1. Air Masses (Peso de Aire) and Weather (Tiempo)

2. Weather influences our lives every day. It helps us determine: What we wear Whether our airplane is delayed Whether or not we go to school What time to start football practice

3. Because of the weather’s influence, we need to know what the weather is going to be ahead of time Meteorology (meteorologia) – the study of the atmosphere and the factors that affect it

4. Changes in our weather are caused by the interaction of air masses

5. An air mass (peso de aire) is a large body of air that has the same temperature and humidity (humedad) throughout Temperature and humidity depend on where the air mass originates

6. When an air mass enters an area, the area takes on the characteristics of the air mass When it gets hot and muggy in Topeka, it is because of an air mass from the Gulf of Mexico

7. Types of Air Masses Air masses are named according to where they were formed

8. The temperature of each air mass depends on where it was formed Arctic (ártico) – forms above the Arctic Circle (A) Polar – forms over Alaska and Northern Canada (P) Tropical – forms close to the equator (T)

9. The humidity of an air mass depends on whether it formed over land or water Continental – forms over land, dry (c) Maritime (marìtimo) – forms over an ocean, moist (m)

10. Continental Arctic (cA) Characterized as very cold and very dry. These air masses produce cold weather, in winter but don’t occur in summer because the sun heats the poles

11. Continental polar (cP) Warmer than cA air masses, but still cold and dry. These air masses can produce precipitation if they pass over a large body of water

12. Continental Tropical (cT) Characterized as hot and dry. These air masses produce heat waves in the summer

13. Maritime Polar (mP) Characterized as cold and damp. These air masses produce heavy snows in winter and cool temperatures in summer

14. Maritime Tropical (mT) Characterized as warm and damp. These air masses produce thunderstorms