This document provides information about various weather-related topics in 4 sections: 1) Water in the atmosphere and the water cycle including terms like condensation, precipitation, humidity, and clouds. 2) Air masses and fronts that form boundaries between different air masses including cold fronts and warm fronts. 3) Severe weather such as thunderstorms, hurricanes, and tornadoes. 4) Tools used in weather forecasting like thermometers, barometers, weather balloons, radar, and satellites that provide data to predict weather conditions.

1. Chapter 16 Understanding Weather Section 1 Water in the Air

2. Weather Condition of the atmosphere at a particular time and place

3. Water Cycle Continuous movement from sources such as lakes and oceans into the air

4. Condensation Water vapor cools and changes back to liquid droplets

5. Precipitation When rain, snow, sleet or hail falls from the clouds

6. Runoff Water usually from precipitation that flows across land

7. Transpiration Process in which plants release water vapor into the air

8. Evaporation Liquid water changes into water vapor

9. Humidity The amount of water vapor or moisture in the air

10. Relative Humidity The amount of moisture the air contains compared with the maximum amount it can hold

11. Psychrometer Instrument used to measure relative humidity

12. Condensation Process by which a gas becomes a liquid

13. Dew Point The temperature at which air must cool to be completely saturated

14. Cloud A collection of millions of tiny water droplets or ice crystals

15. Cumulus Clouds Puffy white clouds with flat bottoms

16. Stratus Clouds Clouds that form in layers

17. Cirrus Cloud Thin feathery, white clouds at high altitudes

19. Precipitation Water in solid or liquid form that falls to the Earth

20. Snow Solid precipitation

21. Sleet Freezing rain

22. Hail Solid precipitation that falls as balls

23. Rain Gauge An instrument for measuring the amount of rainfall

24. 1) Cloud that forms in layers 2) Puffy, white cloud with a flat bottom 3) Cloud that forms near the ground 4) Cloud that produces thunderstorms 5) Cloud that produces light, continuous rain 6) Thin, feathery, high-altitude cloud A) Fog B) Nimbostratus C) Stratus D) Cirrus E) Cumulonimbus F) Cumulus C F A E B D

25. Chapter 16 Understanding Weather Section 2 Air Masses and Fronts

26. Air Mass A large body of air that has similar temperature and moisture throughout

27. Cold Air Masses 3 North American Polar air masses Develop over land Develop over the Atlantic Ocean Develop over the Pacific Ocean

28. Warm Air Masses 4 North American Polar warm air masses Develop over the Desert region of Mexico Develop over the Atlantic Ocean Develop over the Pacific Ocean Gulf of Mexico

30. Front Boundary formed when two different air masses meet

31. Cold Front When a cold air mass meets and displaces a warm air mass

32. Warm Front When a warm air mass meets and overrides a cold air mass

33. Occluded Front Faster moving cold front overtakes a slower moving cold front

34. Stationary Front When a Cold air mass meets a Warm air mass and little movement occurs

35. Where do the air masses that are responsible for cold, winter weather in the United States come from? Canada, the North Atlantic Ocean & the North Pacific Ocean What is the weather like at a front? Cloudy and stormy When a warm air mass overrides a cold air mass a __________ forms. warm front

36. Chapter 16 Understanding Weather Section 3 Severe Weather

37. Severe Weather Weather that can cause property damage or even death

38. Thunderstorms Small intense weather systems that produce strong winds, heavy rain, lightning & thunder

39. Lightning Large electrical discharge that occurs between two opposite charged surfaces

40. How Lightning Forms

41. Thunder The sound that results from the rapid expansion of air along the lightning strike

42. Severe Thunderstorms Severe thunderstorms produce one or more of the following conditions High winds Hail Flash Floods Tornadoes

43. Tornado Small rotating column of air that has high speeds and low central pressure that touches the ground.

45. Hurricane Large rotating tropical storm with wind speeds at least 119km/hr.

46. Hurricane Eye wall Cumulonimbus clouds that produce heavy rains & forceful winds

47. Hurricane Eye Center of the hurricane.

48. Rain Bands Spiraling bands of clouds

49. Name three examples of severe weather Thunderstorms, hurricanes, and tornadoes What is the relationship between a funnel cloud and a tornado? A funnel cloud is called a tornado when it makes contact with the Earth’s surface.

50. Hurricanes that form over the western Pacific Ocean are called __________, while those that begin in the Indian Ocean are called ___________. Typhoons – Cyclones Which type of a cloud would most likely lead you to predict a thunderstorm? a cumulonimbus cloud

51. Chapter 16 Understanding Weather Section 4 Forecasting the Weather

52. Weather Forecast A prediction of weather conditions over the next 3 to 5 days

53. Thermometer A tool used to measure air temperature

54. Barometer An instrument used to measure air pressure

55. Windsock or Wind Vane The wind enters through the wide end and exits through the narrow end. Therefore the wide end points toward the wind.

56. Anemometer An instrument used to measure wind speed

57. Weather Balloons Measure weather conditions as high as 30 km above earth

58. Radar Used to find the location, movement and intensity of precipitation

60. Weather Satellites Orbit the Earth and provide weather information that can not be obtained from the ground

61. Station Model A small circle showing the location of a weather station along with a set of symbols and numbers surrounding it that represent weather data

63. Isobars Lines that connect points of equal air pressure

64. What is the name of the tool used to measure each atmospheric condition. Wind Direction Air Pressure Air Temperature Wind Speed Windsock/Wind vane Barometer Thermometer Anemometer

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