Chicago, Illinois – A space weather alert is in effect tonight as a rare G4 (Severe) geomagnetic storm creates the potential for Northern Lights to be visible across parts of Illinois, according to the NOAA Space Weather Prediction Center.
NOAA’s latest aurora forecast shows the auroral oval expanding farther south than usual, placing northern Illinois, especially areas closer to Lake Michigan and the Wisconsin border, within reach of possible aurora visibility late tonight. Forecast guidance indicates a Kp index near 7 to 8, a level capable of producing auroras well outside their typical northern range.
The aurora occurs when charged particles from the Sun collide with oxygen and nitrogen high in Earth’s atmosphere, producing glowing green and red light displays. This activity is being driven by a coronal mass ejection currently interacting with Earth’s magnetic field.
For viewers in northern Illinois, auroras may appear as faint green bands or a subtle glow low on the northern horizon, particularly in rural or lakeshore areas away from city lights. Visibility in Chicago and surrounding metro areas will likely be limited by light pollution, though a dim glow may still be detectable under clear skies.
The best chance to see the aurora is expected late tonight through the early morning hours, generally between 10 p.m. and 2 a.m., weather and cloud cover permitting. Observers are encouraged to seek dark locations, face north, and allow time for eyes to adjust.
Auroras are harmless to people on the ground, though the same geomagnetic storm is prompting monitoring of satellites, GPS systems, and power infrastructure.
Auroral visibility may fluctuate overnight as geomagnetic conditions evolve.
