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Chapter 18 Notes Weather. Fronts, pressures, clouds. Fronts - leading edge of a moving air mass. Pressures – areas of sinking or rising air. Clouds – visible mass of water or ice in the atmosphere. Cold Fronts. Cold air mass replaces warm air mass. Large clouds form –
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Fronts, pressures, clouds • Fronts - leading edge of a moving air mass. • Pressures – areas of sinking or rising air. • Clouds – visible mass of water or ice in the atmosphere.
Cold Fronts • Cold air mass replaces warm air mass. • Large clouds form – • Cumulonimbus (dark gray storm cloud) • Nimbostratus (dark gray, thick snow cloud)
Warm Front • Warm air mass replaces a cold air mass. • Produces a series of clouds: • Cirrus (wispy and transparent) • Cirrostratus (white veils) • Cirrocumulus (rolled patches) • Altostratus (gray sheet or layer) • Altocumulus (patches or rolls) • Stratocumulus (lumpy)
Stationary Front • Occurs when air masses stop moving. • Noticeable temperature and wind direction change.
Occluded Front • Occurs in a Low Pressure system. • Cold front catches up with a warm front.
High Pressure H • Areas of sinking air that move clockwise – called anticlones. • Clear, nearly cloudless skies. • Pushes bad weather away
Low Pressure L • Area of rising air in a counter-clockwise direction called cyclones. • Cloudy, sometimes rainy days.
Meteorology • Meteorologists are scientists who study the causes of weather and try to predict it. • They use maps, charts, and computers to analyze weather data and prepare forecasts. • Use radar to track precipitation • National Weather service tracks weather and issues warnings and watches.
Weather Technology • Weather balloons – carry instruments high into atmosphere to measure temp., pressure, and humidity. • Satellites – in upper atmosphere; measure temp, humidity, wind speed and direction, solar radiation, and give images of clouds and storms.
Weather Technology (con’t) • Weather stations – on surface; measure temp, pressure, humidity, rainfall, and wind speed and direction. • Computers – process gathered info quickly and help forecasters make predictions using calculations.
Reading Weather Maps • This is the type of weather map produced by the National Weather Service. It shows data collected from many weather stations.
Reading Weather Maps • Weather maps in newspapers use symbols to show fronts, high- and low-pressure areas, and precipitation. Color bands indicate different temperature ranges.
