Plain English Meaning

The wall of cold, gusty wind that races out ahead of a thunderstorm, several minutes before the rain arrives.

Full Definition

The leading edge of the cool, rapidly moving outflow of air that spreads outward along the surface ahead of a thunderstorm. It is produced when rain-cooled air descends from the storm and pushes out in all directions when it hits the ground, creating a sharp boundary of shifting wind, gusts, and temperature drop.

Context Anchor

Seen in thunderstorm avoidance, airport weather reports, tower advisories, and visual signs such as blowing dust or a ahead of a storm.