Andrew Mahre-February 16

Analysis of the 16 May 2015 Tipton, Oklahoma EF-3 Tornado at High Spatiotemporal Resolution Using the Atmospheric Imaging Radar

In this study, data collected by the Atmospheric Imaging Radar (AIR) are analyzed in conjunction with WSR-88D data (KFDR) for a tornado near Tipton, Oklahoma on 16 May 2015. Analysis is conducted via PPIs from both radars, polarimetric data from KFDR, time-height plots from the AIR, and a ground-based velocity track display (GBVTD) analysis. This study is novel in that it uses high-resolution mobile radar data (update time of 6-7 s) in tandem with polarimetric data from KFDR in order to identify possible areas of debris. Leveraging the high spatiotemporal resolution of the AIR with the polarimetric capability of KFDR leads to analysis of reflectivity distributions, debris lofting, kinematic changes, and oscillations in tornado intensity during a portion of the mature stage of the tornado. Debris is lofted in a concentric ring of increasing radius and height around the tornado over several minutes, while debris lofting and asymmetric reflectivity distribution around the weak echo hole coincide with changes in vortex tilt on multiple occasions during the mature stage of the tornado. In one instance, hydrometeor fallout appears to precede a possible descending reflectivity core. Using GBVTD-derived radial convergence, near-surface convergence intensifies at the same time and location as when the debris ring is lofted. Additionally, strengthening of the tornado via multiple modes of vertical evolution (i.e., bottom-up intensification over time versus simultaneous intensification throughout the lowest few hundred meters) is observed.