Understanding Thunderstorms and Tornadoes

1. Thunder, Lightning, and Tornadoes

2. What is a thunderstorm? A heavy storm accompanied by rain, __________, lightning, and strong winds. The storm may have ____ and tornadoes. Created by surface heating, convection of the warm, moist air rising. A way for the _____________ to release energy. thunder hail atmosphere

3. The three stages of a thunderstorm. • Developing/Cumulus - • Warm, moist air rises, water vapor ________ to form cumulus clouds. • Little to no rain, Lightning present • Mature – • Updraft feeds the storm. ________________clouds form. • Heavy rain falls along with air (downdraft) forming a line of gusty winds • Most likely time for hail, heavy rain, frequent lightning, strong winds, and ___________. • Dissipating – • Downdraft weakens the updraft, which cuts off the supply of _______. • Rainfall decreases, and the cloud begins to evaporate. condenses Cumulonimbus tornadoes water

4. Stages

5. Stages

6. Severe Storms Severe storms are those with one or more of the following: • ______ one inch or greater • ______ gusting over 57.5 mph • A _______ 16 million thunderstorms occur each year worldwide. 100,000 in the US alone. 10% reach severe levels. 2,000 thunderstorms at any given time. Hail Severe Storm in Sky Harbor, AZ Winds Tornado

7. Season for Storms? Most common in ________ and summer months, in the afternoon and evening. WATCH vs WARNING: • _______ = watch and prepare for severe weather • ________ = serious threat to life and property. ACT now and find safe shelter spring Watch Warning

8. Watch versus Warning

9. Types of Thunderstorms

10. Squall line

11. Supercell

12. Lightning… what is it? electricity A giant spark of _________ in the atmosphere. • From cloud to cloud. • From cloud to ground. • From ground to cloud. Due to the build-up of ______ and _______ charges in atmosphere (occurring within a thunderstorm cloud or cloud and ground). Causes _______ - Energy from a lighting channel heats the air to 18,000℉, causing the air to rapidly expand… BOOM (thunder). positive negative Thunder

13. Lightning

14. What causes Lightning - The Debate *

15. How far away is the lightning?

16. Tornadoes • A tornado is a small, short-lived, _______-shaped storm that extends below the base of a cumulonimbus cloud. • The base of the funnel may be 6 feet to 2 miles wide. • The tornado _______ rapidly. • Winds may be up to ___ mph. funnel rotates 250

17. Tornadoes • Tornadoes are white if there is water condensation when they ___________. • Tornadoes become dark when they suck up ________. • Most tornadoes travel less than ___ miles. first form debris 6

18. Tornadoes • There are about ________ tornadoes in the United States every year. • ____ of the world’s tornadoes occur in the Great Plains of the US. • This is called __________. 1,000 75% Tornado Alley

19. Tornadoes • Tornado Alley may be shifting to the ______. east

20. Tornadoes- Tornado Alley may be moving east

21. Tornadoes • Tornadoes over water are called ____________. • The waterspout can suck up fish and frogs and then they rain down up to 100 miles away. waterspouts

22. Tornadoes conditions • A tornado watch means __________ are right for a tornado. • A tornado warning means a tornado has been __________. • The average warning time is 13 minutes. spotted

23. Tornadoes • Tornado season is the _______. (March-May in Illinois) • However, tornadoes may occur any time of year. • The ___________ tornado was August 28, 1990. • It struck Plainfield High School at 3:30 pm. spring Plainfield

24. Tornadoes

25. Tornadoes

26. Tornadoes

27. Tornado scale • The _______ Scale rates the intensity of the tornado. • It was developed by Tetsuya Fujita at the University of Chicago. • In 2007 it was replaced with the Enhanced Fujita Scale (EFS). Fujita

28. Enhanced Fujita Scale