Chapter 24 Section 2 Handout Fronts

1 When two unlike air masses meet, what usually keeps them separate? Differences in density

2 The boundary that forms between two air masses when they meet is called a: Front

3 Cold front: The front edge of a moving mass of cold air that pushes beneath a warmer air mass like a wedge.

4 Warm front: The front edge of an advancing warm air mass that replaces colder air with warmer air.

5 Stationary front: A front of air masses that moves either very slowly of not at all.

6 Occluded front: A front that forms when a cold air mass overtakes a warm air mass and lifts the warm air mass off the ground and over another air mass.

7 Describe the storms that form along a cold front. They are usually short-lived and sometimes violent. A long line of heavy thunderstorms , called a squall line, may occur in the warm, moist air just ahead of a fast moving cold front.

8 What kind of weather does a warm front generally produce? It produces precipitation over a large area and may cause violent weather.

9 The boundary where cold polar air meets the tropical air mass of the middle latitudes, especially over the ocean, is called the ________. polar front

10 Bends that form in a stationary or cold fronts that are the beginnings of low-pressure storm centers are called _____. waves

11 Also known as midlatitude cyclones, _______ are low-pressure storm centers. wave cyclones

12 An area of low pressure that is characterized by rotating wind that moves toward the rising air of the central low-pressure region is called a _________ ______. midlatitude cyclone.

13 Unlike the air in a midlatitude cyclone, the air of a(n) _________ sinks and flows outward from a center of high pressure. anticyclone

14 Describe an anticyclone. The air of a anticyclone sinks and flows outward from a center of high pressure. Because of the Coriolis effect, the circulation of air is clockwise in the Northern Hemisphere.

15 What kind of weather does an anticyclone Bring? Dry weather If it stagnates for a few days it causes air pollution problems If it lingers for a few weeks, it may cause droughts.

16 List three weather events that are considered severe weather. Large amounts of rain Lightning Hail Strong winds Tornadoes

17 Thunderstorms: A usually brief, heavy storm that consists of rain, strong winds, lightning, and thunder.

18 Lightning: Electricity that is discharged during a thunderstorm.

20 Mature stage: The second stage of a thunderstorm, in which condensation continues as the cloud rises and becomes a dark cumulonimbus cloud, perhaps producing torrential rain and hail.

21 Dissipating stage: The third stage of a thunderstorm, in which strong downdrafts stop air currents from rising and the storm dies out as water vapor deceases.

22 Cumulus stage: The first stage of a thunderstorm in which warm, moist air rises and water vapor in the air condenses to form a cumulus cloud.

23 Thunder: An effect created when electricity heats the air, and the air expands rapidly.

24 A severe storm that develops over tropical oceans and whose winds of more than 120 km/h or 74.56 mph spiral in toward the intensely low-pressure storm center is called a(n) ________. hurricane.

25 During a hurricane, large amounts of ____ ____ are released, increasing the force of the rising air. latent heat

26 A fully developed hurricane consists of a series of thick ______________________ that spiral upward around the center of the storm. cumulonimbus cloud bands

27 Winds increase toward the calm, clear ___ of the storm and may reach speeds of 275 km/h or 170.88 mph. eye

28 The most dangerous aspect of a hurricane is a rising sea level and large waves, called a __________. storm surge.

29 Every hurricane is categorized on the ________________. Safir-Simpson scale.

30 Define tornado: A tornado is a destructive, rotating column of air that has very high wind speeds and that may be visible as a funnel-shaped cloud.

The End