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AIR MASSES AND FRONTS. Chapter 16 Section 2. Fronts. A front is a boundary between air masses . Four types of fronts and map symbols Cold front Warm front Occluded front Stationary front. WARM FRONT. Warm air mass meets a cold air mass and pushes the cold air mass out of the way.
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AIR MASSES AND FRONTS Chapter 16 Section 2
Fronts • A front is a boundary between air masses. • Four types of fronts and map symbols • Cold front • Warm front • Occluded front • Stationary front
WARM FRONT • Warm air mass meets a cold air mass and pushes the cold air mass out of the way. • Brings drizzly precipitation. • Followed by clear warm weather.
Symbol: Warm Fronts A warm front occurs when a less dense air mass rides up over a more dense air mass.
Clouds, Storms, and rain accompany warm fronts. Moving warm air mass collides with a slowly moving cold air mass • Warm Front Animation: • http://ww2010.atmos.uiuc.edu/(Gl)/guides/crclm/act/gifs/fpr4.gif • http://earthsci.org/processes/weather/weaimages/2e.gif
COLD FRONT • Cold air mass meets a warm air mass and pushes the warm air mass out of its way. • Bring thunderstorms, rain or snow. • Most tornadoes develop from • thunderstorms on the edge of a cold front. • Cold front followed by cooler drier air.
Cold Fronts Symbol: A cold front occurs when a more dense air mass pushes under a less dense air mass.
Cold Fronts can cause heavy snow or ice if there is enough water vapor in the air.
STATIONARY FRONT • Cold air meets warm air. • Not enough force to move either front. • Many days of cloudy, wet weather.
Stationary Front Symbol: • Warm air mass and cold air mass meet • Neither has enough force to move the other so they just stay in the same place. • Where they meet, water vapor in the warm air condenses into rain, snow, fog or clouds • Can stall out for days
Stationary Fronts: • Stationary Front Animation: • http://www.usatoday.com/weather/tg/wsfront/wsfront.htm Unlike a fast-moving front, Stationary fronts often bring several days of cloudy, wet weather that can last a week or more.
OCCLUDED FRONT • Warm air caught between two cold air masses. • Brings cool temperatures with large amounts of rain or snow
Occcluded Fronts:The two cooler air masses meet in the middle and may mix. The warm air mass is cut off (or occluded) from the ground. • http://www.uwsp.edu/geo/faculty/ritter/images/atmosphere/weather/cold_occlusion.gif
Occluded Front Symbol: A warm air mass is caught between two cooler air masses
Cold Front, Warm Front and Occluded Front Animation • http://www.3villagecsd.k12.ny.us/Murphy/medina/weather.html • http://www.classzone.com/books/earth_science/terc/content/visualizations/es2002/es2002page01.cfm?chapter_no=visualization • Click on the above links.
Humidity • the amount of water vapor in the air
Air Masses An air mass is an extremely large body of air whose properties of temperature, moisture content (humidity) and air pressure are similar throughout . Air masses can cover hundreds of thousands of square miles. • Warm air forms over tropical regions near the equator. T- Tropical • Coldair forms over polar regions. P- Polar • Wetair masses form over water m- maritime Dry air masses from over land. c- continental
Air masses • Moisture content is noted by the first letter. m – maritime – wet c – continental – dry • Temperature is noted by the second letter. P – polar – cool T – tropical - warm
Description of air masses: • Continental polar (cP)- cold and dry-forms over land, High Pressure • Continental tropical (cT)- warm (hot) and dry- forms over land (Low Pressure) • Maritime polar (mP)- Cold and Humid (wet); Forms over cold water (High Pressure) • Maritime tropical (mT)- Warm and humid(wet); Forms over warm water (Low Pressure)
Air Masses • mP- maritime polar air mass • cP – continental polar air mass • mT – maritime tropical air mass • cT – continental polar air mass
An air mass is a large body of air that has similar temperature and moisture properties
Describe each type of air mass. (Temp. Humidity, and Pressure) 1. 2. 3 5 4 6