AIR MASSES AND FRONTS

FOR YOUR NOTEBOOK:

Air Masses and Front Types

Define Air Masses and Front Types

• Continental (c)- dry

• Maritime (m)- moist

  • Arctic air masses (A) are very cold, coming from the Arctic or Antarctic regions

  • Polar air masses (P) are not as cold, originate over higher latitudes of land and sea

  • Tropical air masses (T) are warm/hot, originate over the lower latitudes of land and sea

  • cA, cP,cT, mA, mP, mT

• Fronts are identified by a change of temperature based on their motion (have a vertical structure)

  • Cold front- a colder air mass replaces a warmer air mass

  • Warm front- a warmer air mass replaces a colder air mass 

  • Stationary front- the boundary between two air masses does not move

  • Occluded front- a warm air mass pushes into a colder air mass and then another cold air mass pushes into the warm air mass (cold fronts move faster than warm fronts)

• The motion of air masses affects where precipitation occurs

  • Cold Front: The air of cold air masses is more dense than warmer air masses and the cold air forces the warm air up and over the colder air making it rise into the atmosphere. With a steep slope, the air is forced upward quickly, leading to a narrow band of showers and thunderstorms along or ahead of the front.

  • Warm Front: Have a gentle slope that gives a broad area of rising air causing cloudiness and precipitation along and to the north of the front.