Air Masses

Air Masses

Thunderstorms - how do they form?

• Warm humid air rises and clouds form

• The water vapor releases energy

• Ice particles form at the top of the cloud where it’s cold

• The ice particles fall and pull cold air down

• There is rain or hail

Multiple Choice

Thunderstorms begin with the rising of...

• warm, humid air

• cool, humid air

• warm, dry air

• cool, dry air

Air Masses are Large Bodies of Air

• An air mass is a large volume of air in which temperature and humidity are nearly the same in different locations at the same altitude

• Air takes on characteristics of land or water below it

Multiple Choice

What qualities are nearly the same at different locations in air masses?

• temperature and humidity

• temperature and pressure

• pressure and wind speed

• pressure and humidity

Multiple Choice

What characteristics are typical for an air mass that forms over the ocean and near the equator?

• warm and dry

• warm and moist

• cold and moist

• cold and dry

Multiple Choice

What characteristics are typical for an air mass that forms over the land and near the equator?

• Warm and wet

• Warm and dry

• Cold and wet

• Cold and dry

High-Pressure Systems

• When air moves around a high-pressure center and slowly sinks down and then spreads out towards low pressure areas.

• Type of weather: clear skies (no clouds), and calm air or gentle breezes.

Low-Pressure Systems

• When air moves around a low-pressure center and rises up.

• Type of weather: stormy

Multiple Choice

Why type of weather is associated with high pressure systems?

• Thunderstorms

• Sunny, light breeze

• Snow showers

• High winds, cloudy

Multiple Choice

What type of weather is associated with low pressure systems?

• No winds, humid

• Sunny, light breeze

• High winds and dry

• Cloudy and raining

Hurricanes

• Hurricanes form over ocean water

• The water is warm

• The water evaporates and energy moves from the ocean water into the air

• The energy makes the warm air rise faster

• Tall clouds and strong winds develop

Multiple Choice

Hurricanes form over...

• cold, dry land

• warm, moist land

Multiple Choice

What conditions can lead to the formation of a hurricane?

• A low-pressure system near the equator

• A high-pressure system over the ocean far from the equator

• A high-pressure system over hot, dry land

• A low-pressure system over snow-covered land

Movement of an Air Mass

• Travels away from regions where they form

• Move with global winds

Weather Changes Where Air Masses Meet

• Front = boundary between air masses

• There are cold, warm, and stationary fronts

Cold front

• When a cold, dense air mass pushes warmer air upward.

• You get tall clouds and brief, heavy storms

• After the storms there are clear skies and the air is cooler.

Warm Front

• When a warm air mass pushes colder air and the warm air moves up and over the colder air

• You get flat clouds and hours of steady rain or snow

• After the air is warmer

Multiple Choice

What would happen to the temperature and pressure of a location when a cold air mass pushes a warm air mass?

• drop in temperature and falling pressure

• drop in temperature and rising pressure

• rise in temperature and rising pressure

• rise in temperature and falling pressure

Multiple Choice

What would happen to the temperature and pressure of a location when a warm air mass pushes a colder air mass?

• Drop in temperature and falling pressure

• Drop in temperature and rising pressure

• Rise in temperature and rising pressure

• Rise in temperature and falling pressure

Types of Air Masses

• Categorize air masses based on moisture and temperature

• Continental = land

• Maritime = water

• Tropical = near equator

• Polar = far from equator

Multiple Choice

If there is a Continental Polar air mass, what would you expect the weather to be like?

• Rainy and cool

• Rainy and warm

• No rain and warm

• No rain and cool