Air masses An air mass is a large body of air with consistent temperature and moisture characteristics throughout. Two air masses that affect the United States are the continental polar air mass and the maritime tropical air mass.

How do air masses move? . Changing conditions and global winds cause these air masses to move. Prevailing westerlies push air masses from west to east.

Fronts When air masses meet, a front is formed; the collision often causes storms and weather changes. A front may be 15 to 200 kilometers wide and extend as much as 10 kilometers up to the troposphere.

There are four types of fronts. Cold Fronts. Warm Fronts. Stationary Fronts. Occluded Fronts.

Cold Fronts A cold front occurs when cold air moves in and replaces warm air.

Warm Front A warm front occurs when warm air moves in and replaces cold air.

Stationary Fronts Sometimes cold and warm air masses meet but neither one has enough force to move. Where the warm and cold air meet, water vapor in the warm air turns into rain, snow, fog, or clouds.

Occluded Fronts A warm air mass is caught between two cooler air masses. As warm air cools and its water vapor condenses, the weather may turn cloudy, rainy, or snowy.

Cyclones                                                                                             As warm air at the center of a cyclone rises , the air pressure decreases. winds in a cyclone spin counterclockwise in the Northern Hemisphere & clock wise in southern hemisphere. As air rises in a cyclone the air cools forming clouds and precipitation Hurricanes are very large cyclones.

Anticyclones Winds spiral outward from the center of an anticyclone, moving towards areas of low pressure. Winds in an anticyclone spin clockwise in the Northern Hemisphere.

Vocabulary Air mass- a huge body of air that has similar temperature, humidity, and pressure. Front- the area where the masses meet and do not mix. Cyclone- a swirling center of low air pressure. Anticyclone- area of high pressure centers of dry air.

Temperature Humidity Section 1 Review 1.) Which two main characteristics are used to classify air masses? Temperature Humidity

Section 1 Review 2.) What's a front? Name and describe the four fronts. Front- the area where the masses meet but do not mix. Cold Fronts- when a rapidly moving cold air mass runs into a slowly moving air mass, the denser cold air slides under the lighter warm air. Warm Fronts- a moving warm air mass collides with a slowly moving cold air mass. Stationary Fronts- sometimes cold and warm air masses meet but neither one has enough force to move. Occluded Fronts- a warm air mass is caught between two cooler air masses.

Section 1 Review Cyclone- a swirling center of low air pressure. 3.) What is a cyclone? What kind of weather does it bring? Cyclone- a swirling center of low air pressure. A cyclone usually brings precipitation and usually forms clouds.

Difference between tropical and temperate cyclone Tropical cyclone the temperate cyclones are those which occur in mid latitudes i.e. 400 to 600 N & S. These are formed due to convergence of the warm (tropical) and Cold (Polar) airmasses.  the tropical cyclones are those which occur in lower latitudes, normally 100 to 300 N & S latitudes. are caused due to the low pressure centre where convergence of warm dry and warm moist airmasses. These cyclones do not experience fronts