Lesson 26 What is an air mass?

What will the weather be tomorrow? Is rain on the way? Will sunny weather be moving in?

Weather moves from place to place, but where does it come from Weather moves from place to place, but where does it come from? Where does weather start? Most weather comes from air masses. An air mass is a huge body of air.

An air mass covers a large area. Places within this area have about the same temperature and humidity. (moisture)

An air mass can start over the ocean or over a large body of land An air mass can start over the ocean or over a large body of land. The air that makes up an air mass stalls over the water or land.

It stands still for several days or weeks It stands still for several days or weeks. During this time, the land or water gives the air its temperature and humidity. The air mass then moves on.

The humidity of an air mass depends on where they form. Air masses formed over oceans are called maritime air masses. -Maritime air is moist.

-Air masses formed over the land are called continental air masses. -Continental air is dry

The temperature of air masses also depends on where they are formed. -Air masses formed near the poles are called polar air masses -Polar air masses are cold

-Air masses formed near the tropics are called tropical air masses -Tropical air is warm

The name of an air mass has two parts: The first part tells us where it was formed….. continental maritime or

The second part tells us the temperature. polar or tropical

What would you call a moist cold air mass? Moist = maritime Cold = polar So………… maritime polar

What would you call a dry warm air mass? continental Dry = ???? tropical Warm = ??? Continental tropical

Dry, cold air mass? continental polar Moist, warm air mass? maritime tropical