1. A rotating column of air within a thunderstorm, typically 2 to 6 miles in diameter, that can produce tornadoes.
Usage: meteorology; technical term

Examples

• Meteorologists detected a mesocyclone on radar before the tornado touched down.
• The mesocyclone rotated counterclockwise as it moved across the plains.
• Storm chasers monitor mesocyclones to predict tornado formation.
• A strong mesocyclone developed within the supercell thunderstorm.
• The National Weather Service issued a tornado warning after identifying a mesocyclone on Doppler radar.