Definition
A roughly linear band of thunderstorms, often forming along or ahead of a cold front, where individual storm cells are aligned closely enough that they form a continuous or near-continuous wall of severe weather across a wide area.
Plain English
A long row of thunderstorms strung together, usually stretching for many miles, that acts as a barrier of bad weather across the sky.
Context Anchor
Seen in weather briefings, forecasts, radar images, and cold-front discussions when planning whether a route is safe to fly.
Derivation
Line comes from a Latin word meaning a string or thread. That helps here because the storms are arranged like a long string across the map rather than appearing as one separate storm.
Why Pilots Care
These formations create a continuous hazard zone with severe turbulence, wind shear, hail, and lightning that can force major route changes or ground stops.
Grounding Statement
Picture a cold front pushing into warm, moist air and setting off storms one after another along the front.
Intuition Check
Do not think of “line” as just a thin mark on a chart. Here it means a long band of stormy weather that may be many miles wide and very hazardous to cross.
Example Sentence 1
The forecast showed a line of thunderstorms moving east ahead of the cold front, so the pilot delayed departure until it had passed.
Example Sentence 2
A solid line of thunderstorms moved across the route, requiring an early departure change to remain in visual conditions.