Severe Weather

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Severe Weather
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Thunderstorms

• Three Causes
• Abundant moisture in lower layers of atmosphere
• Mechanism to lift air, allowing condensation
• Unstable air mass
• Air Mass Thunderstorms
• Unequal heating within 1 air mass
• Occur midday, last ½ hour
• Frontal Thunderstorms
• Caused by cold front

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Lightning

• Lightning occurs when there is a charge
  separation in the cloud.
• As a thunderstorm grows, electrical charges build
  up within the cloud, with positive charges at the
  top, and negative charges at the bottom.
• Oppositely charged particles gather at the
  ground below the cloud.

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Tornadoes

• A tornado is a violent, whirling column of air in
  contact with the ground.
• Come from supercells most intense thunderstorms
• Most tornadoes form in the central and southern
  United States
• Continental polar air collides with maritime
  tropical air from Gulf of Mexico

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How are Tornadoes Measured?
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Hurricanes

• Hurricanes are large, rotating, low-pressure,
  storms
• Form from energy in warm, tropical oceans
• Air rises due to existing disturbance and
  low-pressure system is formed
• What causes rotation?
• Coriolis effect
• Hurricane Season is from June to November

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