Directions: Study the following words by reading and rereading them each evening so you will be prepared for the word study test each week. You may use one index card to write as many words and definitions on as possible to use for the test. The card must written in ink, be in your handwriting, and have your name, period, and chapter recorded in the top, right corner with no obvious erasures or mark outs. If all the criteria are met, you may use your index card during the test. It will then be stapled to your test.
continental air masses – air masses that form over land; there are two types of continental air masses: continental polar (cP) and continental tropical (cT); because these air masses form over land, the level of humidity is low; however these air masses will eventually move into other regions because of global wind patterns and generally bring dry weather conditions
maritime air masses – air masses that form over the ocean or other large bodies of water; there are two types of maritime air masses: maritime polar (mP) and maritime tropical (mT); these air masses have high humidity and commonly bring precipitation and fog
cP – continental polar air masses that are cold and dry
mP – maritime polar air masses are cold and moist
cT – continental tropical air masses that are warm and dry
mT – maritime tropical air masses that are warm and moist
cold front – the front edge of a moving mass of cold air that pushes beneath a warmer air mass like a wedge
stationary front – the front of air masses that moves slowly or not at all
occluded front – a front that forms when a cold air mass overtakes a warm air mass and lifts the warm air mass off the ground and over another air mass
midlatitude cyclone – a large traveling atmospheric cyclonic storm up to 2000 kilometers in diameter with centers of low atmospheric pressure;an area of low pressure that is characterized by rotating wind that moves toward the rising air of the central low-pressure region
thunderstorm – a usually brief, heavy storm that consists of rain,, strong winds, lightning, and thunder; it forms when an air mass becomes so unstable that it overturns (convects) violently; "Unstable" means that the air in the lowest layers is unusually warm and humid, or that the upper layers are unusually cool, or oftentimes, both
hurricane – a severe storm that develops over tropical oceans and whose strong winds of more than 120 km/h spiral in toward the intensely low-pressure storm center; the Atlantic hurricane season is officially from 1 June to 30 November because 97% happen during this time but they can occur anytime the conditions are right
tornado – a destructive, rotating column of air that has very high wind speeds and that may be visible as a funnel-shaped cloud/Tornadoes usually lasts only a few minutes. Their wind speeds range from 18 to 140 m/s. The damaged path of a tornado is usually less than 500 meters wide and it travels at less than 16 m/s. Each year, the United States ranks number one in tornado incidence with Australia coming in second.
blizzard – A blizzard is a severe snowstorm characterized by strong winds and low temperature. By definition, the difference between blizzard and a snowstorm is the strength of the wind. To be a blizzard, a snow storm must have sustained winds or frequent gusts that are greater than or equal to 56 km/h (35 mph) with blowing or drifting snow which reduces visibility to 400 meters or a quarter mile or less and must last for a prolonged period of time — typically three hours or more.
thermometer – an instrument that measures and indicates temperature
barometer – an instrument that measures atmospheric pressure
anemometer – an instrument used to measure wind speed
wind vane – an instrument used to determine direction of the wind
radiosonde – a package of instruments that is carried up by balloons to measure the upper atmospheric conditions, including temperature, dew point, and wind velocity
radar – radio detection and ranging, a system that uses reflected radio waves to determine the velocity and location of objects
Doppler radar – a specialized radarthat makes use of the Doppler effect to produce velocity data about objects at a distance, it does this by beaming a microwave signal towards a desired target and listening for its reflection to bounce back
station model – a pattern of meteorological symbols that represents the weather at a particular observing station and this is recorded on a weather map
WMO – World Meteorological Organization - An intergovernmental organization with a membership of 189 Member States and Territories. It originated from the International Meteorological Organization (IMO), which was founded in 1873. Established in 1950, WMO became the specialized agency of the United Nations for meteorology (weather and climate), operational hydrology and related geophysical sciences. It has its headquarters in Geneva, Switzerland.
knots – (1 knot = 1.136 mph) A knot is a unit of measure for speed.