According to the May 23, 2017, U.S. Drought Monitor, moderate to extreme drought covers 4.5% of the contiguous United States, a decrease from last week’s 5.6%. Areas in extreme drought held steady at around 0.4% for a second week. Exceptional drought, the worst category, continued to remain absent from the country for the 18th consecutive week.
A deep trough and closed low in the upper atmosphere slowly moved across the contiguous United States during this U.S. Drought Monitor week, pumping abundant moisture into the Great Plains, Midwest, and Southeast. The circulation characteristics of the upper-level trough combined with surface lows and cold fronts to generate days of severe weather and widespread heavy rain.
The above-normal precipitation contracted drought and abnormally dry areas in the Southern Plains and Southeast. But, the precipitation missed parts of the Northern Plains and Southwest, where drought and abnormal dryness expanded.
The clouds, rain, and snow associated with the upper-level trough, and cooler air behind the cold fronts, resulted in below-normal temperatures across much of the West and Great Plains. A southerly flow ahead of the trough brought warmer-than-normal temperatures to much of the country east of the Mississippi River.
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.