Solar Flare Alert: Massive CME Threatens Radio Blackouts and Dazzling Auroras

The Sun decided to throw another warning shot at Earth, this time with a powerful flare from sunspot region AR4436 triggering radio blackouts in certain regions, while sending coronal mass ejection (CME) toward Earth, raising the odds of northern lights in parts of the U.S. and U.K. this week.

The flare, measured at M5.7, sits below the rare X-class eruptions that produce the Sun’s most intense outbursts, but it was still intense enough to disrupt high-frequency radio traffic over the Atlantic and parts of eastern Africa. 

Now that the radio blackouts are mostly past, folks are turning their attention to the incoming CME. The ejection—racing here at roughly 400 miles per second—is expected to graze the atmosphere this week, possibly as soon as tonight (Tuesday), which could be enough to brighten auroral activity if the geometry lines up. NOAA’s Space Weather Prediction Center and the U.K. Met Office both see the chance of a glancing impact rather than a direct hit, which means the most likely outcome is a modest geomagnetic disturbance rather than a major storm.

Still, modest can be enough for skywatchers. Clear skies in northern Scotland (as well as locations in similar geomagnetic latitudes) could reveal the aurora if the CME strengthens the auroral oval, and U.S. viewers in northern states may also get a look if conditions improve. Remember: northern lights are not caused by the flare itself but by charged solar material colliding with Earth’s magnetic field and dumping energy into atoms high in the atmosphere, which then glow in greens, reds, and occasional blues.

If this event sounds familiar, two years ago on May 10, 2024, Earth experienced its first extreme G5 storm in more than two decades, with auroras spilling far beyond their usual range. More recently, the Sun shot four X-class storms towards Earth, causing widespread GPS and comms interruptions.

It's unlikely that this week’s burst won't match those scales, but the Sun is clearly in a restless mood, with AR4436 and AR4432 continuing to evolve and the possibility of more M-class flares or even X-class eruptions still on the table.