Kelvin-Helmholtz instability in an anvil cloud

On the evening of 21-22 July 2002, the University of Miami documented large-amplitude Kelvin-Helmholtz billows. The billows lasted more than 3 h, suggesting that internal anvil circulations helped continuously regenerate the instability, even more than an hour after the demise of all deep convection. In addition to the main shear axis along which the Kelvin-Helmholtz instability developed, several identifiable weaker shear layers existed in the anvil, evident in the Doppler spread.