June 21st had good promise with a strong short wave trough ejecting through the northern and central high plains. Plenty of moisture, shear, and good instability would provide the fuel needed for supercell storms. A surface boundary formed on the north side of the Black Hills and extended all the way to east of Billings, Montana. Storms formed and anchored themselves along the boundary, while spinning nicely. Two supercells we encountered produced tornadoes this day. Storm structure was fantastic and the tornadoes were very nice, churning across the hills of southeast Montana causing no damage.