Temperatures are expected to plummet in southern Wisconsin this weekend.
The National Weather Service issued an extreme cold warning Thursday and Friday, and an extreme cold watch through Saturday. Wind chills could be as cold as -40.
Milwaukee-based meterologist Paul Roebber calls these conditions unusual.
“I think in the 30-plus years that I’ve lived here, we’ve had these kinds of outbreaks probably a half a dozen times,” he says.
Roebber knows a thing or two about weather. Now a distinguished professor emeritus at the University of Wisconsin-Milwaukee, Roebber founded the school's former Innovative Weather program in 2007. Currently, he’s a research scientist at the NOAA Cooperative Institute for Research in the Atmosphere.
“Certainly with climate change...we’ve had a lot more situations where the weather has been warmer in the winter, but it doesn’t mean you can’t get these kinds of outbreaks,” Roebber says.
What’s happening right now, Roebber says, is called radiation imbalance. “Which just means that you don’t get as much, or even in some cases depending on how far north you are, any sunshine. And meanwhile that air on the ground underneath it is losing energy to space and so over time that cools the air,” he says.
With the right wind flows, very cold air can be transported from the north to the south.
“In fact, that’s what the atmosphere wants to do," Roebber says. "It wants to mix the warm air further south with the the cold air further north to reach some sort of equilibrium. And so occasionally you get these very extreme situations. You’ve got very cold air available for mixing and it mixes down from the south and we get the ‘benefit’ of that.”
While Wisconsin sits in the grip of frigid temperatures, the National Weather Service forecasts a massive winter storm from the southern Rockies into the Mid-South.
Roebber says Wisconsin is not likely to be impacted. “The projections are right now is that that cold air will be sufficiently well in place [so] that the storm won’t really be able to really affect us and it will travel to the southwest,” Roebber says.
How will future winters play out in Wisconsin?
Roebber says even though on average, temperatures are expected to increase due to climate change, that doesn't preclude extreme weather events like the severe cold Wisconsin is currently experiencing.
