(Adopted by AMS Council on 14 February 2000)
Bull. Amer. Met.Soc., 81, 1347
The broadcast media are a critical element of the public–private partnership, particularly in the dissemination of weather forecasts, watches, warnings, and advisories that enhance public safety and the protection of property (see Bull. Amer. Meteor. Soc., 80, 2099–2101). Major advances in radar technology and display over the past two decades allows for improved severe weather warning lead times, more accurate depiction of weather phenomena, and improved communication to the public.
The U. S. government’s Next Generation Weather Radar ("NEXRAD" or "WSR-88D") network is composed of over 150 Doppler-capable units across the country, providing coverage for over 98% of the nation’s population. It is a tri-agency program, managed by the National Oceanic and Atmospheric Administration/National Weather Service (NWS) on behalf of the U.S. Air Force and Federal Aviation Administration. Each radar independently scans the atmosphere, using a "volume scan," whereby every five to ten minutes, the radar interrogates the atmosphere at many levels. Dozens of graphical products are then generated that meteorologists can use to view weather phenomena. Through the public–private partnership, the NWS has an agreement (NEXRAD Information Dissemination System, or "NIDS") with a number of commercial organizations that receive these graphic products and make them available to end users such as the broadcast media in near–real time, in both unaltered and value-added forms. One of the most popular such value-added products is the radar mosaic, which combines the output of many single radars into one image, providing a wide-area view.
Many broadcast outlets have chosen to purchase and operate their own commercially available radar units, independent of the government. Some of these systems allow the operator to focus on local weather phenomena of interest and put the displays immediately on air. Although many of these radar units are not as sophisticated as NEXRAD, they do allow the media outlet to control the operation of the unit. Many media outlets choose to utilize both types of products on air, providing the advantages of each to their viewers. Because there may be uncertainty as to the timeliness of the radar products, the American Meteorological Society urges care in using the term "live radar" and recommends that all radar products be displayed with a "time stamp" that indicates the time the data in the image were acquired, and not the time that the graphic was generated, nor the time it is being displayed. In the case of severe weather, the public interest is best served in providing accurate, timely information and not hyperbole that might distract the viewer from the critical information necessary to protect lives and property.