Editing NEXRAD (section)

==Deployment==
[[File:Wea03317 - Flickr - NOAA Photo Library.jpg|thumb|Testbed of the WSR-88D on display at the [[National Severe Storms Laboratory]].]]
In the 1970s, the U.S. Departments of Commerce, Defense, and Transportation, agreed that to better serve their operational needs, the existing national radar network needed to be replaced. The radar network consisted of '''[[WSR-57]]''' developed in 1957, and '''[[WSR-74]]''' developed in 1974. Neither system employed [[Doppler effect|Doppler]] technology, which provides wind speed and direction information.

The Joint Doppler Operational Project (JDOP) was formed in 1976 at the [[National Severe Storms Laboratory]] (NSSL) to study the usefulness of using [[Weather radar|Doppler weather radar]] to identify severe and tornadic [[thunderstorm]]s. Tests over the next three years, conducted by the National Weather Service and the Air Weather Service agency of the [[United States Air Force|U.S. Air Force]], found that Doppler radar provided much improved early detection of severe thunderstorms. A [[working group]] that included the JDOP published a paper providing the concepts for the development and operation of a national weather radar network. In 1979, the NEXRAD Joint System Program Office (JSPO) was formed to move forward with the development and deployment of the proposed NEXRAD radar network. That year, the NSSL completed a formal report on developing the NEXRAD system.<ref name="wsr-88d">{{cite journal|title=The WSR-88D and the WSR-88D Operational Support Facility|author=Timothy D. Crum|author2=Ron L. Alberty|journal=Bulletin of the American Meteorological Society|page=74.9|year=1993|doi=10.1175/1520-0477(1993)074<1669:twatwo>2.0.co;2|volume=74|issue=9|bibcode = 1993BAMS...74.1669C |url=https://zenodo.org/record/1234705|doi-access=free}}</ref><ref name="stormwarning1">{{cite book|title=Storm Warning: The Story of a Killer Tornado|author=Nancy Mathis|publisher=[[Simon & Schuster|Touchstone]]|pages=[https://archive.org/details/stormwarningstor00math/page/92 92–94]|year=2007|isbn=978-0-7432-8053-2|url-access=registration|url=https://archive.org/details/stormwarningstor00math/page/92}}</ref>

When the proposal was presented to the [[Presidency of Ronald Reagan|Reagan administration]], two options were considered to build the radar systems: allow corporate bids to build the systems based on the schematics of the previously developed prototype radar or seek [[Independent contractor|contractors]] to build their own systems using predetermined specifications. The JSPO group opted to select a contractor to develop and produce the radars that would be used for the national network. Radar systems developed by [[Raytheon]] and [[Unisys]] were tested during the 1980s. However, it took four years to allow the prospective contractors to develop their proprietary models. Unisys was selected as the contractor, and was awarded a full-scale production contract in January 1990.<ref name="wsr-88d"/><ref name="stormwarning1"/>

{| align="right"
|[[Image:NEXRAD map.jpg|thumb|x150px|NEXRAD sites within the Contiguous U.S.]]
|[[Image:NEXRAD NON-CONTIGUOUS.jpg|x150px|thumb|NEXRAD sites in Alaska, Hawaii, U.S. territories, and military bases.]]
|}
Installation of an operational prototype was completed in the fall of 1990 in [[Norman, Oklahoma]]. The first installation of a WSR-88D for operational use in daily forecasting was in [[Sterling, Virginia]] on June 12, 1992. The last system deployed as part of the installation program was installed in [[North Webster, Indiana]] on August 30, 1997. In 2011, the new [[Langley Hill Doppler radar|Langley Hill NEXRAD]] was added at Langley Hill, Washington to better cover the Pacific Coast of that area;<ref name=Banse2011>{{citation|title=New Weather Radar Heralds More Accurate And Timely Storm Warnings|date=September 29, 2011|author=Tom Banse|publisher=[[NPR]]|url=https://www.npr.org/templates/story/story.php?storyId=140938772}}</ref> other radars also filled gaps in coverage at [[Evansville, Indiana]] and [[Ft. Smith, Arkansas]], following the initial installations.{{citation needed|date=June 2014}} The site locations were strategically chosen to provide overlapping coverage between radars in case one failed during a [[severe weather]] event. Where possible, they were co-located with NWS Weather Forecast Offices (WFOs) to permit quick access by maintenance technicians.<ref name="installation dates">{{cite web|title=WSR-88D Radar, Tornado Warnings and Tornado Casualties|url=http://www.economics.noaa.gov/library/documents/benefits_of_weather_and_climate_forecasts/wsr-88d-radar-tornado_warnings_casualties.pdf|publisher=National Oceanic and Atmospheric Administration|url-status=dead|archive-url=https://web.archive.org/web/20061112155546/http://www.economics.noaa.gov/library/documents/benefits_of_weather_and_climate_forecasts/wsr-88d-radar-tornado_warnings_casualties.pdf|archive-date=2006-11-12}}</ref>

The NEXRAD radars incorporated a number of improvements over the radar systems that were previously in use. The new system provided Doppler velocity, improving [[tornado]] prediction ability by detecting rotation present within the storm at different scan angles. It provided improved resolution and sensitivity, enabling operators to see features such as [[cold front]]s, [[thunderstorm]] [[gust front]]s, and [[mesoscale meteorology|mesoscale]] to even storm scale features of thunderstorms that had never been visible on radar. The NEXRAD radars also provided volumetric scans of the atmosphere allowing operators to examine the vertical structure of storms and could act as [[wind profiler]]s by providing detailed wind information for several kilometers above the radar site. The radars also had a much increased range allowing detection of weather events at much greater distances from the radar site.<ref>{{cite web|title=An Overview of NEXRAD Products Available via UCAR's Unidata Program|url=http://sysu1.wsicorp.com/unidata/intro.html|publisher=Weather Services International|url-status=dead|archive-url=https://web.archive.org/web/20080420195322/http://sysu1.wsicorp.com/unidata/intro.html|archive-date=2008-04-20}}</ref>

WSR-88D development, maintenance, and training are coordinated by the NEXRAD [[Radar Operations Center]] (ROC) located on the grounds of the [[University of Oklahoma Westheimer Airport]] (KOUN) in Norman, Oklahoma.<ref>{{cite web|title=About the Radar Operations Center (ROC)|url=https://www.weather.gov/roc/|website=Radar Operations Center|publisher=[[National Oceanic and Atmospheric Administration]]}}</ref>

The [[University of Louisiana at Monroe]] in [[Monroe, Louisiana]] operates a "WSR-88D clone" radar that is used by local National Weather Service offices in [[Shreveport, Louisiana|Shreveport]], [[Little Rock, Arkansas|Little Rock]] and [[Jackson, Mississippi|Jackson]] to fill gaps in NEXRAD coverage in northeastern Louisiana, southeastern Arkansas and western Mississippi. However, the radar's status as being part of the NEXRAD network is disputed.