Investigating Windsond Observations in Supercells

Supercell thunderstorm data collection has long been restricted to ground observations, radar scans, single aircraft flights, and sporadic weather balloon launches. The Targeted Observations by Radar and Unmanned aircraft systems (UAS) of Supercells (TORUS) 2019 field campaign introduced new data collection approaches to collect in-situ observations in supercell thunderstorm environments. This included multiple UAS missions and targeted deployments of small balloon-borne instruments known as windsondes. The windsondes can act as pseudo-Lagrangian drifters and provide rare wind and thermodynamic observations of air flowing into the low-level mesocyclone. In particular, one feature of the supercell thunderstorm, known as the streamwise vorticity current, has been identified through simulations to influence tornado formation, but has not been observed. This project examined the effectiveness of windsond data collection in near-storm environments and whether SVCs were present in the dataset. After data collection 1-2 km upstream of low-level mesocyclones, the windsond data were quality controlled, visualized through trajectories and thermodynamic profiles, and analyzed in tandem with mobile radar data. Preliminary results reveal that windsond observations in the near-storm environment are valuable in identifying and analyzing storm-scale features of supercells. In one case, cyclonic wind shifts near the surface are evident across a storm-scale boundary with complex trajectories at higher altitudes within the storm. Implementing windsond deployments in future field campaigns will aide in understanding microscale and mesoscale storm features that are otherwise more difficult to observe with conventional data collection techniques.