April 2, 2021 - 3:30 pm
April 2, 2021 - 4:30 pm
CategoriesConvective Meteorology (Mesoscale Dynamics)
Convective Meteorology (Mesoscale Dynamics) Seminar
A Preliminary Radar Investigation of the 17 May 2021 McCook / Farnam, NE Tornadic Supercell during TORUS
Friday, April 2nd
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While numerical simulations have highlighted the importance of the streamwise vorticity current (SVC) in modulating the low-level mesocyclone in supercells, including its role in tornadogenesis and maintenance, the SVC has yet to be documented in detail observationally. Previous observational studies attempting to document the SVC have focused on mobile mesonet or single-Doppler analyses. Thus, data collected during the Targeted Observations by Radars and UAS of Supercells (TORUS) field experiment aims to alleviate this issue through the use of a wide range of instruments (e.g., mobile mesonets, radars, windsondes), including a successful deployment on a long-lived supercell on 17 May 2019, which produced numerous tornadoes in southwest Nebraska. In addition to an event overview of the tornadic supercell, preliminary radar analyses from the NOXP, Ka, and P-3 radars of the tornadic supercell will be presented. Radar analysis from the Ka-band radars provide evidence of an SVC-like signature in a similar region where the SVC has been numerically noted, with 1) inferred horizontal vorticity through range-height indicator (RHI) scans through the hook echo and 2) reflectivity ribbons extending from the forward-flank region into the low-level mesocyclone; both signatures persist through multiple scans.
However, definite identification of this feature as an SVC is not possible without information about the full 3D wind field. Therefore, this presentation will also detail a methodology for future work of a complete 3D investigation into the kinematic and thermodynamic properties of the tornadic supercell and potential SVC. This methodology includes a pseudo-dual-Doppler wind synthesis using NOXP and P-3 radar data to calculate the 3D kinematic field, as well as feeding those results with gridded reflectivity data into a diabatic Lagrangian analysis to acquire 3D thermodynamic fields.