According to the May 12, 2020, U.S. Drought Monitor, moderate to extreme drought covers 14.6% of the United States including Puerto Rico, an increase from last week’s 13.4%. The worst drought categories (extreme to exceptional drought) increased from 0.8% last week to 1.0% this week.
The upper-level circulation consisted of a highly amplified meridional pattern with a low-pressure trough over the eastern North Pacific, a high-pressure ridge over western North America, and another low-pressure trough over eastern North America. This pattern produced a northerly flow over central North America which funneled cold and dry Canadian air masses across the eastern contiguous United States, resulting in well-below-normal weekly temperatures east of the Rockies.
The western ridge brought warmer-than-normal temperatures to the western contiguous United States. This circulation pattern diverted most Pacific moisture away from the contiguous United States and blocked Gulf of Mexico moisture, so most of the contiguous United States was drier than normal. Only a few areas were wetter than normal. There was some contraction of drought and abnormal dryness, but more expansion occurred, especially in the West, Plains, and along the Gulf coast.
Abnormal dryness and drought are currently affecting over 62 million people across the United States including Puerto Rico—about 20.0% 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 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.