Analysis of Polarimetric Radar Signatures in Tornadic Non-supercellular Storms

Polarimetric radar analyses of supercell storms have documented repeatable signatures of operational utility, including the separation of specific differential phase (K_DP) and differential reflectivity (Z_DR) enhancement regions (known as the K_DP foot and Z_DR arc, respectively), signifying hydrometeor size sorting and the presence of storm-relative helicity. In this study, we analyze a three-year data set of 60 tornadic non-supercellular storms in the National Weather Service Eastern Region within 60 km of upgraded dual-polarization WSR-88D radars. This assessment has provided evidence that the Z_DR- K_DP separation is a repeatable feature in some tornadic non-supercellular storms. We developed a technique (discussed in greater detail in Loeffler and Kumjian, this conference) that quantifies this separation distance and direction (“separation vector”). This technique is employed to analyze the separation vector’s evolution leading up to tornadogenesis in numerous cases. Additionally, other repeatable features, such as rearward movement of the K_DP foot and descent of high K_DP values preceding the intensification of the near-surface circulation, will also be discussed.