June 17th was a tough day to forecast. It was clear there were two targets, northeast Nebraska again, or far western South Dakota/eastern Montana. After analyzing both, we decided to head to western South Dakota. In the end both areas produced several tornadoes, however the largest and most powerful tornado ever recorded occurred in southeast Montana and we were privy to watch the event from a safe and spectacular distance! Very strong shear, dewpoints near 70 (unheard of for Montana!), high instability and convergence along the dryline set the stage there for violent supercells and strong tornadoes. By early afternoon the storm of the day formed near Capital, Montana as it sat and steadily intensified. We were racing trying to get there in time (VERY early initiation!!!!) , and managed to catch the tornado and supercell at its strongest and prettiest stages! The result was a nearly mile wide wedge tornado that was rated EF3 (Very high for a remote region!) and was on the ground for nearly an hours time. Fortunately it dissipated just before reaching Camp Crook, SD or the destruction would have been severe.