Anatomy of a Supercell

Key Characteristics

• Height: Up to 60,000 ft
• Features: Large hail (grapefruit-sized), tornadoes (potentially >1 mile wide), torrential rain, continuous lightning

Types of Supercells

1. Organized Supercells
   • Multiple supercells in a parent system
   • Features: Heavy rain, strong wind, hail
   • Often outflow dominant but can produce tornadoes
   • Associated anvil can trail miles, producing lightning
   • Often preceded by ominous shelf clouds
2. Discreet or Semi-Discreet Supercells
   • Classic Supercell: Persistent rotating updraft, heavy rain, hail, mesocyclone
   • Low Precipitation Supercell: Little/no rain around the updraft, moderate rain and large hail in the core
   • High Precipitation Supercell: Updrafts wrapped in precipitation, heavy rain, large hail

Ingredients for Storms

1. Moisture
2. Rising and Unstable Air
3. Lifting Mechanism (e.g., warm front, cold front, dry line, orographic lift, differential heating)

Important Concepts

• Convection: Warm air rising, crucial for thunderstorm development
• CAPE: Convective Available Potential Energy, measures instability
• Capping Inversion: A layer of warm air that forces the Cape below it; if broken, the storm gains strength
• Orographic Lift: Air mass forced to rise over terrain, adiabatically cooling
• Mesocyclone: Persistent rotating updraft within a thunderstorm, crucial for tornado formation

Stages of a Supercell

1. Development: Formation of cumulus clouds
2. Mature Stage: Cumulonimbus cloud, characterized by heavy precipitation and lightning
   • Pulls in warm moist inflow
   • Anvil formation at upper levels
3. Dissipating Stage: Outflow dominant with straight-line winds

Weather-related Phenomena

• Hail: Formed in updrafts, characterized on radar by a hail spike
• Flash Floods: Rapidly rising water, dangerous and a major weather killer
• Wind Shear: Change in wind speed/direction with height; leads to horizontal vorticity tubes
• Tornadoes: Violently rotating columns of air, formed from mesocyclones
  • Indicators: Wall clouds, hook echo on radar
  • Varieties: Single-vortex, multiple-vortex (suction vortices), rain-wrapped
  • Cyclic Supercells: Can produce multiple tornadoes in cycles
  • Rain-wrapped Tornadoes: Difficult to see, highly dangerous
• Outflow Boundaries: Can enhance low-level shear and strengthen tornadoes
• Straight-line Winds & Gustnadoes: Can cause significant damage
• Durations: Intense straight-line wind storms similar to tornadoes

Safety and Awareness

• Media & Weather Services: Critical for public awareness and safety
• Storm Chasers: Attempt risky maneuvers for better views, but highly dangerous
• Flood Safety: Avoid attempting to cross flooded roadways, rapid rising waters can be lethal