Create a clean premium infographic poster illustrating "How a Thunderstorm Forms". FORMAT: 4:5 vertical, modern science-editorial layout. CONTENT: a vertical cross-section of the atmosphere showing warm air rising, cumulonimbus cloud buildup, lightning discharge, downdraft, with labeled arrows at each stage and altitude markers. STYLE: deep blue-to-dark-teal gradient background, glowing cloud illustration, clean sans-serif typography. TYPOGRAPHY: bold title "ANATOMY OF A THUNDERSTORM" at top, clean stage labels. FINISH: 8k, crisp science-editorial design.