Being quite familiar with Tri-Cities and having lived few years in central Iowa.... both have similar hot summers, cold winters, plenty of sunshine. Des Moines probably gets more of its precip from summer thunderstorms than you get in Tri-Cities. Iowa is salt-of-the-earth good folks. Pretty homogenous culturally and ethnically, but mid-america values. People still attent church there! I felt like I'd stepped back a couple decades moving there from Seattle. Good schools. Good sports programs for kids, good college sports programs if you are a fan.
One of my favorites was that there was plenty of good bird hunting and deer hunting throughout the state, and half the people in Des Moines grew up on a family farm in Iowa and will give you introductions to help you find places to hunt (not of much interest if you are not a hunter.) Something like 5 times more hogs in Iowa than people, and it is the land of a million corn fields, though not as flat of terrain as people think. Much of Iowa is rolling "hills".
You can visit lots of areas and cities on weekends: Minneapolis-St.Paul, Chicago, Kansas City, St Louis.
After all that, I assume you mean Des Moines, IA, not Des Moines, WA!