A significant advantage of the S-band National Weather Radar Testbed Phased Array Radar (NWRT PAR) is the capability to adaptively scan storms at higher temporal resolution than is possible by the S-band Weather Surveillance Radar-1988 Doppler (WSR-88D; 1 min or less vs 4 min, respectively). A comparative analysis of three nontornadic severe storms that occurred during the spring and summer of 2006 showed that volumetrically sampling these storms at intervals of 58 s or less provides superior depictions of the evolution of rapidly evolving reflectivity and velocity features key to determining storm severity.

This study examines the impact of high-temporal sampling by PAR on the depiction of low-altitude circulations, including tornadic vortex signatures, compared to the nearby WSR-88D (KTLX). Comparisons between PAR and KTLX will be made for the time of initial (and final) detection of circulations, the evolution of circulation depth and magnitude, and the relation of circulation development to the occurrence of severe weather. The paper will also relate findings from this research to forecaster evaluations of the operational use of PAR for storms with low-altitude circulations.