A “little girl” is going to make the Lowcountry warmer and drier this winter, according to a report out Thursday from the National Oceanic and Atmospheric Administration’s Climate Prediction Center.
The little girl in question is the La Niña weather pattern, whose arrival was announced in the prediction center’s release, and which will likely last through winter, with a better than 50 percent chance of persisting into April of 2018.
“It is not anything that at any given time you’re going to be able to feel. It’s not something that is really detectable until you look at the averages over the entire winter,” said Carl Barnes, meteorologist with the National Weather Service in Charleston. “But in essence it is going on right now, so in a way we’re already feeling the effects of it.”
We experienced a weak La Niña last year according to the release, and this year’s will likely be weak as well, but changes to weather patterns across the country will still be noticeable.
Cooler waters in the equatorial Pacific Ocean are to blame for the weather pattern, which affects the jet streams first on the West Coast and then the east. The changes in those streams change weather across the country.
In the Pacific Northwest and parts of Illinois, Indiana, Ohio and Michigan conditions will be wetter than normal. Across the northern part of the country a typically bitterly cold winter will be even colder.
Some parts of the country will be drier and some will be warmer. The Lowcountry is expected to be both.
“Typically under La Niña, for us in the eastern U.S., the jet stream stays further north, which keeps the majority of the energy that causes the big storms to the Midwest and northeast,” said Barnes. “We’ll stay on the south side of the storms, and since those storms are further north, cold fronts have more of a problem moving through our area.”
While conditions should be warmer and drier, though, you shouldn’t be expecting summer in the desert, according to Barnes.
“It’s still going to be winter time,” said Barnes.
During last year’s weak La Niña, the average temperature at Savannah/Hilton Head International Airport was roughly 59, making it the fifth warmest winter on record at that location according to Barnes.
“I’m not saying we’re going to set record,” said Barnes, “but it is going to be warmer than normal.”
For comparison, during winter 2014/2015, when the country experienced an El Niño pattern — wherein the jet stream swings further south, bringing wet weather and cold air with it — the average temperature was about 51.
The full effects of La Niña’s arrival will be discussed in a Nov. 16 update of NOAA’s 2017/2018 Winter Forecast. Since La Niña was anticipated in their initial October forecast, though, significant changes are not expected, according to the prediction center release.