Photos show the lights illuminating the sky in vivid color across the U.S. this week. They'll be visible again in some states on Thursday.

Nature offers many dazzling displays, from jagged flashes of lightning to radiant sunsets. But perhaps one of the most elusive natural phenomena is the shimmering waves of green, pink, and red dancing across the night sky,

On Tuesday, NOAA issued a G4, or severe, geomagnetic storm watch in response to recent coronal mass ejections, or CMEs, from the sun. CMEs are huge bubbles of coronal plasma that the sun occasionally ejects, NASA says. The highest geomagnetic storm level is G5, which is considered extreme.

Strong geomagnetic storms and a moderate solar radiation storm have led to an aurora view forecast for Wednesday night in the northern U.S.

The northern lights were visible Tuesday night across the Chicago area, illuminating the sky with brightly colorful displays due to severe solar storms.