Science & Nature
Lake Effect Snow Machine Could Crank Up This Year, According to Winter Outlook
(yancymckiddy / iStock)
Last year’s “snow drought” in Chicago — one of the least snowiest years on record — is likely to end this winter, according to a seasonal outlook just released by the Climate Prediction Center.
The strong El Niño that held sway in 2023 — which brought warmer temperatures and lower precipitation to Chicago — is expected to give way to a weak La Niña, which will largely deliver the reverse, said Jon Gottschalck, chief of the Operational Prediction Branch of the Climate Prediction Center.
(National Weather Service / National Oceanic and Atmospheric Administration)
Among the conditions to prepare for: Arctic outbreaks, which El Niño minimized last year.
Because the Great Lakes water temperatures are currently well above normal, “if we do get arctic air ... there could be a high level of lake effect snow,” Gottschalck said during a conference call with reporters on Thursday. “Lake effect could be a real issue in November and December.”
A milder start to the winter in the Great Lakes, temperature-wise, is likely to give way to colder weather in late December, January and February, he added.
Whether a polar vortex will place Chicago in the deep freeze is still very much up in the air, said Gottschalck, adding that while La Niña might make a polar vortex more likely to occur this winter compared with last year, other signals point to it being less likely.
"With respect to the polar vortex, there's a lot of uncertainty; the polar vortex is extremely complicated," he said.
The Climate Prediction Center, which is a division of the National Oceanic and Atmospheric Administration, doesn't forecast potential snowfall totals, Gottschalck emphasized. Seasonal outlooks are meant to provide the likelihood that temperatures and total precipitation amounts will be above-, near- or below-average.
While winter is the fastest warming of all the seasons, other factors such as La Niña can override long-term trends in any given year, said Tom DiLiberto, NOAA climate scientist.
La Niña causes the jet stream to move northward and to weaken over the eastern Pacific. During La Niña winters, the South sees warmer and drier conditions than usual. The North and Canada tend to be wetter and colder. (National Oceanic and Atmospheric Administration)
El Niño and La Niña are climate patterns in the Pacific Ocean that can affect weather worldwide, pushing the jet stream further south in El Niño years and further north with La Niña.
While climatologists are favoring the development of La Niña, given its weak nature, they have less confidence in its impact, particularly compared with the greater reliability of last year's strong El Niño, Gottschalck said.
In El Niño years, weather patterns develop and stick around for weeks at a time, he said, whereas La Niña has high variability, meaning changes are much more frequent — there are more changes within each month and within the season.
In other words, expect the unexpected.
Contact Patty Wetli: @pattywetli | (773) 509-5623 | [email protected]
