INVESTIGATION OF ATMOSPHERIC ENVIRONMENTS CONDUCIVE TO SUPERCELL TRANSFORMATION INTO A MESOSCALE CONVECTIVE SYSTEM

Abstract

The environmental factors that contribute to supercell thunderstorms transitioning into mesoscale convective systems (MCSs) are poorly understood. Numerous studies have investigated these phenomena separately, but few have studied the interconnected dynamics that cause a transition between supercells and MCSs. This lack of knowledge significantly affects the ability to forecast severe weather impacts associated with each system, such as severe lightning, wind, hail, flooding, and tornadoes. Previous studies highlight four specific elements needed for the formation of both supercells and MCSs: low-level vertical wind shear, upper-level vertical wind shear, convective available potential energy (CAPE), and relative humidity (RH). Using a high-resolution cloud model, multiple combinations of the aforementioned environmental factors were investigated to determine which distinct combination contributed to a supercell’s initial development and MCS transition. Through data analysis focusing on areas of convectivity, potential temperature (theta) perturbations, and total mass flux, it was concluded that MCS growth from supercells is favored in environments with highest values of CAPE and RH, with low-level shear and upper-level shear inducing minor impacts. These results will facilitate refinement of MCS transition models.