Northern lights may be visible in these 18 states tonight

Heads up aurora chasers! The northern lights could illuminate skies overnight on Aug. 7-8 as an incoming coronal mass ejection (CME) may spark geomagnetic storm conditions, according to the National Oceanic and Atmospheric Administration (NOAA).

Though only a glancing blow is predicted from the CME, any impact could disrupt Earth's magnetic field, which in turn can trigger geomagnetic storms and impressive auroras.

Space weather forecasters from NOAA's Space Weather Prediction Center (SWPC) and the U.K. Met Office predict a chance of minor (G1) to moderate (G2) geomagnetic storms on Aug. 8 with a slight chance of reaching strong (G3) levels. That means there's a window of opportunity for aurora sightings at northern latitudes — weather and dark skies permitting.

When will the geomagnetic storm hit?

The exact timing of the CME's arrival and whether it will spark significant geomagnetic storming remains uncertain. While solar physicists expect the CME to graze Earth's magnetic field, even a glancing blow could be enough to trigger auroras, depending on the CME's speed and magnetic orientation when it arrives.

NOAA's Kp index forecast suggests activity could begin as early as 11:00 p.m. EDT on Aug. 7 (0300 GMT on Aug. 8), with moderate G2 storming possible from 2:00 a.m. to 5:00 a.m. EDT (0600–0900 GMT) on Aug. 8. That means tonight may offer the best aurora viewing window for parts of the northern U.S. The Kp index is a scale from 0 to 9 used to measure geomagnetic activity. The higher the number, the more likely auroras are to be visible at mid-latitudes, away from the poles.

Meanwhile, the U.K. Met Office forecasts a later impact, suggesting the CME may arrive during the daylight hours of Aug. 8, pushing storming potential into the overnight hours of Aug. 8–9 instead. So, be ready to hunt for auroras either tonight or tomorrow night, as it all depends on when the CME arrives and whether it triggers geomagnetic storm conditions. Solar storms are famously unpredictable, so it's worth keeping an eye on the skies both nights.

Where are the northern lights visible tonight?

Based on the NOAA forecast, we've listed 18 U.S. states that appear fully or partially above the aurora view line. They are approximately ordered from most likely to least likely to see the northern lights based on their proximity to the aurora oval's center and how much of each state is within or near the 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

But remember, auroras are fickle; sometimes they appear much farther south than predicted, and other times they barely show up at all. Many conditions have to align for the perfect display.

Northern Hemisphere aurora forecast courtesy of the Met Office

How can I see the northern lights from where I live?

If you live in one of the 18 U.S. states forecast to potentially catch a glimpse of the northern lights tonight, there are a few things you can do to give yourself the best chance of seeing them.

First, find a north-facing vantage point with a clear view of the horizon, as far away from light pollution as possible. The best time to look for the northern lights will be around 2 a.m. local time, due to the limited hours of darkness in the summer months. However, since the solar storm could arrive at any time, it's worth keeping an eye on the skies as soon as it gets dark.

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.