30 terms

7th Grade Science: Weather 1-5 and 1-6 air masses, fronts, storms

Science 7 Vocabulary for Weather modules 5 and 6
Air mass
A huge body of air that has similar temperature, humidity, and pressure.
Source Region
The area where an air mass forms and acquires its characteristic properties of temperature and humidity.
designation for "continental Tropical" - a dry warm air mass that forms over Northern Mexico or the Desert Southwest.
designation for "maritime Tropical" - a humid warm air mass that forms in the Subtropical waters of the Pacific or Atlantic Oceans or the Gulf of Mexico.
designation for "continental Polar" - a dry cold air mass that forms over northern Canada and Alaska.
designation for "maritime Polar" - a humid cold air mass that forms over the North Pacific or North Atlantic Ocean.
A boundary between air masses. The four major types are cold, warm, stationary, and occluded.
cold front
when a cold, dry air mass takes the place of a warm, moist air mass; brings violent storms followed by fair, cooler weather; move quickly
warm front
a front where warm air moves over cold air and brings drizzly rain and then are followed by warm and clear weather
occluded front
interaction of three air masses (warm, cool, cold); warm air is stuck above the other air masses and moderate precipitation often results; represented on a weather map by purple triangles and semicircles
stationary front
boundary between two different air masses, neither of which is strong enough to replace the other.
A low pressure center area with winds that spiral towards the center. Humid rising air and stormy weather.
high pressure center with winds that spiral out from the center. Dry sinking air and clear skies.
a storm that produces lightning and thunder and often heavy rains and strong winds
Down drafts
Winds that blow downward hitting the land and spreading out in strong gusts of wind.
Gust fronts
Leading edge of cool air rushing down and out from a thunderstorm.
A discharge of electricity between a cloud and the earth.
a storm which contains large amounts of snow OR blowing snow, with winds in excess of 35 mph and visibilities of less than 1/4 mile for an extended period of time
a mobile, destructive vortex of violently rotating winds having the appearance of a funnel-shaped cloud and advancing beneath a large storm system.
Fujita Scale
A scale that tells how severe a tornado is based on wind speed and the damage being caused. F1 is mild and F5 is severe.
Ground Station
An observation post where weather conditions and meteorological data are observed and recorded. Can contain instruments that measure air pressure, temperature, dew point, precipitation, wind speed, wind direction, and cloud cover.
Used to locate clouds and measure height and distance. A special type called "Doppler"can detect air motion and precipitation to help indicate tornados and strong winds.
These orbit the earth above the atmosphere. Images can show cloud cover, warm and cool reigons, and invisible water vapor
Weather Balloon (radiosonde)
An instrument released into the atmosphere that records temperature, pressure, humidity, wind speed and direction at different altitudes. Data is sent by radio to monitoring stations on the ground
Line drawn on a weather map that connects points having equal temperature
A line on a weather map that joins points having the same barometric pressure.
smallest scale of atmospheric motion
(e.g. a small town)
middle scale of atmospheric motions
(e.g. region or state)
continental scale of atmospheric motions
(e.g. whole country)
patterns of atmospheric motion that cover the whole Earth
(e.g. prevailing winds, convection cells)

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