A 10-m resolution quarter-trillion gridpoint tornadic supercell simulation

The most powerful, long-track tornadoes are the least common, but the most deadly and destructive. The processes within supercells resulting in the formation and maintenance of these top-end tornadoes remain poorly understood. These tornadoes, ranked EF4 or EF5 on the Enhanced Fujita scale, form within supercell thunderstorms and are typically found in the plains and southeastern United States. In this presentation, results from a recent CM1 supercell simulation conducted on the Blue Waters supercomputer will be presented. The tornado forms within a supercell simulated on an fully isotropic 10 m grid spanning 11,200 X 11,200 X 2,000 (251 billion) grid volumes. A 270 TB subdomain containing the entire life cycle of the tornado, plus ten minutes prior to tornadogensis, was saved to disk in 0.2 second intervals in LOFS format, a file system comprised of HDF5 files utilizing ZFP lossy floating point compression. The processes involving the tornado's life cycle will be compared to prior work describing a simulation of the same event (24 May 2011, El Reno, OK) at 30 m grid spacing. The challenges of conducting a simulation of this scale and with this amount of output will be discussed, and high definition 3D visualizations of genesis, maintenance, and decay will be shown. Genesis is characterized by an intensification of the updraft near the ground in conjunction with the consolidation of dozens of nontornadic cyclonic misovortices. The tornado undergoes a progression from single-celled to two-celled to multiple vortex to single celled again before decaying over its 35 minute life span. 3D visualizations of the cloud, rain, wind, and vorticity fields will be shown at 0.2 s temporal resolution, focusing on the tornadic region of the storm.