Another solar storm to hit Earth this weekend

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The sun emitted a mid-level solar flare, an M7.9-class, peaking at 4:16 a.m. EDT on June 25, 2015. NASA's Solar Dynamics Observatory, which watches the sun constantly, captured an image of the event.

NASA/SDO

A solar storm hit Earth early this week, sending northern lights across the skies where they're rarely seen. And the sun's not done yet.

Scientists at the National Oceanic and Atmospheric Administration's Space Weather Prediction Center reported that a coronal mass ejection (CME) -- the third in less than a week -- erupted Thursday, sending billions of tons of solar atmospheric material hurtling through the solar system toward Earth. They expected it to reach the planet Saturday afternoon.

"This event is expected to be weaker than the severe geomagnetic storm from earlier in the week," SWPC forecasters said. Moderate geomagnetic storm conditions were expected to begin June 27 and continue into June 28.

Two CMEs -- one on June 20 and another on June 22 -- reached Earth in the first half of the week. When the plasma and magnetic fields in a CME interact with Earth's magnetic field, it causes a geomagnetic storm that can sometimes interfere with high frequency radio communications and GPS signals.

These solar storms can also cause conditions that pull the aurora borealis (northern lights), further south than usual, and this latest one put on a spectacular light show for many Americans who normally wouldn't have the pleasure. Aurora sightings were reported in Minnesota, South Dakota, Virginia, West Virginia, New Hampshire and Wyoming.

Photographer Mike Cavaroc in Jackson Hole created this stunning time lapse of the aurora there:

A Night with Northern Lights from Mike Cavaroc on Vimeo.

While there are no promises of such spectacles this weekend, moderate geomagnetic storms have resulted in aurorae as low as New York and Idaho.

  • Amanda Schupak

    Amanda Schupak is the science and technology editor at CBSNews.com