Indepth discussion of the Greensburg, KS, EF5 tornado of May 4, 2007. We'll discuss the meteorology behind the event before diving into the behavior and mechanics of the parent supercell and Greensburg tornado (and subsequent tornadoes), including the modes of cyclic tornadogenesis, notable radar signatures such as a weakecho column, the tornadoes' deviant motion, and more.

Thumbnail image from R. Fritchie via Tanamachi et al. (2012).

Chapters:

0:00 Introduction
2:35 Meteorological discussion
23:10 May 24, 2015 analog
27:09 Event progression/radar overview
31:06 Why significant tornadoes occurred despite strong CIN
35:05 Initial "splitting" storms
38:36 Change in cyclic tornadogenesis modes
42:17 Hook echo characteristics, progression
46:58 Satellite tornadoes
48:28 Weakecho column
52:36 Deviant tornado motion
01:00:30 Occlusion/handoff process fueled by vorticity stretching
01:03:29 Brief discussion of the tornadoes after Greensburg
01:07:51 Summary

Resources:

"The Greensburg, Kansas Tornadic Storm: A Storm of Extremes" Lemon and Umscheid (2008): https://www.tornadotalk.com/wpconten...

"The Formation and Early Evolution of the Greensburg, Kansas, Tornadic Supercell on 4 May 2007" Bluestein (2009): https://journals.ametsoc.org/view/jou...

"Mobile, Xband, Polarimetric Doppler Radar Observations of the 4 May 2007 Greensburg, Kansas, Tornadic Supercell" Tanamachi et al. (2012): https://journals.ametsoc.org/view/jou...

"Significant Nighttime Tornadoes in the Plains Associated with Relatively Stable LowLevel Conditions" Fischer and Davies (2009): http://nwafiles.nwas.org/ej/pdf/2009...

"The Influence of the ShearInduced Pressure Gradient on Thunderstorm Motion" Rotunno and Klemp (1982): https://www.atmos.albany.edu/facstaff...

"Anticipating Deviant Tornado Motion Using a Simple Hodograph Technique" Nixon and Allen (2021): https://journals.ametsoc.org/view/jou...

"Historic Greensburg Supercell of 4 May 2007" Umscheid (2010): https://www.dupagecounty.gov/OHSEM/We...

"Radar Observations of the 3 May 1999 Oklahoma City Tornado" Burgess et al. (2002): https://journals.ametsoc.org/view/jou...

US Tornadoes article on Greensburg: https://www.ustornadoes.com/2017/05/0...

Cameron Nixon's article on deviant tornado motion: https://cameronnixonphotography.wordp...