The Rivers of Vorticity in Supercells (RiVorS) Field Project

Findings from recent, high-resolution numerical model analysis have provided evidence that concentrated regions of enhanced streamwise vorticity, or “vorticity rivers,” act as a primary source of near-ground rotation in tornadic supercells. In these simulations, the vorticity rivers emanated from the supercell’s main precipitation, moved toward the low-level updraft, and were associated with low-level pressure deficits and cyclonic wind shifts. The goal of the Rivers of Vorticity in Supercells (RiVorS) field project was to confirm or refute the existence of these features in real supercells and analyze their kinematic and thermodynamic characteristics. This was accomplished through a collaboration with several institutions utilizing a wide range of observation platforms, including Mobile Mesonets with sounding capabilities, Doppler radar vehicles, unmanned aerial aircraft, a ground-based profiling system, and quasi-Lagrangian, balloon-mounted, drifting sondes. Initial data collection for RiVorS took place in May-June 2017 across the Great Plains of the U.S., where eight supercells (two tornadic) were sampled. This presentation summarizes the motivation and strategies employed during deployments made by the National Severe Storms Laboratory (NSSL).