Back home and in this alternate scenario, the Ozarks are all that remains of a Proterozoic mountain range hundreds of millions of years ago.
Back home, the Ozarks look like this, highlit in lime:
The tallest point is Buffalo Lookout, standing 2561 feet above sea level. In this alternate scenario, both the Appalachian Mountains and the Black Hills are absent, and the Ozarks look like this, highlit in black:
Not only are they bigger, they are also taller--tallest point, 7242 feet above sea level.
With this kind of detailed information, would these Ozarks be the barrier that northeastern Nebraska (42.4649° North, 96.4131° West) needs to reduce its probability of tornadoes to the bare minimum?