Laboratory experiment for understanding environment of tornado genesis due to cold outflow

Abstract

Non-supercell tornadoes occur on the gust front between cold outflow around cumulonimbus and environmental flow. Because such tornadoes cannot be caught by radar before their generation, we need to know the environment of airflow around tornadogenesis. We tried to reproduce tornado-like vortex in the situation that cold outflow intrudes into environmental flow. As the results, we found that tornado-like vortex was stably generated when the cold outflow slightly faster than the environmental flow. The circulation of tornado-like vortex increased in proportion to the velocities of both flow.