This solar cycle has yielded more colorful auroras farther south and more are likely, said NASA's Kelly Korreck.

"We still could possibly get some good shows in the next few months," she said.

Such storms can also temporarily disrupt power and communications. Ahead of a solar outburst, NOAA would alert operators of power plants and spacecraft in orbit.

In May, NOAA issued a rare severe geomagnetic storm warning. The storm that slammed Earth was the strongest in more than two decades, producing light displays across the Northern Hemisphere. That same month, scientists recorded the biggest flare erupting from the sun, but Earth was out of the way.

Previous solar cycles have produced storms more intense than May's so space forecasters are keeping a close eye on the sun to prepare for any major disruptions, said NOAA's Bill Murtagh.