The northern lights made an incredible display over much of the United States on Thursday – and could perform again on Friday evening.

The aurora borealis was visible as far south as Florida on Thursday. Photos show the sky glowing red and purple, even in some brightly lit areas New York City And Chicago.

The strong geomagnetic storm that caused such a show has waned, according to the National Oceanic and Atmospheric Administration, but some parts of the U.S. could see the Northern Lights again tonight. Here’s what you need to know.

Where will the Northern Lights be visible tonight?

According to the NOAA Space Weather Prediction Center’s aurora forecast, the Northern Lights will be visible for parts of the northern US. The aurora will be visible over much of Canada and Alaska, but the Northern Lights can also be seen up to 600 miles away under the right conditions, NOAA says.

Parts of Idaho, South Dakota, Minnesota and Wisconsin may be able to see the lights Friday night. On the East Coast, the aurora may be visible in northern New York and parts of Vermont and New Hampshire. The Northern Lights can also be seen in parts of Maine.

The lights appear in the north when it is dark outside. If you can’t see them with the naked eye, they may be visible through a phone camera or other device.

When will the Northern Lights be most visible?

The Northern Lights are most visible just after sunset or just before sunrise, NOAA said. During the day the aurora is not visible. Dark, cloudless skies with little artificial light provide the best viewing experience.

Why have the Northern Lights been so visible lately?

Over the past few months, the Sun has been incredibly active, unleashing a series of coronal mass ejections from its surface. CBS Boston reported. This has resulted in several visible aurora shows.

The geomagnetic storm responsible for Thursday’s stunning skies is now subsiding, CBS Boston reported. That means you’re less likely to see the aurora on Friday, but there may be more chances in the future.

Shawn Dahl, a forecast coordinator at the Space Weather Prediction Center, told CBS Boston that the Northern Lights have been so intense lately because of where the Sun is in its eleventh year solar cycle. Dahl said that “we are in the middle of solar maximum.”

“What that means is that the sun is now a twisted mass of strong magnetic fields, and some of them are so localized and intense that they reveal themselves as sunspot groups,” says Dahl. “That’s the source of some of the space weather storms that we’re looking for and predicting.”

What causes the Northern Lights?

According to NOAA, the Northern Lights are caused by interactions between the Sun’s solar winds and Earth’s protective magnetic field. These two phenomena result in geomagnetic storms and increased geomagnetic activity.

The higher the geomagnetic activity, the more likely you are to see the aurora. Increased geomagnetic activity means the aurora will become brighter, more active and more visible farther from the planet’s poles, NOAA said.

Even moderate solar wind causes the aurora, NOAA said, so a faint aurora is usually visible somewhere on Earth. The best places to see these fainter auroras are near the planet’s poles, such as in Greenland or southern Argentina. When you see the aurora near the North Pole, it is called the Northern Lights. The same phenomenon near the South Pole is called the Southern Lights.