What scientists call “a geomagnetic storm watch” is in effect for Sunday night.
In plain language, that means: Look for vibrant northern lights across the nation — visible anywhere in Pennsylvania.
Authorities from the National Oceanic and Atmospheric Administration’s Space Weather Prediction Center said “a coronal mass ejection” will likely arrive and lead to “highly elevated geomagnetic activity.”
** VERY RARE G4 SOLAR STORM WATCH **
This is a map I made based on G4 storm history. If the storm does not achieve G4 levels, the viewing levels will be farther north and vice versa. More information about viewing the Northern Lights will be posted over the next 24 hours. Stay… pic.twitter.com/HAwGwq4hrj
— PA Weather Plus, LLC (@PAWeatherPlus) May 31, 2025
The NOAA defines a coronal mass ejection as “large expulsions of plasma and magnetic field from the Sun’s corona.”
Authorities said conditions will likely intensify as the progression continues. The chance for good viewings of northern lights will continue on Monday.
The geomagnetic storm levels will likely begin subsiding by Tuesday, with mild to moderate storms still possible.