A working group that included the JDOP published a paper providing the concepts for the development and operation of a national weather radar network.

The JSPO group opted to select a contractor to develop and produce the radars that would be used for the national network.

[citation needed] 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 quicker access by maintenance technicians.

The new system provided Doppler velocity, improving tornado prediction ability by detecting rotation present within the storm at different scan angles.

A standard WSR-88D operates in the S band, at a frequency of around 2800 MHz, with a typical gain around 53 dB using a center-fed parabolic antenna.

[8] The NEXRAD radar system continually refreshes its three-dimensional database via one of several predetermined scan patterns.

There are currently seven Volume Coverage Patterns (VCP) available to NWS meteorologists, with an eighth in the process of replacing one of the existing seven.

The radar operator chooses from the VCPs based on the type of weather occurring: The specific VCP currently in use at each NEXRAD site is available.

Early trials showed that rain, ice pellets, snow, hail, birds, insects, and ground clutter all have different signatures with dual polarization, which could mark a significant improvement in forecasting winter storms and severe thunderstorms.

The radar at Vance Air Force Base in Enid, Oklahoma was the first operational WSR-88D modified to utilize dual polarization technology.

This can often allow for more volume scans per hour, improving severe weather detection without the need for hardware upgrades[22][23] AVSET was initially deployed in RPG build 12.3, in Fall of 2011.

One of the primary weaknesses of the WSR-88D radar system was the lack of frequency of base (0.5 degree) scans, especially during severe weather.

TV viewers at home could be lulled into a false sense of security that a tornado was farther away from them than it really was, endangering residents in the storm's path.

Deployment was anticipated by the Radar Operations Center to commence in October 2017, along with the RPG 18.0 build, on a non-operational basis.

[31] Due to untimely radar data and time being taken to complete the entire volume, these vortices often spawn without warning or prior notice.

The program is anticipated to be finished by 2022, which coincides with the beginnings of a nationwide implementation of multi-function phased array radars (see below).

As a result of the coverage gap, initial reports of tornadic activity were treated with skepticism by the local National Weather Service forecast office.

For example, a hardware failure on July 16, 2013 resulted in an outage and coverage gap for the Albany, New York area that lasted through early August.

[36] A coverage gap in North Carolina encouraged Senator Richard Burr to propose S. 2058, also known as the Metropolitan Weather Hazard Protection Act of 2015.

[35] In 2011, a known coverage gap was filled when the Langley Hill radar in southwestern Washington was installed, using the last remaining spare.

This radar opportunity was spearheaded by a public campaign led by Professor Cliff Mass at the University of Washington, and likely helped the NWS office in Portland, Oregon issue a timely warning for the Manzanita, OR EF-2 tornado in October, 2016.

[39] The NEXRAD site located in Cayey, Puerto Rico was destroyed during the passage of Hurricane Maria through the region in September 2017.

[41] In June 2018, this NEXRAD radar site was restored to fully operational condition and was reinforced with several lightning rods and secured with a stronger fiberglass dome that included using more than 3,000 bolts.

After initially being restored back into operation, the installation suffered from ongoing issues and, as of April 24, 2024, has been reported as "unserviceable" in NOTAMs.

[49][50] The National Severe Storms Laboratory predicts that a phased array system will eventually replace the current network of WSR-88D radar transmitters.

It is used by National Weather Service meteorologists and (under provisions of U.S. law) is freely available to users outside of the NWS, including researchers, media, and private citizens.

Combined with ground reports, tornado and severe thunderstorm warnings can be issued to alert the public about dangerous storms.