On the morning of May 10, 2026, a bright flash erupted from a cluster of sunspots near the center of the solar disk, launching a massive cloud of magnetized plasma into space. Now, space weather forecasters in the United States and the United Kingdom are watching to see whether the fringe of that cloud, possibly amplified by a faster stream of solar wind racing up from behind, could rattle Earth’s magnetic field enough to paint auroras across skies that rarely see them.
The window to watch: late May 12 into the early hours of May 13. If conditions align, people in the northern United States, southern Canada, and parts of the United Kingdom and northern Europe could catch shimmering curtains of green and purple light low on the northern horizon.
But forecasters are careful to stress that this is a possibility, not a promise. Here is what we know, what we do not, and how to follow along in real time.
The flare and what it threw into space
The eruption registered as an M5.7-class solar flare, a moderate but significant burst of X-ray and ultraviolet radiation from sunspot Region 4436. It peaked at 1339 UTC and was strong enough for NOAA’s Space Weather Prediction Center (SWPC) to classify the resulting radio disruption as an R2, or “Moderate,” blackout. For roughly an hour, high-frequency radio signals used by airlines and ships on the sunlit side of Earth degraded or dropped out entirely.
More consequential for the days ahead, the flare also expelled a coronal mass ejection (CME), a billion-ton bubble of charged particles and tangled magnetic field that is now barreling outward through the solar system at hundreds of kilometers per second.
Why most of the cloud will miss us
SWPC’s modeling, built around the WSA-Enlil simulation that ingests coronagraph imagery of the eruption and projects how the plasma cloud will move through the background solar wind, indicates that the densest, fastest core of the CME is not aimed at Earth. Most of the material should sweep well behind our planet’s orbit.
That matters because a direct hit from a CME of this size could drive a moderate geomagnetic storm. A glancing blow, by contrast, delivers only a fraction of that energy. Still, even a sideswipe can compress Earth’s magnetosphere enough to trigger minor storming and push the aurora oval southward.
SWPC’s forecast discussion flags a narrow window late on May 12 into early May 13 when the CME’s outer edge or the shock wave running ahead of it could brush past Earth. The UK Met Office’s space weather forecast puts it in similarly cautious terms: a “Slight Chance of Active to G1/Minor storm (Kp 4-5) intervals, due to any possible CME glancing blow.”
The wild card: a high-speed stream trailing the CME
A second factor could change the calculus. Forecasters have identified a high-speed solar wind stream flowing from a coronal hole, a region of open magnetic field on the sun, that trails the CME. If that faster wind catches up to the slower-moving CME sheath before or near the time of Earth passage, it could compress the magnetic structure and amplify the geomagnetic response.
This kind of CME-stream interaction is a known recipe for storms that punch above their weight class. During Solar Cycle 25, which has been running hotter than many early predictions suggested, several notable aurora displays at mid-latitudes have been driven or intensified by exactly this mechanism. The historic May 2024 geomagnetic storm that brought aurora as far south as Florida and the Caribbean, for instance, was fueled in part by overlapping CMEs and fast solar wind.
The catch: predicting the exact timing and degree of compression remains one of the harder problems in operational space weather forecasting. No real-time data from the ACE or DSCOVR spacecraft stationed at the L1 Lagrange point, roughly 1.5 million kilometers sunward of Earth, have yet confirmed the stream’s speed or when it will arrive relative to the CME front. Until those instruments detect a shock or density jump, the high-speed stream remains an important but still theoretical enhancement factor.
What has not happened yet
As of the latest available data, SWPC has not issued a formal G-scale geomagnetic storm watch for this event. The absence of a watch signals that forecasters judge the probability of sustained G1 or higher conditions to be below their issuance threshold. The UK Met Office’s “Slight Chance” language reinforces that read: this is worth monitoring, not worth canceling plans over.
Predicted arrival times on NASA’s CME Scoreboard, which compiles model runs from multiple teams, show spreads of several hours between ensemble members. That means the disturbance could arrive earlier, later, or not register in any geomagnetically meaningful way at all.
One more variable will not be known until the CME’s edge is nearly at Earth’s doorstep: the orientation of its embedded magnetic field. A southward-pointing field couples far more efficiently with Earth’s magnetosphere, opening the door to stronger storming and more vivid aurora. A northward orientation tends to slide past with little effect. Forecasters cannot reliably determine this until in-situ instruments at L1 sample the approaching plasma, typically 15 to 45 minutes before it reaches Earth.
Where and how to look for aurora
If the CME’s flank and the trailing high-speed stream do combine to push the Kp index to 5 or above, aurora could become visible from locations that sit under roughly 50 to 55 degrees geomagnetic latitude. In practical terms, that includes the northern tier of U.S. states (Washington, Montana, Minnesota, Wisconsin, Michigan, upstate New York, and New England), much of southern Canada, and across the United Kingdom, Scandinavia, and the Baltic states.
Visibility depends on more than geomagnetic activity, though. Light pollution is the biggest obstacle for most people. Getting at least 20 to 30 miles from major city centers, finding an unobstructed view of the northern horizon, and letting your eyes adjust to darkness for 15 to 20 minutes all dramatically improve your chances. Auroras from glancing CME impacts at mid-latitudes often appear as a diffuse greenish or reddish glow hugging the horizon rather than the dramatic overhead curtains seen in polar regions, and smartphone cameras with night mode frequently pick up colors the naked eye struggles to detect.
The best hours to watch are typically between 10 p.m. and 2 a.m. local time, when your location rotates under the nightside magnetosphere where auroral particle precipitation is strongest. For this event, that means the prime window falls on the night of May 12 into the predawn hours of May 13.
How to track this event in real time
The most reliable way to follow developments is to watch the same data streams forecasters use. SWPC’s real-time solar wind page displays live readings from the DSCOVR satellite at L1, including solar wind speed, density, and the critical north-south component of the interplanetary magnetic field (Bz). A sudden jump in speed and density, followed by a sustained southward swing in Bz, is the signature of an arriving CME or shock front.
SWPC also publishes a real-time planetary Kp index updated every three hours, along with a 30-minute Kp estimate that gives a faster read on changing conditions. The UK Met Office’s space weather page and the NASA CME Scoreboard provide additional model updates and arrival-time refinements as new data come in.
For aurora chasers, the bottom line is straightforward: keep expectations modest, keep your schedule flexible, and keep one eye on the solar wind data. This is not shaping up to be a blockbuster geomagnetic storm. But Solar Cycle 25 has repeatedly shown that even modest eruptions can surprise when the geometry and timing line up, and the trailing high-speed stream gives this particular event a puncher’s chance of delivering a brief, memorable light show across the northern sky.
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*This article was researched with the help of AI, with human editors creating the final content.
