Air and the Sun * Weather reporter meteorologist wind, air pressure, and temperature. * Weather starts with the sun; source of heat. * Sun’s rays.

Air and the Sun* Weather reporter meteorologist wind, air pressure, and temperature.

*Weather starts with the sun; source of heat.

*Sun’s rays direct rays at equator more heat; slanting rays at Poles less heat.

*Uneven heating causes air to move and make weather.

A large body of air with similar temperature and moisture.

Air masses form over large land or water masses.

MAP TAP 2002-2003 Weather Fronts 3

When 2 air masses meet, they do not mix. They form a border called a front. Most of the weather happens along fronts.

Cold Fronts Heavy, cold air forces the warm air up.

Warm air goes up, cools and forms clouds. This leads to rain and thunderstorms at a cold front.

Temperature drops after a cold front has passed.

blue line with triangles; show where cold front is moving

Warm air slides over the cold, dense air. Stratus clouds form. Steady rain or snow. After front passes, clear skies, warm temperatures.

Red line with half circles pointing where warm front is moving.

COLD FRONTSMove faster.Often violent weather.Gusty winds; turbulenceWeather change happens when front is passing through.

WARM FRONTSSlow, gradual change.Weather change happens BEFORE front arrives.Low clouds (stratus) cause poor visibility.

Tall, cumulonimbus clouds.

When a warm front is trapped by 2 cold fronts.

Purple line with alternating triangles and semicircles pointing the direction the front is moving.

MAP TAP 2002-2003 Weather Fronts

A front that stops moving or is moving very slowly.

Alternating red semicircles pointing away from the warm air and blue triangles pointing away from the cold air.

MAP TAP 2002-2003

Weather Fronts 17

You are planning to travel to Alabama in 2 days. The high temperature there for today is 68º F.

You are planning to travel to Alabama in 2 days. The high temperature there for today is 68º F.

Use the map to help you predict whether the temperature in Alabama will increase, decrease, or stay the same. Explain why you think so.

18

There is a cold front approaching. The temperatures will probably be cooler behind the front.

There is a cold front approaching. The temperatures will probably be cooler behind the front.

Of course, meteorologists (weather forecasters) use much more data than fronts and air masses to help them forecast the weather more accurately. But any forecast is just a prediction of what might happen. Even with the best data, weather forecasts can be wrong.

MAP TAP 2002-2003 Weather Fronts 19