ST. LOUIS (AP) — The nation's worst drought in decades has worsened in parts of the nation's midsection, further frustrating ranchers and growers of winter wheat in Kansas and Oklahoma. The U.S. Drought Monitor's weekly update posted Thursday shows that 60 percent of the land in the lower 48 states is experiencing some degree of drought as of Tuesday. That's down less than a percentage point from the previous week. But the nation's worst drought in decades intensified in Kansas, the top U.S. producer of winter wheat. Thursday's update shows that the expanse of that state in extreme or exceptional drought — the two worst classifications — rose roughly 6 percentage points, to 83.8 percent. Nearly 76 percent of Oklahoma is mired in the two highest forms of drought, up 8 percentage points.