Evolution of a tornadic supercell thunderstorm sampled by phased array radar

On 24 May 2008, a cyclic tornadic supercell thunderstorm was volumetrically sampled by both the S–band National Weather Radar Testbed Phased Array Radar (PAR) in Norman, OK and the S–band WSR–88D (KTLX) located about 20 km to the northeast. The storm was located about 100–110 km from both radars and thus afforded an opportunity to compare 1.0–min volume scans from PAR with 4.25–min volume scans from KTLX. This study focuses on an hour–long portion of the storm that produced a 16–km–long tornadic damage track and documents the ability of the PAR to follow changes in the storm on a minute–by–minute basis. Evolutionary characteristics of the hook echo, bounded weak echo region, mesocyclone signature and tornadic vortex signature during the hour–long period suggest that more than one tornado may have been responsible for the documented damage track. The ability of the PAR to monitor a storm on such a fine time scale has the potential of permitting the researcher to discover subtle aspects of storm evolution, while permitting the forecaster to issue more timely warnings.