U.S. Drought: Weekly Report for July 25, 2023

According to the July 25, 2023 U.S. Drought Monitor, moderate to exceptional drought covers 22.7% of the United States including Puerto Rico, an increase from last week’s 21.6%. The worst drought categories (extreme to exceptional drought) stayed about the same as last week’s 2.2%.

The upper-level circulation across North America during this U.S. Drought Monitor week (July 19–25) consisted of a strong ridge of high pressure over the southern contiguous U.S. with a jet stream across the U.S.-Canadian border. 

The ridge extended northward across the western CONUS and western Canada, but began shifting eastward into the Plains as the week progressed. Upper-level troughs of low pressure were centered over the Gulf of Alaska and Hudson Bay. By week’s end, the Gulf of Alaska trough migrated over western Canada while the Hudson Bay trough extended southward over the eastern contiguous U.S. The ridge as well as these upper-level troughs controlled the weather over North America during the week. The ridge brought above-normal temperatures across the western contiguous U.S. and Gulf of Mexico Coast, with record heat in the Southwest, while temperatures averaged cooler than normal from the central Plains to the Mid-Atlantic Coast beneath the eastern trough. The ridge inhibited precipitation, so most of the West, northern and southern Plains, Upper Mississippi Valley, Gulf of Mexico Coast, and Southeast Coast were drier than normal. 

Fronts and surface low-pressure systems that were associated with the eastern trough generated showers and thunderstorms across parts of the Plains, Midwest, and Northeast. These resulted in above-normal precipitation over parts of northern Texas to Nebraska, the Mid-Mississippi and Tennessee Valleys, and the Ohio Valley to the Northeast. Record-setting rains and significant flooding occurred over western Kentucky. 

Drought or abnormal dryness contracted or was reduced in intensity in areas that were wetter than normal, especially in the central Plains and parts of the Mississippi and Ohio Valleys to the Northeast. But drought or abnormal dryness expanded or intensified where it continued dry, especially across parts of the Southwest, northern Rockies, northern and southern Plains, and Upper and Lower Mississippi Valley. 

Nationally, expansion exceeded contraction, so the nationwide moderate to exceptional drought area increased this week. Abnormal dryness and drought are currently affecting over 139 million people across the United States including Puerto Rico—about 44.9% of the population