A massive eruption on the sun that flung solar plasma toward Earth on Friday may trigger a strong geomagnetic storm this weekend that could supercharge auroras across the northern United States.
The solar eruption, called a coronal mass ejection (or CME), exploded on Friday (March 21) even as a so-called “coronal hole” opened on the sun to unleash a separate high-speed stream of solar particles toward Earth. The result: A tag-team of solar material that should reach Earth this weekend to amplify northern lights displays late Saturday and early Sunday (March 22-23).
“A coronal hole high speed stream and coronal mass ejection arrival are likely to combine this coming night (Sat 22 Mar), bringing Enhanced to Strong solar wind speeds for a time,” the Meteorological Office of the United Kingdom wrote in an update today.
In the U.S., the National Oceanic and Atmospheric Administration issued an alert for a strong G3-class geomagnetic storm watch for Sunday, which could make auroras visible as far south as Oregon and U.S. states across the lower Midwest.
“Watches at this level are infrequent, but not uncommon,” NOAA officials wrote in the alert.
Auroras occur when charged particles from the sun’s solar wind reach Earth, where they are funneled over our planet’s polar regions to Earth’s magnetic field. When those particles interact with the upper atmosphere, they cause a glow (usually in green) visibel to skywatchers. Spikes in those interactions can reach geomagnetic storm levels like the G3 storm watch issued by NOAA.
When the sun unleashes major solar flares, erutions or particle streams, that baseline aurora activity amps up, with the northern lights visible farther south than its typical polar regions. Increased solar activity can also lead to different colors of auroras, such as stunning reds and purples, in addition to green.
If you live in the visibility region for this weekend’s potential northern lights and want to try and see the auroras, you’ll need to find the darkest skies possible. Light pollution from city lights and even street lights can spoil the view (just like during meteor showers).
The space weather that drives northern lights displays can be unpredictable, so it’s helpful to use an app you can personalize to your viewing location to get updates during storm watches like this weekend’s. We typically recommend “My Aurora Forecast & Alerts,” available on both iOS and Android, as well as “Space Weather Live” app on iOS and Android.
Editor’s note: If you observe the northern lights this weekend and capture a stunning photo or video that you’d like to share with Space.com, we want to see it! You can send in photos, video and observing comments in to [email protected].
