According to the June 12, 2018, U.S. Drought Monitor, moderate to exceptional drought covers 23.3% of the United States, an increase from last week’s 22.6%. Extreme and exceptional drought—the worst categories—held steady, covering about 7.7% of the nation for a third week.
High pressure dominated much of the contiguous United States during this U.S. Drought Monitor week, with upper-level weather systems keeping the main storm track across the northern states and southern Canada. The overall upper-level weather pattern favored the dominance of low pressure troughs over the Pacific Northwest and Northeast, with high pressure ridging from the Southwest to northern Plains. Temperatures averaged well above normal beneath the ridge and cooler than normal along the West Coast and in the Northeast beneath the troughs.
With the storm track and most of the surface fronts and lows keeping to the north, precipitation was above normal across parts of the Pacific Northwest to northern Rockies, northern Plains to Ohio Valley, and Mid-Atlantic region. A few areas of the southern Plains to Southeast were wetter than normal, where summerlike convection and remnants of fronts and lows triggered precipitation. But, with high pressure dominating, much of the West and large parts of the southern and central Plains to southern Appalachians were drier than normal. Much of the Northeast, being north of the main storm track, was also drier than normal for the week.
Drought and abnormal dryness contracted across parts of the Plains and Midwest, but expanded in other parts of the Plains to Mississippi Valley, parts of the Southwest, and interior Washington.
Abnormal dryness and drought are currently affecting over 102 million people across the United States—about 32.9% of the country’s population.