Northern Lights May Be Returning to Our Skies

The region of sunspots that delivered epic aurora viewing to people around the world earlier this month is back in sight, bringing more potential viewing opportunities as early as Friday. After rotating behind the western edge of the sun mid-month, the region of the sun formerly named Active Region 13664 and now relabeled AR 13697 appeared at the eastern edge of the sun on Monday, per Space.com. "Making an entrance worthy of its earlier reputation," the solar region quickly produced a solar flare of the highest class possible, the outlet reports. The X2.9 solar flare isn't as strong as some observed earlier this month, but it shows the sunspot cluster, to remain visible over the next two weeks, is still capable of producing impressive geomagnetic storms.

Monday's solar flare "caused a lengthy shortwave radio blackout over the Americas," the Washington Post reports. Two days later, a coronal mass ejection launched from the sun's southwestern rim. It's expected to deliver a glancing blow to Earth on Friday. Experts predict a moderate geomagnetic storm—level 2 on a scale of 1 to 5—which could mean visible auroras as far south as New York and Idaho. Earlier this month, 12 X-class solar flares over six days combined to trigger the first G5 geomagnetic storm since 2003 and widespread auroras. That's not likely to happen again so soon "if the current trend of fewer X-class solar flares continues," Space.com reports. But a G3 or G4 storm is possible as the sunspot cluster comes to face Earth over the next several days.

"Unlike flares, CMEs are directional, and their potential impact on Earth relies heavily on the location of its source on the sun," Space.com explains, noting AR 13697 will reach optimal position, just right of the sun's center, around June 4-6. "Eruptions close to this window will have the best odds of producing a geomagnetic storm and enhanced aurora display," the outlet reports. Forbes notes the new moon arrives June 6, meaning the night sky will at that point be free of moonlight, which can obscure auroras. (More aurora borealis stories.)