![]() Spotters who observe significant weather relay the information to their local NWS office or appropriate local authority based on the hazard observed. SKYWARN® Weather Spotters play a crucial role in their communities and are often part of the NWS warning process. However, we are always seeking additional “eyes on the ground” especially in rural communities and open country.Īdditional details can be found on the National SKYWARN® Webpage. The NWS in Tucson, AZ has hundreds of SKYWARN® spotters in its County Warning and Forecast Area, which includes the counties of Cochise, Graham, Greenlee, Pima, SE Pinal and Santa Cruz. SKYWARN® storm spotters are volunteer citizens who form the nation's first line of defense against severe weather. ![]() Since the program’s inception, the information provided by SKYWARN® spotters, coupled with Doppler radar technology, improved satellite and other data, has enabled the NWS to issue more timely and accurate warnings for a variety of weather hazards. The NWS communicates these warnings to county Emergency Managers, who take appropriate action to help protect life and property of citizens in their jurisdiction. In the event of observed severe weather, SKYWARN® Spotters contact their local NWS office, who use the information to issue warnings for severe thunderstorms, tornadoes, flash floods, and dust storms, or verify warnings already issued for these hazards. SKYWARN® was developed in the early 1970’s as a partnership between the National Weather Service (NWS), county Emergency Managers and the general public. Meanwhile, NOAA researchers continue to investigate the next generation of weather radar technology, phased array, as a possible future replacement for NEXRAD.In an average year, the United States experiences more than 10,000 severe thunderstorms, 5,000 floods and more than 1,000 tornadoes. (Photo Courtesy: National Severe Storms Laboratory)Įven though the NEXRADs have now exceeded their original life-span estimate of 20 years, the radars are currently undergoing a Service Life Extension Program to keep them operating reliably into the 2030’s. The insert in the images shows the dual polarization correlation coefficient (CC) product denoting the location of debris produced by the tornado. Radar reflectivity (left) and radar velocity (right) around time of an EF1 tornado west of Marion, Wisconsin. The NWS currently operates 159 of these NEXRAD systems and they have undergone several upgrades during 20+ years of operation, including a further increase in resolution, and most recently, an upgrade to dual polarization technology, which provides forecasters a new wealth of information about precipitation including size and shape, better amount estimates, ability to see different types such as rain, snow, and hail, and the ability to differentiate from non-precipitation returns like birds, bugs, and even tornado debris! Also, the addition of Doppler velocities increased the ability for severe weather detection and warning by allowing forecasters to see wind fields and possible rotation within thunderstorms. It increased the resolution of the data, allowing forecasters to see storms in much finer detail. The NEXRAD System provided marked improvements for the NWS. After being developed and tested through the 1980s by the NOAA National Severe Storms Laboratory and partners, the first of these Next-Generation Radar systems (NEXRAD) were deployed operationally beginning in 1992. This allowed forecasters not just to see location and intensity of the precipitation along with basic storm movement, but the movement of the precipitation and winds within the storm itself. NWS Wilmington (OH) WSR-57 Radar image of supercells with hook echoes during 1974 Super Outbreak (courtesy of NCDC)Īround the same time period, researchers began developing a new generation of radars that would incorporate the use of Doppler radar. These radars provided similar data but with newer and more reliable components. An updated version, the WSR-74, supplemented and replaced the older radars beginning in 1977. The technology was refined and in 1959 the NWS began rolling out its first network of radars dedicated to a national warning network. Navy donated 25 surplus radars to the NWS (then known as the Weather Bureau), marking the start of a U.S. Investigation into this phenomenon resulted in the discovery that these echoes were returns from the precipitation, unmasking a further use for the technology. Analysts noted in periods of heavy weather, the radar would return strange signals. But the use of radar for weather observations occurred by accident. The concept of RAdio Detection and Ranging (Radar)began in the late 1800’s and by World War II, radar was in use by militaries around the world, scanning for incoming airplanes. ![]() Doppler radar sends the energy in pulses and listens for any returned signal.
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