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Glossary

Some of the weather-related terms heard in our field trip:

ATMOSPHERE | a gaseous envelope that surrounds the Earth. Other planets of the solar system, as well as a few of the large satellites of the outer planets, also have atmospheres, though each one has a different mixture of gases. Earth’s atmosphere consists primarily of nitrogen and oxygen. This envelope, commonly called “the air,” also contains numerous less abundant gases.

AVIATION FORECAST | a forecast put out by the short-term forecaster which gives aircraft pilots important information about weather conditions both on the ground and up in the air. One critical function of this forecast is to warn pilots of a possibly dangerous condition known as wind shear.

ADVANCED WEATHER INTERACTIVE PROCESSING SYSTEM (AWIPS) | a computer system that collects and crunches data gathered from radar, satellite, and other data collection devices at NWS offices around the country to produce a “snapshot” of what the atmosphere will look like at a given time. This system is used extensively by forecasters to create different types of forecasts. The weather events simulator, a training tool, is also part of the AWIPS.

CLIMATE | the average weather pattern in a given place over many years.

COMPUTER MODEL | a data-driven system that uses a built-in set of rules to predict the results of a process or to simulate how a given set of conditions will change over time. By comparing the model’s predictions to experimental and observational results, scientists can refine the underlying rules to make the model itself more accurate. The AWIPS, seen in action during the field trip, is an example of a computer model of the atmosphere. As data about current wind conditions, precipitation, cloud cover, temperature, and other variables is fed into it from various places around the world, it uses sophisticated built-in theories about how those variables interact to predict how the atmosphere will respond over the next seven days.

COOPERATIVE WEATHER OBSERVER PROGRAM | a project involving more than 11,000 volunteer weather observers across the country who record daily temperature and precipitation data. They may also report additional information such as soil temperature, evaporation and wind movement, agricultural data, water equivalent of snow on the ground, river stages, lake levels, atmospheric phenomena, and road hazards.

Doppler Weather Radar

DOPPLER RADAR | a specialized form of radar used in weather forecasting. Unlike ordinary radar, which can report only the location and strength of precipitation, Doppler radar is also capable of indicating wind direction, wind speed, and boundaries between warm and cold fronts. Doppler radar may also be referred to as WSR 88-D or NEXRAD.

HYDROLOGIST | a scientist who studies the distribution, circulation, and physical properties of underground and surface waters as well as the form and intensity of precipitation, its rate of infiltration into the soil, its movement through the earth, and its return to the ocean and atmosphere.

LONG-TERM FORECASTING | the creation of extended forecasts to predict weather patterns as much as a week ahead—a very important tool for anyone planning an outing or an event like a vacation or wedding!

METEOROLOGIST | an atmospheric scientist—a scientist who studies the atmosphere’s physical characteristics, motions, and processes and how they affect the rest of our environment. The best-known application of this knowledge is forecasting the weather.

NATIONAL OCEANOGRAPHIC AND ATMOSPHERIC ADMINISTRATION (NOAA) | a federal agency—part of the U.S. Department of Commerce—that conducts research and gathers data about the global oceans, atmosphere, space, and sun and applies this knowledge to science and service that touch the lives of all Americans.

NATIONAL WEATHER SERVICE (NWS) | a government agency under the auspices of the U.S. Department of Commerce and the National Oceanographic and Atmospheric Administration. The NWS is the primary source of weather data, forecasts, and warnings for the United States. Television weathercasters and private meteorology companies prepare their forecasts using this information. The NWS is also the sole official voice in the United States for issuing warnings during life-threatening weather situations. The NWS mission is to “protect the life and property of our citizens from natural disasters by issuing warnings and forecasts for all manners of severe or extreme weather and to enhance the national economy.”

NOAA WEATHER RADIO | a nationwide network of radio stations broadcasting weather information from a nearby National Weather Service office around the clock.

PRECIPITATION | different forms of water that fall from clouds in the sky. Some types of precipitation are rain, snow, hail, and sleet.

RAIN GAUGE | an instrument that collects and measures rainfall. NWS will install rain gauges free of charge for volunteers participating in the Cooperative Weather Observer Program.

SHORT-TERM FORECASTING | hour-by-hour monitoring of weather conditions in order to provide warnings about possible severe weather, including aviation forecasting of wind shear and other possibly dangerous weather events.

tornado

TORNADO WARNING | A warning means that an actual tornado has been sighted in the area or detected by weather radar. Seek shelter immediately!

TORNADO WATCH | A watch means that conditions are favorable for tornadoes to develop, so stay alert for changing weather.

WEATHER | the mix of events that happen every day in our atmosphere, including temperature changes, winds, rainfall, and humidity. Weather is not the same everywhere—in fact, it can be different in different parts of town at the same time!

WEATHER EVENTS SIMULATOR | An AWIPS computer system used to “play back” or review past weather events collected from NWS offices around the U.S. This system is used as a training tool: Meteorologists can examine a set of conditions from the past, make a weather prediction based on that data, and then compare their forecast to what actually happened.

WIND SHEAR | a dramatic change in wind speed and/or direction within a short distance. These sudden bursts result in “shearing” forces that can cause problems for airplanes by putting extra stress on their component parts.

Photos:
  1. NSSL’s first Doppler weather radar, located in Norman, OK. 1970s research using this radar led to the NWS NEXRAD WSR-88D radar network. Photo courtesy NOAA Photo Library, NOAA Central Library; OAR/ERL/National Severe Storms Laboratory (NSSL).
  2. A tornado just south of Dimmitt, TX on June 2, 1995. Photo courtesy NOAA Photo Library, NOAA Central Library; OAR/ERL/National Severe Storms Laboratory (NSSL).
Sources:

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