Numerical Modeling of Hailstone Growth and Trajectory

Abstract

A numerical model of a convective storm is used to generate conditions in which the study of the growth and trajectories of hailstones is made. The model consists of a one-dimensional, time-dependent system in which adiabatic conditions are assumed to exist. It was designed for conditions existing in the Texas panhandle-Oklahoma region with a maximum vertical velocity of 30 m sec⁻¹. The hailstone growth equations used in the computations account for wet growth, dry growth, and melting of the hailstone. Four sizes of hail embryos consisting of frozen droplets are considered starting at six different heights resulting in twentyfour hailstones. The embryos are produced by the cloud. Results indicate that hailstones would reach the ground with a diameter of 1.00 cm within fifteen minutes of precipitation formation in the cloud and have an internal ring structure characteristic of naturally occurring hailstones.