Air Masses Air masses are large bodies of
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![Air Masses • Air masses are large bodies of air where temperature and moisture Air Masses • Air masses are large bodies of air where temperature and moisture](http://slidetodoc.com/presentation_image_h/10985e2b2aa2ee46d6fe14183b6e1c79/image-2.jpg)
Air Masses • Air masses are large bodies of air where temperature and moisture content are constant throughout. • Moisture content and temperature of a mass are determined by the area over which the air mass forms. • These areas are called source regions.
![Air Masses that Affect weather in North America Air Masses that Affect weather in North America](http://slidetodoc.com/presentation_image_h/10985e2b2aa2ee46d6fe14183b6e1c79/image-3.jpg)
Air Masses that Affect weather in North America
![Cold Air Masses – Continental polar (c. P) forms over northern Canada; brings extremely Cold Air Masses – Continental polar (c. P) forms over northern Canada; brings extremely](http://slidetodoc.com/presentation_image_h/10985e2b2aa2ee46d6fe14183b6e1c79/image-4.jpg)
Cold Air Masses – Continental polar (c. P) forms over northern Canada; brings extremely cold weather during winter; brings cool dry weather during summer – Maritime polar (m. P) forms over North Pacific Ocean; cool, very wet; rain and snow during winter; foggy during summer
![Warm Air Masses • There are three warm air masses that affect the U. Warm Air Masses • There are three warm air masses that affect the U.](http://slidetodoc.com/presentation_image_h/10985e2b2aa2ee46d6fe14183b6e1c79/image-5.jpg)
Warm Air Masses • There are three warm air masses that affect the U. S. – Maritime tropical (m. T) forms over warm water in the Pacific Ocean – Maritime tropical (m. T) forms over the Gulf of Mexico and the Atlantic Ocean; brings hot, humid weather and hurricanes and thunderstorms during the summer; In winter, brings mild, cloudy weather – Continental Tropical (c. T) forms deserts of Mexico and Southwestern U. S. ; brings clear, hot, dry weather during summer
![Fronts • The boundary between air masses of different densities and different temperatures are Fronts • The boundary between air masses of different densities and different temperatures are](http://slidetodoc.com/presentation_image_h/10985e2b2aa2ee46d6fe14183b6e1c79/image-6.jpg)
Fronts • The boundary between air masses of different densities and different temperatures are called Fronts • There are four different fronts that you need to know : Cold, warm, occluded, and stationary
![Cold Front • Cold Front – cold air moves under warm air • Cold Cold Front • Cold Front – cold air moves under warm air • Cold](http://slidetodoc.com/presentation_image_h/10985e2b2aa2ee46d6fe14183b6e1c79/image-7.jpg)
Cold Front • Cold Front – cold air moves under warm air • Cold fronts can move quickly and bring thunderstorms, heavy rain, or snow • Cooler weather usually follows a cold front because the air mass behind the cold front is cooler and drier than the air mass replacing it
![Warm Front • Warm Front – warm air moves over cold air • In Warm Front • Warm Front – warm air moves over cold air • In](http://slidetodoc.com/presentation_image_h/10985e2b2aa2ee46d6fe14183b6e1c79/image-8.jpg)
Warm Front • Warm Front – warm air moves over cold air • In a warm front, the warm air gradually replaces the cold air • Warm fronts generally brings drizzly rain followed by clear and warm weather.
![Occluded Front • Occluded Front – warm air mass is caught between two colder Occluded Front • Occluded Front – warm air mass is caught between two colder](http://slidetodoc.com/presentation_image_h/10985e2b2aa2ee46d6fe14183b6e1c79/image-9.jpg)
Occluded Front • Occluded Front – warm air mass is caught between two colder air masses. Brings cool temperature and large amounts of rain and snow.
![Stationary Front • Stationary Front – cold air mass meets warm air mass; remain Stationary Front • Stationary Front – cold air mass meets warm air mass; remain](http://slidetodoc.com/presentation_image_h/10985e2b2aa2ee46d6fe14183b6e1c79/image-10.jpg)
Stationary Front • Stationary Front – cold air mass meets warm air mass; remain separate; not enough energy to move warm air above cold air mass; can bring many days of cloudy, wet weather.
