Plain English Meaning

It's the leading edge of cold air pushing into an area of warmer air. The cold air shoves under the warm air and lifts it up quickly, which often kicks off heavy showers or thunderstorms along a fairly narrow line.

Full Definition

The boundary along which a mass of cold, dense air is advancing and displacing a mass of warmer, lighter air. As the cold air wedges underneath the warm air, the warm air is forced rapidly upward, often producing a narrow band of strong vertical weather including cumulus and cumulonimbus clouds, showers, thunderstorms, gusty winds, and a sharp drop in temperature behind the front.

Context Anchor

Seen in , , , and weather discussions when planning a or deciding whether are safe to fly.