Quasi-Linear Convective System and Supercell Tornado Environments in Central Alabama
In discrete supercell cases, 0-1 km storm-relative helicity (SRH) was found to be the most useful individual parameter for discriminating between tornadic and non-tornadic events. Among widely known composite indices, significant tornado parameter (STP) and energy-helicity index (EHI) performed well in supercell cases. A new combination of parameters proved to be the most accurate in identifying supercell events as producers or non-producers. For QLCS cases, no single environmental parameter yielded significant results except 0-3 km convective available potential energy (CAPE). EHI was found to be the most reliable of the widely accepted composite indices in QLCS events. Two new combinations of parameters, involving multiple measures of instability and low-level wind fields, were most effective in separating QLCS producers from non-producers.