Presentation on theme: "Weather study guide answer. Humidity Humidity is the amount of water vapor in air. The air cannot hold much more water when humidity is high so your."— Presentation transcript:
Warm air is less dense than colder air and rises in the atmosphere. Rising moist air causes areas of low pressure, creates clouds, and is associated with stormy weather.
High and Low Pressure Systems Cool air is more dense than warmer air and sinks in the atmosphere. Sinking dry air causes areas of high pressure, evaporates clouds, and is associated with fair weather
Wind forms Air molecules move from areas of high pressure to low pressure; these moving molecules create wind.
Thunderstorms Thunderstorms form when warm, moist air rises quickly and then cold air sinks quickly.
Thunderstorms Three dangers of thunderstorms include: heavy rains (flash floods), lightning, strong winds, tornadoes, and hail.
Thunderstorms Lightning is produced in a cloud when different parts of the cloud become oppositely charged. When current flows between regions of opposite electrical charge, lightening flashes
Thunderstorms Thunder is caused by the rapid heating of air around a bolt of lightening
Tornadoes Tornadoes form when the up and down movement of air in a thunderstorm begins to move in a circular motion.
Tornadoes Weather that is associated with tornadoes includes hail and lightning.
Tornadoes The Fujita Scale is used to rate tornadoes based on the wind speed. (F-0 through F-6)
Tornadoes Warm moist air from the Gulf of Mexico collides with cool air from Canada and dry air from the Rockies. This collisions of air mass is often triggers thunderstorms, often very strong ones. Tornadoes form during thunderstorms, when unstable hot air near the ground rises and meets the cooler air above in the thunder clouds.
Hurricane Low pressure system over the ocean near the equator Hurricanes form when warm, moist air rises quickly over warm water.