Satellites operated by NASA and the National Oceanographic and Atmospheric Administration photographed the storm system over the south-central United States, the space agency said Tuesday.
The tornado that struck Moore, spawned by the supercell thunderstorms in the satellite images, was an F-4 tornado on the enhanced Fujita scale, the National Weather Service determined, with winds between 166 and 200 mph.
Satellites provided imagery and data to forecasters before, during and after the tornado, NASA said, allowing them to issue a first warning almost an hour before the tornado touched down in Moore, where it caused dozens of deaths and widespread destruction.
This tornado was about twice as wide as the one that struck Moore on May 3, 1999.
Moore is 10 miles south of Oklahoma City.
NOAA's GOES-13 satellite provided forecasters with images of the storm system every 15 minutes, NASA said.