1. Weather & Climate Chapter 20.3

2. FRONTS Warm Cold Stationary

3. Warm Fronts Mass of warm air moves toward and over a slower mass of cold air Warm air is pushed up, it cools and forms clouds Cirrus clouds are seen first, followed by lower clouds (possibly nimbostratus)

4. Cold Fronts Mass of cold air moves toward and under a slower mass of warm air The cold air mass has a steep edge, forcing the warm air up quickly (again forming clouds) High winds and thunderstorms (maybe tornadoes) are a possibility

5. Stationary Fronts Two air masses meet but neither is displaced The air masses move side by side along the front Weather is similar to warm fronts

6. SEVERE WEATHER Lightning Tornadoes Hurricanes

7. Lightning Discharges of atmospheric electrical energy Very similar to static electricity like when you shuffle your feet Thunder comes from lightning heating the air, causing it to expand rapidly

8. Tornadoes Funnels of high speed, rotating winds Formed from cool, dry air from the north hitting warm, moist air from the south

9. Hurricanes Extremely large storm systems Their strength depends on energy from warm, evaporated ocean water Same storm, different name Cyclones Typhoons

10. CLIMATE The general weather conditions over many years Climate may change over time Position of continents Change in tilt Increased greenhouse effect Volcanic eruptions

11. Climate Factors Temperatures tend to be warmer nearer the equator (Why?) Earths tilt and rotation account for our seasons (How?) Earths surface features affect climate, also (How? & Examples)

12. Homework Question Define the greenhouse effect and describe its effect on Earth. Provide two examples of how human activity contributes to the greenhouse effect. (4 point question)