G5 – Extreme geomagnetic storm likely as another set of CMEs merges and impacts Earth on May 12

Coronal mass ejection (CME) produced by the X5.8 solar flare from Region 3664 at 01:23 UTC on May 11, 2024, is expected to merge with the previous in-transit CMEs and impact Earth by 12:00 UTC on May 12.

G4 – Severe to G5 – Extreme geomagnetic storms are likely on May 12 due to continued CME activity and the anticipated arrival of another series of CMEs associated with eruptive activity from Region 3664 from May 9 to 11, SWPC forecasters said at 00:30 UTC today.

This includes a fast, halo CME produced by the X5.8 flare on May 11 merging with slower-moving CMEs ahead of it and forming one strong CME (Cannibal CME).

Periods of G2 – Moderate to G3 -Strong storming are likely on May 13 due to continued CME activity and positive polarity coronal hole high speed stream (CH HSS) influences.

In addition to the X5.8 flare, Region 3664 (beta-gamma-delta) produced an X1.5 solar flare (at 11:44 UTC on May 11) and multiple M-class flares over the past 36 hours.

LASCO C3 coronagraph imagery acquired after midnight UTC on May 12 shows 2 more Earth-directed CMEs in addition to the one created by the X5.8 flare on May 11.

Solar radiation storm reached S2 – Moderate levels at 17:45 UTC on May 10 and is now slowly declining.

Solar activity is expected to persist at high to very high levels through May 14, with M-class (95%) and X-class flares (75%) expected, due primarily to the flare potential of Region 3664.

Yesterday’s X5.8 solar flare is the second strongest flare of the current solar cycle — Solar Cycle 25 — after X6.3 on February 22, 2024.

Featured image credit: NASA/ESA LASCO C3, Helioviewer, The Watchers. Acquired at 03:37 UTC on May 11, 2024