During the NASA African Monsoon Multidisciplinary Analysis (NAMMA) in summer 2006 (August and September), several mesoscale convective systems (MCS) and Saharan Air Layer (SAL) outbreaks were observed over the West African Sahel. Preliminary SAL satellite and NPOL radar analysis shows both a squall line (SL) and a SAL outbreak developed on 11 September 2006. In this study, we will explore how the SL evolved, maintained itself, and dissipated during the SAL event. A suite of meteorological parameters will be used to describe it before, during and just after its passage through southern Senegal and off of the coast. The approach concerns the analysis of structure, dynamics, cloud aerosol and microphysics properties, lightning and rainfall production of the SL. The work will be based on satellite images, surface observations, radiosondes, radar cross sections, lightening detection, and NCEP Reanalysis.