The object of this research is the simulation, by numerical means, of the initiation and growth of hail using two and three dimensional cloud models incorporating various microphysical structures and processes. The study will focus on proving or disproving a series of hypotheses developed for the Hailswath II field program. The hypotheses involve the origin of ice and hailstone embryos in the storms, the growth of hailstones, and the development of feeder cells and the main updrafts of the storm system. Several well-observed case studies will be used to test various hypotheses. Cases from the Cooperative Convective Precipitation Experiment (CCOPE), the North Dakota Thunderstorm Project (NDTP), and the Alberta hail study have been published and provide outstanding insights into the development of hail and the dynamics of the hailstorm. Some of these cases have been simulated in our two-dimensional bulk water and 20-category hail models. Further simulations using these models and the Clark three- dimensional cloud model will be used to compare with the observations. An important development of the model will be the addition of hailstone growth equations to the basic microphysics of the 3D cloud model.
