Boulder, Colorado—May 11, 2026, 14:04 MDT.
Forecasters at NOAA’s Space Weather Prediction Center said a solar flare that erupted on May 10 sent a coronal mass ejection into space, but it looks like the bulk of that solar material is set to pass by Earth. Still, a glancing blow—or a shock arrival—could reach Earth late on May 12 or early May 13 UTC, the agency noted.
Northern lights activity isn’t off the table, though it won’t reach major storm status, according to NOAA. The agency’s latest three-day outlook shows no G1, or minor, geomagnetic storm likely through May 13. Highest predicted Kp reading lands at 4.33 — comfortably short of storm territory on the 0-to-9 scale.
Radio operators felt the impact. According to NOAA’s alert feed, the M5.7 X-ray flare started at 1319 UTC, hit its peak at 1339 UTC, and wrapped up at 1402 UTC on May 10. That was enough for an R2-level, classified as a moderate radio blackout—high-frequency signals on Earth’s sunlit side could have dropped out for tens of minutes.
A coronal mass ejection, or CME, blasts out plasma and a magnetic field from the sun. If it hits Earth, the planet’s magnetic field can get rattled and the aurora zone stretches farther than usual. When the CME misses, radio disruptions are possible, but there’s usually not much to see in the sky. NOAA puts G1 storms at the lower end: small power grid hiccups, minor satellite issues, and auroras sometimes reaching places like northern Michigan or Maine.
According to Space.com, the flare erupted out of sunspot region AR4436, which is now swinging into a spot on the sun’s northeastern limb that faces Earth more directly. That shift could boost the odds that any further eruptions from AR4436 end up firing material our way.
The U.K. Met Office left the door open for some aurora action, noting activity is expected to stick close to background levels. Still, a glancing CME brushing past early on May 13 could light up the auroral oval—potentially visible over northern Scotland and similar latitudes, provided the skies cooperate. G1 storm intervals are also on the table for May 13.
C. Alex Young, a solar astrophysicist who also handles heliophysics communications at NASA Goddard, told EarthSky readers—along with his co-authors—that most of the material ejected seemed to be heading far east of Earth. Still, early model runs left the door open to a glancing encounter early May 13. EarthSky flagged the possibility that Earth might only see a weak disturbance, or perhaps nothing at all.
NOAA’s forecast discussion noted that the M5.7 flare triggered Type-II radio emissions—considered evidence of a shock wave in the solar atmosphere—with speeds clocked between 650 and 1,736 km per second. The CME showed up in SOHO/LASCO images at 1348 UTC on May 10, although NOAA said the bulk of the material seemed aimed east of the Sun-Earth line.
Models remain in flux. Should the CME just graze Earth, the aurora’s uptick could remain muted, limited mostly to high latitudes. But if the shock front arrives with a more favorable magnetic setup, storm levels might quickly overshoot the projections. NOAA’s 1505 UTC geophysical alert said no space-weather storms are expected over the next 24 hours.
But the story doesn’t end with the May 10 eruption. NOAA and the Met Office singled out active regions AR4436 and AR4432 as trouble spots, flagging continued flare risk. NOAA estimates a 45% probability of R1-R2 radio blackouts for each day between May 11 and May 13, along with a 10% shot at something R3 or higher.
Aurora hopefuls are eyeing high-latitude skies, where chances look best. In the northern U.S. and the U.K., though, a brighter show hinges on that glancing blow turning out stronger than NOAA’s baseline calls. The sun delivered the spark—now, it’s down to whether Earth actually takes the hit.
