Download Study Guide for Chapter 17 Weather

Study Guide for Chapter 17 Weather
Test Tuesday and Wednesday December 6th and 7th
I.
Air masses and fronts
A. Four types of air masses in N. America (Maritime means wet because the
clouds formed over the ocean, continental means dry because the clouds
formed over land, polar is cold and tropical is hot)
1. Maritime tropical
2. Continental tropical
3. Maritime polar
4. Continental polar
B. Four types of fronts
1. Cold front-Front moving into an area bringing cold air (Cold air
moves under warm air because it is more dense)
2. Warm front-Front bringing warm air
3. Stationary front-Front that has stalled over an area
4. Occluded front- two cold fronts trapping a warm air mass
C. Cyclones and decreasing air pressure are associated with storms and
precipitation
D. The faster front usually moves in first
II.
Storms
A. Thunderstorms and tornadoes form within large cumulonimbus clouds
1. During thunderstorms avoid touching metal objects
B. A hurricane begins over warm water in a low pressure area
C. Snow falls when humid air-cools below 0C.
1. If you are caught in a snowstorm, try to find shelter from the
wind.
2. During a tornado a basement is the safest place to be
D. The difference in a cyclone and an anticyclone is
1. The direction of their rotation
2. A cyclone is centered around a low pressure area and brings bad
weather
3. An anticyclone is centered around a high pressure area and
brings good weather
E. A Tornado is a funnel-shaped cloud that touches the surface of the earth
1. About 800 tornados occur in the United States each year
F. Hurricanes
1. Hurricanes need wind speeds of at least 119 Kilometers per hour
2. The eye of a hurricane is calm
G. Thunderstorms form within large cumulonimbus clouds
H. Lake effect snow is caused by cold air blowing over large lakes then over
land
III.
Floods
A. Floods occur when so much water pours into a stream or river that it
overflows its banks on either side of the channel.
B. Flood safety
1. Move to higher ground and stay away from flood waters
2. Boil water from sources that have been flooded
3.
C. Sudden storms, broken dams, and ice jams that break can produce flash
floods
IV.
Predicting the Weather
A. Meteorologists interpret weather information from local weather
observers, instruments carried by balloons, satellites and weather stations
around the world
B. Changes in weather technology have changed in two ways
1. Gathering weather data
2. Using computers to make forecasts
C. El Nino
1. is a weather pattern that forms in the tropical Pacific Ocean
2. Occurs every 2-7 years
D. Weather maps
1. Small lines at the end of the shaft that represents wind direction
indicates wind speed
2. On weather maps a line with half circles indicates a warm front
3. A line with triangles represents a cold front
4. Places with the same temperature are connected by isotherms
5. Isobars are areas with the same air pressure