Abstract: Based on the characteristics of SR storms and plateau storms obtained by early studies, a given three-dimensional cloud model is presented. Several runs were made with various embryo radii, initial levels and initial times. The preliminary results show that hail growth is sensitive to the initial level and to the embryo size combined with time, which would be useful to study the optimum conditions for hailstorm seeding. Some trajectories of hailstones are also investigated. In addition, a three-dimensional interpolation formula developed from one-dimensional Lagrangian interpolation is pressented in this paper.