Major X1.2 solar flare erupts from Sun’s west limb
A major solar flare measuring X1.2 erupted from Active Region 4086 at 15:38 UTC on May 13, 2025. The event started at 15:25 and ended at 15:44 UTC. This is the seventh X-class solar flare of the year and the first since March 28, tying for the third strongest with the X1.2 flare on January 3.
X1.2 solar flare on May 13, 2025. Credit: NASA/SDO AIA 304, Helioviewer, The Watchers
A large coronal mass ejection (CME) was produced during the event. However, the region is located at the Sun’s west limb, so the Earth-directed component is not expected.
While the location of Region 4086 does not favor Earth-directed CMEs, the location is well-connected to Earth via interplanetary magnetic field lines, increasing the probability of a solar proton event (SPE).
Western limb eruptions, particularly those beyond W60, are known to efficiently accelerate and channel high-energy protons toward Earth, potentially triggering elevated radiation levels in space and polar aviation routes.
Radio frequencies were forecast to be most degraded over the Atlantic Ocean, the Americas, and parts of Europe and Africa at the time of the flare.
A large filament centered near N40E02 exhibited sustained linear motion and gradually disappeared from NSO/GONG H-alpha imagery after 12:00 UTC on May 12, with SUVI 304 imagery indicating a lift-off at 22:05 UTC the same day.
While the bulk of the ejecta is directed northward, analysis and modeling suggest a possible glancing impact on May 17.
Solar wind parameters in 24 hours to 12:30 UTC today indicated a gradual decline in coronal hole high-speed stream (CH HSS) influences. However, a steady increase in interplanetary magnetic field (IMF) strength later in the period suggests the possible approach of a co-rotating interaction region (CIR) ahead of another CH HSS.
Total IMF strength peaked at 12 nT, with the Bz component mostly oriented northward. The phi angle was in a negative sector. Solar wind speed gradually declined from a peak near 470 km/s to approximately 385 km/s.
Solar wind speed is expected to increase on May 13 due to an anticipated magnetic connection with a CH HSS. The rising IMF strength indicates the pending or initial arrival of a CIR. Elevated solar wind conditions are expected to continue into May 14 under ongoing CH HSS influence. Another CH HSS is likely to disturb solar wind parameters again on May 15, according to the Space Weather Prediction Center (SWPC).
The geomagnetic field was quiet over the past 24 hours. Quiet to unsettled geomagnetic conditions are expected, with isolated active intervals possible on May 13 in response to the approaching CH HSS. Activity is forecast to weaken on May 14, with primarily quiet to unsettled conditions.
A return to quiet to active levels is likely on May 15 as solar wind conditions intensify under the influence of the next CH HSS.
I'm a dedicated researcher, journalist, and editor at The Watchers. With over 20 years of experience in the media industry, I specialize in hard science news, focusing on extreme weather, seismic and volcanic activity, space weather, and astronomy, including near-Earth objects and planetary defense strategies. You can reach me at teo /at/ watchers.news.
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