United States: Water deficits forecast in the Plains

19 October 2022

THE BIG PICTURE
The 12-month forecast ending June 2023 indicates widespread water deficits of varying intensity from the Central Plains into parts of the Upper Midwest, and along much of the East Coast and many regions in the West and Rockies.

In the Central Plains, deficits will be exceptional in Nebraska and western Kansas. Deficits nearly as intense are expected in southern Minnesota, northwestern Iowa, and the Llano Estacado in Texas. Texas will also see deficits in the northern Gulf Coast including Houston, reaching into Louisiana, and intense deficits are forecast at the mouth of the Mississippi River.

Much of California south of San Francisco can expect deficits as can the Shasta Cascades region in the northeast where anomalies will be exceptional. Deficits will also be intense in pockets south of Fresno, the Mojave Desert, and Oregon’s southeast quadrant. A patchwork of mixed conditions is forecast in Washington, Idaho, Nevada, Montana, and Wyoming though deficits will be more pervasive. Utah can expect exceptional deficits through the Rockies. In the Southwest, exceptional deficits are forecast in southwestern Arizona, pockets of surplus in the east and in New Mexico, and moderate deficits in southeastern New Mexico.

In the Northern Plains, extreme surpluses are expected west of Lake Sakakawea on the Missouri River in North Dakota, and mixed conditions in the eastern half of the state. Elsewhere in the Midwest, generally moderate deficits are forecast in northern Wisconsin and pockets in Michigan, Indiana, and Missouri. Arkansas, too, can expect pockets of moderate deficit. A few isolated pockets of moderate surplus are forecast in the Ohio River Basin.

On the East Coast, deficits are expected from southern New Hampshire through New Jersey, with pockets in nearby regions, and from Virginia through Peninsular Florida and pockets in Alabama. Areas with a forecast of intense deficit include Massachusetts into New Hampshire, the Cape Fear River Watershed in North Carolina, and north central Florida and near Lake Okeechobee.

Outside the contiguous U.S., severe deficits are forecast in western Puerto Rico and surpluses in Hawaii. Alaska can expect deficits in the northeast, widespread surpluses from the Alaska Peninsula well into the interior, and surpluses in the Alaska Range, the Kobuk River Basin, Nome, and Juneau.

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

The forecast through December indicates widespread deficits from the Upper Midwest to the Gulf, moderate overall but more intense in southern Wisconsin, northern Iowa, and the eastern halves of Nebraska and Kansas reaching into Missouri. Transitional conditions (pink/purple) are forecast in eastern regions of the Dakotas. Texas can expect deficits in the Panhandle and Gulf Coast into Louisiana. Deficits, again mostly moderate, will be widespread in the Deep South, northern Florida, and through the Carolinas into Virginia. Anomalies will be extreme in northern Florida and the Lower Cape Fear River of North Carolina. Surpluses are forecast in Orlando and along the southeast coast from Tampa. In the Northeast, deficits are expected in Boston, New Jersey, and the Delmarva Peninsula. The Great Lakes States, too, will see pockets of deficit. In the Rockies, normal conditions will be pocked with deficits and a few surpluses, exceptional deficits in the Salmon River Mountains and border region of Idaho, Utah, and Wyoming. Deficits are forecast in southeastern New Mexico, but pockets of surplus are expected elsewhere in the Southwest. In the West, deficits are forecast from the desert region in California to La Vegas, and pockets of surplus elsewhere in Nevada. Mixed conditions are predicted in Washington.

From January through March 2023, deficits are expected from North Carolina through much of Florida and coastal Louisiana; Minnesota through Iowa and into Nebraska, Kansas, and Arkansas; and pockets in northern Wisconsin and northern Michigan. Intense deficits will persist in the Salmon River Mountains and a few small pockets in the Rockies while pockets of surplus emerge. Surpluses will re-emerge in the Dakotas and emerge on the Missouri into Montana. Widespread moderate surpluses are forecast from Ohio to Vermont and surpluses are expected in eastern Wisconsin and Illinois.

The forecast for the final months – April through June 2023 – indicates moderate deficits in Peninsular Florida, southern Arizona, and Death Valley, and surpluses in the Rockies, a few pockets in New Mexico and Tennessee, and Lake Sakakawea, North Dakota.

Please note that WSIM forecast skill declines with longer lead times.

IMPACTS
In late September, Hurricane Ian swept through the U.S. Southeast, cutting a devastating path through Florida that left at least 127 people dead in the Sunshine State alone. Around 2.7 million Floridians lost power as more than 3,500 square miles of the state was drenched in 10 or more inches of rain over just 24 hours, leaving downtown Ft. Myers underwater as storm surge reached 8 to 10 feet (2.4 to 3 meters) above ground level in some areas of southwest Florida. Private market insured damage is estimated at $67 billion for Florida, Georgia, the Carolinas, and Virginia, and the National Flood Insurance Program could see an additional $10 billion loss. While standard insurance policies cover damage from wind and rain, they do not include flood loss, available in a separate rider that only 18 percent of Florida homes carry.

In the nation’s mid-section, drought has left the mighty Mississippi River near record lows. The U.S. Coast Guard has established barge load limits in an effort to prevent groundings that create back-ups like a recent 2,000 traffic jam. The river transports 92 percent of agricultural exports and if it becomes unnavigable due to low levels, costly dredging or alternative transport would be required to keep the ag industry’s product moving.

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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