Diurnal Distribution of Very Heavy Precipitation Over the Central and Eastern United States

A climatology of heavy precipitation events for the states of Nebraska, Missouri, Illinois, Kentucky, Tennessee, West Virginia, Pennsylvania, and Virginia is developed from 10 years (1968-1977) of Hourly Precipitation Data. Hourly precipitation events are categorized by severity, ranging from 1 to 2 inches (2.5 to 5.1 cm) in one hour or less (Type 1) to 4 or more inches (greater than 10.2 cm) in eight hours or less (Type 4). Hourly distributions of heavy precipitation events indicate that intense rainfalls of short duration occur most frequently during the afternoon and evening hours; whereas Type 4 events, which pose the most serious threat of flash flooding occur most often during the night and early morning hours in the central and eastern United States