Thunderstorms

Thunderstorms pose a significant hazard to all aircraft. They are produced by a cumulonimbus cloud, and always accompanied by lightning and thunder, usually with strong gusts of wind, heavy rain, and sometimes with hail.

Thunderstorm ingredients:

1. Sufficient moisture
2. Unstable conditions
3. A lifting mechanism
   • For instance converging winds around surface lows and troughs, fronts, upslope flow, drylines, and local winds, such as sea breeze, lake breeze, land breeze, and valley breeze

Stages of Thunderstorm

1. Towering cumulus stage
   • Characterized by strong convective updrafts
2. Mature stage
   • Begins when rain reaches the surface
   • Characterized by strong updrafts and downdrafts
3. Dissipating stage
   • Characterized by strong downdrafts

Types of Thunderstorms

• Single cell thunderstorms
  • A single cloud forming into a single cell
  • Generally rare, most thunderstorms are multi-cell
• Multicell Thunderstorms
  • A cluster of cells, in different stages of development
  • New cells often form upwind of an existing cell as it develops and moves with the wind
• Supercell thunderstorms
  • Single, quasi-steady rotating updraft that persists for an extended period of time
  • Incredible damaging winds and hail are common
  • About 25 percent produce a tornado

References

• AC 00-06B