Final answer:
A non-frontal narrow band of active thunderstorms that often develop ahead of a cold front is known as a squall line. These squall lines are characterized by a long line of severe thunderstorms that have a fast-moving cold front as its leading edge. They can bring heavy rain, strong wind gusts, and sometimes even tornadoes.
Step-by-step explanation:
A non-frontal narrow band of active thunderstorms that often develop ahead of a cold front is known as a squall line. These squall lines are characterized by a long line of severe thunderstorms that have a fast-moving cold front as its leading edge. They can bring heavy rain, strong wind gusts, and sometimes even tornadoes.