| A | B |
|---|
| air pressure | the pressure that a column of air exerts on the air or surface below it |
| dew point | temperature at which air near the ground becomes fully saturated with water |
| humidity | amount of water vapor in the air |
| precipitation | water, in liquid or solid form, that falls from the atmosphere |
| relative humidity | amount of water vapor present in the air relative to the maximum amount of water vapor the air can contain at that temperature |
| water cycle | a series of natural processes in which water continually moves among oceans, land, and the atmosphere |
| weather | atmospheric conditions of a certain place at a certain time |
| air mass | large body of air with distinct temperature and moisture characteristics |
| blizzard | violent winter storm characterized by freezing temperatures, strong winds, and blowing snow |
| front | boundary between two air masses |
| high-pressure system | large body of circulating air that has high pressure at its center and lower pressure on the outside |
| hurricane | intense tropical storm with winds exceeding 119 km/h |
| low-pressure system | large body of circulating air that has low pressure at its center and higher pressure on the outside |
| tornado | violent, whirling column of air that comes in contact with the ground |
| computer model | detailed program that solves a set of complex mathematical formulas |
| Doppler radar | specialized radar that can detect precipitation and movement of small particles and can approximate wind speed |
| isobar | line on a map used to connect all places where air pressure has the same value |
| surface report | describes a set of weather measurements made on Earth’s surface |
| upper-air report | describes wind, temperature, and humidity conditions above Earth’s surface |
