Northern Lights
The sun remains in a peak period for solar activity, with the last major aurora display over the UK recorded in late March 2026 Jonatan Pie/Unsplash

A solar flare that knocked out radio communications across the Atlantic Ocean on Sunday has sent a cloud of plasma racing toward Earth, and forecasters say it could trigger northern lights displays as early as Tuesday night.

The Flare That Already Hit

The eruption, classified as M5.7 on the solar activity scale, burst from sunspot region AR4436 at 9:39 a.m. EDT on May 10. Within minutes, it ionised Earth's upper atmosphere and wiped out high-frequency radio signals over the Atlantic, according to NOAA's Space Weather Prediction Center (SWPC). The blackout affected transatlantic pilots, mariners navigating open ocean, and amateur radio operators who rely on those frequencies to communicate.

NOAA classified the disruption as an R2, or moderate, radio blackout. The flare also produced a Type II radio sweep with an estimated speed of 650 km/s (404 miles/sec) confirming that a coronal mass ejection (CME) had been launched from the sun's surface.

Where the Plasma Is Heading

Most of the ejected material is travelling on a path behind Earth's orbit. But both NOAA and the UK Met Office said the outer edge of the expanding plume may deliver a glancing blow to the planet around early May 13. If it connects, it could produce G1 geomagnetic storm conditions, the lowest tier on NOAA's five-level scale, but still strong enough to push aurora activity into lower latitudes.

Sky watchers in Scotland, northern England, and parts of the northern US, including Seattle and Minneapolis, could have a chance to see the northern lights if skies are clear. The aurora was last widely visible across the UK on 23-24 March 2026.

How to Catch the Display

Anyone hoping to see the aurora this week should get away from city lights and find a location with a clear, unobstructed view of the northern horizon. NOAA's aurora forecast page and SWPC's 30-minute aurora model both provide real-time updates on where the auroral oval is expanding. The best viewing window is typically between 10 p.m. and 2 a.m. local time, when the Earth's position favours the widest auroral spread. A darker moon phase also helps. The current waning crescent moon won't interfere too much with visibility, giving watchers a slight advantage.

Smartphone cameras can often pick up auroral colours that are too faint for the naked eye, so setting a long exposure or using night mode is worth trying even if the sky looks quiet.

Why Forecasters Are Still Watching

The flare itself is only part of the story. AR4436 is currently rotating into what space weather forecasters call Earth's 'strike zone' on the sun's northeastern limb. As the active region swings further into direct alignment with the planet over the coming days, any additional flares or CMEs it produces will have a much higher probability of being Earth-directed.

Both AR4436 and a neighbouring sunspot region, AR4432, are continuing to evolve and remain capable of producing M-class and possibly X-class eruptions, according to NOAA's SWPC. The sun is still near the peak of its 11-year solar cycle, and 2026 has already delivered significant space weather events. In January, Earth experienced the largest solar radiation storm in more than 20 years, rated S4 on a five-level severity scale. SWPC declared at the time that the last event of that strength was the Halloween storms of October 2003, which caused power outages in Sweden and damaged transformers in South Africa.

The May 10 CME is expected to be far weaker than January's event. But with AR4436 now turning Earthward, forecasters say the coming days could bring more activity, and more chances to see the northern lights, if the sun cooperates.

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