Post on 04-Jan-2016
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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 – – 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
Areas of sinking air that move clockwise – called anticlones.
Clear, nearly cloudless skies.Pushes bad weather away
HH
Low Pressure
Area of rising air in a counter-clockwise direction called cyclones.
Cloudy, sometimes rainy days.
LL
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 precipitationNational 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.
Weather Maps
The figure below shows what various weather symbols mean.
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.
Skills activity
Cumulonimbus
Cirrus
Cirrostratus
Cirrocumulus
Altostratus
Altocumulus
Nimbostratus
Stratocumulus