1. Chapter 13.1 Thunderstorms
A. 3 Conditions must exist for a T-Storm to occur
1. Abundant source of moisture in the troposphere
2. A mechanism that lifts the air so the moisture can condense and release latent heat to create an unequal heating of Earth’s surface
3. The area in the atmosphere needs to be unstable.

2. 1. Air Mass: Unequal heating of the Earth
1. Air Mass: Unequal heating of the Earth
2. Frontal: Associated with advancing cold fronts

3. C. Stages of Development
1. Classified according to the direction in which the air is moving
a. Cumulus Stage: Air rises vertically upward = UPDRAFT
Condenses moisture forming rain drops
b. Mature Stage: Rain cools the air and sinks= DOWNDRAFT
c. Dissipation Stage: Downdraft loses energy, no warm air to fuel the cell, clouds run out of moisture

4. D. Thunderstorms can be more severe, depending on the amount of moisture and pressure system= SUPERCELL

5. E. Results of a Thunderstorm
1. Lightning= electricity caused by a rapid rush of air, from the friction between the updrafts and downdrafts Electrons separate resulting in areas of oppositely charged air
2. Wind
3. Hail
4. Flooding
5. Tornadoes

6. Tornado Violent, whirling column of air which touches the ground
Funnel Cloud-->
doesn’t touch the
ground

7. F. Formation 1. Forms in the most severe Thunderstorms = Supercells
2. Winds shift directions and speed
3. Horizontal columns of air, dust, debris, and water vapor forms
4. This column hits an updraft, tilting to a vertical position
5. Column rotates and accelerates, removing air from the center
6. This creates a low pressure system in the center with extreme wind surrounding the ‘eye’

8. G. Tornadoes are more likely to form in the spring, during the late afternoon and evenings.
Occur in the central United States because of the large temperature contrast with air masses colliding

9. H. Tornadoes are classified by the Fujita Tornado Intensity Scale
1. Scale goes from F0- F5
2. Only 1% of tornadoes ever reach F4/F5 range
3. Ranked by
- Duration
- Wind Speed
- Path of Destruction
*Watch Storm Chasers Video

10. Chapter Hurricanes
1. Large, rotating, low- pressure storms are called Tropical Cyclones
a. For this storm to occur large amounts of water evaporates from the ocean surface
b. Latent Heat is then stored from the warm water
c. This heat is released when air begins to rise and water vapor condenses
d. Forms clouds and rain
e. Once wind speeds reach 65 km/h the system becomes a tropical storm
f. As air pressure increases winds can reach up to 120 km/h (74 mph), classified as a hurricane

11. e. Within a hurricane an eye forms- a calm center of the storm.
g. Surrounding the eye is the eye wall where the strongest winds occur

12. a. Pacific Ocean has TYPHOONS
2. Name of the Hurricane depends on the location
a. Pacific Ocean has TYPHOONS
b. Indian Ocean has CYCLONES
c. Atlantic Ocean has HURRICANES

13. 3. Hurricanes are classified based on the Saffir-Simpson Scale
a. Classifies the hurricane based on
- Wind Speed
- Air Pressure in the Center
- Property Damage
b. The scale has 5 categories, with #5 being the highest wind speed and most damage