Air Masses & Fronts

Air Masses

►An air mass is a defined as a large body of air with very similar characteristics. 

►Air masses are generally defined by temperature and dewpoints (moisture parameters.)

►Air masses are named based on the source region of the air mass itself

4 Types of Air Masses

• Tropical – warm or hot air masses that form over the tropics (lower latitudes)

• Polar – cold air masses that form over the poles (higher latitudes)

• Maritime – air masses that form over the ocean (very humid)

• Continental – form over land – (are dry)

Major Types of Air Mass in the United States

• maritime tropical (mT)-- formed over warm water

• continental tropical (cT) formed over warm land

• maritime polar (mP) formed over cold water

• continental polar (cP) formed over cold land

Multiple Choice

A body of air that has the same temperature and moisture levels throughout is called what?

• Fronts

• Air Masses

• A cold front

• A warm front

Multiple Choice

How do we name air masses?

• Water and temperature

• Air pressure

• Humidity and temperature

• Cold and warm

Multiple Choice

A dry and hot air mass would be...

• Maritime arctic

• Maritime tropical

• Continental tropical

• Continental polar

Multiple Choice

A dry and cold air mass would be...

• Maritime polar

• Continental polar

• Maritime tropical

• Continental tropical

Multiple Choice

A wet and cold air mass would be a...

• Maritime polar

• Continental polar

• Maritime tropical

• Continental tropical

Multiple Choice

How do we characterize an air mass that forms near the poles?

• Dry

• Wet

• Warm

• Cold

Multiple Choice

How do we characterize an air mass that forms over near the equator?

• Dry

• Wet

• Cold

• Warm

Multiple Choice

How do we characterize an air mass that forms over land?

• Dry

• Wet

• Cold

• Warm

Multiple Choice

How do we characterize an air mass that forms over the ocean?

• Dry

• Wet

• Cold

• Warm

Weather Fronts

Pressure & Fronts-- Air pressure is an important factor that affects weather.

High pressure weather system is usually associated with warm, drier weather.

A low pressure system is associated with cooler wetter weather. 

Weather Fronts

• When air masses move and collide, they

  create a weather boundary called a

  front.

• A front often exhibits:

  • rapid changes in weather conditions.

• storms and unsettled weather.

• temperature and air pressure differences on either side.

4 Types of Fronts

• Cold Front forms when a cold air mass

  advances against a warmer air mass.

• Warm Front occurs when a warm air mass moves over a cold air mass.

• Stationary Front forms between a warm air mass and a cold air mass.

• Occluded Front is when a warm air mass

  is caught between two cold air masses.

Cold Front

• The cold air mass is moving quickly,

  and the warm air mass is

  moving slowly.

  
  

• The dense, cold air mass pushes

  the warm air mass upward

Warm Front

• The warm air mass is moving

  quicker than the cold air

  mass.

• If the warm air is humid, rain or

  snow may fall.

• If the warm air is dry, clouds

  may form.

• Warm fronts move slowly, causing

  days of cloudy or rainy

Stationary Front

• Neither air mass moves much.

• The water vapor in warm air condenses into rain, snow, fog or clouds.

• It can stay in the area for several days, causing clouds and precipitation.

Occluded Front

• Warm air is pushed up, and cool

  air masses meet and may mix.

• The warm air is cut off from the

  ground.

• The ground temperature

  gets cooler.

• This may result in widespread

  clouds, rain, or snow.

Multiple Choice

When a warm air mass and a cold air mass meet, but they push at each other and neither one can move, it is called a/an -

• warm front

• cold front

• occluded front

• stationary front

Multiple Choice

What type of storm front is this?

• warm front

• cold front

• stationary front

• occluded front

Multiple Choice

What type of front is this?

• warm front

• cold front

• stationary front

• occluded front

Multiple Choice

A/An ____ is a large body of air that has the same properties as the Earth's surface over which it develops.

• front

• air mass

• cloud

• tornado

Multiple Choice

When a warm air mass slides on top of a cold air mass, and you have drizzly rain and then warmer weather, what type of front is it?

• warm front

• cold front

• occluded front

• stationary front

Multiple Choice

When a fast moving cold air mass moves into a slower moving warm air mass, we may experience severe storms and we will have cooler weather. What type of front is this?

• warm front

• cold front

• occluded front

• stationary front

Multiple Choice

The boundary between two air masses is called a/an -

• flood

• front

• climate

• storm