1. Air Masses and Air Mass WeatherBy
Diana L. Duckworth
Rustburg High School
Campbell County Virginia

2. Air Masses Very large body of air with uniform heat and moisture
Forms in region with uniform conditions of heat and moisture
Source area
Described by temperatures & humidity
Use air temperature & dew point temperature

3. Five Types of Air Masses
mT Maritime Tropical
Forms over tropical oceans (low latitudes)
High humidity & high temperatures
mP Maritime Polar
Forms over polar oceans (high latitudes)
High humidity & low temperatures
All Maritime air masses have high humidity

4. Five Types cont’d cT Continental Tropical cP Continental Polar
Forms over tropical land masses (low latitudes)
Dry (low humidity) and high temperatures
cP Continental Polar
Forms over polar land masses (high latitudes)
Dry (low humidity) and low temperatures
cA Continental Arctic
Forms over the arctic land masses (near poles)
Very dry & very cold
All continental air masses are dry

5. cA cP mP mP cT mT mT

6. Air Mass Source Regions
Polar air masses form at high latitudes
North of Polar Front & Jet Stream
All polar air masses are cold
Tropical air masses form at low latitudes
South of the subtropical Jet Stream
All tropical air masses are hot

7. Air Mass Weather 75% of the time weather is controlled by air masses
Air masses form in one place and move into another area of different condtions
Kind of weather depends on two things:
Difference in temperature between air mass & ground
Amount of moisture in air

8. Tropical Air Masses Move North
Warm air over colder surface
Heat flows from air to land (air cools)
Cold air is stable, does not rise
Continental air masses dry, clear weather
Maritime air masses humid, fog forms when air cools

9. Polar Air Masses Move South
Colder air over warmer surface
Heat flows from land to air, so air gets warm
Warm air rises – unstable atmosphere
Continental air masses – fair weather cumulus clouds
Maritime air masses – rising air produces showers