United States: Widespread water surplus to persist in SD, NE, KS, OK

16 September 2019

THE BIG PICTURE
The 12-month forecast ending May 2020 indicates that water surpluses of varying intensity will form a column down the middle of the country in the Missouri River Basin from South Dakota through Kansas as well as in Oklahoma. Surpluses are expected to be extreme to exceptional in South Dakota; along the Platte River west of Omaha, Nebraska; and at the intersection of Kansas, Missouri, and Oklahoma.

ISciences_United_States_Composite_Adjusted_201906-202005_12mo_panel.png

Severe surpluses are forecast along much of the Arkansas River, and from Kansas City to St. Louis along the Missouri River. Moderate to severe surpluses will reach across southern Minnesota through central Wisconsin. Texas, too, can expect surpluses in the western Edwards Plateau and in the northeast.

Surpluses are also forecast scattered throughout the Rockies and in eastern Nevada. Some moderate surpluses are expected in the southern Sierra Nevada Mountains in California. On the opposite side of the country, moderate surpluses are expected in Upstate New York and in the Tampa Bay region of Florida.

Deficits are forecast in the Pacific Northwest, southwestern Arizona, south-central New Mexico, north-central Minnesota, along the Atlantic coast from the Carolinas into pockets of Georgia and southern Alabama, and the central Everglades in Florida.

Outside the contiguous U.S., surpluses are forecast for much of Hawaii. In Alaska, surpluses are forecast in the Koyukuk River watershed. Deficits are forecast along the southern shore of the state from the Alaska Peninsula through Kodiak, Anchorage, and Valdez, and north to Fairbanks and the Tanana River region. Moderate to severe deficits are forecast for western Puerto Rico

FORECAST BREAKDOWN
The 3-month maps (below) show the evolving conditions in more detail.

From September through November 2019, widespread surpluses observed in prior months will shrink leaving nearly normal conditions in the U.S. Northeast, Ohio River Valley, Lower Mississippi River Basin and much of the Upper Mississippi River Basin. However, a broad column of intense water surplus is forecast from southern North Dakota through South Dakota, Nebraska, Kansas into Missouri, Oklahoma, and reaching into north-central Texas. Surpluses are expected to be extreme to exceptional in South Dakota. Surpluses of varying intensity are also forecast for parts of Montana, Wyoming, Colorado, southern Idaho, western Utah, and eastern Nevada.

ISciences_United_States_Composite_Adjusted_201906-202005_3mo_panel.png

Moderate surpluses are expected in central Arizona and in California around Sacramento, from San Francisco through the southwest, and in the southern Sierra Nevada Mountains. Some pockets of moderate surplus are forecast for central Oregon. Intense deficits are expected in the Salmon River Mountains of central Idaho. In the U.S. Southeast, mild to severe deficits will dapple the region from West Virginia through southern Alabama and into the Florida Panhandle. Surpluses are forecast near Tampa Bay, Florida, leading south along the coast. A pocket of exceptional deficit is expected in the central Everglades.

From December 2019 through February 2020, surpluses will be the dominant anomaly, persisting in a column from South Dakota into Oklahoma, and will be especially intense in South Dakota. Surpluses of varying intensity are forecast for Wyoming, western Utah, eastern Nevada, and pockets of southwestern Colorado. Moderate surpluses are also forecast in central Minnesota, pockets of Wisconsin and central Illinois, and throughout northern Missouri. Moderate surpluses will emerge in southeastern Michigan through northern Ohio and into northern Pennsylvania and Upstate New York. Small, isolated pockets of deficit are forecast in the Salmon River Mountains of Idaho, central Colorado, northern Minnesota, and the central Everglades.

The forecast for the final months – March through May 2020 – indicates that a column of surplus will persist from South Dakota through Oklahoma but will shrink and downgrade overall in intensity. Exceptional surpluses will persist in South Dakota. Moderate surpluses are forecast scattered throughout the Rockies and some isolated pockets in the West.

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

IMPACTS
[added 19 September 2019]
The Florida tourism industry is hoping a social media campaign using the hashtag “#LoveFL” will bolster tourism to the state after vacations were canceled and revenues plummeted in the wake of this month’s Hurricane Dorian, which skirted the state’s eastern coastline. Facing $10 million in property insurance claims, the state insurance commissioner said that companies still have yet to close thousands of claims resulting from Hurricane Michael, which struck last October.

As Dorian traveled up the eastern seaboard it closed some of the busiest seaports on the east coast, including the Port of Charleston in South Carolina. The storm struck North Carolina as a Category 1 storm, stranding 800 people on Ocracoke Island and ravaging the Outer Banks with tornadoes and storm surge.

Some areas of eastern Nebraska have yet to dry out months after flood waters ravaged the region this spring. Lasting damage on a Missouri River levee in Peru, Nebraska continues to allow water to flow through, keeping a few thousand acres of farmland submerged. Damage to the levee, meanwhile, can’t be assessed until the water recedes, leaving the city in limbo.

South Dakota farmers are reeling from the state’s second major flooding event this year. After spring flooding prevented nearly 4 million acres from being planted, early September’s deluge could delay or prevent the harvest of remaining sown acreage. Fields are too wet to bring tractors in and roads and bridges have washed out.

Farmers in South Carolina say drought is threatening crop devastation at harvest time. Of South Carolina’s 46 counties, 31 of them were classified as experiencing moderate drought by a special committee formed by the state, though some farmers contend that their farms have seen nearly zero rainfall in two months.

NOTE ON ADMINISTRATIVE BOUNDARIES
There are numerous regions around the world where country borders are contested. ISciences depicts country boundaries on these maps solely to provide some geographic context. The boundaries are nominal, not legal, descriptions of each entity. The use of these boundaries does not imply any judgement on the legal status of any territory, or any endorsement or acceptance of disputed boundaries on the part of ISciences or our data providers.

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