Northern Lights May Be Visible This Weekend In PA: When To Watch

PENNSYLVANIA — If you’ve been looking for some pure delight after a week of heavy news headlines, you may get your chance this weekend with the potential that one of nature’s most enchanting shows, the northern lights, may be visible in Pennsylvania.

A large swath of the northern United States, including Pennsylvania, is included in this weekend’s aurora watch, according to the National Oceanic and Atmospheric Administration's Space Weather Prediction Center.

The agency said geomagnetic activity is expected to rise Friday, Sept. 27, and likely reach moderate storm levels on Saturday, the 28th. The colorful, dancing lights could also be visible early Sunday morning.

Under ideal circumstances, we could get a glimpse of the weekend show. The weather forecast for the Philadelphia region calls for clear skies overnight Friday, and a slight chance of showers overnight Saturday.

The Space Weather Prediction Center will continue to update its Aurora forecast through the weekend.

According to the Aurora forecast from the Geophysical Institute at the University of Alaska Fairbanks, "highly active" auroral displays may be visible low on the horizon as far south as Maryland.

The science behind the northern lights is a bit complicated — all you really need to know is that they are jaw-dropping beautiful. Basically, they become visible to the human eyes when electrons from solar storms collide with the upper reaches of the Earth’s atmosphere.

In normal circumstances, the Earth’s magnetic field guides the electrons in such a way that the aurora forms two ovals approximately centered at the magnetic poles. But during geomagnetic storms, the ovals expand away from the poles and give some lucky people in the United States a sky show they’ll never forget.

Most often, the auroras appear as tall rays that look like a colorful curtain made of folds of cloth, according to the Space Weather Prediction Center.

“During the evening, these rays form arcs that stretch from horizon to horizon,” the agency said on a website. “Late in the evening, near midnight, the arcs often begin to twist and sway, just as if a wind were blowing on the curtains of light. At some point, the arcs may expand to fill the whole sky, moving rapidly and becoming very bright. This is the peak of what is called an auroral substorm.”

Here’s a helpful map from the Space Weather Prediction Center to help you determine your chances of seeing the Aurora Borealis this weekend.

To understand it, find the blue, green, red and yellow Kp lines. The higher the number assigned to it, the greater your chances are to see the northern lights.