ATLANTA — Snow Jam in 2014, January 2011’s Snowmaggedon and the Super Bowl Ice storm of 2000: three of Atlanta’s most recent head-turning winter storms. So could we see another blockbuster this year?
Here’s what this upcoming winter may hold for Atlanta and North Georgia.
If you’re a cold-weather lover, this winter probably isn’t for you.
A wooly worm or other weather folklore didn't predict this. We've dug into the science of the upcoming winter season for Georgia.
La Niña: The driver of the winter outlook
This winter's outlook is based on the forecast of a La Niña. La Niña, which translates from Spanish as “little girl”, is not a storm. It's part of a climate pattern called the El Niño Southern Oscillation, or ENSO for short. It occurs in the equatorial Pacific Ocean and drives seasonal weather trends around the globe. ENSO not only impacts trends for the winter months but also plays a role in hurricane season in the Atlantic basin.
When the ocean surface waters are below normal, we call it a “La Niña”. On the flip side, when waters in that region are above normal, it is referred to as an "El Niño. The neutral phase of this back-and-forth see-saw is called a "La Nada".
A weak to moderate La Niña is developing this fall and is predicted to last through the winter months. We had a La Nina last winter, so this one is called a “double-dip” La Nina.
Why does the phase of ENSO matter? The ocean surface temperatures can affect the position of the jet stream, storm tracks, and areas of high and low pressure. In essence: it can influence who has a wet vs. dry and mild vs. cold winter.
ENSO isn't the only player into weather trends, it's just the clearest basis for what an upcoming winter may hold. There are other atmospheric patterns that can contribute to cold air intrusions. But they aren't something we can look at several months out, but rather weeks out.
What Does It Mean: Temps and Snowfall
In La Niña winters, the jet stream is farther north. For Georgia, this means we see warmer than average temperatures. That's the 'highest confidence' part of the seasonal outlook.
For precipitation, we often end up near average or slightly below average.
Does this mean we will not see any snow? Not necessarily, but the odds are overall not in our favor.
Digging through the top 10 winters of snowfall for the Atlanta area, only 1 of them since 1950 was during a La Niña winter. That just so happens to be the year of the January 2011 Snowmaggedon.
Last year’s La Niña resulted in just a Trace of snow… a snow drought that has persisted for the last 3 years! Atlanta averages 2.2 inches. We haven’t had any measurable snow in the city since January of 2018!
There are two main storm setups that can give us a winter mess in the capital of the Peach State. Often, the struggle is that we're too warm.
Many of our biggest winter storms, like the Blizzard of '93 or Storm of the Century, originate in the northeastern Gulf of Mexico. The deep moisture plume tracks into Georgia as cold air meets up from the north with an arctic front. If we get a 'Goldilocks and the Three Bears' situation, Atlanta can get hit with some decent snow.
Our ice storm setups originate from cold air damming, or the wedge. Cold and dry air is nestled up against the mountains and into northeast Georgia at the surface and moisture overruns it. This leads to ice rather than snow.
In a La Niña winter, we can also get an early start to Severe Weather Season. This is because of the higher positioned storm tracks that place Atlanta in the warm and unstable air. During last year’s La Niña winter, we had severe weather and tornadoes on New Year’s Day.
Recap: Winter 2021 to 2022 Main Points
- A La Niña is forecast to develop and remain in place through the winter and will influence Georgia's winter season of weather
- This winter will be warmer than average for our temperatures. We will still get cold snaps, but as a whole, temps will end up warmer than average.
- Although our snow chance isn't favorable based on history, it only takes 1 good storm to make it a great year for snow-lovers in the Peach State!
- In La Niña winters we can also be more prone to winter or early spring storms across North Georgia