Supercell Thunderstorms

The environments and characteristics of supercell thunderstorms are reviewed, followed by a theoretical discussion of the dynamical origins of supercell rotation and propagation. Supercell thunderstorm environments are characterized by large vertical wind shear. The large wind shear promotes longevity, organization, and severity for several reasons: (1) large storm-relative winds associated with the wind shear minimize the degree to which precipitation interferes with the updraft; (2) large horizontal vorticity associated with the wind shear is tilted into the vertical to produce a midlevel mesocyclone; (3) the rotation within the updraft and the interaction of the updraft with the large environmental wind shear give rise to strong dynamic pressure gradients which can feed back to the intensity and organization of the supercell.