Two thunderstorms form on the Mexican side of the Rio Grande, WNW of Del Rio, in the northern foothills of the Serranias del Burro mountain range. These echoes cross the river and merge (upper left part of the frames). The resulting storm quickly strengthens and evolves into a supercell over Val Verde County, Texas. The supercell then turns toward the ENE and takes on a classical shape with a forward flank core on its N side, hook echo on the SW side, and spreading rear-flank gust front farther S.

Meanwhile, a spreading blob of weaker echoes fans out from a point in western Edwards County, in the NE (upper right) part of the view. These are bats. Initially a circular or donut shape, this echo is where the radar beam samples a flock of bats fanning outward and upward from a cave for their evening meal. The bats' echo gets distorted as they spread NE and SW, and as many of the bats fly farther upward, out of the angle cut by the radar beam. Some of the bats that flew toward the SW get caught in the inflow of the supercell, and in time, are drawn into the storm itself. A separate storm-relative velocity image pair indicates the acceleration of the bats as they get closer to the storm, apparently "sucked into" the supercell's mesocyclone.