Evaluation of Severe Weather Outbreak Diagnoses for Multiple Ranking Indices
Recent evidence suggests that the spatial extent for which magnitudes of severe weather diagnostic variables exceed values favorable for significant severe weather can be used to diagnose the severity of the outbreaks with substantial skill. This study attempts to quantify the uncertainty in skill associated with this so-called areal coverage technique by varying the weights of severe weather report variables used to rank the outbreaks. All severe weather events exceeding threshold report number and density criteria from 1979 to 2013 are evaluated. The weights of each report variable used in the ranking indices are changed objectively to generate over 30,000 ranking indices. Preliminary findings suggest that (1) considerable skill exists in the identification of the most significant events for each index developed, (2) large variability in this skill exists among the indices, and (3) consistently greater skill is noted when tornado and hail report variables are weighted higher than wind report variables.