United States: Water surplus ahead for E. Texas, Louisiana, S. Mississippi

28 June 2017

The Big Picture
The 12-month forecast through February 2018 (below) indicates more pockets of near normal water conditions – shown in white – than in previous months, including much of the Ohio River Valley, working southward to the Gulf, and in eastern Virginia and eastern North Carolina. However, moderate to severe deficits are forecast for nearly all of Florida, and pockets of moderate deficits are forecast for Georgia, South Carolina, Maryland, Delaware, Connecticut, Massachusetts, Maine, northern Minnesota, and parts of Texas. Extreme water surpluses are forecast for eastern Washington, Oregon, and all of Idaho. Moderate to extreme water surpluses are expected in: southern Minnesota, Wisconsin, Iowa, northern Illinois and Indiana, Michigan, New York, southern Missouri, eastern Tennessee into Virginia, and parts of Oklahoma, Nebraska, Colorado, and California.

Impacts
Drought? What drought? Parts of the southeastern US that had suffered unusually dry conditions over the past several months are now dealing with the impacts of intense precipitation. On May 30 the US Drought Monitor classified 72 percent of Florida under drought; by June 20 that figure dropped to 0. In early June heavy rain and flooding in South Florida canceled nearly 150 flights at Miami International Airport and 50 at Fort Lauderdale International Airport, and shut down the gigantic Sawgrass Mills Mall in West Broward as parking lots and nearby condo garages filled with water. Every road on Marco Island was reportedly flooded, where rainfall totaled 23 inches (58 cm).

More recently, flooding was reported along the Gulf Coast near the Texas/Louisiana border as storms moved in. And though Tropical Storm Cindy was downgraded to a tropical depression as it moved north, a state of emergency was declared for Alabama and Louisiana as a precaution. Also in preparation, oil and gas workers were evacuated from production platforms in the Gulf, flood control gates were closed along Louisiana's coast, FEMA moved 125,000 meals and 200,000 bottles of water into the state, and the Louisiana National Guard positioned high water vehicles and helicopters near flood-prone areas. Parts of St. Mary's Parish, LaFourche Parish, and Morgan City, Louisiana flooded, and Alabama’s Dauphin Island. The Alabama Cooperative Extension Service warned about flood dispersion of fire ants, and residents of Ocean City, Mississippi were advised to keep an eye out for alligators.

Drought in the Dakotas is causing feed shortages due to poor grass growth prompting cattle producers to sell calves now rather than wait for higher prices commanded by mature livestock in the fall. Winter wheat production has also been negatively affected.

In mid-June nearly 50 flights were canceled at Sky Harbor International Airport in Phoenix, Arizona due to extreme heat conditions. Temperatures forecast at 120°F (48.9°C) exceeded aircraft maximum operating temperature of 118°F (47.8°C).

Forecast Breakdown
The 3-month maps (below) show the evolving conditions in more detail. The forecast for June through August is dominated by two large regions of water surpluses. Exceptional water surpluses are expected in a large area including Washington, Oregon, Idaho, Wyoming, and Nevada; and moderate to extreme surpluses are expected in a large band including eastern Texas, Louisiana, and Alabama extending northward through Arkansas, Missouri, Iowa, Indiana and Wisconsin and extending northeasterly through Tennessee, North Carolina, Virginia, and New York. Moderate to exceptional drought is forecast for Alaska. Moderate drought is forecast for northern Florida, southern Georgia, northern Minnesota, Arizona, and Puerto Rico. Conditions generally become less extreme with longer lead times (September through February). However, exceptional surpluses are forecast for southern Idaho, northern Nevada, and northern Utah. Moderate surpluses are forecast for Iowa, southern Minnesota, western Wisconsin, Central California, and New York.

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