Urbanization may enhance tornado potential: A single case report

Tornadoes pose a risk of catastrophic economic loss and casualty in the United States. Modification of land use by urbanization alters the meteorological conditions that may impact tornado formation and intensification processes. Here we explored the simulated impact of Kansas City urbanization on the tornado potential of a supercell storm. In this studied case, we found that urbanization might enhance tornado potential by a) strengthening the low-level streamwise vorticity in the storm inflow region, thus forming stronger rotating updrafts; and b) intensifying near-surface horizontal vorticity near the boundary of the forward-flank cold pool which increases the ingestion, tilting, and stretching of streamwise horizontal vorticity into vertical vorticity. The former results from the stronger east-to-west pressure perturbation gradient due to the faster, stronger outflow boundary, and the latter is mainly a result of stronger cold fronts and a better alignment of storm-relative inflow with the horizontal vorticity vector. We emphasize that our conclusions only represent one possibility of how urbanization would affect tornado potential, and a more systematic examination is needed to achieve a more general conclusion.

Automated summary

Urbanization modifies the meteorological conditions for tornado formation and intensification, increasing the risk of tornadoes in the United States. In this study, it was found that urbanization may enhance tornado potential by strengthening low-level streamwise vorticity and intensifying near-surface horizontal vorticity near the cold pool boundary. These effects are mainly due to stronger outflow boundaries and better alignment of storm-relative inflow with horizontal vorticity. Further research is needed for a more comprehensive understanding of the impact of urbanization on tornado potential.