Madison, Wisconsin – A space weather alert is in effect tonight as a rare G4 (Severe) geomagnetic storm creates strong potential for the Northern Lights to be visible across much of Wisconsin, according to the NOAA Space Weather Prediction Center.
NOAA’s latest aurora forecast shows the auroral oval expanding well south of its usual range, placing most of Wisconsin, including areas near Lake Superior, Lake Michigan, and central portions of the state, within reach of possible aurora visibility late tonight. Forecast guidance indicates a Kp index near 7 to 8, a level often associated with widespread auroral displays across the Upper Midwest.
The aurora forms 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 Wisconsin, auroras may appear as bright bands or curtains overhead, especially in darker rural areas. Across central and southern Wisconsin, including the Madison and Milwaukee regions, the lights may appear as a greenish or reddish glow low on the northern horizon, with visibility improving away from city lights.
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 intensity may fluctuate overnight as geomagnetic conditions evolve.
