Chapter 10 Thunderstorms and Tornadoes

  1. Cumulus Stage
    Strong updrafts provide moisture that condenses and builds the cloud
  2. Mature Stage
    Is marked by heavy precipitation.  Updrafts exist side by side with downdrafts and continue to enlarge the cloud.
  3. Dissipating Stage
    Dominated by downdrafts and entrainment, which causes evaporation of the structure.
  4. Entrainment
    The creation of a downdraft is further aided by the influx of cool, dry air surrounding the cloud.
  5. Wind Shear
    Changes in wind direction and/or speed at different heights.
  6. Mesocyclone
    Cyclonically rotating air.
  7. Squall line
    is a relatively narrow band of thunderstorms
  8. Dry Line
    A narrow zone along which there is an abrupt change in the air's moisture content.
  9. Mesoscale convective complex
    Consists of many individual thunderstorms organized into a large oval to circular cluster.
  10. Sheet Lightning
    Produces a bright but diffuse illumination of the parts of the cloud in which the flash occurred.
  11. Cloud-to-ground lightning
    The electrical discharge occurs between the cloud and Earth's surface.
  12. Flash
    Total discharge-which lasts only a few tenths of a second and appears as a bright streak.
  13. Strokes
    Individual components that make up each flash are termed strokes.
  14. Leader
    Once ionized, the air becomes a conductive path with a radius of roughly 10 centimeters and a length of 50 meters.
  15. Step Leader
    During this electrical breakdown, the mobile electrons in the cloud base begin to flow down this channel.  This flow increases the electrical potential at the head of the leader, which causes further extension of the conductive path through further ionization. Because this initial path extends itself toward Earth in short, nearly invisible bursts, it is called a step leader.
  16. Return Stroke
    Because the path of electron flow is continually being extended upward, the accompanying electrical discharge has been appropriately named a return stroke.
  17. Tornadoes
    Are violent windstorms that take form of a rotating column of air, or vortex, that extends downward from a cumulonimbus cloud.
  18. Multiple-Vortex Tornadoes
    A tornado may consist of a single vortex, but within many stronger tornadoes are smaller intense whirls called suction vortices that orbit the center of the larger tornado circulation.
  19. Mesocyclone
    Is a vertical cylinder of rotating air, typically about 3 to 10 kilometers (2 to 6 miles) across, that develops in the updraft of a severe thunderstorm.
  20. Speed Wind Shear
    Winds are stronger aloft than at the surface
  21. Swath
    Any kind of path someone takes.
  22. Enhanced Fujita Scale (EF Scale)
    Guide to tornado intensity
  23. Tornado watches
    Alert the public to the possibility of tornadoes over a specified area for a particular time interval.
  24. Tornado Watch
    Is issued by local offices of the National Weather Service when a tornado has actually been sighted in an area or is indicated by weather radar.
Card Set
Chapter 10 Thunderstorms and Tornadoes
Chapter 10 Thunderstorms and Tornadoes