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:
- a wide belt of moderate to exceptional surpluses is expected from the Central Plains eastward;
- Southeast states are forecast to have characteristics of both water deficits and surpluses.
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)

- February 2019 15
- January 2019 2
- December 2018 14
- November 2018 14
- October 2018 14
- September 2018 14
- August 2018 14
- July 2018 14
- June 2018 14
- May 2018 14
- April 2018 14
- March 2018 14
- February 2018 14
- January 2018 15
- December 2017 21
- November 2017 7
- October 2017 15
- September 2017 14
- August 2017 14
- July 2017 14
- June 2017 14
- May 2017 14
- April 2017 14
- March 2017 15
- February 2017 15
- January 2017 14
- December 2016 18
- November 2016 10
- October 2016 14
- September 2016 14
- August 2016 15
- July 2016 14
- June 2016 14
- May 2016 15
- April 2016 14
- March 2016 15
- February 2016 14
- January 2016 14
- December 2015 14
- November 2015 14
- October 2015 12
- September 2015 11
- August 2015 11
- July 2015 16
- June 2015 6
- May 2015 9
- April 2015 10
- March 2015 6