1. Bell Ringer
Two types of isopleths are isobars and isotherms. Isobars show areas of equal __________ and isotherms show areas of equal ______________.
air pressure
temperature

2. Thunderstorms

3. Thunderstorm Factors
At any given moment, nearly 2000 thunderstorms are occurring around the world
Thunderstorms form from cumulonimbus clouds (anvil-shaped clouds)
Can be very severe, but usually last only about 30 minutes

4. Anvil?

5. Thunderstorm Factors Thunderstorms need: Warm, humid air
Unstable atmosphere (allows a convection current to occur)

6. Thunderstorm Factors
Latent Heat -- heat energy stored in water vapor that is released during condensation
When air rises, it begins to cool down. The water vapor condenses into liquid water and releases the latent heat energy into the air.

7. Thunderstorm Factors
This heat warms up the cloud and causes it to lift up higher (because warm air rises), which causes more and more water vapor to condense… and release heat…

8. Thunderstorm Formation
Three stages to thunderstorm formation
Cumulus Stage – cumulus cloud forms, latent heat is released, cloud droplets join together (coalesce) and fall as precipitation

9. Thunderstorm Formation
Mature Stage – precipitation cools the air, creates a convection current of updrafts (warm air rises) and downdrafts (cool air sinks)
Dissipation Stage – air cools, convection slows and then stops (and the storm dies out)

10. Dangers of Thunderstorms
Only about 10% of thunderstorms are considered severe, and even fewer are considered supercells
Supercells – self-sustaining, extremely powerful storms with intense rotating updrafts

11. Supercell Timelapse

13. Dangers of Thunderstorms
Lightning – a discharge of electrons (electricity) from a thundercloud to the ground, cloud to cloud, or ground to cloud

14. Dangers of Thunderstorms
The negatively-charged air in the cloud moves towards the positively-charged ground, which creates lightning

15. Dangers of Thunderstorms
Lightning heats the air to around 30,000oC, which is 5 times hotter than the surface of the Sun!
At this temperature, air expands explosively and creates the sound of thunder (thunder is the effect of lightning)
Because sound travels more slowly than light, you typically see lightning before you hear thunder

16. Dangers of Thunderstorms

17. Dangers of Thunderstorms
Each year, lightning causes about forest fires, 300 injuries, and deaths

18. Lightning Strike Cary, NC

20. Dangers of Thunderstorms
Hail – precipitation in the form of lumps of ice
Rain droplets get caught in the updrafts and downdrafts, creating a cycle of adding moisture and refreezing until it gets too heavy and falls out of the cloud as hail

21. Dangers of Thunderstorms
Floods – occur when a thunderstorm moves slowly over one location, dumping all its rain in one place
Main cause of thunderstorm-related deaths in the US

24. Spend the next few minutes studying for your quiz.
Write clearly, put answers in blanks, and attempt all questions! Hand in to the front basket when done and get vocab.
Vocabulary needs to be completed in class. VOCAB QUIZ ON ASSIGNMENTS 1&2 TUESDAY!

25. You Be the Teacher
Your group will become experts in either a type of severe weather or about climate.
You will research this topic and on review day present this information to the class.
EVERYONE MUST PARTICIPATE. Part of your grade will be based on participation.

26. You Be the Teacher You supply the notebook paper.
Computer paper (for your drawing) is at Stn 2.
Markers (1 box/group only) and rulers are at Stn 1.
EACH PERSON needs a textbook. Return textbooks to a BOOKSHELF at the end of class.