On Thunderstorm Forecasting in the Central United States

This study is directed toward a better understanding of the occurrence and forecasting of thunderstorms as an element of general weather patterns or sequences of patterns. The principal area studied is the Central United States. Following a review of the literature, the climatology of thunderstorms is examined. Then, from an analysis of many thunderstorm situations, the typical features and important synoptic patterns of areas of thunderstorm activity and their movement and life cycle are described. Finally some of the parameters suggested by the study are incorporated into a systematic technique to aid in the preparation of forecasts of thunderstorms during a 24-hour period at Chicago. The procedure is based upon 850-mb. chart types, previous occurrence of thunderstorms, and moisture and stability. A test on independent data gives good results.