Happy Wednesday! 1-11-17 Come in Quietly You will need to pick up the 3 papers on the front table Have your planner out for me to check Please have your binder open to page 201 You will also need a pencil, highlighter and 4 colors (markers, pencils, or crayons)

Air Masses and their Movements Chapter 6.3

Air mass A huge body of air that has similar temperature, humidity, and air pressure at any given height.

Tropical Warm air masses that form in the tropics and have low air pressure. TROPICAL

Polar POLAR Cold air masses that form north of 50o north latitude and south of 50o south latitude, with high air pressure.

Maritime Air masses that form over oceans, usually very humid.

Continental Air masses that form over land, usually drier than maritime air masses.

4 Major types of air masess There are 4 major types of air masses that influence weather in North America: A. maritime tropical B. maritime polar C. continental tropical D. continental polar

What are the major air masses? Maritime tropical Continental tropical Maritime polar Continental polar

Maritime Polar: Cool, humid air masses form over North Atlantic often pushed out to sea by westerly winds. These can also form over the Pacific Ocean and can bring cool weather to the west coast.

Continental Polar These form over Canada and Alaska, can bring bitterly cold weather with low humidity.

Maritime Tropical Warm, humid air masses that form over the Gulf of Mexico and the Atlantic Ocean. Often bring thunderstorms with heavy rain or snow. If they form over the Pacific Ocean they bring hot, humid weather with summer showers.

Continental Tropical: Hot, dry air masses that form mostly in the summer over the Southwest or N. Mexico. They can bring hot, dry weather to the great plains.

What moves Air Masses? Prevailing Westerlies- Major wind belts over the U.S. Jet Streams: Bands of high-speed winds about 10 km above Earth’s surface; generally blow from west to east.

Front The boundary where air masses meet.

What are the main types of fronts?  Warm Front Cold Front  Stationary Front Occluded  Front

Weather @ the Front pgs. 204-205 Clouds, many days of precipitation Clouds, heavy precipitation Clouds, many days of precipitation Clouds, precipitation

Occluded Cut off, as in a front where a warm air mass is caught between two cooler air masses. Most complex of the different fronts

Cyclone A swirling center of low air pressure.

Anticyclone High-pressure centers of dry air.

What weather do cyclones and anticyclones bring? Cyclones and decreasing air pressure are associated with … clouds, wind, and precipitation. Anticyclones are associated with … dry, clear weather.

Air Masses and Their Movements Cyclones and Anticyclones Which image is a cyclone and which is an anticyclone? What is the air motion direction of each? Cyclone Anticyclone

Air Masses and Their Movements Pg. 207 Which circles are low-pressure centers and which are high-pressure centers? L H L H