Earth Science Chapter 20 Vocabulary
Air mass: A large body of air in the lower sphere that has similar characteristics throughout.
Blizzard: A winter storm characterized by winds exceeding 56 kilometers per hour, temperatures
of 27° C or lower, and falling or blowing snow that reduces visibility.
Cold front: The boundary between an advancing cold air mass and the warm air mass it is
displacing.
Front: The boundary that separates dissimilar air masses
Hurricane: A large, rotating storm of tropical origin with sustained winds of at least 119
kilometers per hour.
Lightning: A discharge of electricity from a thundercloud to the ground, to another cloud, or to
another spot within the cloud itself.
Meteorology: The study of processes that govern Earth’s atmosphere.
Occluded front: The front that is formed when a cold front overtakes a warm front and displaces
it upward in an area of low pressure.
Saffir-Simpson scale: The 1-to-5 scale used to rate a hurricane’s instensity and estimate
potential property damage and flooding.
Squall line: A line of thunderstorms that occurs ahead of a front, often preceded by strong winds.
Station model: A compact expression of weather information for an area, including temperature,
dew point, weather conditions, wind speed and direction, barometric pressure, and cloud cover.
Stationary front: the boundary between two dissimilar air masses, neither of which is displacing
the other, usually resulting in cloudy weather and mild temperatures.
Storm surge: The rapid rise in water level along the coast as a hurricane or other tropical storm
approaches.
Supercell: A very large, single-cell thunderstorm with particularly strong updrafts.
Thunderstorm: A storm with rain, lightning, and thunder, and sometimes hail and tornadoes.
Tornado: A violent, rotating column of air that extends down from dark clouds and moves
overland in a narrow, destructive path.
Warm front: The boundary between an advancing warm air mass and the colder air it is
displacing.