Mesoscale convective systems occur worldwide and year-round and are accompanied by the potential for severe weather and flooding. This lesson describes typical system evolution by examining squall line, bow echo, and MCC characteristics throughout their life cycles. This lesson has less emphasis on the physical processes controlling MCS structure and evolution than our previously released Mesoscale Convective Systems: Squall Lines and Bow Echoes lesson. Instead, this newly updated lesson includes more material on tropical squall lines, MCC's, and on NWP’s ability to predict convective systems. The lesson starts with a forecast scenario and concludes with a final exam. Rich graphics, audio narration, and frequent interactions enhance the learning experience.