1. Weather Fronts and Storms
CHAPTER
NEW CHAPTER
Weather Fronts and Storms
the BIG idea
The interaction of air masses causes changes in weather.
Weather Fronts and Storms
3.1
Weather changes as air masses move.
3.2
Low-pressure systems can become storms.
3.3
Vertical air motion can cause severe storms.
3.4
Weather forecasters use advanced technologies.
CHAPTER OUTLINE

2. 3.1 Weather changes as air masses move.
Air masses meet and produce fronts, which can bring lowered pressure and stormy weather. Fronts can be cold, warm, or stationary.
air mass
front
Cold Front
high-pressure system
low-pressure system
SECTION
OUTLINE

3. 3.1 Weather changes as air masses move.
Air masses meet and produce fronts, which can bring lowered pressure and stormy weather. Fronts can be cold, warm, or stationary.
air mass
front
Warm Front
high-pressure system
low-pressure system
SECTION
OUTLINE

4. 3.1 Weather changes as air masses move.
Air masses meet and produce fronts, which can bring lowered pressure and stormy weather. Fronts can be cold, warm, or stationary.
air mass
front
Stationary Front
high-pressure system
low-pressure system
SECTION
OUTLINE

5. 3.1 air mass Weather changes as air masses move.
front
A large volume of air that has nearly the same temperature and humidity at different locations at the same altitude.
high-pressure system
low-pressure system
KEY CONCEPT
SUMMARY

6. 3.1 front Weather changes as air masses move.
The boundary between air masses.
high-pressure system
low-pressure system
KEY CONCEPT
SUMMARY

7. 3.1 high-pressure system Weather changes as air masses move.
front
A generally calm and clear weather system that occurs when air sinks down in a high- pressure center and spreads out toward areas of lower pressure as it nears the ground.
high-pressure system
low-pressure system
KEY CONCEPT
SUMMARY

8. 3.1 low-pressure system Weather changes as air masses move.
front
A large and often stormy weather system that occurs when air moves around and into to a low-pressure center, then moves up to higher altitudes.
high-pressure system
low-pressure system
KEY CONCEPT
SUMMARY

9. Low-pressure systems can become storms.
3.2
Low-pressure systems can become storms.
Hurricanes and winter storms develop from low-pressure systems. Hurricanes form over warm ocean water.
tropical storm
hurricane
storm surge
blizzard
SECTION
OUTLINE

10. Low-pressure systems can become storms.
3.2
Low-pressure systems can become storms.
Ice storms are a type of winter storm.
tropical storm
hurricane
storm surge
blizzard
SECTION
OUTLINE

11. 3.2 tropical storm Low-pressure systems can become storms.
hurricane
storm surge
A low-pressure system that starts in the tropics with winds of at least 65 kilometers per hour (40 mi/h) but less than 120 kilometers per hour (74 mi/h).
blizzard
KEY CONCEPT
SUMMARY

12. 3.2 hurricane Low-pressure systems can become storms.
tropical storm
hurricane
hurricane
storm surge
A tropical low-pressure system with sustained winds of 120 kilometers per hour (74 mi/h) or more.
blizzard
KEY CONCEPT
SUMMARY

13. 3.2 storm surge Low-pressure systems can become storms.
tropical storm
storm surge
hurricane
storm surge
A rapid rise in water level in a coastal area that occurs when a hurricane pushes a huge mass of ocean water, often leading to flooding and widespread destruction.
blizzard
KEY CONCEPT
SUMMARY

14. 3.2 blizzard Low-pressure systems can become storms.
tropical storm
blizzard
hurricane
storm surge
A blinding snowstorm with winds of at least 56 kilometers per hour (35 mi/h), usually with temperatures below –7°C (20°F).
blizzard
KEY CONCEPT
SUMMARY

15. Vertical air motion can cause severe storms.
3.3
Vertical air motion can cause severe storms.
Rising moist air can produce thunderstorms. The up-and-down motion of air in a thunderstorm can produce a tornado.
thunderstorm
tornado
SECTION
OUTLINE

16. Vertical air motion can cause severe storms.
3.3
Vertical air motion can cause severe storms.
Rising moist air can produce thunderstorms. The up-and-down motion of air in a thunderstorm can produce a tornado.
thunderstorm
tornado
SECTION
OUTLINE

17. 3.3 thunderstorm Vertical air motion can cause severe storms.
tornado
A storm with lightning and thunder.
KEY CONCEPT
SUMMARY

18. 3.3 tornado Vertical air motion can cause severe storms.
thunderstorm
tornado
tornado
A violently rotating column of air stretching from a cloud to the ground.
KEY CONCEPT
SUMMARY

19. Weather forecasters use advanced technologies.
3.4
Weather forecasters use advanced technologies.
Weather information comes from many sources.
meteorologist
isobar
Radar
Station
Ground
Station
Satellite
SECTION
OUTLINE

20. Weather forecasters use advanced technologies.
3.4
Weather forecasters use advanced technologies.
Meteorologists use weather data and computer models to forecast weather.
meteorologist
isobar
SECTION
OUTLINE

21. 3.4 meteorologist Weather forecasters use advanced technologies.
isobar
A scientist who studies weather.
KEY CONCEPT
SUMMARY

22. 3.4 isobar Weather forecasters use advanced technologies.
meteorologist
isobar
isobar
A line on a weather map connecting places that have the same air pressure.
KEY CONCEPT
SUMMARY

23. 3.1 Weather changes as air masses move.
I. Weather changes as air masses move.
air mass
A. Air masses are large bodies of air.
front
1. Characteristics of an Air Mass
high-pressure system
2. Movement of an Air Mass
B. Weather changes where air masses meet.
low-pressure system
1. Fronts and Weather
2. High-Pressure Systems
3. Low-Pressure Systems
KEY CONCEPT
SUMMARY

24. Low-pressure systems can become storms.
3.2
Low-pressure systems can become storms.
II. Low-pressure systems can become storms.
tropical storm
A. Hurricanes form over warm ocean water.
hurricane
1. Formation of Hurricanes
storm surge
2. Effects of Hurricanes
blizzard
B. Winter storms produce snow and ice.
KEY CONCEPT
SUMMARY

25. Vertical air motion can cause severe storms.
3.3
Vertical air motion can cause severe storms.
III. Vertical air motion can cause severe storms.
thunderstorm
A. Thunderstorms form from rising moist air.
tornado
1. Formation of Thunderstorms
2. Effects of Thunderstorms
B. Tornadoes form in severe thunderstorms.
1. Effects of Tornadoes
KEY CONCEPT
SUMMARY

26. Weather forecasters use advanced technologies.
3.4
Weather forecasters use advanced technologies.
IV. Weather forecasters use advanced technologies.
meteorologist
A. Weather data come from many sources.
isobar
B. Weather data can be displayed on maps.
1. Air Pressure on Weather Maps
2. Satellite Images and Special Maps
C. Forecasters use computer models to predict
weather.
KEY CONCEPT
SUMMARY