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Thanks for stopping by. I am an atmospheric scientist with the Cooperative Institute for Meteorological Satellite Studies (CIMSS) / Space Science and Engineering Center (SSEC) at the University of Wisconsin. This site is primarily a collection of media highlighting my research on supercell thunderstorms and tornadoes. The goal of this research is to understand the internal workings of supercell thunderstorms well enough to significantly improve our forecasting of their behavior. What makes this work significant is the use of supercomputing resources to produce simulations of supercells where data is saved with extremely high spatial and temporal resolution, and the use of visualization techniques (such as volume rendering and trajectory clouds) to produce video that exposes the highly variable flow features that occur throughout the life of the simulated storms. Some of these simulations contain long lived tornadoes producing near-surface winds exceeding 300 mph. Thus far this effort has been focused primarily on the 24 May 2011 El Reno event, initializing the CM1 model with a RUC sounding representative of the actual environment adjacent to the storm that produced the observed EF5 tornado.
Selected presentations are found below in reverse chronological order. For other presentations I have given since 2014, please see my youtube channel, which contains all of the video material I have created, which is a mix of scientific and general public presentations.
Under the Education tab you can find videos and other information specifically designed for a general audience. Much of this material was not produced by myself, but includes interviews and video of storm simulations.
Knowable magazine article:
The quest to understand tornadoes
My talk at the Tornado Hazard Wind Assessment and Reduction Symposium
Supercells In Polygondwanaland
New video highlighting the new Paraview illumination code operating on a LES supercell simulation.
This video, produced by Lawrence Livermore, showcases ZFP, the lossy floating point compression that I use in all of my simulation and analysis data – my research wouldn’t be possible without it! You can see some of my simulations in the video as well as a bit of testifying.
UPDATE: Congratulations to ZFP author Peter Lindstrom! ZFP is a R&D 100 Winner for 2023!
Leigh Orf’s Dark Skies Severe Weather Seminar Presentation at Madison College.
Steamboat Weather Summit 1 hr long talk “Simulations and Visualizations of Violent, Tornado-Producing Supercell Thunderstorms”
New article: Finley, C. A., M. Elmore, L. Orf, and B. D. Lee, 2022: Impact of the streamwise vorticity current on low‐level mesocyclone development in a simulated supercell. Geophys. Res. Lett., https://doi.org/10.1029/2022gl100005.
AMS Conference on Severe Local Storms 2022 talk, “A vortex-relative perspective on tornadogenesis in a large-eddy supercell simulation containing a violent long-track tornado”
New article: Bannigan, N., L. Orf, and E. Savory, 2022: Tracking the Centre of Asymmetric Vortices Using Wind Velocity Vector Data Fields. Bound.-Layer Meteorol., https://doi.org/10.1007/s10546-022-00739-0. Publisher’s shareable PDF of paper.
Hannah Osborne (Newsweek magazine): “Peering Into the Deadliest, Most Destructive Tornadoes with Supercomputers”
New page dedicated to AACP research, contains recent talk:
“Hydraulic jump dynamics associated with Above Anvil Cirrus Plumes”
Seminar, UW-Madison, Department of Atmospheric and Oceanic Sciences
“CFD Simulation of Downbursts” presented virtually at THUNDERR / Genoa. Supplemental materials are found by clicking here.
New article out in Science! “Hydraulic jump dynamics above supercell thunderstorms”
I produced a video for the Computer Museum of America about supercomputers and cloud modeling:
Q&A session on youtube
New paper published describing recent research conducted on the NSF-sponsored Frontera supercomputer: Orf, L., 2021: Modeling the World’s Most Violent Thunderstorms. Computing in Science Engineering, 23, 14–24.
AMS On The Air interview (from the 100th Annual AMS meeting in Boston, 1/2020). I am one of several people interviewed by Dakota Smith 100th AMS Annual Meeting. I talk primarily about my recent high resolution supercell simulations and the problems we’re trying to solve in understanding tornadoes and supercells.
I was a guest on the Chaser Chat podcast with Gabriel Harber:
The Texas Advanced Computing Center (TACC) has written an article about some of my latest research: