The Iowa state climatologist says the 2012 drought is even worse than the 1988 event and the worst since 1936.
Climatologist Harry Hillaker says the heat and dry July has pushed this year's drought above '88 drought for breadth and severity.
Hillaker says the 1936 drought in Iowa also was fueled by a torrid July, the hottest and second-driest in 140 years.
Climatologist Brian Fuchs at the National Drought Mitigation Center in Lincoln, Neb., says "heat makes droughts drier, and droughts make heat hotter."
Fuchs says a high-pressure system that has kept many storms from watering the nation's grain belt has strengthened and could remain as a rain barrier for two more months.
The center reported last week that the drought covers two-thirds of the continental U.S.