line squall

A squall line is a meteorological term for a line of squalls or thunderstorms. It can be defined as a boundary between cold and warm winds, often found ahead of a cold front. A squall itself is a sudden increase in wind speed, typically by 18 miles per hour or more for at least one minute.12

Line squalls are often associated with organized multiple-cell storms and can create a continuous gust front. They can occur along a cold front or tens to hundreds of kilometers ahead of it in the warm air mass. These phenomena are significant weather systems that can produce violent weather.34