Air Masses & FrontsAir Masses & Fronts

pgs. D68-D73pgs. D68-D73

Chapter 10 Lesson 7Chapter 10 Lesson 7

1. air mass1. air mass

A large region of the atmosphere A large region of the atmosphere where the air has similar properties where the air has similar properties throughout.throughout.

2. fronts2. fronts

Where warm and Where warm and cold air come cold air come together, but do together, but do not mixnot mix

A narrow boundary A narrow boundary forms between the forms between the cold and warm air.cold and warm air.

3. cold fronts3. cold fronts Cold air moves in under a warm air Cold air moves in under a warm air

mass.mass. Often bring brief, heavy storms, Often bring brief, heavy storms,

there may be thunderstorms and there may be thunderstorms and strong winds.strong winds.

After the storm the skies are usually After the storm the skies are usually clearer, and the weather is usually clearer, and the weather is usually cooler and drier.cooler and drier.

4. warm fronts4. warm fronts

Warm air moves in over a cold air Warm air moves in over a cold air mass.mass.

Often bring light, steady rain or Often bring light, steady rain or snow.snow.

The precipitation may last for days.The precipitation may last for days. Winds are usually light.Winds are usually light.

warm fronts continued…warm fronts continued… May also bring fog—stratus clouds May also bring fog—stratus clouds

that form near the ground.that form near the ground. Afterward the weather usually Afterward the weather usually

warmer and more humid.warmer and more humid.