On 3 May 2000, the fourth in the series of NOAA’s new generation of geostationary satellites, GOES-11, was launched. As with other satellites in this series, GOES-11 is fitted with instruments that provide frequent scans of the western hemisphere in 5 imaging channels, and 19 sounder channels (18 thermal infrared, and 1 visible).

Before being placed in its present standby mode, a brief science test was conducted. The first half of the six-week period was devoted to testing system components and optimizing instrument performance – the latter half focused on capturing real-time weather events. During the second half of the experiment, the default programming called for the imager to routinely collect 5-minute interval imagery over the continental United States, and the sounder to collect 30-minute interval data over a slightly smaller region. Science-test coordinators also had the option of increasing the scan frequency of the imager to a 1-minute interval (a scheduling strategy commonly referred to as super-rapid scan operations, or SRSO), over a limited area to capture significant mesoscale weather events.

On 24 July 2000, a day on which the satellite had been placed in its SRSO scan mode, a severe supercell thunderstorm formed in south-central South Dakota. Shortly after forming, the storm appeared to split. The left–moving component propagated to the northeast and dissipated after about 2-hr, while the right-mover ended up traveling due south across central Nebraska. During a 10-hr period, the storm resulted in several confirmed reports of hail exceeding 2 inches in diameter, and 3 confirmed tornado sightings – all of which were in rural areas.

This paper presents an overview of the event with an emphasis on SRSO imagery and 30-min interval sounder data. Sounder products are presented that illustrate the added value of having frequent interval sounder data available to forecasters in near real-time.