Thunderstorms, Hurricanes and Tornadoes

1. Thunderstorms, Hurricanes and Tornadoes

2. Thunderstorm Facts • Right now there are about 2,000 thunderstorms occurring worldwide • There are about 45,000 thunderstorms per day!! • U.S. gets 100,000 per year!

7. Severe Thunderstorms • Torrential Downpours • Strong winds at greater than 58 mph • Hail ¾ inch diameter (or larger) • Frequent lightning

8. Severe Thunderstorm Watch • Issued by National Weather Service • This means that conditions are favorable for a thunderstorm • Length is multiple hours.

9. Severe Thunderstorm Warning • Issued By Local Weather Service • Means a severe storm has been spotted by doppler radar • Usually only an hour

10. Lightning

12. Types of Lightning • Cloud-to-ground (CG) • Intra-cloud (IC) • Ribbon lightning • Sheet lightning • Heat lightning • Ball lightning

13. Cloud-to-ground (CG) Lightning

16. Intra-cloud (IC) Lightning

19. Ribbon Lightning

22. Sheet Lightning

24. Heat Lightning

26. Ball Lightning

28. Lightning Safety • Stay indoors, away from doors and windows. • Do not take baths or showers. • Do not use phones with cords.

29. Cars are pretty safe…

30. Thunder

31. How Far Away Was That Lightning? • When you see the flash, start counting seconds. • When you hear the thunder, stop counting. • Every 5 seconds is equal to 1 mile.

32. Tornadoes

34. F-Scale • F0 – Light damage • F1 – Moderate damage • F2 – Considerable damage • F3 – Severe damage • F4 – Devastating damage • F5 – Incredible damage (Auntie Em!)

37. Tornado Watch • Conditions are favorable for a tornado to form

38. Tornado Warning • A tornado has formed.

39. Tornado Safety • Get indoors and stay there • Stay away from doors and windows • Get to lowest level possible • Don’t get near things that can fall on you

40. When to expect • Hurricane season is June through November • Peak is in September

41. Formation of Hurricanes • Tropical Depression • Tropical Storm • Hurricane

42. Tropical Depression • Cluster of organized thunderstorms • Not very compact • Sustained winds of at least 30 mph • Given a number

43. Tropical Storm • Winds above 39 mph • Given a name • More organized • If hits land, most damage caused is by rainfall.

44. Hurricane • Winds over 74 mph • Well defined center of circulation • Eye Wall • Damage from includes: • Wind • Storm surge • Rain

45. Pressure in hurricane • A way to tell strength of hurricane is by its pressure • Measured in millibars (mb) • Higher pressures are weak, lower are stronger

46. Naming System • A list of names from A-W (excluding Q) • Alternate from male to female • 6 lists, repeated in cycle • Big name storms replaced

47. Saffir-Simpson Scale • Designed by Herbert Saffir and Bob Simpson • Divides hurricanes into categories based on maximum sustained winds.

48. Category 1 • Winds- 74-95 mph • Storm Surge- 4-5 ft. • Pressure- 986mb • Damage- mobile homes, trees, minor costal flooding

49. Category 2 • Winds- 96-110 mph • Storm surge- 6-8 ft. • Pressure- 965- 979 mb • Damage- Some roof and window. Damage to piers on coast. Small crafts. vegetation

50. Category 3 • Winds- 111-130 mph • Storm surge- 9-12 ft. • Pressure- 945-964 mb • Damage- structure damage to homes and buildings. Mobile homes destroying. Major coastal flooding with a potential for inland flooding.