| Term | Definition |
|---|---|
| Weather | The short term state of the atmosphere, including temperature, humidity, precipitation, wind and visibility. |
| Humidity | The amount of water vapor in the air. |
| Relative Humidity | The ratio of the amount of water vapor in the air to the amount of water vapor needed to reach saturation at a given temperature. |
| Water Cycle | The continuous movement of water from sources on the Earth's surface into the air, onto and over land, into the ground, and back to the surface. |
| Condensation | When water vapor cools and changes from a gas to a liquid. Clouds form by this process. |
| Evaporation | When liquid water changes into water vapor, which is a gas. |
| Runoff | Water, usually from precipitation, that flows across the land and collects in rivers, streams and eventually the ocean. |
| Precipitation | When rain, snow, sleet, or hail falls from the clouds to the Earth's surface. |
| Saturated | When air holds all of the water that it can at a given temperature. |
| Pyschrometer | An instrument that is used to measure relative humidity. It contains both a wet and dry bulb thermometer. |
| Dew Point | The temperature at which a gas condenses into a liquid. |
| Cloud | A collection of millions of tiny water droplets or ice crystals. |
| Cumulus Clouds | Puffy white clouds that tend to have flat bottoms. Usually indicates fair weather but can produce thunderstorms. |
| Cumulonimbus Clouds | Large cumulus clouds that produce lightning. |
| Stratus Clouds | Clouds that form in layers and can produce all types of weather.. |
| Nimbostratus Clouds | Dark stratus clouds that produce light to heavy rain. |
| Fog | A Stratus cloud that forms near the ground. |
| Cirrus Clouds | Thin, feathery white clouds found at high altitudes. |
| Air mass | A large body of air where the temperature and moisture content are similar throughout. |
| Source regions | Area over which air mass forms. |
| Front | The boundary between air masses of different densities and usually different temperatures. |
| Cyclone | An area in the atmosphere that has lower pressure than the surrounding areas and has winds that spiral toward the center. |
| Anticyclone | The rotation of air around a high pressure center in the direction opposite to Earth's rotation. |
| Cumulus Clouds | Heaping puffy clouds |
| Stratus | Layered clouds |
| Cirrus | Curled |
| Cirro | High clouds |
| Alto | Medium level clouds in the atmosphere. |
| Nimbo | clouds that produce precipitation |
| Strato | Lowest |
| Thunderstorm | A usually brief heavy storm that consists of rain, strong winds, lightning and thunder. |
| Lightning | An electric charge that takes place between two oppositely charged surfaces, such as between two clouds, or between two parts of the same cloud. |
| Thunder | The sound caused by the rapid expansion of air along an electrical strike. |
| Tornadoes | A destructive rotating column of air that has very high wind speeds, is visible as a funnel shaped cloud and touches the ground. |
| 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. |
| Typhoons | Hurricanes in the western Pacific Ocean. |
| Cyclones | Hurricanes that form over the Indian Ocean. |
| Hurricane Eye | Center of the hurricane, a core of warm calm air with low pressure and light winds. |
| Hurricane Eye Wall | Surrounds the eye made of bands of cumulonimbus clouds. |
| Rain Bands | Bands of rain outside the eye wall of the hurricane. |
| Storm Surge | A wall of water that builds up over the ocean because of strong winds and low atmospheric pressure. |
| Tornado Watch | A weather alert that lets people know that tornado might happen. |
| Tornado Warning | A weather alert that lets people know that a tornado has been spotted. |
| Weather Forecast | A prediction of weather conditions over the next 3 to 5 days. |
| Meteorologist | A person who observes and collects data on atmospheric conditions to make weather predicitions. |
| Weather Balloons | Carry equipment into the atmosphere that aids in measuring temp, winds speed, etc… |
| Thermometer | A tool used to measure air temperature. |
| Barometer | An instrument used to measure air pressure. |
| Anemometer | An instrument used to measure wind speed. |
| Radar and Doppler Radar | Used to find the location, movement, and amount of precipitation. |
| Weather Satellites | Orbit the earth providing images of weather systems. |
| Severe Weather | Weather that can cause property damage and sometimes death. |
