Multicell cluster

Multi cell storms form as clusters of storms but may then evolve into an organized line or lines of storms ( http://en.wikipedia.org/wiki/Thunderstorm#Multicell_cluster). They often arise from convective updrafts in or near mountain ranges and linear weather boundaries, usually strong cold fronts or troughs of low pressure (http://en.wikipedia.org/wiki/Thunderstorm#Multicell_cluster). This tyoe of storm can be very dangerous because they form one after another.