An air-mass thunderstorm is a type of thunderstorm in which air rises because of unequal heating of Earth's surface within a single air mass and its most common during the afternoon and evening.
A frontal thunderstorm is a type of thunderstorm usually produced by an advancing cold front, which can result in a line of thunderstorms hundreds of kilometers long, or, more rarely, an advancing warm front, which can result in a relatively mild thunderstorm.