According to the November 7, 2017, U.S. Drought Monitor, moderate to exceptional drought continues to cover around 12.0% of the contiguous United States for a third week. Extreme drought decreased from 0.9% last week to 0.8%. And, exceptional drought remained absent from the Lower 48 for a fourth week.
The atmospheric circulation during this U.S. Drought Monitor week was dominated by a struggle between subtropical high pressure across the southern contiguous United States and weather systems moving in the jet stream flow across the north. Cold fronts and low pressure systems brought above-normal precipitation to parts of the Pacific Northwest, northern Rockies, northern Plains, eastern Texas to southern Louisiana, and the mid-Mississippi valley to eastern Great Lakes. The weather systems mostly missed the Southwest to southern Plains and western Great Lakes, and much of the Southeast and coastal Northeast, where it was drier than normal and, in some cases, little to no rain fell.
Temperatures were cooler than normal behind the fronts in the Pacific Northwest, northern Rockies, central to northern Plains, and western Great Lakes. But, temperatures remained warmer than normal ahead of the fronts and where subtropical high pressure dominated, specifically in the Southwest, South, and East. As a result, drought and abnormal dryness contracted further in some northern states and expanded further in some southern states.
Abnormal dryness and drought are currently affecting over 79 million people across the United States—about 25.5% of the country’s population.