Bill Gray and His Students' Impacts on TC Genesis Theory and Forecasting

Fifty years ago, Bill Gray authored one of the seminal papers on tropical cyclogenesis, providing key environmental parameters that explain when and why tropical cyclones occur. His paper was the most comprehensive to date that described the importance of vertical wind shear for genesis (and intensification). Later papers by Bill and his students (including Bill Frank, John McBride and Ray Zehr) further elucidated the most important dynamic and thermodynamic predictors for genesis. These efforts provided insights into understanding the differences between very active TC basins and more marginal ones and the mechanisms associated with particular genesis events. These papers' contributions will be discussed along with their applications to modern genesis forecasting.