Northern lights may be visible in 24 states tonight as massive CME races toward Earth

A colossal coronal mass ejection (CME) is currently hurtling toward Earth and is forecast to arrive within the next 24 hours. The impact could ring Earth's magnetic field like a bell, triggering severe (G4) geomagnetic storm conditions and pushing the northern lights much farther south than usual.

NOAA space weather forecasters have issued a G4 (severe) geomagnetic storm watch for tonight, when the main bulk of the CME is expected to hit. If the eruption's magnetic field is favorably aligned, or "geoeffective", and G4 conditions are reached, auroras could be visible even farther south than current forecasts suggest, potentially reaching as far as northern California and Alabama.

The CME was launched during a powerful X-class solar flare on Jan. 18 and is racing toward Earth at speeds of 620–870 miles per second (1,000–1,400 km/s). Aurora chasers, get those camera batteries charged and your alerts switched on — tonight could be quite the night.

Where can I see the northern lights tonight?

States that could see auroras tonight

Based on the latest NOAA aurora forecast map, the following 24 U.S. states appear fully or partially above the aurora view line:

1. Alaska
2. Washington
3. Oregon
4. Idaho
5. Montana
6. North Dakota
7. Minnesota
8. South Dakota
9. Wisconsin
10. Wyoming
11. Michigan
12. New York
13. Vermont
14. Maine
15. New Hampshire
16. Massachusetts
17. Nebraska
18. Iowa
19. Illinois
20. Indiana
21. Ohio
22. Pennsylvania
23. Missouri
24. Colorado

But remember, auroras can be very fickle. The list is based on current forecast data at the time of publication, but if conditions strengthen, northern lights could reach much farther south than expected. Equally, if conditions don't align, we could end up twiddling our thumbs, with no auroras at all.

Whether tonight's CME delivers a dazzling aurora show or ends in disappointment depends largely on its magnetic orientation when it hits Earth.

If the CME's magnetic field is aligned southward — a component known as Bz — it can link up with Earth's magnetic field, allowing solar energy to stream into our atmosphere and fuel geomagnetic storms. But if it's oriented northward, Earth's magnetic field deflects much of that energy, and the show may never materialize.

Some CMEs contain both north- and south-facing fields, which can lead to patchy or fluctuating activity — keeping forecasters and aurora chasers on their toes. We won't know the CME’s true magnetic orientation until it's sampled directly by solar wind satellites like DSCOVR and ACE, positioned about a million miles from Earth.

Northern Hemisphere aurora forecast courtesy of the U.K. Met Office

When is the best time to look for the northern lights tonight?

If skies are clear, make sure to look for the northern lights as soon as it gets dark tonight as geomagnetic activity is currently forecast to be high. At the moment, the best time to look for the northern lights looks like between 1 and 4 a.m. EST (Jan. 20) as this is when the severe (G4) geomagnetic storm conditions are currently forecast to occur.

According to NOAA's 3-day forecast, geomagnetic storm activity is expected to be best at the following times:

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

If you're in one of the 24 U.S. states where auroras might make an appearance tonight, a little preparation can go a long way toward improving your odds of seeing them.

1. Start by finding a spot with an unobstructed view toward north, preferably somewhere dark and well away from city lights. The clearer your view of the northern horizon, the better.
2. Start scanning the sky with your phone's camera as they are usually good at picking up faint auroral glows that aren't immediately obvious to the naked eye, helping you identify where activity may be starting.
3. Dark adaptation is crucial and often overlooked when aurora chasing. If you can, give your eyes at least 30 minutes to fully adjust to the darkness so you can detect subtle auroral features. Keep in mind that even a quick look at a bright light or phone screen can reset the process, forcing you to start over
4. Dress for the wait. Aurora shows can be unpredictable and if conditions look promising you may find yourself waiting outside for a while. Make sure to wear plenty of layers!

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. Want to capture the perfect northern lights photo? Our how to photograph auroras guide can help.

Editor's Note: If you snap a photo of the northern or southern lights and would like to share it with Space.com's readers, send your photo(s), comments, and your name and location to spacephotos@space.com.