Air Masses and Air Mass Weather

1
Air Masses and Air Mass Weather

• By
• 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 contd

• cT Continental Tropical
• 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