Southeast drought situation improves

Significant rainfall during the winter months has helped to improve dry conditions throughout the Southeast region, according to the U.S. Drought Monitor’s mid-January report.

Improvements were seen especially in Tennessee, Virginia and Georgia. However, the report warns that substantial long-term dryness remains with stream flows in parts of the region remaining at below-normal levels.

The rainfall outlook for the remainder of the winter months is uncertain, says David Stooksbury, state climatologist for Georgia. “At this time, we don’t know what we’ll get. Whether Georgia experiences a wet or dry winter will depend on the number of low-pressure systems that develop in the northern Gulf of Mexico and move across the state,” he says.

What we do know, he adds, is that the past 15 winters have been drier than the long-term average. “Given this trend, the best rainfall outlook for the winter is to hedge our bets that the winter will be drier than the long-term average.”

A dry winter is not what Georgia or the Southeast needs, says Stooksbury. “Northeast and north-central Georgia are still in extreme drought. Lakes Lanier, Hartwell, Russell and Clarks Hill are near or below their record lows. A very wet winter is needed for these lakes to fully recover,” he says.

Additionally, a dry winter will set the state up for another drought, says Stooksbury. “Georgia depends on winter rains to recharge the soil moisture, groundwater and reservoirs for the heavy water use in summer. If the state does not receive adequate rains this winter, the probability of the drought expanding will increase.”

According to the Southeast Climate Consortium (SCC) — a coalition of six Southeastern Universities — sea surface temperatures along the equator in the eastern and central Pacific Ocean have cooled substantially recently, marking a return to La Niña. La Niña refers to colder than normal waters along the equator in the eastern and central Pacific, and can be thought of as the opposite of El Niño.

The Pacific Ocean had been in the Neutral phase since April of 2008, following another La Niña in the fall and winter of 2007/2008. Multi-year La Niña events are not uncommon in the historical record and are known to bring extended drought to parts of the Southeast, according to the SCC.

“During the past several months, the atmosphere over the tropical Pacific Ocean has been giving indications that a La Niña might be building. The Southern Oscillation Index, the difference in average surface pressure between the western and central Pacific, has been highly positive since early October.

“In addition, stronger than normal easterly trade winds have been measured in the central and western Pacific since October and it is these trade winds which drive the change in Ocean temperatures. In spite of these atmospheric signals, the sea surface temperatures had remained near normal, or in the neutral range. In late December, however, cold water that had been building below the surface broke through and surface waters cooled rapidly,” states the SCC.

This La Niña is expected to last at least through the remainder of the winter and spring seasons. La Niña is known to bring a warmer than normal and dry climate pattern to the Southeast during this time.

In other weather related news, the U.S. Supreme Court ruled in January that it will let stand a lower court ruling that threatens to unravel Georgia's long-term water plans for the Atlanta region, giving Florida and Alabama a pivotal victory in the states’ long-running water wars.

The court’s decision raises fundamental questions about Georgia's rights to Lake Lanier, a huge federal reservoir outside Atlanta that serves as the city's main water source. It could also play a key role in deciding related water-rights disputes in lower courts.

“Today's decision by the U.S. Supreme Court confirms that federal law does not permit Atlanta to take more and more water from Lake Lanier to the detriment of downstream interests,” Gov. Bob Riley of Alabama said. “Georgia tried to pull off a massive water grab, and this decision makes clear that Georgia’s actions were in blatant violation of federal law.”

The case involves a 2003 water-sharing agreement with the Army Corps of Engineers that would have allowed Georgia to take far more water from Lanier for its drinking supply over the coming decades. The deal would have allowed Georgia's withdrawals to jump from about 13 percent of the lake’s capacity to about 22 percent.

Florida and Alabama contested the pact, saying the lake was initially built for hydropower and providing water to Georgia was not an authorized use.

A federal district court sided with Georgia. But last February, the U.S. Court of Appeals in Washington overturned that decision and invalidated the agreement. Georgia had appealed to the Supreme Court for another review.

Alabama, Florida and Georgia have been in a legal and political battle over water rights for two decades, and the fight has intensified in the past year as extreme drought has gripped the region.

The dispute centers on how much water the Army Corps of Engineers holds back in federal reservoirs near the head of two river basins in north Georgia that flow south into Florida and Alabama.

The fast-growing Atlanta region relies on the lakes for drinking water. But Florida and Alabama depend on healthy flows downstream for commercial fisheries, farms, industrial users and municipalities. The corps also is required to release adequate flows to ensure habitats for species protected by the Endangered Species Act.

With prodding from President George W. Bush, the governors of the three states began fresh negotiations in late 2007 to seek a settlement. But the talks stalled last year, and the states have grown increasingly critical of one another.

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