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Thanks for stopping by. I am an atmospheric scientist with the Space Science and Engineering Center 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.

Latest stuff:

October 22, 2018:

“The Role of the Streamwise Vorticity Current in Tornado Genesis and Maintenance” presented by Leigh Orf at the 29th Conference on Severe Local Storms in Stowe, VT on October 22, 2018.

Leigh Orf presentation at 29th Conference on Severe Local Storms

June 5, 2019: Blue Waters Annual Symposium, Sunriver, OR: “Understanding the Development and Evolution of Violent Tornadoes in Supercell Thunderstorms”:

Leigh Orf presentation at 2018 Blue Waters Symposium in Sunriver, OR, June 5, 2018

For the NCSA produced video of this talk, which includes separate video of the presenter (but no followup questions), click here.

May 9, 2018: Materials Research Science & Engineering Center (MRSEC) Computations in Science Seminar, University of Chicago:

Leigh Orf research seminar at the University of Chicago, 5/9/18

March 24, 2018: Presentation at the Dark Skies Seminar at Madison College:

Leigh Orf 2018 Dark Skies Severe Weather Seminar presentation at Madison College

January 23, 2018: Presentation at the 29th Annual Weather Summit at Steamboat Springs, CO. In this talk I present some new animations where every model time step is visualized, both during tornadogenesis and maintenance where the multiple vortex structure of the tornado is fully displayed:

Leigh Orf 1/23/18 Steamboat Springs Weather Summit presentation

Dec 11, 2017: Here is a link to the poster I presented at the 2017 AGU conference. The Use of ZFP lossy compression in tornado-resolving supercell thunderstorm simulations

November 22, 2017: Storm chaser extraordinaire Hank Schyma (“Pecos Hank”) produced a documentary where we discuss my latest research and compare some of his own observations of supercells and tornadoes to some of my own simulations:


November 1, 2017: WIRED article about my research team, and a narrated video with recent simulations:


September 7, 2017: Invited presentation at the HPC User Forum in Milwaukee [Link to 1080p version without podium video]:

HPC Challenges in Simulating the World's Most Powerful Tornados

June 28, 2017: Presentation at Wednesday Nite @ the Lab at UW-Madison

May 16, 2017: Presentation at Blue Waters annual symposium, Sunriver, OR [Link to 1080p version without podium video]

Leigh Orf: Unlocking the Mysteries of the Most Violent Tornadoes

May 12, 2017: Presentation at Argonne National Laboratory Physics Colloquium, Chicago, IL.

Leigh Orf presentation at Argonne National Labs Physics Symposium, May 12, 2017

May 3, 2017: PBS Newshour segment:

How studying simulated tornadoes could help save real lives

April 14, 2017: PBS Newshour article/q&a session with Julia Griffin

April 11, 2017: I was a guest on Weatherbrains, an informal weekly discussion about weather and weather related topics. In Episode 586 I talk at length about aspects of my research and answer questions from host Bill Murray.

March 26, 2017 (air date): I was a guest on Wx Geeks, hosted by Dr. Marshall Shepherd, on The Weather Channel.

Leigh Orf as a guest on Wx Geeks (The Weather Channel), March 2017

March 25, 2017: Presentation at the 2017 Dark Skies Seminar at Madison College

Leigh Orf 2017 Dark Skies Seminar presentation

March 13, 2017: UW-Madison press release regarding this work.

February 16, 2017: University of Western Ontario, Mechanical and Materials Engineering Distinguished Lecture Series seminar

MME Distinguished Lecture Series seminar (Feb. 2017)

November 16, 2016: Robert Wilhelmson and I both received HPC Innovation Excellence Awards.

November 9, 2016 Severe Local Storms presentation:

Orf, Finley, Lee, Wilhelmson presentation at SLS2016 in Portland, OR

August 2016: “Inside a Supertwister” – part of the NSF sponsored CADENS project. Click here for NCSA’s page dedicated to this documentary on devastating tornadoes.

June 19, 2016: NVIDIa blogs about their new IndeX software, using some of my supercell model data.

June 13, 2016: Presentation at fourth annual Blue Waters Symposium in Sunriver, Oregon

The first major publication on this work can be found in the January 2017 issue of BAMS:

Orf, L., R. Wilhelmson, B. Lee, C. Finley, and A. Houston, 2017: Evolution of a Long-Track Violent Tornado within a Simulated Supercell. Bull. Am. Meteorol. Soc., 98, 45–68. http://dx.doi.org/10.1175/BAMS-D-15-00073.1.