Hail in Iowa, May 24, 1996

A mesoscale convective complex formed over eastern Nebraska and moved into Iowa during the early morning hours. Thunderstorms did produce some severe weather at the onset over eastern Nebraska, but as they formed and moved into Iowa, they were not as severe. The weather situation was quite complicated with an east to west cold front extending across southern Iowa and a strong warm frontal boundary over central Missouri. The air mass was not tremendously unstable. Lifted indices were near +5 C., with a deep layer of cold air in place over Iowa. Convection took off from above the 700 mb level. During much of the night, the main feature with the storms was heavy rainfall. Upwards of 3 to 6 inches of rain fell in a narrow band from central into southwest Iowa. The low level jet stream strengthened during the late night hours and the storms intensified after passing central Iowa. During the night the storms produced pea to marble size hail. After sunrise, the hail became larger with numerous reports of one to two inch diameter hail to the southeast of Des Moines. The largest hail reported came from Mahaska County, where two and one half inch diameter hail fell at Lake Kenoma.