Northern Lights could be visible across 19 US states Monday night

A coronal mass ejection that departed the sun late on 26 June is expected to generate increased geomagnetic activity as it reaches Earth, potentially creating conditions for the aurora borealis to be visible across 19 states on the night of 29 June. According to the National Oceanic and Atmospheric Administration, observers should anticipate enhanced conditions early to mid on 30 Jun due to the CME that left the Sun late on 26 Jun. While the disturbance is initially forecast to reach levels classified as a G1 minor geomagnetic storm, reports from the UK Met Office indicate a possibility of intensity reaching G2 moderate levels, with the risk of activity continuing into 1 July.

The visibility of the northern lights remains contingent on the orientation of the interplanetary magnetic field. Experts specifically monitor the Bz component of this field. When the Bz component points south, it facilitates a connection between the solar wind and the Earth’s magnetosphere. A sustained southward Bz of -5 nT or stronger is typically required to signal an imminent aurora. Because the arrival of solar material is difficult to predict with precision, forecasts become significantly more reliable only when solar wind reaches satellites positioned upstream of Earth, often providing only 30 to 60 minutes of advance notice.

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Geographic Reach and Optimal Viewing

The states with the highest probability of observing the aurora include Washington, Idaho, Montana, North Dakota, South Dakota, Minnesota, Wisconsin, Michigan, and Maine. Additionally, skywatchers in Oregon, Wyoming, Nebraska, Iowa, Illinois, Indiana, Ohio, New York, Vermont, and New Hampshire are advised to monitor the northern horizon, as the intensity of the storm may fluctuate. The visibility of the aurora depends heavily on latitude, with lower-latitude regions generally requiring higher geomagnetic activity—often classified by a Kp index of 5 or above—to bring the lights into view above the horizon.

The timing of this event coincides with the full Strawberry Moon, which rises on the evening of 29 June. While the moon provides a striking backdrop, its brightness may make a faint aurora display harder to discern. Tim Brothers, an observatory manager and instructor, emphasizes the importance of environment for successful viewing.

"We typically suggest getting away from cities and find an open field or hilltop to lay out under the stars and wait for the show to really peak at the late evening or early morning hours."

Tim Brothers, observatory manager and instructor, via Wicked Local

Observational Guidelines

For those attempting to view or capture the lights, experts recommend the following strategies:

• Location: Seek out the darkest area possible, preferably a conservation area or park away from urban light pollution.
• Adaptation: Allow your eyes 15 to 20 minutes to adjust to the dark without checking bright screens, as light pollution significantly reduces the ability to spot weaker displays.
• Technology: Utilize long-exposure settings or "Night Mode" on smartphone cameras. Cameras are often capable of detecting the faint glow of an aurora before the human eye can distinguish its color or structure.
• Persistence: Activity often arrives in short, intense bursts known as substorms, which may last 10 to 30 minutes. Consistent monitoring throughout the night, particularly between 10:00 p.m. And 2:00 a.m., is recommended over giving up after a single check.

Data and Forecast Updates

The intensity of geomagnetic activity is measured on a scale of 0 to 9, known as the Kp index, which is updated every three hours. Current projections suggest a range between G1 and G2, meaning the aurora may appear as a faint glow on the northern horizon for most of the listed states rather than the overhead displays common at higher latitudes. Observers are encouraged to use real-time tracking tools, including the NOAA experimental aurora dashboard and various mobile applications, to monitor solar wind data and the Bz component as the night progresses. As the coronal mass ejection's effects may linger, skywatchers should continue to observe and check for updated bulletins through 1 July.