Public Domain. Credit: OAR/ERL/National Severe Storms Laboratory (NSSL) via [pingnews].
Project Vortex-99. Occluded mesocyclone tornado. Occluded means old circulation on a storm; this tornado was forming while the new circulation was beginning to form the tornadoes which preceeded the F5 Oklahoma City tornado. Photo #3 of sequence.
Image ID: nssl0210, NOAA's National Severe Storms Laboratory (NSSL)
Location: 7 miles south of Anadarko, Oklahoma
Photo Date: May 3, 1999
Credit: OAR/ERL/National Severe Storms Laboratory (NSSL)