The 12-month map ending October 2016 (below) depicts the widespread moderate to extreme deficits forecast for Montana, Wyoming, North Dakota, Minnesota, Michigan, much of the Mississippi Valley, and New England. Surpluses are forecast for the Southern Plains, east Texas, and southern Florida. Both deficits and surpluses are expected in in the Pacific Northwest, and parts of the Southeast. 

Torrential rains in southern Florida flooded major growing regions, affecting the state's multibillion dollar agriculture industry. In January rainfall in the south was 350% higher than normal according to the South Florida Water Management District, prompting Florida's governor to declare a state of emergency in southeast and southwest Florida. Water surpluses took the form of blizzards across the Great Plains, generating 60-MPH winds, dumping up to 18 inches of snow across eight states, causing power outages in Des Moines, and grounding planes in Denver. Likewise, along the East Coast, a powerful snowstorm dumped a record-setting two feet of snow on Baltimore, New York, and parts of Washington, DC, and left hundreds of thousands without power.

The 3-month maps (below) for the same time period show the evolving conditions in more detail. From February through April deficits are forecast to emerge in southern Michigan southward through the Ohio River Valley, Kentucky, Tennessee, northern Alabama and Mississippi, and eastern Arkansas. Deficits are also forecast during this period for eastern North Dakota and western Minnesota. Exceptional surpluses are forecast for rivers flowing from the Southern Rockies and in Florida. Both deficits and surpluses are forecast for the Pacific Northwest; moderate surpluses for northern California and in the Mississippi Valley.

For the six-month period from May through October the forecast indicates moderate to exceptional deficits will dominate much of the eastern half of the country as well as much of the north. Widespread and persistent deficits are forecast for 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 October, 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 May through July; deficits are forecast in Hawaii in April and May, then moderate surpluses August through October; and, Puerto Rico will transition from deficit to surplus May through October.

(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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