A massive solar storm could trigger Northern Lights as far south as Alabama tonight, according to officials with the National Oceanic and Atmospheric Association.

On Thursday, NOAA’s Space Weather Prediction Center upped its geomagnetic solar storm watch from a level 3, or moderate, to level 4, or severe, something officials described as “very rare.” The severe geomagnetic storm watch is the first issued by NOAA since 2005.

The upgrade is due to the anticipated merger of two coronal mass ejections, or eruptions of solar materials, that are expected to arrive at Earth by late May 10 or early May 11. Charged particles from these bursts will hit the Earth’s magnetic field producing the glowing aurora borealis over much of the northern half of the country and possibly as far south as Alabama to northern California, NOAA said.

Several strong flares have been observed over the past few days, each associated with a sunspot cluster that’s roughly 16 times the diameter of Earth. Additional solar activity is expected from that region, NOAA said.

Friday night, the lights could be visible with the naked eye to people in Virginia, Missouri, Colorado and Northern California.

The best viewing conditions for this session are expected to be across the northern Plains and Pacific Northwest. Cloud cover will prevent viewing for most people in the Northeast and part of the Midwest, AccuWeather explained, though there could be pockets around the Ohio Valley where the lights can be seen.

If cloud cover doesn’t block out the celestial show, it’s recommended you go to a place without light pollution and where you can take in as much of the sky as possible.  The early hours of Saturday morning and generally considered the best times.

This is the second time in two months NOAA has issued a warning as the result of higher-than-average solar activity. In March, a G4 out of 5 storm was reported, though cloud cover prevented auroras being seen in the central and southern parts of the U.S.

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