![Front Illustrations • Front Illustrations Front Illustrations • Front Illustrations](http://slidetodoc.com/presentation_image_h/10985e2b2aa2ee46d6fe14183b6e1c79/image-11.jpg)
Front Illustrations • Front Illustrations
![Air Pressure and Weather • Cyclones – areas in the atmosphere that has lower Air Pressure and Weather • Cyclones – areas in the atmosphere that has lower](http://slidetodoc.com/presentation_image_h/10985e2b2aa2ee46d6fe14183b6e1c79/image-12.jpg)
Air Pressure and Weather • Cyclones – areas in the atmosphere that has lower pressure – Air masses come together ( converge) and rise – Spiral – Causes Stormy weather • Anticyclones – Areas that have high pressure – Air masses move apart ( diverge) – Sinking air denser then surrounding air and pressure is higher – Brings dry, clear weather.
![Cyclone and Anticylone Cyclone and Anticylone](http://slidetodoc.com/presentation_image_h/10985e2b2aa2ee46d6fe14183b6e1c79/image-13.jpg)
Cyclone and Anticylone
![Quick Check Air that has similar characteristics and covers a large region is called Quick Check Air that has similar characteristics and covers a large region is called](http://slidetodoc.com/presentation_image_h/10985e2b2aa2ee46d6fe14183b6e1c79/image-14.jpg)
Quick Check Air that has similar characteristics and covers a large region is called a. a cloud b. a(n) air mass c. a storm d. weather
![Quick Check Continental Polar air masses form over a. Canada b. the Caribbean Sea Quick Check Continental Polar air masses form over a. Canada b. the Caribbean Sea](http://slidetodoc.com/presentation_image_h/10985e2b2aa2ee46d6fe14183b6e1c79/image-15.jpg)
Quick Check Continental Polar air masses form over a. Canada b. the Caribbean Sea c. the gulf of Mexico
![Quick Check Maritime Polar masses form over a. Canada b. the Gulf of Mexico Quick Check Maritime Polar masses form over a. Canada b. the Gulf of Mexico](http://slidetodoc.com/presentation_image_h/10985e2b2aa2ee46d6fe14183b6e1c79/image-16.jpg)
Quick Check Maritime Polar masses form over a. Canada b. the Gulf of Mexico c. the North Atlantic Ocean
![Quick Check Maritime Tropical air masses form over a. Canada b. the North Pacific Quick Check Maritime Tropical air masses form over a. Canada b. the North Pacific](http://slidetodoc.com/presentation_image_h/10985e2b2aa2ee46d6fe14183b6e1c79/image-17.jpg)
Quick Check Maritime Tropical air masses form over a. Canada b. the North Pacific Ocean c. the ocean near the equator
![Quick Check Air masses usually move _____ across the United States. a. east b. Quick Check Air masses usually move _____ across the United States. a. east b.](http://slidetodoc.com/presentation_image_h/10985e2b2aa2ee46d6fe14183b6e1c79/image-18.jpg)
Quick Check Air masses usually move _____ across the United States. a. east b. west c. southwest d. northwest
![Quick Check A front forms a. inside an air mass. b. on the surface Quick Check A front forms a. inside an air mass. b. on the surface](http://slidetodoc.com/presentation_image_h/10985e2b2aa2ee46d6fe14183b6e1c79/image-19.jpg)
Quick Check A front forms a. inside an air mass. b. on the surface of an air mass. c. around an air mass. d. between two air masses.
![Quick Check A cold air mass forces a warm air mass to move a. Quick Check A cold air mass forces a warm air mass to move a.](http://slidetodoc.com/presentation_image_h/10985e2b2aa2ee46d6fe14183b6e1c79/image-20.jpg)
Quick Check A cold air mass forces a warm air mass to move a. b. c. d. downward. upward. to the side. to the back.
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