According to the June 1, 2021, U.S. Drought Monitor, moderate to exceptional drought covers 36.5% of the United States including Puerto Rico, a slight increase from last week’s 36.3%. The worst drought categories (extreme to exceptional drought) decreased from 17.8% last week to 17.5% this week.
The atmospheric circulation over the contiguous United States shifted with several Pacific weather systems tracking across the country in a westerly flow. The week began with an upper-level ridge over the East Coast and troughs moving across the West. It ended with a ridge over the West Coast and troughs moving across the East. Surface fronts and low-pressure systems were dragged across the contiguous United States by the upper-level systems in two main storm tracks.
The first storm track was across the northern states, bringing above-normal precipitation to the Northeast and parts of the Upper Midwest. The second storm track brought widespread above-normal rainfall to the southern Plains. Most of the West and much of the Southeast continued drier than normal. The interplay between the surface fronts and upper-level systems allowed cool Canadian air to spread into the contiguous United States, resulting in a cooler-than-normal week across most of the country east of the Rockies, while the West Coast ridge brought a warmer-than-normal week to the southwestern states.
Drought or abnormal dryness contracted where welcome rain fell across parts of the northern Rockies to southern Plains, southern parts of the Northeast, and parts of the Midwest. But drought or abnormal dryness expanded or intensified across parts of the Northwest and northern Plains in areas missed by the rain, and especially in the Tennessee Valley to Mid-Atlantic and Southeast states. Expansion exceeded contraction, so the nationwide moderate to exceptional drought area rose this week.
Abnormal dryness and drought are currently affecting over 143 million people across the United States including Puerto Rico—about 46.0% 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 MitigationCenter. 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.