The Oklahoma Squall Line of 19 May 1977. Part II: Mechanisms for Maintenance of the Region of Strong Convection

Abstract

Abstract Mechanisms for maintenance of the strong convection along the leading edge of a broad squall line that occurred in Oklahoma on 19 May 1977 are investigated. The findings are based upon analysis of data from a surveillance radar, a surface mesonetwork, Doppler radars, proximity soundings and aircraft data, and upon the results of a two-dimensional, cloud-scale numerical simulation. The detailed results of the multiple Doppler analysis are contained in the Part I paper reporting results of research on this squall line. It is found that at a preferred location along the squall line, an area of intense convection is maintained over a long time period. A meso-β scale organized structure, which includes an area of low pressure near the southeast edge of the intense convection and an associated area of convergence extending to the east, promotes the formation of small showers in short line segments. These showers, due to their differing motion from elements within the main line, merge with the line to t...