A squall line is a group of storms arranged in a line, often accompanied by “squalls” of high wind and heavy rain. Squall lines tend to pass quickly and are less prone to produce tornadoes than are supercells.

Can a squall line form a tornado?

Squall lines can also produce tornadoes that are generally more difficult for forecasters to both predict and detect than tornadoes in supercell storms, Calianese said. Squall-line tornadoes — which usually form at the leading edge of the line — generally tend to be short-lived and weak, but there are exceptions.

What are squall lines usually associated with?

Squall Lines: Squall lines generally form along or ahead of cold fronts and drylines and can produce severe weather in the form of heavy rainfall, strong winds, large hail, and frequent lightning. Squall lines can extend to hundreds of miles in length, simultaneously affecting several states at a time.