1. Robert W. Christopherson Charlie Thomsen Chapter 8 Weather

3. Weather Forecasting Figure 8.17

4. Violent Weather Thunderstorms Tornadoes Tropical Cyclones

5. Thunderstorms: cumulonimbus clouds create heavy precipitation, lightning, thunders, hail, wind and tornadoes Figure 8.19 Florida has the highest frequency of T-storms

6. Thunderstorms Figure 8.20

7. Lightning: flashes of light caused by enormous electrical discharges (10-100 millions of volts, super heat the air to 15000- 30000ºC) Thunder: violent expansion of air sends shock waves through atmosphere Lightning hazards: people, animals. Trees, and structures. About 200 death and thousands of injuries in US and Canada

8. Hailstones Figure 8.21

9. Mesocyclone and Tornado Figure 8.22

10. Tornado: funnel clouds touch the earth’s surface; a few meter to 100m in size; Its intensity is measured by Fujita scale Figure 8.22

11. Tornado Figure 8.22

12. Super Cell Tornado and Eye Wall Figure 8.23

13. Tornado Path Figure 8.22

14. Tornadoes: spatial and temporal distribution Figure 8.24 Tornado Alley: Texas, Oklahoma, Kansas. Peak season: May and June in United States

15. Tropical storms start in easterly waves. Easterly Waves : waves move from east to west, thunderstorms occur over the east side of the trough Figure 8.25

16. Tropical Cyclones Figure 8.26

17. Hurricanes Gilbert and Catarina Figure 8.26 Hurricane: tropical cyclone when its maximum wind speed exceed 65 knots (119kph, 74mph)

19. Profile of a Hurricane Figure 8.27 Eye in the center (clear sky, calm) Eyewall: vertical rising air, thick clouds, strong wind

20. Hurricane Isabel, Cape Hatteras and the Outer Banks Figure 8.28

21. 2005: Record-Breaking Storm Season Figure FS 8.1.1 Hurricane season is during later summer and early fall Requirements: warm surface water temperature, 5º away from equator