Great atmospheric instability and vertical cloud development. Cumulonimbus clouds that tower to the troposphere. Lightning and thunder. Heavy rainfall and sometimes hail. B. Requirements for formation 1.
Most important ingredient is lots of water vapor.
Warm, moist unstable air mass means lots of latent heat release when buoyant air is lifted and cooled. High surface temperatures to enhance low-level instability. Often occur in afternoon and evening hours, on or after peak max net radiation for the day. C. Three general regions of formation 1. Isolated thunderstorms in mT air masses.