A day after the Northern Lights lit up the Illinois sky, the spectacle could be visible again as charged particles continue to hit Earth’s atmosphere.
A geomagnetic storm continues to impact Earth, according to the Space Weather Prediction Center, and forecast models suggest the arrival of these charged particles could make the Northern Lights visible in Illinois Tuesday night and Wednesday morning.
The latest estimates show a “K-Index” of approximately 7.33 between 10 p.m. and 1 a.m. Central Daylight Time, and a “K-Index” of 6.67 in the preceding three-hour window.
According to the National Weather Service, the K index shows “fluctuations in the Earth’s magnetic field” over a three-hour period. Anything above a five on a scale of 0 to 9 is considered a geomagnetic storm and can make the Northern Lights visible much farther south than usual.
In cases where the K index is seven or greater, the northern lights can be seen as far south as Illinois and Oregon, officials say.
Luckily for Illinois residents, it appears Mother Nature will cooperate if the Northern Lights appear Tuesday night and Wednesday morning. Mostly clear skies are expected throughout the night, although things will get quite chilly outside, with lows in the upper 30s and lower 40s in remote areas of Chicago.
The best chance of seeing the Northern Lights may be between 10 p.m. and 1 a.m., but residents are encouraged to get away from city lights if possible and look toward the northern horizon for the best chance to see the show.
The northern lights are enhanced when coronal mass ejections, or CMEs, erupt from the sun and travel through space before hitting Earth’s atmosphere. According to the SWPC, CMEs are “large explosions of plasma and magnetized particles originating from the solar corona.” These ejections increase in size as they approach Earth’s atmosphere and can cause geomagnetic storms upon arrival.
The Northern Lights occur when these charged particles strike the Earth’s magnetic field, interacting with atoms and molecules in the upper atmosphere and producing bright, wavy colors in the sky.
The northern lights are usually only visible at high altitudes, but instances like this week’s geomagnetic storm can make these particles visible at greater distances.
