July 18th had good hope for supercells, but less chance for tornadoes. Good shear, along with moderate instability and weak low level moisture would be sufficient for storms to form. By mid afternoon, supercells exploded along the Big Horn mountains and moved eastward across northeast Wyoming. I intercepted this storm north of Gillette. The supercell contained 2″ diameter hail, very strong winds and it tried very hard to produce as it blasted across the Black Hills.