The northern lights could be visible around Philadelphia tonight. Here's when to look for them.
While early birds and night owls in central Pennsylvania got a glimpse of the northern lights earlier this week, a major geomagnetic storm could make the aurora visible to even more people across the Delaware Valley between sunset Thursday and sunrise early Friday morning.
The northern lights are visible when a solar flare spews large amounts of magnetized plasma known as coronal mass ejections (CMEs) into space. When those CMEs are directed at Earth, they can create a geomagnetic storm, which, according to NASA, creates a major disturbance in our magnetic field. These storms produce the northern lights, but they can also lead to power outages and sometimes radio blackouts.
On Wednesday, the National Oceanic and Atmospheric Administration (NOAA) issued a G4 severe geomagnetic storm watch for Oct. 10-11. According to NOAA, a fast CME erupted from the sun Tuesday night and could impact Earth "as early as the morning to midday" on Thursday, Oct. 10.
Will the northern lights be visible around Philadelphia?
Yes, Philadelphia is within the viewing line, and the NEXT Weather Team is forecasting clear skies. You may recall that we were cloudy last May when an extreme geomagnetic storm lit up the skies for the most spectacular show since the 1960s.
In the United States, the lights were seen from the Canadian border to the Mexican border. We were not lucky that night, but this will be a second chance for the Philadelphia area to view the heavenly sight.
So, grab a chair, blanket and heavy coat. It will be chilly but worthwhile if the northern lights do indeed appear. You will need to get away from city lights and look north to the horizon for any lights. They should be visible to the naked eye, but take your cellphone because the camera will capture even more vivid images.
The National Park Service links here to multiple night sky maps showing you where to get away from light pollution around Pennsylvania, New Jersey and Delaware.
We are currently at the peak of solar cycle 25. This has been one of the more active solar cycles on record, and it begins winding down in 2025. Solar cycles usually last 10-12 years.
Derrick Pitts, chief astronomer at the Franklin Institute in Center City, said not to worry if you miss the Northern Lights.
"The sun's level of activity is going to continue to be high for probably another year," Pitts said. "So as long as there are large sunspots and large flares and big eruptions off the sun, there's always the possibility to see aurora again."
John Paz, who is visiting Philadelphia from his home in Naples, Florida, said he saw the aurora borealis once while flying in an airplane over Lake Michigan.
"There's nothing like it," Paz said. "Nothing else like it. Beautiful colors all across the sky. A lot of green. It's pretty magnificent."