Abstract

Hail is a significant convective hazard causing aviation delays and damage to property. However, accurately forecasting hail occurrence is problematic because convective hazards suffer from an additional penalty; a model must first generate convection at the correct time and location before the h... Show moreHail is a significant convective hazard causing aviation delays and damage to property. However, accurately forecasting hail occurrence is problematic because convective hazards suffer from an additional penalty; a model must first generate convection at the correct time and location before the hazard can be correctly predicted. These errors in the timing and location of predicted convection, are also present in the forecasts of hail. Herein, we evaluate a hail classification scheme using object-based techniques from the Method for Object Based Diagnostic Evaluation (MODE), part of the Model Evaluations Tools (MET) software. These object-based techniques are designed to alleviate some of the aforementioned issues. Specifically, hail is added to an existing precipitation phase classification generated in a regional version of the Weather Research and Forecasting (WRF) model. The classification is based on graupel predicted as part of the Thompson microphysics scheme. Classified hail is examined on several military ranges across the United States and verified against the NEXRAD level 3 Hydrometeor classification. The ranges are located in diverse geographical regions with different storm modes and sizes to evaluate algorithm performance under a variety of conditions. This presentation will give results from some of these cases. Show less