2. Parameters

Shear Assessment » Helicity Strengths and Limitations

SREH is perhaps the parameter most widely used to provide a good diagnosis for the potential for tornado-producing supercells. Like CAPE values, there is no magic value of (positive) helicity over which rotating thunderstorms will develop. Furthermore, the calculation of SREH is quite sensitive to assumptions about storm motion and the environmental wind shear. SREH, like other parameters, must be used with caution, especially with rapidly changing environmental conditions.