Early signs suggests Georgia is in for a warm, dry fall and winter, but that doesn’t necessarily mean trouble for Lake Lanier.
At the moment, the United States is in a “neutral pattern,” said Georgia Climatologist Bill Murphey, meaning there’s not a current trend in temperature or rainfall. Colder temperatures are heading for North Georgia early next week, but after that it will warm. Similar shifts are likely until the winter weather pattern becomes more clear.
And the hurricane season continues, which creates dramatic shifts in both temperature and rainfall. This year has been among the busiest hurricane seasons on record, and another system is forming in the Atlantic.
“We still have some work left in the tropical season,” Murphey said. “We’re not out of the complete woods on tropical activity yet.”
In the longer term, it’s looking like a La Nina pattern is shaping up in the Pacific Ocean. Cooler ocean temperatures in the eastern Pacific near the West Coast cause cold, wet air to blow over the northern United States and warm, dry air to flow into the South.
The opposite is true in years of El Nino, but Murphey noted that the rules aren’t a “100 percent slam dunk.” Conditions in the Gulf of Mexico could push rain to the north.
There’s been an above-average amount of rain so far this year, with almost 50 inches since January and almost 7 inches more than historical averages.
Gainesville received more rainfall than average in September because of the tropical storms that passed near the area, but the drier months of the year are on their way.
Thanks to that above-average rainfall, U.S. Drought Monitor has no areas of Georgia listed in any kind of drought.
The average rainfall in October is only 3.9 inches, and it doesn’t look much better through March, according to Murphey.
If a La Nina forms for the winter, it could knock out the rain North Georgia needs in the winter to refill Lake Lanier before summer. In September, the Lake Lanier Association published a post on its website showing the connection between rainfall and lake level.
The Georgia Environmental Protection Division permits water use in Georgia and is one of the agencies monitoring Lake Lanier. For now, it has no plans for new restrictions on outdoor water use.
“The forecast does call for a warmer and drier than normal fall and winter, but that doesn’t mean we won’t get any rain,” said EPD spokesman Kevin Chambers. “Lake Lanier’s water level is near its historical elevation for this time of year and we expect it to continue to refill.”
Even with a dry winter, water use generally drops off in the cooler months because landowners are doing much less outdoor watering.
But the lake has farther to go to get to full pool this year. As of Friday, Lake Lanier was at 1,065.3 feet above sea level. That’s about one-and-a-half feet better than 2016, but it’s more than two feet below the 2015 level in mid-October.
Recent history shows two extreme examples of what’s possible in the next few months.
In 2015, the lake continued to fill through the fall and hit 1,075.5 by the end of the year. By the end of 2016, the lake was 15 feet lower than that.
The rest of the year and the winter to follow will make a “critical” difference in the lake level, Murphey said, as well as soil moisture, streamflow and all the other indicators of drought that make life harder on water supplies, wildlife and farmers.
But for now, Georgia just has to wait and see.
“We’re in a La Nina watch,” Murphy said. “It’s not an advisory, but some of the conditions in the equatorial Pacific are hinting … that we could be heading towards a La Nina event.”