Visible by August 18th and peaking on the following night, some lucky Pennsylvanians got the chance to see the breathtaking, sky-illuminating phenomenon known as Aurora borealis, or the Northern Lights.
Aurora borealis is an atmospheric phenomenon that occurs when charged particles released from the sun’s atmosphere collide with gaseous particles in Earth’s northern atmosphere. If you’re in the right place at the right time, you can see the night sky light up in colors like yellowish green and pink.
The Northern Lights are rarely seen in the Pennsylvania area, usually occurring in places closer to the North Pole like Iceland, Alaska, Finland and Canada.
However, solar eruptions on August 14th generated powerful geomagnetic storms, which traveled towards Earth.
“Currently, the sun is producing Coronal Mass Ejections (CMEs) during a geomagnetic storm on the sun,” said Pittsburgh National Weather Service meteorologist Myranda Fullerton on August 19th. “It should make for a decent chance to view the northern lights, but you have to look north and low on the horizon.”
Meteorologists predicted high auroral activity from western Pennsylvania to Pittsburgh and the Philadelphia area, given the right conditions.
“One of the keys to seeing the northern lights in our area is for the weather to cooperate, for skies to be clear,” says NBC10 First Alert Weather meteorologist Bill Henley.
Fullerton notes that one of the biggest obstacles to catching the Northern Lights is light pollution, especially in urban areas. “It’s pretty hard to view them from Pittsburgh,” she said. “The farther south you get in the lower 48 states, the more difficult it is to view them.”
Meteorologists recommend viewing the phenomenon from dark, outdoor rural areas at a higher elevation. Fullerton also says clear winter night skies have less water vapor in the atmosphere and therefore provides more optimal viewing conditions.
Henley says that “it is rare that we get a magnetic storm powerful enough to allow us to see the northern lights in Pennsylvania.”
According to the National Oceanic and Atmospheric Administration (NOAA) Space Weather Prediction Center, the Pennsylvania area has a planetary index (Kp) value of 9, meaning that in order to produce visible light at that given latitude, the NOAA Geomagnetic Storm Index (which measures the intensity of CMEs entering the atmosphere) must as high as the value 5, the highest rating from 0.
Nevertheless, for those fortunate enough to witness the lights this south of the North Pole, they will not forget seeing the night sky over Pennsylvania burst with color.