Weather

The weather map below shows the locations of a warm and a cold front over part of North America. The numbered lines on the weather map connect locations with the same

• wind direction
• air temperature
• wind speed
• air pressure

What type of air pressure develops along fronts?

• low air pressure
• high air pressure
• rising air pressure
• no air pressure

An air mass is a large body of air that has about the same


• temperature and moisture conditions throughout
• moisture and pressure conditions throughout
• temperature and pressure conditions throughout
• temperature and precipitation conditions throughout

A dry air mass is most likely to form over

• the Gulf of Mexico
• the Pacific Ocean
• the Atlantic Ocean
• Canada

Air masses that strike southern California commonly form over the South Pacific Ocean. These air masses are


• warm and dry
• warm and moist
• cool and dry
• cool and moist

Which factor has the greatest influence on the movement of an air mass?

• ocean currents
• prevailing westerlies global winds
• sea breezes
• mountain barriers

The source of energy that sets Earth’s atmosphere in motion and causes weather changes is

• volcanism
• the ocean
• gravity
• the sun

In the figure below, the air pressure would be greatest at point

• a
• b
• c
• d

A falling barometer usually indicates

• an approaching high-pressure system and stormy weather
• an approaching high-pressure system and fair weather
• an approaching low-pressure system and stormy weather
• an approaching low-pressure system and fair weather

Compared to cool air, warm air is

• more dense and rises
• less dense and rises
• the same density
• less dense and sinks