Nonsupercell Tropical Cyclone Tornadoes: Documentation, Classification and Uncertainties

An ingredients-based approach (e.g., Johns and Doswell 1992) is used in the operational prediction of tornado threat, regardless of whether the favorable environment results from midlatitude or tropical perturbations. Since the majority of tropical cyclone (TC) tornadoes are associated with supercells (Edwards et al. 2012a; hereafter E12), the forecaster typically can focus on the same ingredients known to favor midlatitude supercells—moisture, instability, (sources for) lift, and vertical wind shear. As in midlatitude settings (e.g., Markowski et al. 1998; Garner 2012), supercellular tornado potential may be focused further by the presence of baroclinic and/or kinematic boundaries within the TC envelope (Edwards and Pietrycha 2006).