1. Chapter 18 Notes Weather

2. 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.

3. Cold Fronts  Cold air mass replaces warm air mass.  Large clouds form – –Cumulonimbus Cumulonimbus(dark gray storm cloud) –Nimbostratus Nimbostratus(dark gray, thick snow cloud)

4. Warm Front  Warm air mass replaces a cold air mass.  Produces a series of clouds: –Cirrus Cirrus(wispy and transparent) –Cirrostratus Cirrostratus(white veils) –Cirrocumulus Cirrocumulus(rolled patches) –Altostratus Altostratus(gray sheet or layer) –Altocumulus Altocumulus(patches or rolls) –Stratocumulus Stratocumulus(lumpy)

5. Stationary Front  Occurs when air masses stop moving.  Noticeable temperature and wind direction change.

6. Occluded Front  Occurs in a Low Pressure system.  Cold front catches up with a warm front.

7. High Pressure  Areas of sinking air that move clockwise – called anticlones.  Clear, nearly cloudless skies.  Pushes bad weather away H

8. Low Pressure  Area of rising air in a counter- clockwise direction called cyclones.  Cloudy, sometimes rainy days. L

9. 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.

10. 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.

11. 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.

12. Weather Maps

13.  The figure below shows what various weather symbols mean.

14. Reading Weather Maps  This is the type of weather map produced by the National Weather Service. It shows data collected from many weather stations.

15. 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.

16. Skills activity

17. Cumulonimbus

18. Cirrus

19. Cirrostratus

20. Cirrocumulus

21. Altostratus

22. Altocumulus

23. Nimbostratus

24. Stratocumulus