Storm mergers. Part 2: Observations of merger events from VORTEX2

A few recent studies have suggested that many tornadogenesis events happen shortly before or after a merger involving a supercell. However, not all mergers yield tornadic supercells. In fact, many mergers have a detrimental effect on the structure and evolution of the resulting storm. Moreover, the underlying dynamics and physics determining the outcome of a merger are poorly understood. Thus, gaining a better understanding of the meteorology of storm mergers involving supercells may be of immense help to the operational community.

Among the research goals of the Verification of the Origin of Rotation in Tornadoes Experiment (VORTEX2) is an increased understanding of supercell mergers. The National Severe Storms Laboratory mobile mesonets, the Center for Severe Weather Research X-band Dopplers on Wheels, the S-band Weather Surveillance Radar 88D network, and other available data sources are analyzed to investigate mergers during VORTEX2. For example, a cyclonically rotating right-moving supercell collided with a left-mover on 13 June 2009 near Panhandle, Texas. This resulted in a brief intensification of the storm, followed by rapid dissipation.