If you were thinking this winter has been fairly mild so far, it has been, but gear up.
Frigid temperatures could be gripping Ohio, the Midwest, and the Northeast around the last week of January.
The polar vortex, a wide area of swirling cold air near the North Pole, has weakened and split in two, which happens from time to time when air in the stratosphere above it warms. With the split, forecasts indicate one of the portions of the vortex may drift south toward Canada and the northern United States.
These weakened polar vortex conditions often drop temperatures well below normal (think single digits and sub-zero) and may lead to more snow, said Aaron Wilson, climate specialist with The Ohio State University College of Food, Agricultural, and Environmental Sciences (CFAES).
“We’re watching this evolve,” Wilson said. “It’s eye-catching from a meteorologist’s standpoint. It can obviously cause some storms and lead to very cold conditions.”
And it’s possible snow could come with those cold temperatures if the conditions are right, he said.
That’s because this winter’s weather is also being influenced by La Niña, meaning the temperature of the Pacific Ocean off the coast of Central and South America is colder than average. Those conditions can influence weather around the world.
For Ohio, a La Niña year typically means a wetter and warmer-than-average winter and spring.
Whether that additional precipitation will mean more snow or more rain, is uncertain, Wilson said.
“We’ve experienced La Niña years where we got a lot of snow and some in which we didn’t.”
But the trend has been for a bit more snowfall than average during La Niña conditions.
“We’re not talking about a lot more snow—more like 1 to 3 inches above average for the season,” he said.
Central Ohio typically gets 25–30 inches of snow, on average, a year, with southern Ohio getting less and northern Ohio much more, with about 60–70 inches of snow near Lake Erie.
The typically coldest seven-day period of winter in Ohio has yet to come: Jan. 18–25.