Tornadoes and waterspouts in the Balearic Islands: phenomena and environment characterization

In the Balearic Islands, located in the Western Mediterranean, 27 tornadoes and 54 waterspouts have been recorded during the period 1989-1999. A clima tology focusing, which focuses on path length, F-scale velocity, season and time of occurrence, is presented. September and October appear to be the m onths with the highest frequency of appearance. The environment in which th understorm producing tornadoes and waterspouts developed has been analysed. Main thermodynamic stability indices reveal that no specific conditions ar e required for the tornado and waterspout genesis. It is also found that th ese events form in air masses colder than that indicated by the climatology of the region. Analyses of helicity and CAFE demonstrate that, in most of the cases, the environments were not favourable for mesocyclone formation a nd supercell development. (C) 2001 Elsevier Science B.V. All rights reserve d.