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 lowpressure 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 lowpressure 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