The aurora borealis was visible again Sunday night, the result of a severe geomagnetic storm that began at 1:37 p.m. EDT and persisted until 2 a.m. EDT on Monday, as reported by the Space Weather Prediction Center. The storm was measured at a level 4 out of 5 on the National Oceanic and Atmospheric Administration’s space weather G-scale, according to the center’s website.

SWPC, which operates under NOAA, had issued a minor (G1) geomagnetic storm watch for Sunday and a moderate (G2) geomagnetic storm watch for Monday. However, a strong-extreme geomagnetic storm warning was issued by the center at 3:26 p.m. EDT on Sunday, as the storm had arrived earlier and was strong than expected, SWPC reported.

The storm brought sightings of auroras to areas across parts of Europe and Asia, the Associated Press reported Monday. In the Lower 48, lights were visible from places not often treated to the displays, including Wisconsin, Washington state, Colorado, California, New Mexico and Arizona, according to the AP.

The aurora borealis (northern lights) and aurora australis (southern lights) are the result of electrons colliding with the upper reaches of Earth’s atmosphere, according to the Space Weather Prediction Center’s website.

“Earth’s magnetic field guides the electrons such that the aurora forms two ovals approximately centered at the magnetic poles. During major geomagnetic storms, these ovals expand away from the poles such that aurora can be seen over most of the United States. When space weather activity increases and more frequent and larger storms and substorms occur, the aurora extends equatorward. During large events, the aurora can be observed as far south as the US, Europe, and Asia,” SWPC states.

Aurora forecasts and live data can be accessed on the Space Weather Prediction Center at spaceweather.gov.