Understanding Hailstone Characteristics and Contributing Factors over the United States Southern Great Plains

Hailstones pose a significant threat to property and economic losses each year in the United States. Detailed understanding of their characteristics is essential to mitigate natural hazard impact. Identifying the dynamic and physical factors contributing to hail formation and hailstone sizes is of great importance to weather and climate prediction and policymakers. In this study, we have analyzed the temporal and spatial variabilities of severe hail occurrences over the United States Southern Great Plains (SGP) states from 2004–2016 with two hail datasets: hail reports from the Storm Prediction Center and the newly-developed radar-retrieved the maximum expected size of hail (MESH). It is found that severe and significant severe hail occurrences have a considerable year-to-year temporal variability at the SGP region. The interannual variabilities have strong correspondences with the factors including aerosols that might be mainly from the northern Mexico, sea surface temperature anomalies over the northern Gulf of Mexico, and El Niño-Southern Oscillation. Statistical analysis suggests the aerosol loadings to be a significant contributor in spring severe hail occurrence.