We use observations and results of a numerical thunderstorm model <Solomon and Baker, 1994> with the addition of a lightning parameterization <Solomon and Baker, 1996> to examine thunderstorm development and lightning flash rates in a tropical maritime, subtropical continental, and midlatitude continental storms. We examine the dependence of lightning occurrence and flash rate on cloud condensation nucleus concentrations, primary and secondary glaciation mechanisms, liquid water flux, and updraft velocities. ¿ 1998 American Geophysical Union