United States: Water Forecast Indicates Deficits in the Northwest, Surpluses in the Central Plains

As we reported last month, the continental United States is forecast to experience numerous regionally significant water anomalies:

  • Exceptional drought will persist in northern California through the Pacific Northwest;
  • Southern California is forecast to have characteristics of both water deficits and surpluses;
  • Exceptional water surpluses are forecast for portions of Texas, Oklahoma, Kansas, Nebraska, Colorado, New Mexico, and Louisiana.

In addition, the current forecast indicates:

WSIM Composite Water Anomaly Index for April 2015 through March 2016
(12-Month)

The 3-month composites (below) for the same 12-month period show the evolving conditions in more detail. (It should be noted that forecast skill declines with longer lead times.)

  • Deficits on the West Coast may spread through September, moderate October through December, and then transition to surpluses in California December through March;
  • The region of exceptional surpluses in the Southern and Central Plains is forecast to expand into the US Southwest and northwest Mexico July through March;
  • The October through December forecast includes 10-20 year water surpluses along the Mississippi River;
  • A broad band of surpluses may emerge in the Central Plains July through September and expand from October through March to encompass much of the country;
  • Surpluses are forecast to emerge in the Southeast January through March with exceptional surpluses forecast for southern Florida.

WSIM Composite Water Anomaly Index for April 2015 through March 2016
(3-Month)