THE OCCURRENCE OF TORNADOES IN SUPERCELLS INTERACTING WITH BOUNDARIESDURING VORTEX-95

During the Verifications of the Origins of Rotation in Tornadoes Exper iment, nearly 70% of the significant tornadoes occurred near low-level boundaries not associated with the forward or rear flank downdrafts o f supercells. In general, these were preexisting boundaries readily id entified using conventional data sources, Most of the tornadoes occurr ed on the cool side oi these low-level boundaries and generally within 30 km of the boundaries. It is likely that the low-level boundaries a ugmented the ''ambient'' horizontal vorticity, which, upon further gen eration in the forward-flank region, became sufficient to be associate d with tornadic low-level mesocyclones. Some implications for forecast ing and further research are discussed.