Tornado climatology and potentially severe convective environments in Mexico

Abstract

Tornadoes are extreme meteorological phenomena that can produce significant damage. The Mexican territory is prone to tornadogenesis; however, these phenomena are poorly studied in the country, and several characteristics of their behavior are unknown. We analyzed the spatiotemporal distribution of tornadoes and waterspouts in Mexico (2000-2020) and compared them with potentially severe convective environments. The updated climatology consists of 378 tornado and 99 waterspout reports and is the product of previous research and recent documentation obtained from official and non-official sources. Given the significant influence of population density on the distribution of tornado reports and the lack of meteorological instrumentation for severe weather monitoring, we used the ERA5 dataset to complement the documentary data by computing potentially severe convective environments. The results show an increasing trend in tornado reports, from an annual average of 12 (2000-2012) to 44 (2015-2020). Tornadoes are mainly documented along the Trans-Mexican Volcanic Belt in central Mexico, while waterspouts are reported in the central and southern portions of the Pacific Ocean and the Yucatán Peninsula. The tornado season spans from May through August, while waterspouts are common during June. Tornadic activity is most frequent between 15:00 and 21:00 h local time (20:00-02:00 h UTC). The results obtained from the reanalysis data indicate favorable conditions for severe storm development in northeastern and northwestern Mexico during late spring and summer. These regions coincide with those where significant tornadoes and supercell storms have been previously documented. The computed covariates based on convective available potential energy and wind shear allowed the identification of regions vulnerable to the impact of diverse severe storm manifestations (e.g. tornadoes) and the coverage of areas without documentary information.