This year, the National Weather Service's (NWS) annual winter forecast was delayed by more than a month due to the federal shutdown. But on Nov. 18, the federal agency released a recorded webinar, forecasting an overall warmer, drier winter for Southeast Georgia.
But that doesn't mean there won't be a chance of frost or other unexpected weather. Sub-season variability is a defining factor this season.
This winter will be marked by a La Niña event, warmer North Pacific waters, and an undulating polar vortex where cold air might escape into the continent. The combined phenomenon may result in a rather rocky winter season.
"We do expect similar to last year, a very high variability (and) frequent sub-seasonal changes over the three months" from December to February," said National Oceanic and Atmospheric Agency's Climate Prediction Center Chief of Operations John Gottschalck in the webinar.
Influences from all sides
Much of the winter forecast is influenced by the west in the Pacific Ocean.
Another La Niña will arrive, which will likely persist from December to February, said Gottschalck.
La Niña is a cooling event in the Pacific Ocean's surface waters that occurs every three to five years, bringing cold weather and rain to the Pacific Northwest, and milder, even warmer conditions to the Southeast U.S. Although this year, La Niña's strength looks slightly weaker, and thus its effects will be short-lived.
"There's a really warm anomaly over the North Central Pacific right now," said AccuWeather Senior Meteorologist and Lead Long-Range Forecaster Paul Pastelock, which Gottschalck also mentioned in the webinar. That could bring even drier conditions to the Southeast U.S.
And there's also another factor stirring up north.
The stratospheric polar vortex will be weaker this winter, which means a higher probability of a slower, wavier jet stream is higher, said Gottschalck. "So, arctic outbreaks are more likely across both eastern and western hemispheres."
"The polar vortex is being bounced and knocked around right now," said Pastelock. "Some cold will escape over the pole in the stratosphere and come down into North America as we head into the very end of the month and start in December."
Over 90% of the years studied that included a combination of La Niña and a weaker straospheric polar vortex, "we've had a stratospheric warming," said Gottschalck. "When that happens, there tends to be polar outbreaks into the continental areas... in either the eastern or western hemisphere."
What does La Niña mean for Southeast Georgia?
For the Southeast U.S., winter temperatures from December to February are leaning above average, while Pacific northwest temperatures should fall below.
And it also looks like the Southeast will likely see below-average precipitation. Drought will likely persist or begin developing in most of Georgia through the end of January.
As for a snow event that occurred last year, "We do think there's going to be another episode where the cold air rushes down, but it may be a little farther west this year and then comes into the southeast," said Pastelock.
Frost and freeze concerns may arrive sometime mid-December and possibly again in January, said Pastelock.
"The only thing that concerns us is that the water temperatures in the Gulf are still warm," said Pastelock. "They haven't been attacked by any tropical systems this year, and so anytime a front comes in that has a little extra punch... the Southeast is the most prone area."
Jillian Magtoto covers climate change and the environment in coastal Georgia. You can reach her at [email protected]. This reporting content is supported by a partnership with Green South Foundation, Prentice Foundation and Journalism Funding Partners.