By David E. Stooksbury
University of Georgia
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.
(David Emory Stooksbury is associate professor of Biological and Agricultural Engineering at University of Georgia's College of Agricultural and Environmental Sciences.)