Cloud-to-Ground Lightning Activity in the Contiguous United States from 1995 to 1999

The spatial and temporal distributions of cloud-to-ground lightning are examined over the contiguous United States from 1995 to 1999 using data from the National Lightning Detection Network. Annual flash density, annual lightning days, cumulative frequency distributions of daily flash counts, and annual and summertime diurnal distributions of lightning are documented. The spatial, annual, and summertime diurnal distributions of positive and negative polarity cloud-to-ground lightning are also documented. Over the same five-year period, the production of positive and negative lightning is examined over two case study areas located in the northcentral United States and along the Gulf Coast, centered on Sioux Falls, South Dakota, and Fort Rucker, Alabama, respectively. Case studies include radar-lightning analyses of significant lightning episodes from 1996.