1.  Weather that causes damage and destruction  Comes in 3 basic forms, each an escalation of the previous  Thunderstorms  Tornadoes  Hurricanes

2.  Caused by violent updrafts of air (form cumulonimbus clouds)  Usually form within marine tropical air (warm and humid)  Severe thunderstorms: large and long- lived (several hours) thunderstorms that produced frequent lightning, damaging winds, and sometimes hail  Usually form along or ahead of cold fronts (forceful uplift)

3.  Lightning: Bottom of cloud gets negative charge- positive flow from earth to balance this out  Thunder: Caused by the rapid heating/expansion of air due to lightning

4.  Violently rotating column of air which descends from a thunderstorm  Associated with “supercell” thunderstorms- severe rotating thunderstorm  Intensity measured using Fujita Tornado Damage Scale

5.  Tropical cyclones with fast moving winds (greater than 74 miles per hour)  Progression of windspeed:  Tropical depression  Tropical storm  Hurricane  Eye: center of the hurricane; Eye wall: the area of intense updraft just outside the eye—fastest winds and heaviest rainfall

6.  Hurricanes are fueled by latent heat! Need massive quantities of warm air with plenty of water vapor so air keeps rising  Need water above 27  C (80  F)  Need to be greater than 5  from the equator (need Coriolis effect)