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What is a supercell?

A supercell is a thunderstorm with a persistent rotating updraft called a mesocyclone. Supercells produce most of the strongest tornadoes, along with very large hail and damaging straight-line winds.

Anatomy of a supercellA cross-section of a supercell thunderstorm moving to the right: warm moist inflow enters from the lower right and rises in the rotating updraft under a wide anvil; the wall cloud and tornado hang below the updraft; heavy rain and hail fall in the forward-flank downdraft; the rear-flank downdraft wraps around the back.ANVILUPDRAFTWARM, MOISTINFLOWREAR-FLANKDOWNDRAFTRAIN + HAILFORWARD FLANKWALL CLOUDTORNADOSTORM MOTION
Supercell cross-section. Warm, moist air flows in low on the right and rises in the rotating updraft; the wall cloud and tornado form under it, between the rain-and-hail core and the rear-flank downdraft.

The rotating updraft

Wind shear, wind that changes speed or direction with height, makes horizontal rolls of spinning air near the ground. A strong updraft tilts that rotation upright, creating the mesocyclone that defines a supercell.

The parts of the storm

Chasers learn to read the parts of a supercell as a map of what is happening.

  • Inflow: warm, moist air feeding the storm, usually on the south and east side
  • Updraft and anvil: the rising column and the spreading cloud top
  • Wall cloud: a lowered, often rotating cloud base under the updraft where tornadoes often form
  • Forward-flank downdraft: the heavy rain and hail core
  • Rear-flank downdraft: a descending air stream that can wrap around the rotation and sometimes clears the sky behind it

Why supercells matter

Most supercells never produce a tornado. But when one does, the tornado tends to be stronger and longer-lived than the weak tornadoes from other storms.

Sources

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Last reviewed 2 November 2026