Supercell low-level mesocyclones in simulations with a sheared convective boundary layer

The effects of boundary layer convection on the general characteristics and the low-level mesocyclones of the simulated supercells are investigated for rolls oriented either perpendicular or parallel to storm motion, as well as with and without the effects of cloud shading.

Bulk measures of storm strength are not greatly affected by the presence of rolls in the near-storm environment. Though boundary layer convection diminishes with time under the anvil shadow of the supercells when cloud shading is allowed, simulations without cloud shading suggest that rolls affect the morphology and evolution of supercell low-level mesocyclones. Initially, CBL vertical vorticity perturbations are enhanced along the supercell outflow boundary, resulting in nonnegligible near-ground vertical vorticity regardless of roll orientation.