AIR MASSES AND FRONTS Chapter 16 Section 2

Air Mass A large body of air where temperature and moisture content are similar throughout

Air Masses Warm air forms over tropical regions near the equator. T- Tropical Cold air forms over polar regions. P- Polar Wet air masses form over water m- maritime Dry air masses from over land. c- continental

Air masses Moisture content - first letter. m – maritime – wet c – continental – dry Temperature - second letter. P – polar – cool T – tropical - warm

Description of air masses: Continental polar (cP)- cool and dry Continental arctic-type of continental polar mass that is much colder-forms in the arctic circle Continental tropical (cT)- warm (hot) and dry Maritime polar (mP)- humid (wet) and cold; unstable Maritime tropical (mT)- humid (wet) and warm; unstable

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

Fronts A boundary between air masses. Cold front Warm front 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

Clouds, Storms, and rain accompany warm fronts. 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. Followed by cooler, drier air.

Symbol: Cold Fronts

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: 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

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

Symbol: Occluded Front

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.