The type of front associated with a thunderstorm is a cold front.
Air masses are continuously changed through the process of heating or cooling from below, lifting or sinking, and absorbing or releasing moisture. An important feature of the air mass is its temperature relative to the land or water it is passing over. If the air is colder than the surface it is passing over, it will be warmed and convection currents will result. A cold front acts similar to a snowplow pushing under the warmer air and thrusting it aloft, cooling the warm air. This air can be described as turbulent or unstable. Characteristics of the cold front include thunderstorms, hail, sleet, or snow.