Illinois could see the Northern Lights again tonight – NBC Chicago

A day after the Northern Lights illuminated the skies over Illinois, the spectacle may be visible again as charged particles continue to hit Earth's atmosphere.

According to the Space Weather Prediction CenterThe geomagnetic storm continues to affect the Earth, and forecast models indicate that the arrival of these charged particles may cause the northern lights to appear in Illinois Tuesday night and into Wednesday morning.

The latest estimates show the “K Index” to be around 7.33 between 10 PM and 1 AM Central Daylight Time. And 6.67 “K-Index” in the previous three-hour window.

According to what was reported by the National Meteorological Directorate The K index shows “fluctuations in the Earth's magnetic field” Over three hours. Anything above five on a scale of 0 to 9 is considered a geomagnetic storm, and can cause the northern lights to be seen further south than usual.

If the K index is seven or higher, the northern lights can be seen as far south as Illinois and Oregon, according to officials.

Fortunately for Illinoisans, it looks like Mother Nature will cooperate if the northern lights shine Tuesday night and into Wednesday morning. Skies are expected to be mostly clear throughout the overnight hours, although things will get quite chilly outside, with lows in the upper 30s and low 40s in areas far from Chicago.

The best chance to see the northern lights may be in the 10pm to 1am window, but residents are encouraged to stay away from city lights if possible and look towards the northern horizon for the best chance of seeing the spectacle.

The northern lights are enhanced when coronal mass ejections, or CMEs, erupt from the Sun and accelerate through space before reaching Earth's atmosphere. According to SWPC, CMEs are “large explosions of plasma and magnetized particles from the Sun’s corona.” These projectiles expand in size as they approach the Earth's atmosphere, and can cause geomagnetic storms upon arrival.

The northern lights occur when these charged particles collide with the Earth's magnetic field, interacting with atoms and molecules in the upper atmosphere and producing brilliant, wavy colors in the sky.

The northern lights can generally only be seen at high altitudes, but situations like this week's geomagnetic storm can cause those particles to appear over greater distances.