Harrisburg, Pennsylvania – A space weather alert is in effect tonight as a rare G4 (Severe) geomagnetic storm creates the potential for Northern Lights to be visible across parts of Pennsylvania, according to the NOAA Space Weather Prediction Center.
NOAA’s latest aurora forecast shows the auroral oval expanding unusually far south, placing northern and central Pennsylvania within reach of possible aurora visibility. Forecast models indicate a Kp index near 7 to 8, a strength capable of producing auroras well outside their typical northern range.
The aurora is caused by a coronal mass ejection from the Sun interacting with Earth’s magnetic field. As charged solar particles collide with oxygen and nitrogen high in the atmosphere, they generate glowing green and red light displays known as the Northern Lights.
For viewers in northern Pennsylvania, including areas near the New York border, auroras may appear as visible bands or shimmering patches in the sky if storm conditions intensify. Farther south, including central Pennsylvania, the lights are more likely to appear as a faint green or reddish glow low on the northern horizon. Visibility near large cities may be limited due to light pollution.
The best opportunity to see the aurora is expected late tonight through the early morning hours, generally between 10 p.m. and 2 a.m., weather and cloud cover permitting. Observers are advised to seek dark locations away from city lights and allow time for eyes to adjust.
Auroras are harmless to people on the ground, though the same geomagnetic storm is prompting monitoring of satellites, GPS systems, and power infrastructure.
Auroral visibility may fluctuate overnight as space weather conditions evolve.
