Frontal thunderstorm

Frontal thunderstorms develop at the boundary (front) between two different masses of air, so they are less dependent on the season of the year than are thermal thunderstorms.

The movements of air masses that cause thunderstorms are mainly found at cold fronts. The denser cold air pushes under the warmer air of the warm front, lifting it up. Frontal thunderstorms occur over larger areas than thermal thunderstorms, but they are less violent.