Residents in several northern U.S. states may have the chance to witness the aurora borealis, commonly known as the Northern Lights, on Tuesday, September 8, and Wednesday, September 9. The National Oceanic and Atmospheric Administration’s Space Weather Prediction Center forecasts that the best viewing conditions will be between 6 p.m. and 6 a.m. US Central Time.
The states with the highest likelihood of seeing the display, provided skies are clear, include Alaska, Washington, Idaho, Montana, North Dakota, South Dakota, Minnesota, and Wisconsin. Northern Alaska is predicted to have the most favorable viewing conditions, while states closer to the U.S.-Canadian border have a lower probability.
The phenomenon occurs when charged particles from the sun interact with Earth's magnetic field, causing atmospheric gases like nitrogen and oxygen to emit light. While invisible during daylight, the aurora is often observable shortly after sunset or before sunrise. The current new moon is expected to provide darker skies, potentially improving visibility.
September is considered a prime viewing month due to the vernal equinox, which can lead to increased geomagnetic activity. This effect, sometimes referred to as the Russell-McPherron effect, happens when Earth's magnetic poles are more perpendicularly aligned with the sun, a condition that occurs during equinoxes.
To enhance viewing, experts recommend finding locations away from urban light pollution. Checking live aurora forecasts can also be beneficial, as the lights are unpredictable and can appear in waves. Information on current activity and short-term forecasts is available through NOAA's Space Weather Prediction Center.
Previous auroral displays in the Northern U.S. have been attributed to coronal holes on the sun, which release high-speed streams of solar wind. When these streams reach Earth, they can intensify auroras by increasing geomagnetic activity.