Air Masses & Fronts

Air Mass Air Mass: a huge body of air that has similar temperature, humidity, and pressure Can be spread out over millions of km2 and up to 10 km deep

Types of Air Masses Descriptors: Types of Air Masses: Tropical = warm Polar = cold Arctic = very cold Continental = dry Maritime = wet Types of Air Masses: Maritime Tropical: warm & wet Continental Tropical: warm & dry Maritime Polar: cold & wet Continental Polar: cold & dry Continental Arctic: very cold & dry

How Air Masses Move Westerlies – major wind belt over the US, generally pushes air masses from west to east Jet Streams: bands of high-speed winds about 10 km above Earth’s surface, also blow west to east Front: the boundary between air masses When air masses collide, they do not easily mix

Types of Fronts Cold Front: fast moving cold air mass collides with slower moving warm air mass Cold fronts tend to move quickly

Types of Fronts Warm Front: faster moving warm air mass collides with slower moving cold air mass Warm fronts tend to move slowly

Types of Fronts Stationary Front: when two air masses collide and don’t move for many days

Types of Fronts Occluded Front: a warm air mass is trapped between two colder air masses

Highs & Lows Cyclone: a spiral of warm, rising air, creating an area of Low air pressure (L) Spins counter-clockwise Anticyclone: a spiral of cold, falling air, creating an area of High air pressure (H) Spins clockwise