Northern lights may be visible in these 18 US states Sept. 1-2

A potent solar storm is on its way and could put on a spectacular northern lights display for Labor Day across the U.S.

A fast-moving coronal mass ejection (CME), launched by a long-duration M2.7 flare from sunspot AR 4199 on Aug. 30, is expected to slam into Earth's magnetic field late on Sept. 1 into early Sept. 2 (UTC), according to NOAA's Space Weather Prediction Center (SWPC).

When it arrives, the CME is likely to spark a G2 (moderate) geomagnetic storm, intensifying to G3 (strong) levels as the main body of the solar storm passes, NOAA says. That means auroras could extend much farther south than usual — giving millions across the northern U.S. a shot at catching the lights.

What's causing the aurora activity?

The incoming solar storm is the result of a powerful, Earth-directed coronal mass ejection (CME) that erupted from the sun on Aug. 30. CMEs are massive clouds of charged particles and magnetic field hurled from the sun's atmosphere. When they slam into Earth's magnetic field, they can trigger geomagnetic storms and spark spectacular auroras and occasionally disrupt satellites, radio signals, and power grids.

NOAA modeling suggests the CME will arrive late on Sept. 1 into early Sept. 2 (UTC), potentially triggering G2 (moderate) to G3 (strong) geomagnetic storming.

However, this may be more than a typical CME event.

Space weather physicist Dr. Tamitha Skov pointed out that there may actually be two Earth-directed solar eruptions involved in this event, with one possibly catching up to and merging with the other. In a post on X, Skov explained that "the larger one catches up with the smaller one just ahead of Earth," which could trigger an initial disturbance before the main storm hits. "Impact is expected by late September 1. G2+ conditions possible," she added. This type of interaction, where one CME overtakes another, is known as a "cannibal CME" — a possibility that may be unfolding with this event.

Read more: Aurora alert! Incoming cannibal solar storm could spark Labor Day northern lights show

Earth's auroral oval is expected to be "significantly enhanced" following the CME's arrival, raising the chance of visible auroras as far south as East Anglia, the Midlands, and Wales under clear skies, according to the U.K. Met Office.

When and where can you see the northern lights?

According to NOAA's Kp index forecast, geomagnetic storming is expected to build through Sept. 2, peaking at Kp 6.67 (G3 storm) between 06:00 and 09:00 UTC (2 a.m. to 5 a.m. EDT) on Sept. 2.

That makes Monday night into Tuesday morning (Sept. 1–2) the best window for aurora viewing. Additional minor to moderate storming may continue into Tuesday night, Sept. 2–3.

Based on the latest NOAA aurora forecast map, the following 18 U.S. states appear fully or partially above the aurora view line:

States that could see the northern lights tonight

1. Alaska
2. Montana
3. North Dakota
4. Minnesota
5. Wisconsin
6. Michigan
7. Maine
8. South Dakota
9. Vermont
10. New Hampshire
11. Idaho
12. Washington
13. Oregon
14. New York
15. Wyoming
16. Iowa
17. Nebraska
18. Illinois
    

Auroras are highly unpredictable, so even if you're within the view line, your chances improve with clear skies, low light pollution, and a good view facing north.

Northern Hemisphere aurora forecast courtesy of the Met Office

How to see the northern lights where you live

If you're in one of the 18 U.S. states listed above, here are some tips for catching the display:

• Head to a dark location far from city lights.
• Find a north-facing view with a clear horizon.
• Look up around midnight to 2 a.m. local time, but keep watch as soon as skies darken.
• Be patient. Auroras often come in waves and can appear faint at first.

We recommend downloading a space weather app that provides aurora forecasts based on your location. One option I use is "My Aurora Forecast & Alerts," available for both iOS and Android. However, any similar app should work well. I also use the "Space Weather Live" app, which is available on iOS and Android, to get a deeper understanding of whether the current space weather conditions are favorable for aurora sightings.

What is a G3 geomagnetic storm?

NOAA classifies geomagnetic storms on a scale from G1 (minor) to G5 (extreme). G3 storms can push auroras to latitudes as low as Illinois, New York, and Oregon, depending on local conditions. They can also cause radio disruptions and minor power grid fluctuations in some regions.