The beautiful phenomenon known as aurora borealis, or northern lights, will be seen in unexpected parts of the United States today and tomorrow, including as far south as Colorado.

"This is very rare, especially for as far south as Denver and Boulder," Joe Kunches, a forecaster with the National Oceanic and Atmospheric Administration (NOOA) Space Weather Prediction Center, told Denver Post. 

According to the NOOA Space Weather Prediction Center, a spectacle of green and possibly even blue, red and greenish-yellow might be visible in the skies of Illinois, Michigan, Washington and Colorado. Associated Press reports that Boston, Cleveland and Des Moines may also get a glimpse of the vibrant sky "low on the horizon."

"The CME [coronal mass ejection] is forecast to set off G3 (Strong) Geomagnetic Storm activity through January 9 and 10," NOAA wrote on Wednesday. "Aurora watchers should be ready."

According to Kunches, aurora borealis will be most visible Thursday night into Friday at midnight.

"For the best chance to see the lights, go to the mountains or away from other light pollution," he said.

It is not guaranteed that everyone in these locations will be able to witness the show. The conditions of the sky could affect the visbility of the northern lights.

"The weather should be clear, and the moon is not full, so the viewing should be good," Kunches said.

Skygazers are encouraged to check out the Space Weather Prediction Center for updates on unusual event.

The lights will appear as streams of a cloud-like substance. They are caused by a strong solar flare that occurred on Tuesday. As a result, charged particles were sent toward Earth. Once the particles hit Earth's protective magnetic field, they light up the atmosphere, creating the rare show.

"The Jan. 7, 2014, X-class flare was also associated with a coronal mass ejection, or CME, another solar phenomenon that can send billions of tons of particles into space that can reach Earth one to three days later," NASA explained. "These particles cannot travel through the atmosphere to harm humans on Earth, but they can affect electronic systems in satellites and on the ground."

Watch NASA's video of the solar flare below: