Severe Weather Weather describes the conditions in the atmosphere in an area over a short period of time. Weather that is extreme and outside of normal conditions is considered severe weather.

What variables affect weather? Temperature: amount of heat Humidity: amount of water vapor Pressure: amount of force exerted by air Precipitation: amount of water falling from clouds Wind: movement of the air

Types of Severe Weather Hurricane (A column of spinning air and water that forms over warm ocean) Tornado (A column of spinning air that forms over land) Drought (Extended periods of low precipitation) Thunderstorm (An electric rainstorm that forms when cold air masses meet warm air masses) https://www.brainpop.com/science/weather/thunderstorms/ Blizzard (Heavy snow storms)

What Causes Hurricanes? Warm, humid air over the ocean begins to rise and condense Low pressure forms in the center of the rising air Air rushes into the low pressure area and begins to spin Wind created by the spinning air causes even more water vapor to rise and the storm gets stronger If winds reach 74 miles per hour a hurricane has formed https://www.brainpop.com/science/weather/hurricanes/

What Causes Tornadoes? Warm, humid air moves over land and becomes even more heated Cool, dense air meets the warm, humid air The cool air rushes in and the warm air starts to spin Wind created by the spinning air causes more water vapor to rise The center of the funnel has extremely low pressure compared to the outside of the funnel and a “vacuum” forms https://www.brainpop.com/science/weather/tornadoes/

Air Masses A weather front is the place where masses of different temperature air meet.

Weather Map Symbols Cold Front Warm Front Stationary Front

Weather Map Forecasting