According to the October 6, 2020, U.S. Drought Monitor, moderate to exceptional drought covers 37.2% of the United States including Puerto Rico, an increase from last week’s 35.8%. The worst drought categories (extreme to exceptional drought) increased from 12.2% last week to 13.3% this week.
Atmospheric circulation this week was dominated by a high-pressure ridge over the western contiguous United States and a low-pressure trough over the East. This classic pattern deflected Pacific storm systems into western Canada, leaving the western contiguous United States with sunny, dry, and warmer-than-normal weather. The western ridge and eastern trough produced a northwesterly flow over central North America. This flow pattern funneled cooler- and drier-than-normal air into the contiguous United States east of the Rockies.
As they moved south and east, the cold fronts tapped Atlantic moisture to generate precipitation over the Great Lakes to the East Coast, but most of the rest of the contiguous United States was drier than normal with little to no precipitation falling. As a result, drought and abnormal dryness expanded in most vulnerable areas. There was some contraction in the Northeast and Midwest, but expansion dominated in the West, Plains, Midwest, and Northeast, resulting in an expansion of the overall U.S. drought footprint again this week.
Abnormal dryness and drought are currently affecting over 120million people across the United States including Puerto Rico—about 38.7% of the population.
In addition to Drought.gov, you can find further information on the current drought as well as on this week’s Drought Monitor update at the National Drought Mitigation Center. See their recent news releases.
The most recent U.S. Drought Outlook is available from NOAA’s Climate Prediction Center and the U.S. Department of Agriculture provides information about the drought’s influence on crops and livestock.