Concerning this specific tornado, I had a chat with the NWS St Louis guys on Twitter, and they said that this tornado was indeed very much confirmed by radar. They were calling it a 'considerable-threat tornado' due to the close proximity to a large, populated area. Despite the scary-looking TDS on the correlation coefficient, it only turned out to be a weak tornado that caused mainly tree damage. However, that was one of the most pronounced radar-confirmed tornadoes that I have ever seen, and I have no doubt that it was more intense than an EF-1. The only more pronounced signature I've seen since then was the Elk Mound EF-3 from last September.
Here's the NCDC Storm Database summary of this event:
"After crossing the Missouri River into St. Charles County, the tornado uprooted and snapped off numerous trees on Sanders Road and caused extensive damage to a farm outbuilding. Further northeast as it crossed Terry Road, where it caused extensive tree damage. As it continued northeast it caused minor structural damage on a barn and outbuilding on Coates Lane, before causing minor roof damage to a house as well as snapping off several trees. The tornado lifted and dissipated just southeast of the intersection of Coates Lane and Duke Road. This portion of the tornado was rated EF1 with a path length of 4 miles and a max path width of 250 yards. Overall the tornado was rated EF1 with a path length of 5.94 miles and a max path width of 250 yards. No deaths or injuries were reported."