United States: Water surpluses to persist WI to TX, emerge in CA

27 February 2019

THE BIG PICTURE
The 12-month forecast ending October 2019 indicates water surpluses in central and eastern Texas reaching north through Oklahoma, Kansas, eastern Nebraska, Iowa, southern Minnesota, and southern Wisconsin. Surpluses are expected to be extreme to exceptional in the heart of Texas and in central Kansas. Moderate surpluses are forecast along the Arkansas River in Colorado and the Missouri River in Missouri.

In the US East, deficits are forecast in Maine and northern New York. Conditions of both deficit and surplus (purple) are expected in a vast path from southern New Hampshire through northern South Carolina as transitions occur. Primarily moderate surpluses are forecast for Alabama, Georgia and northern Florida. A patchwork of conditions is forecast for the Ohio River Basin and the Lower Mississippi River Basin; anomalies will be mild to moderate.

Moderate deficits are forecast for Michigan’s Upper Peninsula, northern Wisconsin, and northern Minnesota. Moderate to severe deficits are expected in the Pacific Northwest. Wyoming will see moderate deficits in the center of the state, surpluses in the central-south, and intense deficits in the northwest. Some moderate deficits are forecast in northern California near the Oregon border, and some moderate surpluses from the southern Sierra Nevada Mountains to Los Angeles.

Outside the contiguous US, moderate to severe deficits are forecast for Puerto Rico. In Hawaii, surpluses are forecast for western Hawai’a and western Moloka’i, and moderate deficits on Maui.

In Alaska, surpluses are forecast on the Alaska Peninsula reaching inland; southeast of Barrow in the far north; and along the Koyukok and central Yukon Rivers. Deficits are expected in the Seward Peninsula and into western Alaska; along the Tanana River through Fairbanks; around Anchorage; and around Sitka in the Alaska Panhandle.

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

Most notable in the forecast for February through April is the absence of widespread, intense surpluses observed in the East in prior months. Surpluses are forecast for northern Pennsylvania, some isolated small pockets of the Northeast, and pockets of northern Florida. Moderate deficits are forecast for eastern Kentucky, eastern Tennessee, northernmost Georgia, and pockets of northern Maine, Delaware, Virginia, and southern Florida.

Surpluses will persist in the center of the country in a wide path from Wisconsin through Texas, including southern Minnesota, Iowa, eastern Nebraska, Kansas, northern Missouri, Oklahoma, northern Louisiana, and central and eastern Texas. Surpluses will be exceptional in central Kansas and along the Arkansas River into Colorado, and in the northwestern Edwards Plateau in Texas. Moderate deficits are expected along the Canadian River through the Texas Panhandle into New Mexico.

In the western half of the country, primarily moderate surpluses will emerge in the Rocky Mountains, eastern Nevada, the Missouri and Colorado Rivers, much of California south of San Francisco Bay, and central Arizona. Deficits are forecast in pockets of the Pacific Northwest.

From May through July, surpluses in the center of the country will diminish considerably but will persist from the conjoined corners of Minnesota and South Dakota, through eastern Nebraska, Kansas, Oklahoma and large pockets of Texas. Surpluses will be intense in central Kansas and in the northwest corner of the Edwards Plateau in Texas. Some surpluses are also forecast for: northeastern Florida, southern Colorado, in Southern California from Santa Barbara to San Bernardino, and northeastern Nevada and northwestern Utah. Elsewhere in the country, mild to moderate deficits are forecast with some pockets of severe deficit. More specifically, severe deficits are expected in West Virginia, eastern North Carolina, the western half of Michigan’s Upper Peninsula, northern Wisconsin, and pockets of the Pacific Northwest.

The forecast for the final months – August through October – indicates an overall pattern of anomalies similar to the prior three months, but surpluses will continue to downgrade and shrink in the center of the country, and moderate to severe deficits will increase in the West, particularly along major rivers.

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

IMPACTS
The Ohio Department of Transportation closed nearly two dozen roads due to flooding last month, when high temperatures melted a weekend of snowfall and flooded multiple townships.

Arizona agreed to join Wyoming, Colorado, Utah, New Mexico, Arizona, Nevada, California, and Mexico in reducing water usage from the Colorado River. The agreement calls for escalating cutbacks as water levels in Lake Mead drop, to prevent levels from plummeting to “dead pool” level, at which the lake’s surface is below the water gates that let it run. Arizona farmers in Pinal County stand to lose the most in the agreement, which requires Arizona to cut its Colorado River usage by up to 700,000 acre-feet, in part by fallowing as much as 40 percent of the county’s farmland.

The U.S. Census Bureau recently reported that Puerto Rico’s population lost 130,000 people between July 2017 and July 2018, a period spanning the island’s hit by Category 4 Hurricane Maria, which caused an estimated $100 billion in damage in September 2017.

Flash flood warnings were issued for Southern California in early February as water and mud from a series of heavy storms rushed from hillsides, shutting down key highways. The storm system dropped more than four inches of rain in the valleys and several feet of snow in the mountains, evacuating homes and creating dangerous road conditions. Several people were rescued from their cars on flooded roadways, and at least one person was killed in a car accident due to slick conditions.

San Francisco received its first significant snowfall in eight years early this month, as winter weather blasted the American northwest. Unusual snow and cold caused car accidents and cancelled flights from Seattle to Portland and prompted all roads in Yosemite National Park to be closed.

The U.S. Department of Transportation’s Federal Highway Administration announced over $705.7 million in emergency relief funding to 34 states plus American Samoa, Puerto Rico, and the U.S. Virgin Island for repairing storm and flood damage to roads and bridges. Over 20 percent of the funding is directed at damages caused by Hurricanes Harvey, Irma, and Maria.

A polar vortex exposed 90 million people to temperatures of 0 degrees Fahrenheit or lower in early February. At least 21 people were killed in incidents related to the cold snap, which broke over 30 record low temperatures across the Midwest.

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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