2. Shuddle and Atmosphere  Lego Shuttle reached an altitude of 35,000 meters. Which layers of the atmosphere did the shuttle reach before descending back to Earth’s surface?

3. Chapter 20 - Weather  Objectives:  -Identify factors that determine the characteristics of an air mass  -Compare and contrast different types of air masses

4. Layer of Atmosphere

5. Air masses  Large body of air in the lower troposphere that has similar characteristics (temperature, humidity) throughout.  Several thousand km in diameter  Characteristics depends on where the air mass originated

6. Air Masses Continued…  As air masses move they take with it the temperature and humidity with them  For example: As an air mass from Canada moves south, Milwaukee, WI will become cold and dry

7. Types of Air Masses  Continental Arctic (cA)  Continental Polar (cP)  Maritime Polar (mP)  Maritime Tropical (mT)  Continental Tropical (cT)

9. Continental Arctic (cA)  Originate in arctic regions  Extremely cold air which causes cold waves  Very dry air masses

10. Continental Polar (cP)  Originate over inland regions of Alaska and Canada  Somewhat warmer than cA air masses  If cP air masses pass over the Great Lakes, they can pick up moisture  Results in Lake-Effect snow

11. Maritime Polar (mP)  Originate over the ocean in high latitudes  Cold and Damp air  If mP cools to its dew point, fog, clouds, or precipitation results  mP air from North Atlantic can bring heavy snow storms called nor’easters

12. Maritime Tropical (mT)  Originate over warm tropical oceans  Warm and moist air  Brings humidity to Midwestern and Eastern United States  Thunderstorms can develop as a result

13. Continental Tropical (cT)  Originate over deserts  cT air masses are hot (can exceed temps over 100 degrees F.) and dry