Georgia’s Winter Weather will be Extreme

Georgians can expect a roller coaster winter with temperatures jumping between warm and extremely cold.

The southeastern United States is currently in what is called a neutral phase of the El Niño - Southern Oscillation. The ENSO refers to the surface temperatures around the equator in the Pacific Ocean. The ENSO’s other two phases are El Niño and La Niña.

Last winter, a La Niña ENSO phase influenced Georgia’s weather.

The neutral phase normally brings a winter with wide swings in temperatures. This means that Georgia can expect extremely cold periods with single digits in the mountains and the lower 20s in south and coastal Georgia. Between the extremely cold periods, warm temperatures in the 70s can be expected.

All devastating freezes that have affected the Southeast have occurred during neutral winters. Devastating freezes for Georgia have been ones with temperatures below zero in the mountains, around 10 degrees along the coast and single digits in south Georgia.

This does not mean that every neutral winter will have a devastating freeze, but the odds are greatly increased. Because of the greater likelihood of a devastating freeze this winter, all Georgians are urged to take necessary precautions to protect life and property.

The rainfall outlook is less certain. Rainfall during neutral winters is very variable. Some neutral winters are very wet while other are very dry. 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.

We do know, however, 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 the state needs. 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.

Additionally, a dry winter will set the state up for another drought. 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.

By David E. Stooksbury
University of Georgia

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Drought Tightens its Grip on North Georgia

Drought conditions continue to grow harsher across north Georgia. Water levels in reservoirs and streams are at or near record lows across most of the region. Groundwater levels are also low.

Lake Lanier, a primary water source for metro Atlanta, is at a record low for mid-November. The previous mid-November record low was at this time last year.

Hartwell, Russell and Clarks Hill lakes in the Savannah River basin are at record low levels. Both Russell and Clarks Hill have less than two feet of usable pool left. Hartwell water levels are dropping very quickly in order to meet downstream needs. The U.S. Army Corp of Engineers reports that the remaining conservation pool for Hartwell is 34 percent, for Russell it’s 32 percent and for Clarks Hill it’s 10 percent.

Even with normal seasonal rains, it’s doubtful that Lanier, Hartwell, Russell or Clarks Hill lakes will fully recover this winter.

Major rivers that are at record low flows for mid-November include the Etowah River at Canton, the Chattahoochee River near Cornelia, Chestatee River near Dahlonega, the Middle Oconee River at Athens, the Broad River near Bell, the Little River near Washington, the Oconee River at Dublin and the Altamaha River near Baxley.

Because of the extremely low stream flows, many counties in north Georgia have had their drought level classifications changed to a more intense level.

Exceptional drought – the most severe drought level - now exists north and east of a line running through Lincoln, Wilkes, Olgethorpe, Oconee, Barrow, Gwinnett, Hall, Forsyth, Cherokee, Pickens, Gilmer and Fannin counties. This region includes Athens, Gainesville and Atlanta’s northern suburbs.

Extreme drought conditions are now in Columbia, Richmond, McDuffie, Glascock, Taliaferro, Warren, Hancock, Greene, Morgan, Walton, Gwinnett, north Fulton and Cherokee counties. The extreme conditions are also in parts of Pickens, Gilmer, Fannin and Murray counties.

Most of the remaining area north of the fall line is in severe drought. Heard, Troup, Harris and most of Talbot and Muscogee counties are in moderate drought.

The ocean-atmosphere system is in what climatologist call a neutral pattern, meaning it is in neither an El Niño nor a La Niña pattern. Historically, neutral-pattern winters have been very variable.

There is no strong indication that the winter of 2008-09 will be abnormally wet or dry. The trend over the past 15 years, however, has been for dry winters.

There is also no strong indication that the winter will be abnormally warm or cool. An important historical observation is that every major devastating freeze has occurred during a neutral-pattern winter.

With recent winters being our best guide, the most prudent response is to assume that this winter will tend toward the dry side. Water conservation efforts should continue.

Additional drought information and updates can be found at www.georgiadrought.org. Automated weather data across Georgia is at www.georgiaweather.net. Daily rainfall data is at www.cocorahs.org. U.S. Geological Survey data is at ga.water.usgs.gov. Water conservation information is available at www.conservewatergeorgia.net.

By David Emory Stooksbury
University of Georgia

David Emory Stooksbury is the state climatologist and a professor in engineering and atmospheric sciences at the University of Georgia.

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