Thunderstorms form when warm humid air rises in a(n

Answer;

Unstable environment

Thunderstorms form when warm humid air rises in an unstable environment.

Explanation;Thunderstorm refers to a storm that generates lightning and thunder and usually gusty winds, rain and/or hail.  It forms when warm, humid air rises rapidly within a cumulonimbus cloud.Thunderstorm occurs in presence of unstable air, moisture, and lift. Moisture facilitates the formation of clouds and rain. Unstable air which is relatively warm and rises rapidly. Then a lift from fronts, sea breezes and mountains. With these factors then a thunderstorm will occur.Thunderstorms are dangerous since they produce lightening that kills more people each year as compared to tornadoes.