According to the December 10, 2019, U.S. Drought Monitor, moderate to extreme drought covers 9.5% of the United States including Puerto Rico, a decrease from last week’s 9.9%. The worst drought categories (extreme to exceptional drought) remained the same as last week: 0.1%.
Strong Pacific weather systems moved across the contiguous United States, bringing above-normal rain and snow to much of the Southwest. The storm systems came in on a southerly track, leaving the Pacific Northwest drier than normal for the week. As they crossed the Rocky Mountains, the storms were dried out.
The upper-level circulation was generally westerly, so temperatures averaged warmer than normal for much of the country, but a northwesterly flow across the central part of North America funneled dry Canadian air into the contiguous United States east of the Rockies. There were some areas with above-normal precipitation, from the northern Plains to coastal Northeast and parts of western Texas, but the combination of dried-out Pacific systems and dry Canadian air resulted in a drier-than-normal week across much of the country east of the Rockies.
The above-normal precipitation contracted drought and abnormal dryness in the Southwest and parts of Texas. Drought or abnormal dryness expanded where it continued to be dry in the Pacific Northwest, central to southern Plains, and parts of the Southeast. With contraction outweighing expansion, the drought area shrank again this week on a national scale.
Abnormal dryness and drought are currently affecting over 55 million people across the United States including Puerto Rico—about 17.8% 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.