The celestial spectacle known as the northern lights is unlikely grace the skies of Chicago this week based on updated predictions, according to science experts.

Also known as aurora borealis, the lights were initially forecast to be visible low on the horizon in Chicago and seen overhead in Minneapolis and Milwaukee, according to the Geophysical Institute at the University of Alaska-Fairbanks.

Since Monday, the aurora forecast shifted and the prediction area no longer includes Illinois.

Michelle Nichols, director of public observing at Adler Planetarium, said auroras and the weather conditions needed to see them can be unpredictable and fast-changing, so it’s hard to accurately say when and where the lights will be visible, especially days before. 

“The original forecasts were about three days out, which is an eternity for aurora predictions,” Nichols said.

The lights could be visible Wednesday night into Thursday morning in states such as Minnesota, Michigan, Washington and South Dakota.

Billy Reed of Illinois Storm Chasers said with limited data and existing satellites to monitor auroral activity and the sun, it’s difficult to provide reliable aurora forecasts.

“I try to temper expectations,” Reed said.

Though Chicago didn’t get lucky this time, some best practices to see the northern lights include avoiding city light and downtown areas. Light pollution can make it more difficult, especially since the aurora borealis is dim to begin with, said Adam Miller, an astronomy professor at Northwestern University.

“If one could find a relatively open field with sight lines to the north that’s in a dark location, and if you give your eyes the opportunity to adjust to the dark ambient light, that would improve chances to be able to see the aurora,” Miler said.

Generally, the darker the area, the better the show, Nichols added, while Reed said to allow about 30 minutes for eyes to adjust to the darkness.

The best viewing time to see an aurora is 10 p.m. to 2 a.m., according to the Space Weather Prediction Center.

Auroras occur when charged particles from the sun interact with Earth’s magnetic field. The particles become trapped in the magnetic field, then move toward the planet’s magnetic poles. When the charged particles interact with atoms high in Earth’s atmosphere, they cause atmospheric gases to glow, which creates the different colors people see in auroras. The types of atoms help determine which colors appear.

Miller said it’s rare to see the aurora borealis as far south as Chicago. In April, the northern lights were visible throughout parts of Illinois.

Auroras tend to occur when there’s more solar activity, such as sunspots, and we’re approaching a period of greater activity known as a solar maximum, Miller said.

“It’s not unusual that now and maybe over the next several months, there may be other events like this as well,” Miller said.

Though the northern lights likely won’t dazzle Chicago skies this week, to Nichols, the overall beauty of the phenomenon is watching what is essentially the sun touching Earth’s magnetic field.

“You are seeing interaction between the Sun and Earth,” Nichols said. “That in and of itself is amazing. We are not two completely separate objects in the universe. One interacts with the other and you’re seeing that.”