Check out the radar loop I uploaded from yesterday (Monday evening).
Notice two elements: 1) The line or boundary just south of Lake Erie and 2) The other boundary that moved north of Wooster. These boundaries are called "outflow boundaries" or a "Gust Front". Put simply, these boundaries are like waves that propagate away from a boat that passes In this case, The boundary marks an area of sinking, cooler air that moves away from the first line of storms northeast of Cleveland. Some look like this:
As the boundary moved south away from Lake Erie (and north from near Wooster) it acted as a super-small scale cold front lifting the warm/moist air ahead of it enhancing the storm cluster already moving in from the west causing rotation and ultimately a tornado with winds of at least 110 mph. The convergence of these two boundaries and the established storm from the west (which already had minimal rotation according to the Cleveland NWS) provided the necessary ingredients for a rapidly developing tornado. All of this occurred within 10-15 minutes. Something like this is nearly impossible to forecast.