The 12-month map ending September 2016 (below) depicts the widespread moderate to extreme deficits forecast for Montana, Wyoming, Michigan, much of the Mississippi Valley, and New England. Surpluses are forecast for the Southern Plains, east Texas, coastal North and South Carolina, and eastern Florida. Both deficits and surpluses are expected in in the Pacific Northwest, the Southeast, Missouri and Arkansas. 

The 3-month maps (below) for the same time period show the evolving conditions in more detail. Extreme to exceptional surpluses are forecast January through March in Wisconsin, Iowa, the Mississippi River along the Illinois-Missouri border, Rio Grande River through New Mexico and Texas, northern and eastern Texas, eastern Nebraska, New Hampshire and Maine. Moderate to severe surpluses are forecast for the mid-Atlantic, the Southeast, and portions of California, Oregon, and Washington. From April through June widespread severe to extreme deficits are forecast to emerge in the Great Lakes Region, New England, New York, Pennsylvania, and the Ohio and Mississippi River Valleys. During this period surpluses are forecast to persist and intensify in Florida and the rivers flowing from the southern Rockies. Deficits are forecast to persist in the aforementioned areas through September, and to expand to encompass the Pacific Northwest, and the northern Rockies (particularly the northern reaches of the Yellowstone and Missouri Rivers. Most of California is forecast to have characteristics of both surplus and deficit in these latter months.

Outside the contiguous US, much of southern Alaska is forecast to transition from surplus to moderate deficit July through September; Hawaii from surplus to moderate deficit April through June; and Puerto Rico from deficit to surplus April through June.

(It should be noted that forecast skill declines with longer lead times.)


Many analyses reported in ISciences-authored blog posts are based on data generated by the ISciences Water Security Indicator Model (WSIM). Other sources, if used, are referenced in footnotes accompanying individual posts. WSIM is a validated capability that produces monthly reports on current and forecast global freshwater surpluses and deficits with lead times of 1-9 months at 0.5°x0.5° resolution. This capability has been in continuous operation since April 2011 and has proven to provide reliable forecasts of emerging water security concerns in that time-frame. WSIM has the ability to assess the impacts of water anomalies on people, agriculture, and electricity generation. Detailed data, customized visualizations, and reports are available for purchase.

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