The forecast “view line,” or the southernmost spot where skygazers might still be able to view the northern lights, includes states as far down as Illinois and Iowa.
WASHINGTON — The northern lights could light up the night sky this week in the northern half of the continental U.S.
Forecasters issued a severe G4 geomagnetic storm watch for Tuesday, Nov. 11 and Wednesday, Nov. 12. The alert comes after a coronal mass ejection, an eruption of solar material and magnetic fields from the Sun’s surface, was set to hit Earth late Tuesday into Wednesday. Coronal mass ejections, known as CMEs, usually generate spectacular displays of aurora borealis in northern U.S. states.
G4-level watches are rare, with only four alerts issued so far this solar cycle, NOAA says.
According to NOAA’s Space Weather Prediction Center, the geomagnetic activity could impact infrastructure technology and will be “visible over much of the northern half of the country.”
The”Kp,” the scale the National Oceanic and Atmospheric Administration uses to measure the maximum forecasted geomagnetic activity, is a seven on a scale from zero to nine for Tuesday night’s forecast. It will decrease to a 6 for Wednesday night, according to the forecast.
Where will the northern lights be visible tonight?
Most states bordering Canada will have a chance to view the celestial phenomenon. The predicted “view line,” or the southernmost spot where skygazers might still be able to view the northern lights, also includes states as far down as Illinois and Iowa.
- Alaska
- Oregon (partially)
- Washington
- Idaho (partially)
- Montana
- Wyoming (partially)
- North Dakota
- South Dakota
- Nebraska (partially)
- Iowa (partially)
- Minnesota
- Illinois (partially)
- Michigan
- Wisconsin
- New York
- Vermont
- New Hampshire
- Massachusetts (partially)
- Maine (partially)
Some parts of Indiana, Ohio and Pennsylvania fall under the view line, so they could also see the colorful display.
What causes the northern lights?
In layman’s terms, the sun is constantly shooting out charged particles. But sometimes, it emits a particularly violent stream of energy known as solar wind, during solar flares or “coronal mass ejections.”
When these energetic solar winds hit the Earth’s atmosphere, they collide with the gases in the upper atmosphere and charge them. As that energy dissipates, it lets out light that we can see.
The different gases produce different colors, which is why an aurora borealis can shift from green and blue to red and purple.
How to see auroras
Northern lights forecasts can be found on NOAA’s Space Weather Prediction Center website or an aurora forecasting app.
Consider aurora-watching in a quiet, dark area away from city lights. NASA’s Kelly Korreck recommended skygazing from a local or national park. And check the weather forecast because clouds can cover up the spectacle entirely.
Taking a picture with a smartphone camera may also reveal hints of the aurora that aren’t visible to the naked eye.
The Associated Press contributed to this report.