS site southwest of Marshalltown in Marshall County. Winds gusted to 72 MPH. There were scattered reports of damage, mostly by toppled trees. A few reports of damage to out buildings and carports were also received.
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 12, 3:50 AM CST, 5 hours 40 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DES MOINES IA 450 AM CDT THU MAY 12 2005 .DISCUSSION... NOT A LOT OF TIME FOR ANAL THIS AM WITH FLOODING PROBS. WL SEE ANOTHER ROUND OF WX TDA AS LO STILL LOCATED SW OF KFOD AND INV TROF NOT MAKING MUCH PROGRESS. CONVECTION ALRDY SPRDG NW WITH WAA OVR FNT AND WL SEE THAT MOV OVR SERN HLF OF CWA TDA. CONT THE FFA WITH VERY SAT SOILS AND STP SHWG MAX PCPN OVR PAST 72 HRS OF 13+ INCHES. EVEN CUTTING IN HLF, A SIG AMT. MST RVRS NOW AOA FS OR WL BE WITHIN THE NXT 24 TO 48 HRS. ONCE THIS MOVS OUT, WL BE QUITE FOR A FEW DAYS WITH COOL AMS OVR AREA. CUD SEE SCT FROST AGN SUN AM UNDER CLR SKIES AND LGT WNDS. NXT ROUND OF PCPN LKS TO BE ON TRACK FOR TUE NGT INTO WED. FIRST THE WAA TUE NGT, THEN FROPA WED. ATTM FEEL IT IS QUESTIONABLE FOR WAA ON MON NGT AS SHWN BY GFS HWVR. NO REAL MAJOR CHNGS TO GOING FCSTS. && .DMX WATCHES/WARNINGS/ADVISORIES...FLASH FLOOD WATCH TDA THRU 23Z DENISON TO AMES TO WATERLOO &&
HAZARDOUS WEATHER OUTLOOK...CORRECTED NATIONAL WEATHER SERVICE DES MOINES IA 654 AM CDT THU MAY 12 2005 IAZ004>007-015>017-023>028-033>039-044>050-057>062-070>075- 081>086-092>097-131115- 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-AUDUBON-GUTHRIE-DALLAS-POLK-JASPER- POWESHIEK-CASS-ADAIR-MADISON-WARREN-MARION-MAHASKA-ADAMS-UNION- CLARKE-LUCAS-MONROE-WAPELLO-TAYLOR-RINGGOLD-DECATUR-WAYNE- APPANOOSE-DAVIS- 654 AM CDT THU MAY 12 2005 THIS HAZARDOUS WEATHER OUTLOOK IS FOR THE CENTRAL THIRD OF IOWA INCLUDING PORTIONS OF WEST CENTRAL IOWA . .DAY ONE...TODAY AND TONIGHT SHOWERS AND THUNDERSTORMS ARE ANTICIPATED TODAY. A FEW STORMS MAYBE SEVERE SOUTH OF INTERSTATE 80 AFTER 5 PM...WITH LARGE HAIL AND DAMAGING WIND THE MOST LIKELY EXTREMES. HEAVY RAIN IS LIKELY SOUTH OF HIGHWAY 20...AND EAST OF A LINE FROM FORT DODGE TO CRESTON. AMOUNTS OF TWO TO FOUR INCHES ARE POSSIBLE OVERNIGHT. .DAYS TWO THROUGH SEVEN...FRIDAY THROUGH WEDNESDAY SHOWERS WILL BE PREVALENT ON FRIDAY WITH SOME THUNDERSTORMS SOUTH OF INTERSTATE 80...BUT THE THREAT OF SEVERE WEATHER WILL BE LOW. THE NEXT CHANCES FOR SEVERE WEATHER MAY OCCUR LATE TUESDAY. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION MAY BE NECESSARY LATER TODAY IN SOUTHERN IOWA. MYERS
The national radar mosaic for the moment the first event began.
10 high wind. Local standard time, as filed.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Iowa in 2005Every state in 2005This day in weather historyWarnings in Iowa, May 2005
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: 5446444, 5446445, 5446446, 5446447, 5446448, 5446449, 5446450, 5446451, 5446452, 5446453.