May 2007 Tornado Outbreak - Greensburg Kansas Tornado Posted by Addyson - 5:29 AM - Greensburg, Kansas EF-5 tornado: May 4, 2007 - During the late afternoon hours of May 4, 2007, the atmosphere over western Oklahoma and Kansas had become an ominous mixture of high instability and strong low-level wind shear. A potent upper-lev...