It is said that due to global warming, the average temperature and seawater temperature have risen, and extreme weather such as heavy rain has become more frequent. Many of the extreme weather we are socially interested in are accompanied by strong eddy motions. Large-scale numerical simulations of turbulent flows using recent supercomputers have shown that strong eddy motions in turbulent flows are caused by larger-scale flow structures. It would be great if we could analyze various meteorological data using the knowledge obtained from large-scale simulations as a hint, correctly understand the mechanism of extreme weather such as heavy rains and tornadoes, and propose appropriate preparations.