WSR-88D Radar Depiction of Supercell–Bow Echo Interaction: Unexpected Evolution of a Large, Tornadic, “Comma-Shaped” Supercell over Eastern Oklahoma

Abstract

During a severe thunderstorm outbreak on 17 April 1995, a bowing line segment of severe thunderstorms intercepted an isolated supercell over eastern Oklahoma. The result of the supercell?bow echo interaction was unexpected. Instead of showing a weakening supercell, with diminished severe weather potential, as the bow echo?s cold pool undercut, and spread in advance of, the supercell?s updraft, WSR-88D imagery showed a different outcome. The bow echo rapidly weakened, while the supercell maintained its identity and severity for over an hour after the interaction took place. WSR-88D imagery showed the evolution of a large high-precipitation supercell with a ?comma-shaped? echo appearance. The archive II dataset from the WSR-88D radar at Inola, Oklahoma, was retrieved, and the reflectivity and velocity images for this event were reproduced and examined. The images showed the supercell?bow echo interaction and the changes to supercell structure and resultant weather that appeared to result from this interaction. This paper documents the remarkable evolution of a large, comma-shaped supercell, as shown by WSR-88D imagery, and illustrates an important scenario that can result from the interaction between a supercell and a bow echo.