The worst drought conditions in the lower 48 states expanded for the third week in a row as the level of moderate-to-worse drought hit a high for the year, the U.S. Drought Monitor said.

Exceptional drought, the most severe category on a four- step scale, now covers 6.23 percent of the region, an increase from 6.14 percent last week, according to the Monitor, based in Lincoln, Nebraska. The category peaked Aug. 21 at 6.31 percent.