Climatology of nontornadic severe thunderstorm events in the United States

While the climatology of excessive rain and tornadoes is well documented, little is known of storms that produce high winds or large hail. The characteristics of the similar to 75,000 severe thunderstorms that occurred in the U.S. from 1955 to 1983 are analyzed to rectify this situation. The distribution of over 29,000 storms causing hail >19 mm shows marked diurnal, seasonal, and geographic preferences. These storms occur most frequently during the midafternoon hours of May and June in a zone running from central Texas to Nebraska. Spring storms tend to occur south of the Kansas-Nebraska border and summer storms north of it. Thunderstorm winds that produce either structural damage or are reported as faster than 25.8 m sec super(-) super(1) generated similar to 46,000 reports. These storms typically occur during midafternoon in June and July. While the geographic distribution of violent windstorms is similar to that of hailstorms, a zone of weaker severe thunderstorm gusts lies from northern Iowa to central Ohio. During May, windstorms are predominant across the plains area, but by Aug., these storms are indigenous only to the northern Midwest.