Chapter 16 Notes

Section 1  Humidity (measured by a Psychrometer)

•______is the amount of water vapor in the air.

• The air’s ability to hold water vapor ______as the______of the air changes.

•______is the amount of water vapor in the air compared to the maximum amount of water vapor that the air can hold at a ______.

•______: The dew pointis the______at which a______condenses______a ______.

Section 2  Air Masses: (Wind speed is measured by an Anemometer & direction by a Wind Vane or Sock)

  • Changes in weather are caused by the______and interaction of air masses.

• An ______is a large body of air where temperature and moisture content are constant throughout.

Maritime (m) forms over water and is wet.

Continental (c) forms over land and is dry.

Polar (P) air masses are cold and form over Polar regions.

Tropical (T) air masses are warm and form over Tropical regions.

•Cold Air Masses: Most of the cold winter weather in the United States is influenced by ______ polar air masses.

•Warm Air Masses: ______ warm air masses influence the weather in the United States.

Fronts (Temperature is measured by a Thermometer):

•The area in which two types of air masses meet is called a______.

•Cold Fronts: A cold front forms where ______moves under ______which is less dense and pushes the warm air up. (rain/snow followed by cold/clear weather).

•Warm Fronts: A warm front forms where ______moves over ______, ______air. (Light rain followed by warm/clear weather.).

•Occluded Front: An occluded front forms when a______mass is caught between TWO ______masses ( An occluded front has cool temperatures and large amounts of rain and snow.).

•Stationary Front: A stationary front forms when a ______mass meets a ______mass. A stationary front often brings many days of cloudy, wet weather)(see the back for diagrams of each type of fronts.)

Air Pressure (measured by a Barometer):

______are areas that have______pressure than the surrounding areas do and produce rain, clouds and other bad weather.

______are areas that have______pressure and usually produce fair, clear weather.

Section 3  Thunderstorms:______is an electric discharge that occurs between a______charged area and a______charged area. Thunderstorms are very active electrically.

______is the sound that results from the rapid expansion of air along the lightning______.

Tornado: A ______is a small, spinning column of air that has high wind speeds and low

central pressure and that touches the ground. A tornado starts out as a funnel cloud that pokes through the

bottom of a______cloud and hangs in the air. The funnel cloud becomes a tornado

when it makes ______with the ______’s ______.

Hurricanes: How a Hurricane Forms: A______begins as a group of thunderstorms moving over

______waters. ______traveling in ______different directionsmeet and

cause the storm to ______.

Damage Caused by Hurricanes: Hurricanes can cause a lot of damage when they move near or onto land. Wind speeds of most hurricanes range from 120 to 150 km/h.