U.S. Drought: Weekly Report for October 11, 2022

According to the October 11, 2022, U.S. Drought Monitor, moderate to exceptional drought covers 46.4% of the United States including Puerto Rico, an increase from last week’s 44.0%. The worst drought categories (extreme to exceptional drought) increased from 11.5% last week to 12.1%. 

The upper-level circulation across the contiguous U.S. consisted of a strong ridge of high pressure over western North America with a trough along the East Coast. This pattern blocked Pacific weather systems from entering the western contiguous U.S., directing them into Alaska and far northwest Canada. The result was a drier- and warmer-than-normal week over the western contiguous U.S. The pattern produced a northwesterly flow at the jet stream level over central North America. This flow directed dry Canadian air masses into the U.S. east of the Rockies, and these brought cooler-than-normal temperatures to the eastern half of the contiguous U.S. A weather system that was traversing the jet stream flow became detached and stalled out over the Southwest, spreading above-normal precipitation and below-normal temperatures to the region.

Canadian cold fronts brought above-normal precipitation to parts of the Northeast. Otherwise, this was a very dry week across most of the contiguous U.S. Drought and abnormal dryness contracted in the Southwest and parts of the Northeast, where above-normal rain fell. But drought or abnormal dryness expanded in parts of the Pacific Northwest, where dry conditions and dozens of large wildfires continued, in much of the Great Plains to Mississippi Valley, and from the Great Lakes to Southeast. Nationally, expansion exceeded contraction, with the nationwide moderate to exceptional drought area increasing this week.

Abnormal dryness and drought are currently affecting over 214 million people across the United States including Puerto Rico—about 68.9% of the population.