NWC REU 1998



On Hail Forecasting Schemes and Future Directions

Christopher Rozoff, Harold Brooks, and Jeff Craven



Operationally, no objective standards are evaluated for the prediction of hail size. Various hail size prediction schemes have been developed and are observed in this paper. In particular, a parameter defined as the product of convective available potential energy (CAPE) and bulk Richardson number shear divided by the product of the wet bulb zero height level and average wet bulb temperature below the wet bulb zero height level is tested. Forecast skill testing shows this parameter and other thermodynamic variables to be poor indicators of hail size. A scheme using a one-dimensional cloud model and forecast skew-t log-p diagrams, appears to be the most favorable route for future development, based upon this paper's results. Results from the data lead to questions about the observations of maximum hail size.

Paper available upon request.