Quantifying the Distance to Supercell-Boundary Interactions

The interaction of supercell thunderstorms with surface boundaries has been shown to enhance the environment for severe storms by amplifying the vorticity, wind shear, and helicity in both observational (Maddox et al. 1980, Markowski et al, 1998b, Rasmussen et al. 2000, Bunkers et al. 2006b) and numerical studies (Atkins et al. 1999, Fierro et al. 2006, Houston and Wilhelmson 2012, Dahl et al. 2014). Previous studies have identified distances ranging between 5 km (Atkins et al. 1999) and 50 km for such enhancement (Markowski et al. 1998a). The distance between supercells and nearby surface boundaries are measured and compared to reports of large hail, strong wind, and tornadoes over the lifetime of the storm. Initial results suggest that 80 km into the warm sector of an outflow boundary, 50 km into the warm and cool sides of a warm front, and stationary cases heavily favor development within 30 km in the warm sector and 50 km into the cool sector. Future research should use high-resolution models to test the boundary distances produced in this paper and quantify how the environment changes within the distances.