FRONTS

What are Fronts? An interface (boundary) between 2 air masses. Where 2 different air masses meet. Conditions at the front are unstable and usually associated with precipitation

Types of Fronts: Page 13 in E.S.R.T. Icicles Half Suns

Cold Fronts: Cold air moves into an area occupied by warm air Warm air is already in place.

The colder, denser air quickly pushes against and under the warm air The warm air rises, producing tall, thick clouds 5

Wind speed increases, air pressure drops Precipitation occurs – moves quickly and violently 6

Cumulonimbus Cloud forms 7

Cold Fronts: Temperatures are cooler behind a cold front, and warmer ahead of the cold front.

Cold Front Animation

Warm Fronts: Warm air mass moves into an area occupied by cool air

Warm air slides over the cold air.

The warmer, less dense air slowly moves over cold air mass Warm air slowly rises, expands, cools, and clouds form 12

13

Air pressure falls, and precipitation follows Lasts for a longer period of time 14

Warm Fronts: Temperatures are warmer behind a warm front, and cooler ahead of the front.

Warm Front Animation

Stationary Fronts: A cold air mass and a warm air mass collide, with no movement

Widespread rain will last for many days

Stationary Front Animation

Occluded Front: Faster moving cold front overtakes a slower moving warm front

Warm air gets caught in between 2 cold air masses Widespread rain and thunderstorms 21

Precipitation occurs right along the frontal boundary