Transcript Weather
Weather Temperature • Temperature is the measure of the amount of thermal energy in the atmosphere. • How cold or how warm the air is what we call the temperature! Air Pressure • Air pressure is due to the weight of the air and is determined by several factors including the temperature of the air. Barometer • An instrument called a barometer measures air pressure. Weather Front • A weather front is the boundary between air masses of different temperature and humidity. Types of Clouds • Cirrus, stratus, cumulus, and cumulo-nimbus clouds are associated with certain weather conditions. Types of Clouds • Cirrus clouds - Cirrus clouds are feathery clouds. • They are associated with fair weather. • Cirrus clouds often indicate that rain or snow will fall within several hours. Types of Clouds • Stratus clouds - Stratus clouds are smooth, gray clouds that cover the whole sky (block out direct sunlight). • Light rain and drizzle are usually associated with stratus clouds. Types of Clouds • Cumulus clouds Cumulus clouds are fluffy and white with flat bottoms. • They usually indicate fair weather. Types of Clouds • However, when cumulus clouds get larger and darker on the bottom, they become cumulo-nimbus clouds. • Cumulo-nimbus clouds may produce thunderstorms. Precipitation • Precipitation – Water that falls from the clouds to the Earth in the form of rain, snow, hail, or sleet. • Different atmospheric conditions create different types of precipitation. Rain • Rain – When cloud droplets become too heavy to stay in the cloud, they fall toward the Earth’s surface as liquid water. • Rain Gauge – An instrument used to measure the amount of precipitation. Sleet • Sleet – When a falling snowflake melts by passing through warm air, and then suddenly refreezes by passing through cold air, it becomes a tiny chunk of ice called sleet. Snow • Snow – Tiny ice crystals attract each other as they fall toward the ground. • Since the snowflakes do not pass through a layer of air warm enough to cause them to melt, they remain intact and reach the ground as snow. Hail • Hail – These big frozen raindrops occur during severe thunderstorms. • Cold air turns a raindrop into a tiny chip of ice. • Violent winds push the drop back up into the cloud to be coated over and over again with more layers of ice. • Eventually, the hailstone is heavy enough to fall to the ground! Extreme Storms • There are three main types of extreme storms. • They include thunderstorms, tornadoes, and hurricanes. • Anemometer – A tool that measures wind speed. Thunderstorms • Thunderstorm – When cumulo-nimbus clouds are joined by strong winds, heavy rains, and sometimes hail. • Lightning is also a major feature of many thunderstorms. Hurricanes • Hurricane – A huge, slow-moving storm that is fueled by heat and energy from warm ocean waters. • Some hurricanes can be over 500 miles wide and have winds over 150 miles per hour! Tornadoes • Tornado – A dangerous funnel-shaped column of air that reaches from a thundercloud to the ground. • It has spinning winds that can reach over 250 miles per hour! Meteorologists • Meteorologist – A scientist who studies the weather. • They use many tools to help them predict and identify the weather. • Meteorologists use data to predict weather patterns.