NOAA SWPC Forecasting Team

New Capabilities

Active monitoring and issuing alerts for AR4366 activity

Sunspot region AR4366 rotated into view February 1, two weeks after the January 19 X1.9 flare and G4.7 geomagnetic storm. At 23:44 UTC, AR4366 unleashed an X8.1 flare—the 3rd-largest of Cycle 25—triggering an R3 strong radio blackout across Earth's sunlit hemisphere, then fired four more X-class flares (X2.9, X2.8, X1.5, X1.7) within hours. By February 5, it had produced 10 X-class flares in five days and over 100 M-class flares, growing to nearly 10 times Earth's width with a magnetically unstable delta-class configuration.

Updated May 22