Storms Review

Air Parcel

• for an air parcel to rise, it must be warmer (and therefore, less dense) than the air around it
• once it starts to rise, it cools
  • increases air parcels relative humidity
  • absolute humidity stays the because that is just the total amount of water vapor in the air
• when an air parcel reaches a relative humidity of 100%, it’s saturated with water
  • this is called the dew point
• once the air parcel cools lower than the dew point, the water will condense and precipitation will occur
• this condensation causes energy to be released as latent heat
• as an air parcel rises through the atmosphere, the relative humidity will increase

Storms

• when two air masses (one cold and one warm) collide, a severe thunderstorm is produced

• air-mass:

  • key criteria required to form it:
  • inflow of warm, moist air (like tropical climates or late afternoons in the summer)
  • characteristics that differentiate it from other thunderstorm types:
  • local thunderstorms and only last for a short amount of time

• severe:

  • key criteria required to form it:

  • two air masses (a cold and warm front) collide to cause more intense updrafts of warm air and resulting downdrafts of cold air

  • characteristics that differentiate it from other thunderstorm types:

  • must have either:

    1. high winds (>58 mph)
    2. large hail (at least 1” diameter)
    3. generate a tornado/tornadoes

• supercell:

  • key criteria required to form it:
  • extremely large updrafts of warm air
  • rotation of the updrafts to create a vortex
  • characteristics that differentiate it from other thunderstorm types:
  • rotation of the updrafts and tilting of the storm are key criteria that differentiate it from a severe thunderstorm