Drought intensified again over parts of the central United States during the 7 days ending last Tuesday, the U.S. Drought Monitor reported. \"This week, we saw extreme (D3) and exceptional (D4) drought continue to expand or intensify over parts of Missouri, Arkansas, Oklahoma, Kansas, Nebraska, and Illinois,\" Brian Fuchs, a climatologist at the National Drought Mitigation Center said. \"New Mexico has also seen some degradation, and D4 drought has been introduced from east central Kansas to west central Missouri.\" Drought conditions are ranked as abnormally dry (D0), moderate drought (D1), severe drought (D2), extreme drought (D3) and exceptional drought (D4). The Drought Monitor map for Aug. 7 shows 52.27 percent of the United States and Puerto Rico in moderate drought or worse, compared to 52.65 percent last week; 38.48 percent in severe drought or worse, compared to 38.12 percent a week earlier; 20.18 percent in extreme drought or worse, up from 18.62 the previous week; and 3.51 percent in exceptional drought, up from 2.52 percent last week. The U.S. Drought Monitor map, released each Thursday, is jointly produced by the National Drought Mitigation Center at the University of Nebraska-Lincoln, the National Oceanic and Atmospheric Administration, the U.S. Department of Agriculture, and about 350 drought observers across the country.