United States: Intense water deficits to persist in OR, MO, AR, LA; surpluses in FL

24 July 2018

THE BIG PICTURE
The 12-month forecast indicates intense water deficits in the Northeast, from Missouri to the Gulf, the Southern Rockies, and Pacific Northwest, and intense surpluses in the Northern Rockies.

In the Northeast, deficits are forecast through New York State to the Atlantic and will be especially intense in southern Maine. Some pockets of moderate deficit are forecast in the Carolinas. Primarily moderate surpluses are expected throughout most of Florida except the Panhandle, and also in southern Michigan, eastern West Virginia, and western North Carolina.

In the center of the country, deficits of varying severity are forecast from Missouri south to the Gulf, including eastern Kansas, most of Oklahoma, Arkansas, Texas, and Louisiana. Deficits are expected to be intense in Louisiana, eastern Texas, and northern Missouri. Moderate deficits are forecast in Minnesota but may be more severe near the central Canadian border. Intense deficits are forecast for pockets of Utah and Colorado, and deficits will blanket much of western Oregon and western Washington. Deficits will be primarily moderate in northern California. Surpluses are forecast for much of Montana and central Idaho and are expected to be exceptional. Extreme surpluses are forecast for the Missouri and Yellowstone Rivers, moderate to exceptional surpluses for northern Nebraska, and generally moderate surpluses along the western border of Iowa and Minnesota.

Outside the contiguous US, extreme surpluses are forecast for Hawaii, and also Alaska in the northwest, from Bristol Bay well into the interior, and in the southeast in the upper reaches of the Copper and Susitna Rivers. Deficits are forecast around Anchorage and the Kenai Peninsula. In Puerto Rico, severe deficits are expected throughout the country.

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

The near-term forecast through September indicates that, while exceptional deficits will diminish overall and in the Southwest and Southern Rockies in particular, moderate to severe deficits are expected in a wide path from Kansas and Missouri through Oklahoma, Arkansas, eastern Texas, Louisiana, and eastern Mississippi. Deficits may be extreme to exceptional in northern Louisiana. Exceptional deficits are forecast along the Arkansas River through Nebraska and Colorado, and severe deficits are forecast along the Canadian River. Moderate deficits will emerge in many parts of California with more severe deficits along the northern coast. Deficits will increase in Oregon and Washington, remaining especially intense in western Oregon. On the opposite side of the country, deficits will persist in the Northeast and spread further into Maine. Moderate to severe deficits are forecast for pockets South Carolina and southern Georgia. Deficits in the Upper Midwest are expected to moderate.

Significant surplus conditions will persist in Montana and into Idaho, and northern Nebraska. Severe surpluses are forecast for the Missouri River and the border of Iowa and Minnesota. Surpluses will increase in Florida, covering nearly all of the state outside of the Panhandle, and will become more intense in northern Virginia. Surpluses of generally lesser intensity are forecast for southern Michigan and the western tip of Michigan’s Northern Peninsula, and northern Illinois.

From October through December, deficits will decrease nation-wide, leaving some intense deficits in northern Utah, and primarily moderate deficits in the Pacific Northwest, northern Minnesota, northeastern Kansas, Missouri, central Illinois, and northern Indiana. Moderate deficits are also forecast scattered along the East Coast from Maine though the Carolinas. Surpluses will remain widespread in Montana, and will persist in surrounding states as previously described. Surpluses will diminish in Florida but emerge in northern Wisconsin, central Oklahoma, southeastern Texas, Arizona, New Mexico, southwestern Colorado, and pockets of central California.

The forecast for the final months – January through March – indicates the emergence of surpluses in many parts of the western half of the country, including the Southwest, Texas, and along many rivers. Near-normal conditions are expected for most of the nation’s eastern half, along with some surpluses in Florida and the Great Lakes States.

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

IMPACTS
Colorado's San Juan National Forest was closed last month - the first full park closure in 16 years - due to a wildfire burning on 26,000 acres (10,521 hectares) of the park. Residents of over 2,000 homes were told to evacuate.

The Ferguson Fire in the Sierra National Forest of California has burned nearly 30,500 acres (12,340 hectares) as of late July, threatening Yosemite National Park and drawing 3,000 firefighters to the battle. Air quality alerts were issued for the San Joaquin Valley.

Unregulated aquifer access in Arizona's Sulphur Springs Valley has thrust some homeowners into a water war with the region's vast commercial farming operations. As the battle unfolds, it's not unusual for residents to go several days without running water, self-rationing by timing showers and using leftover dishwater to flush toilets.

Exacerbating matters is the state's current drought. One Arizona climatologist says that several big winters and strong monsoon seasons are needed to end the long-term drought, even speculating that the state may be in a “mega drought." Prior mega droughts have lasted more than a century.

Spring wheat growers in North Dakota are reportedly frustrated by weak prices of $6.00 per bushel with drought lingering into a twelfth month in some parts of the state. Prices soared up to $8.00 per bushel amid last year's drought fears.

Lake Meade is a mere two feet away from dropping to a threshold that will trigger federal mandates restricting water use from the Colorado River, which is in its driest 19-year period on record. The Central Arizona Project and the Arizona Department of Water Resources have been in a year-long dispute over the Regional Drought Contingency Plan to reduce water draws from the river. The dispute centered largely on the degree to which tribes would have autonomy in being able to withdraw water left stored in Lake Mead, and after receiving pressure from the Bureau of Reclamation and from other Colorado River states, have resumed work toward a resolution.

Days of rain in late June flooded southern Texas, many areas of which were hit hard by Hurricane Harvey ten months prior. Some areas in Hidalgo County received 18 inches, in what was called an “unprecedented” event. The National Weather Service estimated damages at $100 million in the Rio Grande Valley.

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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