Weather Systems Vocabulary
Thermal Energy – A form of energy that warms matter
Wind – movement of air from an area of high density and pressure to low density and pressure.
Caused by uneven heating of the earth
Air Pressure – The force exerted by the atmosphere on Earth’s surface by the weight of the air
above.
Convection – Transfer of thermal energy through circular motion caused by heating and cooling of
fluids (liquids/gases)
Coriolis Effect – The movement of air as a result of Earths rotation. (Northern Hemisphere it
curves to the right)
Anemometer – tool used to measure wind speed
Atmospheric movement – global wind patterns influenced by convection of warm less dense air
(rises and spreads out) and cold dense air (sinks)
Barometer – a tool that measure eh amount of atmospheric pressure
Humidity – The amount of water vapor in the air
Air Mass - A body of air over large areas that develop and retain specific characteristics of
pressure, temperature, and humidity
High Pressure Air Mass – VERY Dense, cool, dry air. Brings HAPPY weather
Low Pressure Air Mass – low density air brings BAD weather.
Warm Front – Slow moving, cloudy, gentle rain. Warm, moist air masses take over a cool, dense,
and dry air mass. Shown by red domes
Cold Front – A cold, dry air mass overtakes a warm, humid air mass. Dramatic storms, fast moving,
forces the warm air up quickly. Shown by blue spikes
Stationary Front - is a collection of air masses, neither of which is strong enough to
replace the other. On a weather map, this is shown by an inter-playing series of
blue spikes pointing one direction and red domes pointing the other.
Hurricane – tropical cyclones that forms in the southern atlantic along the equator. MUST BE
OVER WARM WATER. It slows down when it reaches land
Typhoon – a tropical cyclone that forms in the Indian and Pacific along the equator. MUST BE
OVER WARM WATER. It slows down when it reaches land Oceans.
Evaporation – changing of a liquid to a gas
Condensation – changing from a gas to a liquid
Density – mass/volume. – The amound of mass in a given space. Its “compactness”
Westerlies - winds in the Mid latitudes (where we are) blow west to east toward the poles (up and
to the right)
Easterlies (Trade Winds)– Wind in the Low latitudes blow east to west toward the Equator (down
and to the right)
El Nino - Abnormally high surface ocean temperatures off the coast of South America. Causes
unusual weather patterns across the globe