Weather Patterns Review
Concepts to Know
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Isotherms are used to show temperature
A hurricane begins as a tropical disturbance
A tornado warning means that a tornado has been spotted on the ground or on radar
Cyclones are low-pressure centers
Continental air masses form over land
Snow falls when humid air cools below zero degree Celsius
A tropical storm with winds of 119 km per hour or higher is called a hurricane
Anticyclones are high-pressure centers of dry air
Scientists who study the causes of weather and try to predict it are called meteorologists
A cold front forms when a rapidly moving cold air mass runs into a slowly moving war air mass
Bands of high-speed winds above Earth’s surface are called jet streams
Lines on a weather map joining places with the same air pressure are called isobars
A warm front forms when a warm air mass overtakes a slowly moving cold air mass
Hurricanes that strike the East Coast of the US are most common in the months of August,
September, and October
The storms that produce the highest winds are tornadoes
Tornadoes form in cumulonimbus clouds
The sudden discharge of electricity in a storm is referred to as lightning
In the Northern Hemisphere, the winds of a cyclone always spin counterclockwise
A occluded front forms when two cool air masses cut a warm air mass off from the ground
Maritime polar air mass brings cool, humid weather to the West Coast of the US
Why are the movements of fronts so important for predicting the weather?
o The movements of fronts are so important for predicting the weather because fronts
form when different air masses meet, and the meeting of different air masses is what
produces all the changes in the weather
Why don’t hurricanes form over the northern Atlantic Ocean?
o Hurricanes don’t form over the northern Atlantic Ocean because hurricanes need the
energy of warm ocean water to form, and the waters of the North Atlantic are too cool
to provide enough energy
All four types of fronts tend to produce clouds and precipitation when they pass through an
area. The weather that follows a front is different depending on which type of front it is.
Explain why both statements are true.
o Whenever a front passes through an area, warm air rises and cools, causing clouds and
precipitation, regardless of the type of front. After a front passes through the area, the
air mass following the front determines the weather. If it is a cold air mass, the weather
will be cool and dry. If it is a warm air mass, the weather will be warm and humid
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Why don’t cities that receive lake-effect snow in the winter also receive lake-effect rain in the
summer?
o The waters of the Great Lakes are cooler than the surrounding land in the summer.
Therefore, west winds blowing across the Great Lakes do not pick up moisture as they
do in the winter, when the lakes are warmer than the surrounding land
As the air in the center of an anticyclone falls toward Earth, it gets warmer. Why does this lead
to low relative humidity?
o As the air gets warmer, it can hold more moisture, leading to low relative humidity
People often are evacuated when there are tornado warnings because tornadoes most often
occur with too little advance warning for people to leave the area
Know the symbols of a weather map, you will have to identify the type of weather that is being
shown on one